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Estimate of serum immunoglobulin G concentration using refractometry with or without caprylic acid fractionation - Corrected Proof K.M. Morrill, J. Polo, A. Lago, J. Campbell, J. Quigley, H. Tyler
ABSTRACT: Objectives of this study were to develop a rapid calf-side test to determine serum IgG concentrations using caprylic acid (CA) fractionation, followed by refractometry of the IgG-rich supernatant and compare the accuracy of this method with results obtained using refractometry using raw serum. Serum samples (n = 200) were obtained from 1-d-old calves, frozen (−20°C), and shipped to the laboratory. Samples were allowed to thaw for 1 h at room temperature. Fractionation with CA was conducted by adding 1 mL of serum to a tube containing 45, 60, or 75 μL of CA and 0.5, 1.0, or 1.5 mL of 0.06 M acetic acid. The tube contents were mixed well, allowed to react for 1 min, and then centrifuged at 3,300 × g for 0, 10, or 20 min at 25°C. The %Brix and refractive index of the fractionated supernatant were determined using a digital refractometer. Nonfractionated serum was analyzed for %Brix (BRn), refractive index (nDn), and IgG concentration by radial immunodiffusion. The mean serum IgG concentration was 19.0 mg/mL [standard deviation (SD) = 9.7], with a range of 3.5 to 47.0 mg/mL. The mean serum BRn was 8.6 (SD = 0.91), with a range of 6.8 to 11.0. The mean serum nDn was 1.34566 (SD = 0.00140), with a range of 1.34300 to 1.34930. Serum nDn was positively correlated with IgG concentration (correlation coefficient = 0.86; n = 185). Fractionated samples treated with 1 mL 0.6 M acetic acid and 60 μL of CA and not centrifuged before analysis resulted in a strong relationship between the refractive index of the fractionated supernatant and IgG (correlation coefficient = 0.80; n = 45). Regression was used to determine cut points indicative of 10, 12, and 14 mg of IgG/mL to determine the sensitivity and specificity of refractometry to identify failure of passive transfer (serum IgG <10 mg/mL at 24 h old). The nDn were 1.34414, 1.34448, and 1.34480 to predict 10, 12, and 14 mg of IgG/mL of serum, respectively. The BRn cut points were 7.6, 7.8, and 8.0, respectively. The nDn cut points of 1.34448 and 1.34480 resulted in similar specificities (82.9%), whereas the 1.34414 cut point had a specificity of 60.0%. The BRn cut point of 7.6 and 7.8%Brix resulted in a similar percentage of correctly classified samples (89.7 and 90.8%, respectively); however, the 7.8% Brix cut point resulted in fewer false positives. These results suggest that Brix refractometry of nonfractionated calf serum provides a strong estimate of IgG concentration and 7.8% Brix may be used as the cut point to identify failure of passive transfer in 1-d-old calves.
Storage of refrigerated raw goat milk affecting the quality of whole milk powder - Corrected Proof C.R. Fonseca, K. Bordin, A.M. Fernandes, C.E.C. Rodrigues, C.H. Corassin, A.G. Cruz, C.A.F. Oliveira
ABSTRACT: The aim of this study was to evaluate the influence of the growth of lipolytic bacteria in raw goat milk stored under refrigeration for different periods on quality parameters of goat milk powder during its shelf life. Fresh goat milk (100 L) was collected after milking, divided into 3 identical fractions, and stored at 4°C for 1, 3, and 5 d. On d 1, 3, and 5, one sample (1 L) was collected and used for microbiological and chemical analysis, and the remaining fraction (almost 30 L) was spray dried and stored at 25°C. Milk powder was submitted to microbiological, chemical, and sensory analysis immediately after production, and on d 60, 120, and 180. Lipolytic psychrotrophic counts and total free fatty acid content did not increase in raw milk during storage. However, peroxide value, caprylic and capric acid concentrations, and total free fatty acid content of milk powder increased during 180 d of storage, with higher levels found in milk powder manufactured with raw milk stored for 5 d. Capric odor and rancid flavors increased in milk powder during storage, regardless the of storage of raw milk for 1, 3, or 5 d. Heat treatments used during powder processing destroyed lipolytic psychrotrophic bacteria, but did not prevent lipolysis in milk powder. Results of this trial indicate that the storage of raw goat milk at 4°C should not exceed 3 d to preserve the quality of goat milk powder during its shelf life of 180 d.
Reaction norm of fertility traits adjusted for protein and fat production level across lactations in Holstein cattle - Corrected Proof A. Menendez-Buxadera, M.J. Carabaño, O. Gonzalez-Recio, R.I. Cue, E. Ugarte, R. Alenda
ABSTRACT: A total of 304,001 artificial insemination outcomes in up to 7 lactations from 142,389 Holstein cows, daughters of 5,349 sires and 101,433 dams, calving between January 1995 and December 2007 in 1,347 herds were studied by a reaction norm model. The (co)variance components for days to first service (DFS), days open, nonreturn rate in the first service (NRFS), and number of services per conception were estimated by 6 models: 3 Legendre polynomial degrees for the genetic effects and adjustment or not for the level of fat plus protein (FP) production recorded at day closest to DFS. For all traits and type of FP adjustment, a second degree polynomial showed the best fit. The use of the adjusted FP model did not increase the level of genetic (co)variance components except for DFS. The heritability for each of the traits was low in general (0.03–0.10) and increased from the first to fourth calving, nevertheless a very important variability was found for the estimated breeding value (EBV) of the sires. The genetic correlations (rg) were close to unity between adjacent calvings, but decreased for most distant parities, ranging from rg = 0.36 (for DFS) to rg = 0.63 (for NRFS), confirming the existence of heterogeneous genetic (co)variance components and EBV across lactations. The results of the eigendecomposition of rg shows that the first eigenvalue explained between 82 to 92% and the second between 8 to 14% of the genetic variance for all traits; therefore, a deformation of the overall mean trajectory for reproductive performance across the trajectory of the different calving could be expected if selection favored these eigenfunctions. The results of EBV for the 50 best sires showed a substantial reranking and variation in the shape of response across lactations. The more important aspect to highlight, however, is the difference between the EBV of the same sires in different calvings, a characteristic known as plasticity, which is particularly important for DFS and NRFS. This component of fertility adds another dimension to selection for fertility that can be used to change the negative genetic progress of reproductive performance presented in this population of Holstein cows. The use of a reaction norm model should allow producers to obtain more robust cows for maintenance of fertility levels along the whole productive life of the cows.
Prediction of urinary nitrogen and urinary urea nitrogen excretion by lactating dairy cattle in Northwestern Europe and North America: A meta-analysis - Corrected Proof J.W. Spek, J. Dijkstra, G. van Duinkerken, W.H. Hendriks, A. Bannink
ABSTRACT: A meta-analysis was conducted on the effect of dietary and animal factors on the excretion of total urinary nitrogen (UN) and urinary urea nitrogen (UUN) in lactating dairy cattle in North America (NA) and northwestern Europe (EU). Mean treatment data were used from 47 trials carried out in NA and EU. Mixed model analysis was used with experiment included as a random effect and all other factors, consisting of dietary and animal characteristics, included as fixed effects. Fixed factors were nested within continent (EU or NA). A distinction was made between urinary excretions based on either urine spot samples or calculated assuming a zero N balance, and excretions that were determined by total collection of urine only. Moreover, with the subset of data based on total collection of urine, a new data set was created by calculating urinary N excretion assuming a zero N balance. Comparison with the original subset of data allowed for examining the effect of such an assumption on the relationship established between milk urea N (MUN) concentration and UN. Of all single dietary and animal factors evaluated to predict N excretion in urine, MUN and dietary crude protein (CP) concentration were by far the best predictors. Urinary N excretion was best predicted by the combination of MUN, CP, and dry matter intake, whereas UUN was best predicted by the combination of MUN and CP. All other factors did not improve or only marginally improved the prediction of UN or UUN. The relationship between UN and MUN differed between NA and EU, with higher estimated regression coefficients for MUN for the NA data set. Precision of UN and UUN prediction improved substantially when only UN or UUN data based on total collection of urine were used. The relationship between UN and MUN for the NA data set, but not for the EU data set, was substantially altered when UN was calculated assuming a zero N balance instead of being based on the total collection of urine. According to results of the present meta-analysis, UN and UUN are best predicted by the combination of MUN and CP and that, in regard to precision and accuracy, prediction equations for UN and UUN should be derived from the total collection of urine.
Invited review: Heat stress effects during late gestation on dry cows and their calves - Corrected Proof S. Tao, G.E. Dahl
ABSTRACT: In dairy cattle, late gestation is a critical period for fetal growth and physiological transition into the next lactation. Environmental factors, such as temperature and light, exert dramatic effects on the production, health, and well-being of animals during this period and after parturition. The aim of this review was to introduce effects of heat stress during late gestation on dairy cattle, and discuss the biological mechanisms that underlie the observed production and health responses in the dam and her fetus. Relative to cooled cows, cows that are heat stressed during late gestation have impaired mammary growth before parturition and decreased milk production in the subsequent lactation. In response to higher milk yield, cows cooled prepartum undergo a series of homeorhetic adaptations in early lactation to meet higher demand for milk synthesis compared with heat-stressed cows, but no direct effect of environmental heat stress on metabolism exists during the dry period. Prepartum cooling improves immune status of transition cows and evidence suggests that altered prolactin signaling in immune cells mediates the effects of heat stress on immune function. Late-gestation heat stress compromises placental development, which results in fetal hypoxia, malnutrition, and eventually fetal growth retardation. Maternal heat stress may also have carryover effects on the postnatal growth of offspring, but direct evidence is still lacking. Emerging evidence suggests that offspring from prepartum heat-stressed cows have compromised passive immunity and impaired cell-mediated immune function compared with those from cooled cows.
Descriptive analysis and early-stage consumer acceptance of yogurts fermented with carrot juice - Corrected Proof M.A. Cliff, L. Fan, K. Sanford, K. Stanich, C. Doucette, N. Raymond
ABSTRACT: This research explored the sensory characteristics and consumer acceptance of novel probiotic unsweetened yogurts. Yogurts were made with 4 carrot juice levels (8, 16, 24, and 32%), 2 firmness levels (regular, 45 g/L milk solids; firm, 90 g/L milk solids), and 2 starter cultures (C1, C2). The sensory profile characterized the color intensity (before and after stirring), carrot flavor, sourness, and 7 texture/mouth-feel attributes (astringency, chalkiness, mouth-coating, thickness, smoothness, creaminess, and graininess). The influence of carrot juice level and firmness level were evaluated using ANOVA, polynomial contrasts, and principal component analysis. Mean scores and standard errors were calculated. Consumer acceptance panels in Wolfville, Nova Scotia (n = 56), and in Vancouver, British Columbia (Asian n = 72, non-Asian n = 72), evaluated the hedonic responses to the C1 and C2 formulations, respectively. We observed increases in color intensity, carrot flavor, creaminess, mouth-coating, and chalkiness with increasing carrot juice levels, as well as increases in color intensity, carrot flavor, creaminess, mouth-coating, thickness, and astringency with increasing milk solids concentrations of the C1 and C2 yogurts. Mean hedonic scores for color, appearance, and texture/mouth-feel were greater than hedonic scores for aroma, flavor/taste, and overall liking. This research identified the sensory qualities that need further development and demonstrated the importance of early-stage consumer acceptance research for directing new product development.
Concentrations of n-3 and n-6 fatty acids in Dutch bovine milk fat and their contribution to human dietary intake - Corrected Proof H.J.F. van Valenberg, K.A. Hettinga, J. Dijkstra, H. Bovenhuis, E.J.M. Feskens
ABSTRACT: Weekly samples representative of Dutch milk were analyzed for concentrations of n-3 and n-6 fatty acids (FA). Concentrations of the n-3 FA α-linolenic acid (ALA), eicosatetraenoic acid, eicosapentaenoic acid, and docosapentaenoic acid were 0.495 ± 0.027, 0.041 ± 0.004, 0.067 ± 0.005, and 0.086 ± 0.008 g per 100 g of fat, respectively, whereas docosahexaenoic acid was absent or present in concentrations lower than 0.020 g per 100 g of fat. Concentrations of the n-6 FA linoleic acid (LeA), γ-linoleic acid, dihomo-γ-linoleic acid, and arachidonic acid were 1.428 ± 0.068, 0.070 ± 0.007, 0.066 ± 0.004, and 0.089 ± 0.004 g per 100 g of fat, respectively; adrenic acid was present in concentrations lower than 0.020 g per 100 g of fat, whereas docosapentaenoic acid was absent in all samples. The concentrations of ALA and LeA were significantly higher in spring and summer, compared with autumn and winter. The concentrations of all other ALA- and LeA-derived n-3 and n-6 FA were not significantly different between seasons. The contribution of milk fat to the daily intake of eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid was calculated for human consumption levels in different countries. Milk fat contributed between 10.7 and 14.1% to the daily intake of eicosapentaenoic acid and between 23.5 and 34.2% to the intake of docosapentaenoic acid; whereas docosahexaenoic acid contribution was marginal. Arachidonic acid from milk fat contributed between 10.5 and 18.8% to the human intake of n-6 FA.
Prediction of bulk milk fatty acid composition based on farming practices collected through on-farm surveys - Corrected Proof M. Coppa, A. Ferlay, C. Chassaing, C. Agabriel, F. Glasser, Y. Chilliard, G. Borreani, R. Barcarolo, T. Baars, D. Kusche, O.M. Harstad, J. Verbič, J. Golecký, B. Martin
ABSTRACT: The aim of this study was to predict the fatty acid (FA) composition of bulk milk using data describing farming practices collected via on-farm surveys. The FA composition of 1,248 bulk cow milk samples and the related farming practices were collected from 20 experiments led in 10 different European countries at 44°N to 60°N latitude and sea level to 2,000 m altitude. Farming practice-based FA predictions [coefficient of determination (R2) >0.50] were good for C16:0, C17:0, saturated FA, polyunsaturated FA, and odd-chain FA, and very good (R2 ≥0.60) for trans-11 C18:1, trans-10 + trans-11 C18:1, cis-9,trans-11 conjugated linoleic acid, total trans FA, C18:3n-3, n-6:n-3 ratio, and branched-chain FA. Fatty acids were predicted by cow diet composition and by the altitude at which milk was produced, whereas animal-related factors (i.e., lactation stage, breed, milk yield, and proportion of primiparous cows in the herd) were not significant in any of the models. Proportion of fresh herbage in the cow diet was the main predictor, with the highest effect in almost all FA models. However, models built solely on conserved forage-derived samples gave good predictions for odd-chain FA, branched-chain FA, trans-10 C18:1 and C18:3n-3 (R2 ≥0.46, 0.54, 0.52, and 0.70, respectively). These prediction models could offer farmers a valuable tool to help improve the nutritional quality of the milk they produce.
Effect of estrus synchronization on daily somatic cell count variation in goats according to lactation number and udder health status - Corrected Proof A. Mehdid, J.R. Díaz, A. Martí, G. Vidal, C. Peris
ABSTRACT: Two repeated experiments were carried out in 2 different years to study the effect of estrus on somatic cell count (SCC) in dairy goats. In the first year, 36 Murciano-Granadina goats were used [12 primiparous and 24 multiparous; 22 healthy and 14 with an intramammary infection (IMI)] and, after a 6-d pre-experimental period, were divided into 2 groups according to lactation number, udder health status, SCC, and milk production. One group was kept as a control, whereas the other received an estrus synchronization hormonal treatment lasting 11 d. At 24, 48, and 72 h after cessation of the hormone treatment, goats were placed in contact with a buck to confirm that they were in estrus. For 32 consecutive days (6 pre-experimental, 11 in hormone treatment, and 15 post-treatment) the SCC per gland and udder were monitored in all animals. In the second year, we repeated the same experimental design using a total of 38 Murciano-Granadina breed goats (12 primiparous and 26 multiparous; 26 healthy and 12 with IMI). Throughout this experiment, milk yield and composition were also recorded daily for each goat. Upon termination of the hormonal treatment, the SCC in udder milk increased significantly in the treatment group compared with the control group over 3 consecutive days. This increase was observed for year (1 and 2), parity (primiparous and multiparous), and udder health status (healthy and IMI). The log10 SCC (cells/mL) increased from 5.5 ± 0.09 before estrus to 6.04 ± 0.09 during treatment; therefore, the geometric mean of the SCC increased 3.5 times during treatment. The maximum values obtained in healthy glands of primiparous goats (geometric mean = 0.37 million cells/mL) were lower than in healthy glands (1.1 million cells/mL) or infected glands (1.7 million cells/mL) of multiparous goats. The increase in SCC observed during estrus (200% increase in geometric means) could not be explained by the changes in milk production, which only fell by 13%. During estrus, the percentage of protein and dry matter in the milk also increased significantly. We concluded that it is necessary to consider the presence of estrus to correctly interpret milk SCC, as an indirect method for detecting IMI or as a commercial milk quality parameter.
Sexually active groups in cattle—A novel estrus sign - Corrected Proof G. Sveberg, A.O. Refsdal, H.W. Erhard, E. Kommisrud, M. Aldrin, I.F. Tvete, F. Buckley, A. Waldmann, E. Ropstad
ABSTRACT: The current study presents a novel objective measure for characterizing sexually active groups (SAG 3–5) and relates this measure to other behaviors of lactating Holstein-Friesian cows. Cows in SAG 3–5 were required to participate in a minimum of 1 estrus behavior per 5 min while staying within 3 m (2 cow lengths) of its partner(s) for a minimum of 5 min. Twenty Holstein-Friesian cows were video-monitored continuously through 1 complete estrous cycle (22 d). Standing behavior, SAG 3–5, secondary estrus signs (SEC), and other social and agonistic behaviors were recorded continuously. The period of mounting estrus (MTE) was divided into the 3 parts: prestand, standing estrus (STE), and poststand. The mean durations of MTE, prestand, STE, and poststand period were 12.9 ± 1.84, 4.0 ± 1.93, 7.1 ± 1.44, and 1.8 ± 0.57 h (n = 13). The fractions of time spent in SAG 3–5 during MTE, prestand, STE, and poststand period were 13, 8, 19, and 1% (n = 11). During MTE, cows participated, on average, in 5.8 ± 1.24 SAG 3–5 and initiated 9.5 ± 2.99 mounts, with mean durations of 0.25 ± 0.03 h and 4.00 ± 0.36 s, respectively. The novel measure SAG 3–5 was a sign of long duration not confined only to groups of STE cows. On one day when no cows were in estrus and during the periods 4 to 24 h before and after MTE, no SAG 3–5 behaviors were observed. Luteal-phase cows participated in SAG 3–5 only when the partner was a single cow in estrus. The time spent in SAG 3–5 increased between 1 and 3 h before MTE and the prestand period (3 vs. 8%) and reached a peak level during STE. From STE to poststand, time spent in SAG 3–5 decreased considerably (19 vs. 1%). The observed decrease in nonmutual agonistic behaviors 4 to 24 h before MTE is suggested as an early sign of pre-estrus. Changes in SAG 3–5, agonistic behaviors, and SEC are suggested as indicators of the specific stages of MTE. Increased SEC initiated and SAG 3–5 were indicators of late pre-estrus and early estrus (prestand). Peak levels of SAG 3–5, SEC, and social agonistic behaviors were indicators of STE. A sudden decrease in behaviors, preceded by frequent interactions, was indicative of late estrus (poststand). On the basis of the findings reported here, we propose that SAG 3–5, as well as proceptive and receptive patterns of SEC and agonistic behaviors, be included in estrus detection protocols. Updated knowledge of these behavioral interactions may assist when determining the stage of estrus and the optimal time to breed dairy cows.
Genetic associations of ketosis and displaced abomasum with milk production traits in early first lactation of Canadian Holsteins - Corrected Proof A. Koeck, F. Miglior, J. Jamrozik, D.F. Kelton, F.S. Schenkel
ABSTRACT: The aim of this study was to investigate the genetic associations of ketosis and displaced abomasum with milk production traits in early first lactation of Canadian Holsteins. Health data recorded by producers were available from the national dairy cattle health system in Canada. Test-day records of milk, fat, and protein yields were obtained from the routine milk recoding scheme. Ketosis and displaced abomasum were defined as binary traits (0 = healthy; 1 = sick) based on whether or not the cow had at least 1 case of the respective disease in the period from calving to 100 d after calving. Mean frequencies of ketosis and displaced abomasum were 4.1 and 2.7%, respectively. The following milk production traits were considered: milk yield, fat percentage (Fat%), protein percentage (Prot%), fat-to-protein (F:P) ratio, and F:P ratio >1.5. The trait F:P ratio >1.5 was scored as 1 or 0, based on whether or not the cow had an F:P ratio >1.5. For milk production traits, the first (5–30 d in milk) and the second (31–60 d in milk) test days were considered. Data were analyzed using bivariate linear animal models. Average heritabilities of 0.02 and 0.04 were obtained for ketosis and displaced abomasum, respectively. For milk production traits, the lowest heritabilities were obtained for F:P >1.5 (0.04 to 0.08), whereas the highest estimates were found for Prot% (0.27 to 0.38). Ketosis and displaced abomasum were genetically uncorrelated with milk yield in early lactation. Moderate favorable correlations were found between metabolic diseases and milk composition traits. Ketosis was significantly correlated with Fat% (0.33), F:P ratio (0.30), and F:P ratio >1.5 (0.35) at the first test day, whereas all genetic correlations with milk composition traits at the second test day were not significant and close to zero. Significant favorable genetic correlations were also found between displaced abomasum and F:P ratio (0.26), F:P ratio >1.5 (0.25) and Prot% (−0.19) at the first test day. Also, Prot% at the second test day was significantly correlated (−0.16) with displaced abomasum. Overall, a higher Fat% and F:P ratio and a lower Prot% at the first test day were associated with an increased susceptibility to metabolic diseases. As genetic correlations between metabolic diseases and F:P ratio were far from unity, dairy producers should be encouraged to keep accurate and complete health data. This will be expected to yield to more accurate genetic evaluations for metabolic diseases.
The motivation of dairy cows for access to pasture - Corrected Proof Gemma L. Charlton, S. Mark Rutter, Martyn East, Liam A. Sinclair
ABSTRACT: Several factors influence whether dairy cattle prefer to be indoors or at pasture, including weather conditions and milk yield, but it is unclear how motivated cows are for access to pasture. One way to measure motivation is to require the animal to work (e.g., walk different distances) for access to a resource. This study investigated whether pasture access located 60, 140, or 260 m from the indoor housing would affect the proportion of time dairy cows spent at pasture. Thirty-two Holstein-Friesian dairy cows were used during the study, which took place in the United Kingdom from May to July 2010. The experiment consisted of four 18-d experimental periods, with 8 cows in each period, which were further divided into 2 groups of 4 cows. Following a training period, the cows were randomly allocated to distances of 60, 140, or 260 m to pasture over three 4-d measurement periods. A video camera was used to record time spent indoors and outdoors 24 h/d, and manual behavior observations (0700 to 2200 h) took place 6 times during each period to record how the cows spent their time in each location. The video data showed that cows spent, on average, 57.8% (±3.44) of their time outside (either at pasture or on the track). One-sample t-tests revealed that this value was different from 0% (t = 16.80), 50% (t = 2.26), and 100% (t = −12.28). Analysis of the percentage time spent outside revealed that distance did not influence nighttime pasture use (2100 to 0430 h; F2,8 = 0.16; 81.0% vs. 81.0% vs. 76.7%, for 60 m vs. 140 m vs. 260 m, respectively). In contrast, during the day (0700 to 2100 h; from behavior observations), time spent at pasture declined as distance increased; that is, cows spent more time at pasture when they had to walk 60 m (F2,80 = 10.09) than when they had to walk 140 or 260 m (45.3% vs. 27.4% vs. 21.2%, respectively). Time spent at pasture decreased on rainy days (y = −1.0672x + 59.646, R2 = 0.09, n = 48 d), but the indoor temperature-humidity index (THI), the outdoor THI, and body condition score did not influence time spent outside. Under the climatic conditions of the current study in the United Kingdom, cows had a partial preference for pasture, which was influenced by distance to pasture during daytime but not at night. This shows that dairy cows were more motivated to access pasture at night compared with during the day.
Effect of pre- versus postmilking supplementation on traffic and performance of cows milked in a pasture-based automatic milking system - Corrected Proof N.A. Lyons, K.L. Kerrisk, S.C. Garcia
ABSTRACT: Cows milked in a pasture-based automatic milking system tend to have a lower daily milking frequency in comparison with cows milked in indoor systems. Milking events with intervals beyond 16 h have been reported to have a negative effect on milk yield and udder health, and therefore it is important to minimize their occurrence. As feed is the main incentive to encourage cow traffic around the system, a study was conducted to compare pre- (PRE) versus postmilking (POST) supplementary feed placement strategies in a pasture-based automatic milking system. We hypothesized that PRE cows would have a stronger incentive to walk voluntarily from the paddock to the dairy facility to get milked (due to the reward being more immediate), thereby reducing their milking interval and increasing daily milking frequency and milk yield. The PRE cows returned to the dairy facility sooner (PRE = 11.9 vs. POST = 13.27 h) but had longer milking intervals (PRE = 15.3 vs. POST = 14.28 h). This was due to the additional time spent in the prefeeding area (PRE = 56 versus POST = 23 min) combined with a longer average time spent in the premilking waiting yard (PRE = 97 versus POST = 77 min). Treatment did not affect daily milk yield per cow. The result of this study demonstrates the potential of manipulating feeding management strategies to influence cow behavior and traffic in voluntary milking systems.
Aggregation and adhesion properties of 22 Lactobacillus strains - Corrected Proof Yanfeng Tuo, Hanli Yu, Lianzhong Ai, Zhengjun Wu, Benheng Guo, Wei Chen
ABSTRACT: In this paper, the autoaggregating, coaggregating, hydrophobicity, and adhering abilities of 22 Lactobacillus strains belonging to different species were assessed. No correlation existed between autoaggregation and adhesion of the strains belonging to different species, whereas a positive correlation (P < 0.05) existed between autoaggregation and adhesion of the strains belonging to the same species. After treating with guanidine HCl, the autoaggregating and adhering abilities of some Lactobacillus strains decreased, indicating that surface-bound proteins and other macromolecules played a role in the adhering and autoaggregating abilities. The strains Lactobacillus plantarum 20 and 66 had higher adhesion and coaggregation abilities and should be further studied for their probable probiotic properties. Aggregating, coaggregating, and adhering abilities of Lactobacillus strains could be used as the preliminary criteria for selecting strains having probiotic potential.
Life cycle assessment of milk production from commercial dairy farms: The influence of management tactics - Corrected Proof M.-J. Yan, J. Humphreys, N.M. Holden
ABSTRACT: Little consideration has been given to how farm management, specifically tactics used to implement the management strategy, may influence the carbon footprint (CF) and land use for milk produced on commercial farms. In this study, the CF and land use of milk production from 18 Irish commercial dairy farms were analyzed based on foreground data from a 12-mo survey capturing management tactics and background data from the literature. Large variation was found in farm attributes and management tactics; for example, up to a 1.5-fold difference in fertilizer nitrogen input was used to support the same stocking density, and up to a 3.5-fold difference in concentrate fed for similar milk output per cow. However, the coefficient of variation for milk CF between farms only varied by 13% and for land use by 18%. The overall CF and overall land use of the milk production from the 18 dairy farms was 1.23 ± 0.04 kg of CO2 Eq and 1.22 ± 0.05 m2 per kilogram of energy-corrected milk. Milk output per cow, economic allocation between exports of milk and liveweight, and on-farm diesel use per ha were found to be influential factors on milk CF, whereas the fertilizer N rate, milk output per cow, and economic allocation between exports of milk and liveweight were influential on land use. Effective sward management of white clover within a few farms appeared to lower the CF but increased on-farm land use. It was concluded that a combination of multiple tactics determines CF and land use for milk production on commercial dairy farms and, although these 2 measures of environmental impact are correlated, a farm with a low CF did not always have low land use and vice versa.
Short communication: Insulin responsiveness is affected by the level of milk replacer offered to young calves - Corrected Proof A. Bach, L. Domingo, C. Montoro, M. Terré
ABSTRACT: Eight male Holstein calves (40.6 ± 2.9 kg of BW and 7.8 ± 1.6 d of age) were individually housed and allocated to either a low milk replacer (MR) allowance of 2 daily doses of 2 L each (478.5 g/d of dry matter from MR), or to a high allowance of 2 daily allotments of 4 L (957.0 g/d of dry matter from MR). In addition all calves had ad libitum access to the same starter feed and water. At d 7, 30, and 60 of experiment all calves were submitted to a glucose tolerance test (GTT) that consisted on an i.v. infusion of 180 mg/kg of BW of glucose at 4 h after the morning MR feeding. Blood was harvested at −15, −5, 0, 4, 8, 12, 18, 25, 35, 45, and 60 min relative to glucose infusions. Blood samples collected at −15, −5, and 0 relative to glucose infusion were used as baseline concentrations of glucose and insulin. Then, the area under the curve (concentration/min) for glucose and insulin was calculated as the increase with respect to the baseline. Next, the clearance rates of insulin (%/min), glucose (%/min), as well as insulin sensitivity were computed. The increase in blood glucose following the GTT (assessed as area under the curve) was similar in both low and high calves, which indicates that all animals were able to control glycaemia effectively. Similarly, clearance rates of glucose and insulin were not different between low and high calves. However, calves in the high group needed a substantially greater serum insulin concentration (98.7 ± 13.2 μU/mL) than low calves (41.5 ± 13.2 μU/mL) to control glycaemia. Furthermore, as age increased, the rise in serum insulin elicited by the GTT continued to increase in high but not in low calves. Insulin to glucose ratio was greater in high (157.5 ± 7.8 μU/mg) than in low (46.7 ± 7.8 μU/mg) calves. This ratio increased with age and in a more pronounced fashion in high than in low calves and the same pattern was observed for insulin sensitivity. We concluded that offering 8 L of MR/d in 2 separate meals decreases insulin sensitivity of young calves. Further research is needed to assess whether the impaired glucose responsiveness of calves can be minimized by feeding milk more frequently.
Intravenous infusions of glucose stimulate key lipogenic enzymes in adipose tissue of dairy cows in a dose-dependent manner - Corrected Proof Mirja Carra, Bahaa Al-Trad, Gregory B. Penner, Thomas Wittek, Gotthold Gäbel, Manfred Fürll, Jörg R. Aschenbach
ABSTRACT: The present study was investigated whether increasing amounts of glucose supply have a stimulatory effect on the mRNA abundance and activity of key lipogenic enzymes in adipose tissue of midlactation dairy cows. Twelve Holstein-Friesian dairy cows in midlactation were cannulated in the jugular vein and infused with either a 40% glucose solution (n = 6) or saline (n = 6). For glucose infusion cows, the infusion dose increased by 1.25%/d relative to the initial net energy for lactation (NEL) requirement until a maximum dose equating to a surplus of 30% NEL was reached on d 24. This maximum dose was maintained until d 28 and stopped thereafter (between d 29–32). Cows in the saline infusion group received an equivalent volume of 0.9% saline solution. Samples of subcutaneous adipose tissue were taken on d 0, 8, 16, 24, and 32 when surplus glucose reached 0, 10, 20, and 30% of the NEL requirement, respectively. The mRNA abundance of fatty acid synthase, cytoplasmic acetyl-coenzyme A synthetase, cytoplasmic glycerol 3-phosphate dehydrogenase-1, and glucose 6-phosphate dehydrogenase showed linear treatment × dose interactions with increasing mRNA abundance with increasing glucose dose. The increased mRNA abundance was paralleled by a linear treatment × dose interaction for fatty acid synthase and acetyl-coenzyme A synthetase enzymatic activities. The mRNA abundance of ATP-citrate lyase showed a tendency for linear treatment × dose interaction with increasing mRNA abundance with increasing glucose dose. The mRNA abundance of all tested enzymes, as well as the activities of fatty acid synthase and acetyl-coenzyme A synthetase, correlated with plasma glucose and serum insulin levels. In a multiple regression model, the predictive value of insulin was dominant over that of glucose. In conclusion, gradual increases in glucose supply upregulate key lipogenic enzymes in adipose tissue of midlactating dairy cows with linear dose dependency. Insulin appears to be critically involved in this regulation.
Capsicum annuum enhances l-lactate production by Lactobacillus acidophilus: Implication in curd formation - Corrected Proof Smriti Sharma, Sriyans Jain, Girija N. Nair, Srinivasan Ramachandran
ABSTRACT: Lactobacillus acidophilus is commonly used lactic acid bacteria for producing fermented milk products. In general household practice, curdling is known to occur faster in the presence of red chili. Herein we analyzed the enhanced effect of red chili (Capsicum annuum) and its major component, capsaicin, on Lactobacillus acidophilus (ATCC 4356) in the production of l-lactate in de Man, Rogosa, and Sharpe medium at various temperatures (15, 20, 25, 30, and 37°C). The addition of red chili showed significant increase in the amount of l-lactate produced by L. acidophilus compared with the control at all temperatures. Similar results were observed with addition of capsaicin alone. This was accompanied by an increase in the consumption of d-glucose. Capsazepine, a known antagonist of capsaicin, inhibited the production of l-lactate by L. acidophilus in the presence of both capsaicin and red chili. Because no increase occurred in the growth of L. acidophilus in the presence of red chili, our results show that the enhanced production of l-lactate in the presence of red chili or capsaicin is due to increased metabolic activity.
The responsiveness of subclinical endometritis to a nonsteroidal antiinflammatory drug in pasture-grazed dairy cows - Corrected Proof N.V. Priest, S. McDougall, C.R. Burke, J.R. Roche, M. Mitchell, K.L. McLeod, S.L. Greenwood, S. Meier
ABSTRACT: The objective of this study was to determine if the inflammation associated with subclinical endometritis (SCE) is a part of the mechanism by which reproductive performance is reduced in cows with this disease. If it is, reducing inflammation associated with SCE with a nonsteroidal antiinflammatory drug (NSAID) should reduce the severity [as measured by average polymorphonuclear cell (PMN) percentage] of uterine pathology and improve reproductive performance. It was also investigated whether the NSAID treatment reduced metabolic indicators of systemic inflammation previously reported to be altered in cows with SCE. Holstein-Friesian and Friesian-Jersey cross dairy cows (n = 213) were paired by calving date and d-14 uterine PMN percentage and randomly assigned to 3 injections at intervals of 3 d of an NSAID (1.4 mg of carprofen/kg; n = 104) between 21 and 31 d postpartum or left as untreated controls (n = 109). Cows with ≥14% PMN (upper quartile of PMN percentage) in the cytological sample collected at d 14 postpartum were defined as having SCE. The average d-14 PMN percentage was low (9.9%) and a high self-cure rate of SCE (>90%) at d 42 was observed. Treatment with an NSAID reduced plasma concentrations of aspartate aminotransferase and increased pregnancy rate in SCE cows. However, no effect of the NSAID treatment was observed on PMN percentage at d 42, postpartum anovulatory interval, or milk production. Compared with cows without SCE, cows with SCE had lower plasma albumin concentration, albumin:globulin ratio, and body condition score, but higher nonesterified fatty acids on the day of calving. These results indicate that cows with SCE are experiencing a physiological dysfunction, including lower body condition, liver dysfunction, and greater metabolic challenge during the periparturient period. Further research is required to determine the effect of NSAID on SCE and to evaluate the influence of timing of drug application on treatment effectiveness.
Effect of inorganic or organic copper fed without or with added sulfur and molybdenum on the performance, indicators of copper status, and hepatic mRNA in dairy cows - Corrected Proof L.A. Sinclair, K.J. Hart, D. Johnson, A.M. Mackenzie
ABSTRACT: The effect of inorganic (INORG) or organic (ORG) Cu, fed without (−) or with (+) additional S and Mo on Cu status and performance was examined using 56 early lactation dairy cows in a 2 × 2 factorial study design. Supplementary Cu was added as either CuSO4 or Bioplex Cu (Alltech Inc., Nicholasville, Kentucky) to provide an additional 10 mg of Cu/kg of dry matter (DM), with S added at 1.5 g/kg of DM and Mo at 6.8 mg/kg of DM to reduce Cu bioavailability. The basal ration was composed of corn and grass silages (2:1 respectively, DM basis) and straight feeds. Cows commenced the study at wk 7 of lactation and remained on treatment for 16 wk. An interaction existed between Cu source and added S and Mo on DM intake, with cows offered INORG− Cu having an increased intake compared with those offered INORG+ or ORG− Cu. Milk yield averaged 35.4 kg/d, and was 5% higher with milk fat content 6% lower in cows fed INORG compared with ORG Cu, but milk fat yield, energy-corrected milk yield, and milk protein content did not differ between treatments. A trend existed for cows to have a higher body weight gain when offered ORG compared with INORG Cu. Cows fed diets containing INORG Cu had a higher milk concentration of C17:0 and C18:3n-3 compared with those fed diets containing ORG Cu. Cows fed added S and Mo had a lower milk concentration of C17:0 and C18:0 compared with those that were not supplemented. No effect was observed of dietary treatment on plasma Cu concentration, which averaged 13.1 μmol/L, except during wk 12 when cows receiving added S and Mo had a lower concentration. No effect was observed of Cu source on mean plasma Mo concentrations, but during wk 16 cows offered INORG Cu had a higher concentration than those offered ORG Cu. Hepatic Cu levels decreased by approximately 0.9 mg/kg of DM per day when fed additional S and Mo, but no effect of Cu source was observed. A trend existed for hepatic ATPase, Cu++ transporting, beta polypeptide (ATP7B) to be upregulated in cows when fed S and Mo along with ORG but not INORG Cu. In conclusion, the inclusion of an ORG compared with an INORG source of Cu reduced milk yield but increased milk fat concentration and body weight gain, with no effect on energy-corrected milk yield. Little effect was observed of dietary Cu supply on plasma mineral concentration, liver mRNA abundance, or milk fatty acid profile, whereas the addition of S and Mo reduced hepatic Cu concentrations.
Development and implementation of a training program to ensure high repeatability of body condition scoring of dairy cows - Corrected Proof E. Vasseur, J. Gibbons, J. Rushen, A.M. de Passillé
ABSTRACT: A body condition score (BCS) in dairy cattle is a subjective assessment of the proportion of body fat that she possesses and is a common measure used in animal welfare assessment. The objectives of our study were to develop and implement a training program to produce highly repeatable BCS by many assessors as part of a cross-Canada epidemiological study on dairy cow comfort and welfare. In preliminary studies, we established that without any proper standard operating procedures (SOP) to describe the practical steps of the process and good standard reference for each score, assessors provided with a BCS chart scored with each other only with substantial agreement within 0.5 points and moderate agreement on exact score (mean weighted kappa coefficient = 0.79 and 0.46, respectively). Detailed SOP were developed to assess BCS in 4 locations on a dairy farm. Assessing BCS presented more challenges in some locations (when cows exited the milking parlor, when the assessor was located outside the freestall pen) than others (when cows were headlocked at the feed bunk, when assessor was located inside the freestall pen). Additionally, training material and a training procedure were developed to ensure that future assessors would achieve almost perfect repeatability with the trainer within 0.5 points (weighted kappa coefficient >0.80). Twelve trainees followed this training and their repeatability was assessed using photographs in classroom sessions and live observations on farm over a 1-wk period. Repeatability was maintained above target agreement at periodic checks over the 6 mo of on-farm data collection. Two trainers were used as a reference standard to which all trainees were compared. This study demonstrates that to obtain reliable measures, a training program must include validated procedures to help assessors cope with a variety of farm setups. Regular repeatability checks are essential to ensure that the reference standard is maintained over time and to secure high data quality. This method to develop a training program as well as the training program implemented can be used as a model to successfully train on-farm assessors.
Model comparison on genomic predictions using high-density markers for different groups of bulls in the Nordic Holstein population - Corrected Proof H. Gao, G. Su, L. Janss, Y. Zhang, M.S. Lund
ABSTRACT: This study compared genomic predictions based on imputed high-density markers (∼777,000) in the Nordic Holstein population using a genomic BLUP (GBLUP) model, 4 Bayesian exponential power models with different shape parameters (0.3, 0.5, 0.8, and 1.0) for the exponential power distribution, and a Bayesian mixture model (a mixture of 4 normal distributions). Direct genomic values (DGV) were estimated for milk yield, fat yield, protein yield, fertility, and mastitis, using deregressed proofs (DRP) as response variable. The validation animals were split into 4 groups according to their genetic relationship with the training population. Groupsmgs had both the sire and the maternal grandsire (MGS), Groupsire only had the sire, Groupmgs only had the MGS, and Groupnon had neither the sire nor the MGS in the training population. Reliability of DGV was measured as the squared correlation between DGV and DRP divided by the reliability of DRP for the bulls in validation data set. Unbiasedness of DGV was measured as the regression of DRP on DGV. The results showed that DGV were more accurate and less biased for animals that were more related to the training population. In general, the Bayesian mixture model and the exponential power model with shape parameter of 0.30 led to higher reliability of DGV than did the other models. The differences between reliabilities of DGV from the Bayesian models and the GBLUP model were statistically significant for some traits. We observed a tendency that the superiority of the Bayesian models over the GBLUP model was more profound for the groups having weaker relationships with training population. Averaged over the 5 traits, the Bayesian mixture model improved the reliability of DGV by 2.0 percentage points for Groupsmgs, 2.7 percentage points for Groupsire, 3.3 percentage points for Groupmgs, and 4.3 percentage points for Groupnon compared with GBLUP. The results showed that a Bayesian model with intense shrinkage of the explanatory variable, such as the Bayesian mixture model and the Bayesian exponential power model with shape parameter of 0.30, can improve genomic predictions using high-density markers.
Effects of weekly regrouping of prepartum dairy cows on metabolic, health, reproductive, and productive parameters - Corrected Proof P.R.B. Silva, J.G.N. Moraes, L.G.D. Mendonça, A.A. Scanavez, G. Nakagawa, J. Fetrow, M.I. Endres, R.C. Chebel
ABSTRACT: The objectives of the current experiment were to determine the effect of 2 prepartum grouping strategies on the health, metabolic, reproductive, and productive parameters of dairy cows. Jersey cows enrolled in the experiment at 253 ± 3 d of gestation (d 0 = calving) were balanced for parity and projected 305-d mature equivalent and assigned to 1 of 2 treatments. Cows assigned to the traditional (TRD; n = 6 replicates with a total of 308 cows) treatment were moved to the study pen as a group of 44 cows and weekly thereafter groups of 2 to 15 cows were moved to the study pen to reestablish stocking density. Cows assigned to the All-In-All-Out (AIAO; n = 6 replicates with a total of 259 cows) treatment were moved to the study pen in groups of 44 cows, but no new cows entered the AIAO pen until the end of the replicate. At the end of each replicate, a new TRD and AIAO group started but pens were switched. Cows were milked thrice daily and monthly milk yield, fat and protein contents, and somatic cell count data were recorded up to 305 d postpartum. Plasma nonesterified fatty acid concentration was measured weekly from d −18 ± 3 to 24 ± 3 and plasma β-hydroxybutyrate was measured weekly from d 3 ± 3 to 24 ± 3. Cows were examined on d 1, 4 ± 1, 7 ± 1, 10 ± 1, and 13 ± 1 for diagnosis of uterine diseases and had their ovaries scanned by ultrasound on d 39 ± 3 and 53 ± 3 to determine resumption of ovarian cycles. Average stocking density was reduced for the AIAO (71.9%) treatment compared with the TRD (86.9%) treatment. Treatment did not affect the incidences of retained fetal membranes (TRD = 10.9, AIAO = 11.6%), metritis (TRD = 16.7, AIAO = 19.8%), and acute metritis (TRD = 1.7, AIAO = 3.6%). Concentrations of nonesterified fatty acids (TRD = 80.4 ± 8.2, AIAO = 62.9 ± 8.5 μmol/L) and β-hydroxybutyrate (TRD = 454.4 ± 10.9, AIAO = 446.1 ± 11.1 μmol/L) were not different between treatments. Percentages of cows that resumed ovarian cycles by d 39 ± 3 (TRD = 70.8, AIAO = 63.1%) and 53 ± 3 (TRD = 90.1, AIAO = 90.2%) were not different between treatments. Similarly, treatment had no effect on rate of removal from the herd {TRD = referent, AIAO [(adjusted hazard ratio (95% confidence interval)] = 0.85 (0.63, 1.15)} or rate of pregnancy [TRD = referent, AIAO = 1.07 (0.88, 1.30)]. Finally, treatment did not affect energy-corrected milk yield (TRD = 34.4 ± 0.6, AIAO = 34.3 ± 0.7 kg/d). In conditions of adequate feed bunk space, the AIAO treatment did not improve health, metabolic, reproductive, or productive parameters compared with the TRD treatment.
Reducing sperm concentration is critical to limiting the oxidative stress challenge in liquid bull semen - Corrected Proof C. Murphy, A.G. Fahey, A. Shafat, S. Fair
ABSTRACT: Because of the short breeding season, the use of liquid bull semen is a viable option in seasonal grass-based dairy systems such as Ireland. Currently in Ireland, liquid bull semen contains approximately 5 million sperm per insemination dose and is used within 2.5 d of collection. The hypothesis of this study was that reducing the sperm number per insemination dose would enable bull sperm to be stored for longer. Semen was collected at a commercial AI center and diluted to 1 (T1), 2 (T2), 3 (T3), 4 (T4), and 5 (T5) million sperm per 0.25-mL dose in caprogen diluent. On d 0.25 (6 h postcollection), 1, 2, 3, 4, and 5 postcollection, viability, oxidative stress, and mitochondrial activity were assessed using flow cytometry and the fluorescent probes propidium iodide, CM-H2DCFDA, and rhodamine 123, respectively. On the same days, glucose consumption, total antioxidant capacity, and progressive linear motility were assessed. We observed an effect of day and treatment on sperm cell viability, with the highest percentage live found in T1 and the lowest in T5 on all days. Oxidative stress in live sperm increased with duration of storage and was affected by treatment, being highest in T5 and lowest in T1 on all days (d 5: 56.4 ± 2.76% and 28.8 ± 1.22%, respectively; mean ± SEM). Both the total antioxidant capacity and percentage of live sperm positive for rhodamine 123 were unaffected by treatment. The concentration of glucose in caprogen declined with time and was lowest in T5 and highest in T1 on d 5. In conclusion, higher concentrations of sperm have detrimental effects on sperm cell viability and increase oxidative stress but have no effect on the mitochondrial activity of sperm.
Short communication: Planning considerations for on-farm dairy processing enterprises - Corrected Proof S.M. Smith, E.A. Chaney, J.M. Bewley
ABSTRACT: Across the world, more dairy producers are considering on-farm dairy processing to add value to the milk produced on their farms. Dairy producers may bottle milk or process their milk into cheese, ice cream, butter, yogurt, or cream. The primary objective of this research was to establish a series of sound factors or indicators of success for those considering on-farm processing. A survey was employed to collect opinions and advice from managers of on-farm processing enterprises. Surveys were distributed online (n = 120), with 31 surveys returned, accounting for a 25.8% response rate. Most (64%) respondents had been involved in on-farm dairy processing for less than 10 yr. Sixty-one percent of respondents attained a positive cash flow in 1 to 3 yr. The primary products manufactured were cheese (69%), milk (59%), ice cream (31%), yogurt (25%), and butter (21%). Factors influencing the decision to start an on-farm dairy processing enterprise included commodity milk prices (61%), desire to work with the public (41%), an opportunity to promote the dairy industry (39%), a desire to maintain or expand a small family operation (29%), and product differentiation (16%). Respondents cited dealing with regulations (26%), product marketing (19%), manufacturing technicalities (19%), and securing funding (17%) as the most difficult parts of starting the business. Open-ended responses provided by the respondents of this survey were also documented to give future dairy producers advice. The most common advice to future on-farm processors was to work on realistic business plans, develop and follow realistic budgets, and observe and use market surveys within the industry. These results provide a useful array of information for future on-farm dairy processing enterprises.
Effect of abomasal ferrous lactate infusion on phosphorus absorption in lactating dairy cows - Corrected Proof X. Feng, K.F. Knowlton, A.D. Dietrich, S. Duncan
ABSTRACT: The objective of this study was to evaluate the effect of ferrous lactate infusion on postruminal P absorption in lactating dairy cows. Four ruminally cannulated lactating cows were used in a 4 × 4 Latin square design with 14 d per period. Cows were fed a basal diet containing 0.39% P, providing 100% of the calculated P requirement. On d 8 to 14 of each period, each cow was infused with 0, 200, 500, or 1,250 mg of Fe/d in the form of ferrous lactate solution (ferrous lactate in 1 L of double-distilled water) into the abomasum. Infusate was formulated to approximate 0, 2, 5, or 12.5 mg of Fe/L in drinking water with 100 L of water intake/d. Total fecal collection was conducted in the last 4 d of each period to measure nutrient digestion and excretion. Dry matter intake, milk yield, and milk composition were not affected by treatment. Digestibility of DM, NDF, and nitrogen decreased linearly with increasing ferrous lactate infusion. Infusion of ferrous lactate did not affect intake and digestibility of total P, inorganic P, or phytate P. In lactating cows, P absorption was not negatively influenced by abomasally infused ferrous lactate up to 1,250 mg of Fe/d.
Associations between herd-level feeding management practices, feed sorting, and milk production in freestall dairy farms - Corrected Proof A.D. Sova, S.J. LeBlanc, B.W. McBride, T.J. DeVries
ABSTRACT: The challenges associated with group-housed dairy cows include within-herd variability in nutrient consumption and milk production, which may be related to feeding management. The objective of this observational study was to examine the association of herd-level feeding management factors, feed sorting, and milk production. Twenty-two freestall herds with an average lactating herd size of 162 ± 118 cows, feeding total mixed rations, were each studied for 7 consecutive days in summer and winter. In cases of multiple feeding groups within a herd, the highest producing group of cows with an even distribution of days in milk and parity was selected for this study. The average group size studied was 83 ± 31 cows. The average study group consisted of cows 187 ± 47 days in milk, with a parity of 2.3 ± 0.6, consuming 24.3 ± 2.6 kg of dry matter, with an average group-level yield of 34.3 ± 6 kg of milk/d, 3.7 ± 0.3% milk fat, and 3.2 ± 0.18% milk protein. Milk production parameters, including yield, fat, and protein, were recorded through regular Dairy Herd Improvement milk testing. A survey of feeding management practices and barn characteristics was administered on each farm. The amounts of feed offered and refused were recorded and sampled daily to assess dry matter intake (DMI) and particle size distribution. Feeding twice per day compared with once per day was associated with an average increase of 1.42 kg of DMI, 2.0 kg of milk yield, and less sorting against long ration particles (>19mm). Every 2% group-level selective refusal (sorting) of long particles was associated with 1 kg/d of reduction in milk yield. A 10 cm/cow increase in feed bunk space was associated with a 0.06-percentage-point increase in group-average milk fat and a 13% decrease in group-average somatic cell count. These results suggest that herd-level management practices to promote feed access, such as increased feeding frequency and bunk space, may improve DMI and promote more balanced nutrient intake and greater milk production.
Optimizing bulk milk dioxin monitoring based on costs and effectiveness - Corrected Proof V.H. Lascano-Alcoser, A.G.J. Velthuis, H.J. van der Fels-Klerx, L.A.P. Hoogenboom, A.G.J.M. Oude Lansink
ABSTRACT: Dioxins are environmental pollutants, potentially present in milk products, which have negative consequences for human health and for the firms and farms involved in the dairy chain. Dioxin monitoring in feed and food has been implemented to detect their presence and estimate their levels in food chains. However, the costs and effectiveness of such programs have not been evaluated. In this study, the costs and effectiveness of bulk milk dioxin monitoring in milk trucks were estimated to optimize the sampling and pooling monitoring strategies aimed at detecting at least 1 contaminated dairy farm out of 20,000 at a target dioxin concentration level. Incidents of different proportions, in terms of the number of contaminated farms, and concentrations were simulated. A combined testing strategy, consisting of screening and confirmatory methods, was assumed as well as testing of pooled samples. Two optimization models were built using linear programming. The first model aimed to minimize monitoring costs subject to a minimum required effectiveness of finding an incident, whereas the second model aimed to maximize the effectiveness for a given monitoring budget. Our results show that a high level of effectiveness is possible, but at high costs. Given specific assumptions, monitoring with 95% effectiveness to detect an incident of 1 contaminated farm at a dioxin concentration of 2 pg of toxic equivalents/g of fat [European Commission's (EC) action level] costs €2.6 million per month. At the same level of effectiveness, a 73% cost reduction is possible when aiming to detect an incident where 2 farms are contaminated at a dioxin concentration of 3 pg of toxic equivalents/g of fat (EC maximum level). With a fixed budget of €40,000 per month, the probability of detecting an incident with a single contaminated farm at a dioxin concentration equal to the EC action level is 4.4%. This probability almost doubled (8.0%) when aiming to detect the same incident but with a dioxin concentration equal to the EC maximum level. This study shows that the effectiveness of finding an incident depends not only on the ratio at which, for testing, collected truck samples are mixed into a pooled sample (aiming at detecting certain concentration), but also the number of collected truck samples. In conclusion, the optimal cost-effective monitoring depends on the number of contaminated farms and the concentration aimed at detection. The models and study results offer quantitative support to risk managers of food industries and food safety authorities.
Antihypertensive and hypolipidemic effect of milk fermented by specific Lactococcus lactis strains - Corrected Proof J.C. Rodríguez-Figueroa, A.F. González-Córdova, H. Astiazaran-García, A. Hernández-Mendoza, B. Vallejo-Cordoba
ABSTRACT: The antihypertensive and hypolipidemic effects of milk fermented by specific Lactococcus lactis strains in spontaneously hypertensive rats (SHR) were investigated. The SHR were fed ad libitum milk fermented by Lc. lactis NRRL B-50571, Lc. lactis NRRL B-50572, Captopril (40 mg/kg of body weight, Sigma-Aldrich Co., St. Louis, MO) or purified water for 4 wk. Results suggested that Lc. lactis fermented milks presented a significant (P < 0.05) blood pressure-lowering effect. No significant difference (P > 0.05) was noted among milk fermented by Lc. lactis NRRL B-50571 and Captopril by the second and third week of treatment. Additionally, milk fermented by Lc. lactis strains modified SHR lipid profiles. Milk fermented by Lc. lactis NRRL B-50571 and B-50572 were able to reduce plasma low-density lipoprotein cholesterol and triglyceride contents. Thus, milk fermented by Lc. lactis strains may be a coadyuvant in the reduction of hypertension and hyperlipidemia and may be used as a functional food for better cardiovascular health.
Grain-based versus alfalfa-based subacute ruminal acidosis induction experiments: Similarities and differences between changes in milk fatty acids - Corrected Proof E. Colman, E. Khafipour, B. Vlaeminck, B. De Baets, J.C. Plaizier, V. Fievez
ABSTRACT: Subacute ruminal acidosis (SARA) is one of the most important metabolic disorders, traditionally characterized by low rumen pH, which might be induced by an increase in the dietary proportion of grains as well as by a reduction of structural fiber. Both approaches were used in earlier published experiments in which SARA was induced by replacing part of the ration by a grain mixture or alfalfa hay by alfalfa pellets. The main differences between both experiments were the presence of blood lipopolysaccharide and Escherichia coli and associated effects on the rumen microbial population in the rumen of grain-based induced SARA animals as well as a great amount of quickly fermentable carbohydrates in the grain-based SARA induction experiment. Both induction approaches changed rumen pH although the pH decrease was more substantial in the alfalfa-based SARA induction protocol. The goal of the current analysis was to assess whether both acidosis induction approaches provoked similar shifts in the milk fatty acid (FA) profile. Similar changes of the odd- and branched-chain FA and the C18 biohydrogenation intermediates were observed in the alfalfa-based SARA induction experiment and the grain-based SARA induction experiment, although they were more pronounced in the former. The proportion of trans-10 C18:1 in the last week of the alfalfa-based induction experiment was 6 times higher than the proportion measured during the control week. The main difference between both induction experiments under similar rumen pH changes was the decreasing sum of iso FA during the grain-based SARA induction experiment whereas the sum of iso FA remained stable during the alfalfa-based SARA induction experiment. The cellulolytic bacterial community seemed to be negatively affected by either the presence of E. coli and the associated lipopolysaccharide accumulation in the rumen or by the amount of starch and quickly fermentable carbohydrates in the diet. In general, changes in the milk FA profile were related to changes in rumen pH. Nevertheless, feed characteristics (low in structural fiber vs. high in starch) also affected the milk FA profile and, as such, both effects should be taken into account when subacute acidosis occurs.
Microbiological and chemical characteristics of Brazilian kefir during fermentation and storage processes - Corrected Proof A.M.O. Leite, D.C.A. Leite, E.M. Del Aguila, T.S. Alvares, R.S. Peixoto, M.A.L. Miguel, J.T. Silva, V.M.F. Paschoalin
ABSTRACT: The microbial community composition and chemical characteristics of a Brazilian milk kefir sample produced during its manufacturing and refrigerated storage were investigated by culture-dependent and -independent methods and HPLC. Lactococcus lactis ssp. cremoris and ssp. lactis, Leuconostoc mesenteroides, Acetobacter lovaniensis, and Saccharomyces cerevisiae were isolated, whereas the detected bands on denaturing gel gradient electrophoresis corresponded to Lactobacillus kefiranofaciens, Lactobacillus kefiri, Lactobacillus parakefiri, and S. cerevisiae. After fermentation, lactic acid bacteria were present at levels of 10 log units, whereas acetic acid bacteria and yeast were present at levels of 7.8 and 6 log units, respectively. The lactic acid bacteria and yeast counts remained constant, whereas acetic acid bacteria counts decreased to 7.2 log units during storage. From fermentation to final storage, the pH, lactose content and citric acid of the kefir beverage decreased, followed by an increase in the concentrations of glucose, galactose, ethanol, and lactic, acetic, butyric, and propionic acids. These microbiological and chemical characteristics contribute to the unique taste and aroma of kefir. This research may serve as a basis for the future industrial production of this beverage in Brazil.
Short communication: Evaluation of the accuracy of an electronic on-farm test to quantify blood β-hydroxybutyrate concentration in dairy goats - Corrected Proof V. Doré, J. Dubuc, A.M. Bélanger, S. Buczinski
ABSTRACT: The objective of this cross-sectional study was to validate the accuracy of a hand-held electronic on-farm test (Precision Xtra) for quantifying the blood β-hydroxybutyrate (BHBA) concentration in dairy goats. A total of 114 dairy goats from 3 commercial herds were sampled once for blood in the jugular vein between 1 mo before and 2 mo after parturition. Blood samples were centrifuged to harvest serum and sera were sent to the Animal Health Laboratory of the Université de Montréal for quantification of BHBA concentration (gold standard). Laboratory BHBA values were between 0.1 and 3.7 mmol/L. Precision Xtra values were compared with gold standard values; Pearson correlation coefficient was 0.98 and coefficient of determination was 0.95. Overall, these results suggested that Precision Xtra provides excellent accuracy for measuring blood BHBA concentration in dairy goats compared with the gold standard test.
Cholesterol reduction from milk using β-cyclodextrin immobilized on glass - Corrected Proof Muhammad Nazir Tahir, Chanho Kwon, Daham Jeong, Eunae Cho, Seung R. Paik, Seunho Jung
ABSTRACT: β-Cyclodextrin (β-CD) was converted into β-CD-undecenyl ether by chemical modification and subsequently covalently attached to a glass surface. The functionalized glass surface was characterized by static water contact angle and x-ray photoelectron spectroscopy. Both techniques confirmed that an excellent monolayer of β-CD was formed on the glass surface. The β-CD solid surface was used to reduce cholesterol levels in milk. In 4 h, 73.6% of the cholesterol was extracted at 25°C with shaking at 170 rpm. This is the highest value ever reported for milk using β-CD immobilized on a solid surface. The same surface was repeatedly used for 10 cycles and maintained its efficiency with 72 ± 2% cholesterol reduction observed in all the cycles. X-ray photoelectron spectroscopy analysis completed after 5 and 10 cycles of cholesterol reduction showed that the β-CD on the glass surface was not degraded. The high efficiency and long-term stability of the functional monolayer was attributed to the specific structure of β-CD, which is composed of a relatively low number of functional groups and long spacer chain lengths that provide great flexibility.
Randomized noninferiority clinical trial evaluating 3 commercial dry cow mastitis preparations: I. Quarter-level outcomes - Corrected Proof A.G. Arruda, S. Godden, P. Rapnicki, P. Gorden, L. Timms, S.S. Aly, T.W. Lehenbauer, J. Champagne
ABSTRACT: The study objective was to compare the efficacy of 3 commercial dry cow mastitis formulations regarding quarter-level prevalence of intramammary infections (IMI) postcalving, cure of preexisting infections over the dry period, prevention of new infections during the dry period, and risk for a clinical mastitis case between calving and 100 d in milk (DIM). A total of 1,091 cows (4,364 quarters) from 6 commercial dairy herds in 4 different states (California, Iowa, Minnesota, and Wisconsin) were enrolled and randomized to 1 of the 3 treatments at dry-off: Quartermaster (QT; 1,000,000 IU of procaine penicillin G and 1 g of dihydrostreptomycin; Pfizer Animal Health, New York, NY), Spectramast DC (SP; 500 mg of ceftiofur hydrochloride; Pfizer Animal Health), or ToMorrow Dry Cow (TM; 300 mg of cephapirin benzathine; Boehringer Ingelheim Vetmedica Inc., St. Joseph, MO). Quarter milk samples were collected for routine bacteriological culture before dry cow therapy treatment at dry-off, 0 to 6 DIM, and 7 to 13 DIM and an on-farm record-keeping system was used to retrieve data on clinical mastitis cases. Noninferiority analysis was used to evaluate the effect of treatment on the primary outcome, risk for a bacteriological cure during the dry period. Multivariable logistic regression techniques were used to describe the effect of treatment on risk for presence of IMI postcalving and risk of a new IMI during the dry period. Cox proportional hazards regression was used to describe the effect of treatment on the risk and time for quarters to experience an episode of clinical mastitis between calving and 100 DIM. The overall crude quarter-level prevalence of infection at dry-off was 19.2%. The most common pathogen isolated from milk samples at dry-off was coagulase-negative Staphylococcus, followed by Aerococcus spp. and other Streptococcus spp. Noninferiority analysis showed no effect of treatment on risk for a cure between dry-off and calving [least squares means (LSM): QT = 93.3%, SP = 92.6%, and TM = 94.0%] and secondary analysis showed no effect of treatment on risk for presence of an IMI at 0 to 6 DIM (LSM: QT = 16.5%, SP = 14.1%, and TM = 16.0%), risk for development of a new IMI between dry-off and 0 to 6 DIM (LSM: QT = 14.8%, SP = 12.3%, and TM = 14.2%), or risk of experiencing a clinical mastitis event between calving and 100 DIM (LSM: QT = 5.3%, SP = 3.8%, and TM = 4.1%). In conclusion, no difference was observed in efficacy among the 3 products evaluated when assessing the aforementioned quarter-level outcomes.
Energy partitioning and substrate oxidation by Murciano-Granadina goats during mid lactation fed soy hulls and corn gluten feed blend as a replacement for corn grain - Corrected Proof M.C. López, C. Fernández
ABSTRACT: The aim of this experiment was to study the effect of substituting corn grain by soy hulls and corn gluten feed blend on energy partitioning, substrate oxidation, and milk performance in dairy goats during mid lactation. Ten multiparous Murciano-Granadina goats in mid lactation were fed 2 isoenergetic and isoproteic diets [19.08 MJ/kg of dry matter (DM) and 18.7% of CP, DM basis] in a crossover design. One group of 5 goats was fed a mixed ration with 373 g of corn grain/kg of DM (CRN diet) and the other diet replaced corn grain with 373 g/kg DM of fibrous by-products [soy hulls and gluten feed (SHGF) diet]: 227 g of soy hulls/kg of DM and 146 g of gluten feed blend/kg DM. Fat was added to the SHGF diet to make it isoenergetic. After 10 d of adaptation, the feed intake, refusal, total fecal and urine output, and milk yield were recorded daily over a 5-d period. Then, gas exchange measurements were recorded by a mobile open-circuit respirometry system using a head box for 10 d. Dry matter intake was similar for both diets (2.07 kg/d, on average). Greater and significant values were found in the SHGF diet for ammonia N, energy in urine, and oxidation of protein. Values were significantly lower for heat production of fermentation, indicating a decrease in rumen fermentation with this diet, probably due to an excess of crude protein in the diet and lack of synchronization of the nonfiber carbohydrates with rumen-degraded protein. The metabolizable energy intake was no different between CRN and SHGF treatments, with an average value of 1,444 kJ/kg of BW0.75. Due to the positive energy balance during mid lactation in this trial, most of the heat production from oxidation of nutrients derived from carbohydrate oxidation (55%, on average), followed by oxidation of fat (29%, on average). No significant differences were observed for milk production, although milk fat was significantly greater for the SHGF diet than the CRN diet (7.0 vs. 5.4%, respectively). Despite the different starch levels and fibrous content used in these mixed diets, no significant differences for the efficiency of use of metabolizable energy for late lactation were observed (0.63, on average). An average nutritive value of 7.52 MJ of net energy of lactation/kg of DM was obtained. This fibrous by-product was utilized by lactating goats without detrimental effect on energy metabolism and resulted in similar performance to grain bases diet. The economic advantages and sustainability of this choice should be evaluated.
Transfer of terpenes from essential oils into cow milk - Corrected Proof J. Lejonklev, M.M. Lükke, M.K. Larsen, G. Mortensen, M.A. Petersen, M.R. Weisbjerg
ABSTRACT: The objective of this study was to investigate the transfer of volatile terpenes from caraway seed and oregano plant essential oils into cow's milk through respiratory and gastrointestinal exposure. Essential oils have potential applications as feed additives because of their antimicrobial properties, but very little work exists on the transfer of their volatile compounds into milk. Lactating Danish Holstein cows with duodenum cannula were used. Gastrointestinal exposure was facilitated by infusing the essential oils, mixed with deodorized sesame oil, into the duodenum cannula. Two levels were tested for each essential oil. Respiratory exposure was facilitated by placing the animal in a chamber together with a sponge soaked in the essential oils. All exposures were spread over 9 h. Milk samples were collected immediately before and after exposure, as well as the next morning. Twelve monoterpenes and 2 sesquiterpenes were analyzed in essential oils and in milk samples using dynamic headspace sampling and gas chromatography-mass spectrometry. In the essential oils, almost all of the terpenes were detected in both essential oils at various levels. For caraway, the monoterpenes limonene, carvone, and carvacrol were most abundant; in oregano, the monoterpenes carvacrol and ρ-cymene were most abundant. For almost all treatments, an immediate effect was detected in milk, whereas little or no effect was detected in milk the following day. This suggests that the transfer into milk of these volatile terpenes is fast, and that the milk will not be influenced when treatment is discontinued. Principal component analysis was used to elucidate the effect of the treatments on the terpene profile of the milk. Terpene content for treatment milk samples was characterized by the same terpenes found in the treatment essential oil used for that animal, regardless of pathway of exposure. The terpenes appear to be transferred unaltered into the milk, regardless of the pathway of exposure. Volatile terpenes in essential oils, which could influence milk flavor, are transferred into milk via both gastrointestinal and respiratory exposure.
Prediction of coagulating and noncoagulating milk samples using mid-infrared spectroscopy - Corrected Proof M. De Marchi, V. Toffanin, M. Cassandro, M. Penasa
ABSTRACT: Recently, a general deterioration of milk coagulation properties (MCP) has been observed in Italy; thus, the prediction of noncoagulating (NC) milk, defined as milk not forming a curd within 30 min from rennet addition, is of immediate interest in the Italian cheese industry. The present study investigated the ability of mid-infrared (MIR) spectroscopy to predict NC milk using individual and bulk samples from Holstein cows. Samples were selected according to MIR analysis to cover the range of coagulation time between 5 and 60 min. Milks were then analyzed for MCP through the reference instrument (Formagraph) over an extended testing period of 60 min to identify coagulating and NC samples. Measured traits were rennet coagulation time, curd-firming time, and curd firmness 30 and 60 min after rennet addition. Results showed no specific spectral information distinguishing NC from coagulating samples. The most accurate prediction model was developed for rennet coagulation time followed by curd-firming time and curd firmness 30 min after rennet addition, whereas curd firmness 60 min after enzyme addition could not be accurately predicted. Based on these findings, MIR spectroscopy might be proposed in payment systems to reward or penalize milk according to MCP. Moreover, the ability of MIR spectroscopy to predict the MCP of samples that form a curd beyond 30 min from enzyme addition may be of interest for genetic improvement of coagulation traits in dairy breeds, because until now most studies have excluded NC information from genetic analysis, leading to possible biases in the estimation of genetic parameters and in the prediction of sire's merit for MCP.
Short communication: Ultrasonographic assessment of the thorax as a fast technique to assess pulmonary lesions in dairy calves with bovine respiratory disease - Corrected Proof S. Buczinski, G. Forté, A.M. Bélanger
ABSTRACT: The aim of this study was to assess inter- and intraoperator agreement when assessing lung consolidation secondary to bovine respiratory disease (BRD) by thoracic ultrasonography. Ten calves were blindly assessed by 3 operators with varying expertise in thoracic ultrasound to look for lung consolidation and the presence of comet-tail artifacts (COMT). Systematic ultrasonography of the thorax was performed using an 18-site per side assessment with a linear 8.5-MHz probe. The status of the calves [healthy (n = 4) vs. treated for BRD (n = 6)] was not known by the operators. The interoperator kappa agreement for detecting consolidation was moderate to almost perfect (from 0.6 to 1.0) depending on the operator's experience (diagnosis of consolidation if depth ≥1 cm). The intraclass correlation coefficient for consistency was 0.71 for a single measurement and 0.88 for average measurement. The intraclass correlation coefficient for agreement was 0.73 for single measurements and 0.89 for average measurements. These values were considered good for single measurements and excellent for average measurements. Systematic ultrasonography of the thorax can be used routinely to assess lung consolidation in dairy calves and can therefore be of importance, especially for assessment of subclinical BRD.
Characterization of Kentucky dairy producer decision-making behavior - Corrected Proof R.A. Russell, J.M. Bewley
ABSTRACT: To address dairy clientele needs, industry professionals need to understand how dairy producers make decisions. A survey was distributed to all licensed Kentucky milk producers (n = 1,074) to better understand factors that influence dairy producer decisions. A total of 236 surveys were returned; 7 were omitted because they were incomplete, leaving 229 for subsequent analyses (21% response rate). The survey consisted of questions about dairy operational success criteria, decision evaluation criteria, information sources, and technology adoption. The mean response to each survey question was calculated after assigning the following numeric values to producer response categories: 1 = not important, 3 = important, 5 = very important. The most important source of influence or information in decision making was advice from consultants, nutritionists, and veterinarians (3.70 ± 1.23), followed by consultation with business partners and family members (3.68 ± 1.29), and intuition and gut feeling (3.10 ± 1.45). Producers with large herds (≥200 cows) relied more heavily on information from consultants, nutritionists, and veterinarians and on employee input than did producers with small herds (1 to 49 cows). Producers with small herds did not use effect on employee morale as a criterion to evaluate decisions as much as those with larger herds did. In regard to adoption of automated monitoring technologies, producers indicated that modest adoption rates were a result of (1) not being familiar with technologies that are available (55%), (2) undesirable cost to benefit ratios (42%), and (3) too much information provided without knowing what to do with it (36%). As herd size increased, the percentage of producers selecting poor technical support and training and compatibility issues as reasons for slow adoption of automated technologies increased. This insight into dairy producer decision making should help industry professionals address dairy producer issues and concerns.
Short communication: Measurements of methane emissions from feed samples in filter bags or dispersed in the medium in an in vitro gas production system - Corrected Proof M. Ramin, S.J. Krizsan, F. Jančík, P. Huhtanen
ABSTRACT: The objective of this study was to compare methane (CH4) emissions from different feeds when incubated within filter bags for in vitro analysis or directly dispersed in the medium in an automated gas in vitro system. Four different concentrates and 4 forages were used in this study. Two lactating Swedish Red cows were used for the collection of rumen fluid. Feed samples were milled to pass a 1.0-mm screen. Aliquots (0.5 g) of samples were weighed directly in the bottles or within the F57 filter bags that were placed in the bottles. Gas samples were taken during 24 and 48 h of incubation, and CH4 concentration was determined. The data were analyzed using a general linear model. Feeds differed significantly in CH4 emission both at 24 and at 48 h of incubation. The interaction between feed and method on methane emission in vitro was significant, indicating that the ranking of feeds was not consistent between the methods. Generally, greater amounts of CH4 were emitted from samples directly dispersed in the medium compared with those incubated within the filter bags, which could be a result of lower microbial activity within the filter bags. The ratio of CH4 to total gas was greater when the feeds were incubated within bags compared with samples directly dispersed in the medium. Incubating samples in filter bags during 48 h of incubation cannot be recommended for determination of CH4 emission of feeds in vitro.
Priming the cow for lactation by rapeseed supplementation in the dry period - Corrected Proof B.M. Damgaard, M.R. Weisbjerg, T. Larsen
ABSTRACT: High-producing dairy cows experience a sudden and significant increase in energy requirements due to the onset of milk production in early lactation. They mobilize body reserves, mainly adipose tissue, resulting in an increased risk of production decline and the development of health disorders. The objective of the present study was to investigate the effects of feeding oilseeds (rapeseed) during the dry period, thereby priming dairy cows for metabolism of body fat in early lactation. Forty-three Holstein dairy cows were used, 14 were primiparous and 29 were multiparous (≥2nd lactation). In the dry period, 8 wk before expected calving until calving, the cows were fed either a diet with a high content of rapeseed in the total mixed ration (HF) or a standard total mixed ration with a low content of fat (CON). During the first 5 wk after calving, all the cows were fed a standard low fat lactation ration. The treatments were evaluated by performance and metabolic variables in blood and liver. The dry period diet had no effects on body weight and body condition score of the cows during the dry period and in early lactation. The daily yield of milk, protein, and lactose did not differ among treatments. However, the milk fat concentration was lower and the daily milk fat production tended to be lower for the cows fed the HF diet in the dry period compared with the cows fed the CON diet. The plasma content of nonesterified fatty acids, cholesterol, and phospholipids in the dry period was increased in the HF dry period diet compared with the CON diet. The lower plasma concentration of uric acid obtained prepartum for the cows fed the HF diet may indicate a lower rumen microbial protein synthesis. Postpartum, the plasma concentration of β-hydroxybutyric acid tended to be lower for the cows fed the HF dry period diet. The liver content of triglycerides was lower and the liver content of glycogen was higher in early lactation among the cows fed the HF dry period diet compared with the cows fed the CON diet. Based on liver glycogen, triglyceride content, and blood β-hydroxybutyric acid concentration, it could be argued that intake of oilseeds during the dry period is a positive strategy for priming dairy cows for fat metabolism in the following early lactation.
Effect of feeding extruded flaxseed with different forage:concentrate ratios on the performance of dairy cows - Corrected Proof C. Neveu, B. Baurhoo, A. Mustafa
ABSTRACT: Twenty Holstein cows were used in a Latin square design experiment with a 2 × 2 factorial arrangement to determine the effects of extruded flaxseed (EF) supplementation with 2 different forage to concentrate ratios on the performance of dairy cows. Extruded flaxseed diets contained 9% (dry matter basis) EF product which consisted of 75% EF and 25% ground alfalfa meal. Four lactating Holsteins cows fitted with rumen fistulae were used to determine the effects of dietary treatments on ruminal fermentation. Intakes of dry matter and crude protein were not influenced by dietary treatments. However, neutral detergent fiber intake was greater for the high-forage (8.4 kg/d) than the low-forage (7.8 kg/d) diet. Milk yield (average 40.2 kg/d) was similar for all dietary treatments. However, cows fed the high-forage diets produced milk with higher fat (3.76 vs. 2.97%) and total solids (12.58 vs. 11.95%) concentrations, but lower protein (3.19 vs. 3.33%) and lactose (4.66 vs. 4.72%) contents. Ruminal pH and total volatile fatty acid concentration were not affected by dietary treatments. However, feeding high forage relative to low forage diets increased molar proportion of acetate but decreased that of propionate. Ruminal NH3-N was reduced by feeding high forage relative to low forage diets. Milk fatty acid composition was altered by both forage level and EF supplementation. Feeding diets containing EF or low forage reduced the concentrations of saturated fatty acids and increased those of mono-unsaturated fatty acids. Concentrations of poly-unsaturated fatty acids were increased by feeding EF or low-forage diets. Extruded flaxseed supplementation increased milk fat α-linolenic acid content by 100% and conjugated linoleic acid by 54%. It was concluded that differences in animal performance and ruminal fermentation observed in this study were mostly due to differences in forage to concentrate ratio. However, EF supplementation caused most of the differences observed in milk fatty acid composition.
Evaluation of the mineral content of infant formulas consumed in Brazil - Corrected Proof Sabrina Vieira da Silva, Paula Mattanna, Cezar Augusto Bizzi, Neila Silvia Peireira dos Santos Richards, Juliano Smanioto Barin
ABSTRACT: The mineral content of 10 commercially available milk-based infant formulas widely consumed in Brazil was investigated. The levels of elements (Ca, Cu, Fe, K, Mg, Mn, Na, and Zn) were determined by inductively coupled plasma optical emission spectrometry after microwave-assisted wet digestion. The results were compared with the producers' label declarations and levels proposed by the Codex Alimentarius and the Brazilian National Health Surveillance Agency. The obtained results were in good agreement with certified reference materials, and the relative standard deviation of the measurements was always below 10%, with the exception of Cu (up to 14%). A high degree of variation between the experimental and producers' data was found for trace elements among different brands, with differences as high as 41 and 68% for Cu and Zn, respectively. The content of minerals in the starting formulas was in accordance with levels established by the Codex Alimentarius, with the exception of 1 brand that had a Zn level that was not in agreement with the Codex minimum value. Among follow-up formulas, 2 brands contained levels of Ca and K that were higher than the maximum established by Brazilian standards, and 1 brand contained less than the minimum value recommended for Zn. The guidance upper levels have not been established in the Codex Alimentarius for follow-up formulas, and the maximum value has been established for only 2 of the analyzed minerals. This lack of a standard could be a problem; as shown in the present study, if the Brazilian standard is used, several formulas could be considered out of specification. Despite the limited number of samples evaluated in this work, the levels of some elements were out of specification and special attention by the Brazilian government on the content of minerals in infant formulas is needed.
Hepatic mRNA expression of acid labile subunit and deiodinase 1 differs between cows selected for high versus low concentrations of insulin-like growth factor 1 in late pregnancy - Corrected Proof M. Piechotta, K. Kedves, M. Gil Araujo, A. Hoeflich, F. Metzger, M. Heppelmann, A. Muscher-Banse, C. Wrenzycki, C. Pfarrer, H.J. Schuberth, M. Hoedemaker, H. Bollwein, M. Kaske
ABSTRACT: The somatotropic axis is a key metabolic pathway during transition from late pregnancy to early lactation in dairy cows. The first objective of this study was to determine the feasibility of selecting cows with persistent differences in total insulin-like growth factor 1 (IGF-1) concentration by taking only a single antepartum blood sample. The second objective was to elucidate the underlying causes of differences in peripheral IGF-1 concentrations throughout late pregnancy and whether hormonal axes also differed in dairy cows with low versus high IGF-1. Twenty clinically healthy Holstein Friesian cows were chosen based on their plasma IGF-1 concentration at 244 to 254 d after artificial insemination (AI) and other selection criteria (health status, body condition score, number of lactations). These cows were selected from a large-scale farm, transported to the clinic, and monitored daily from 261 to 275 d after AI. The concentrations of IGF-1, growth hormone, IGF binding proteins 2, 3, and 4, insulin, cortisol, thyroid hormones, progesterone, and estradiol were measured. Ultimately, 7 IGF-1-low and 7 IGF-1-high cows were statistically analyzed. Additionally, a liver biopsy was taken on d 270 ± 1 after AI for analysis of gene expression of somatotropic family members, liver deiodinase 1, and suppressor of cytokine signaling-2. It was possible to select cows with different IGF-1 concentrations based upon only 1 blood sample collected in late pregnancy. Concentrations of IGF-1 in IGF-1-low versus IGF-1-high animals (n = 7 each) remained significantly different between groups from the day of selection of the animals until d 275 after AI. Second, the differences in total plasma IGF-1 concentration between experimental groups may be attributed to differences in hepatic production of acid labile subunit. The ability of IGFBP-3 to bind IGF-1 declined before calving in all cows. Furthermore, in addition to decreased mRNA expression of growth hormone receptor 1A and IGF-1 relative to calving, serum binding capacities for IGF-1 also decreased. Insulin-like growth factor binding protein 4 mRNA expression was higher in cows with low IGF-1 concentrations; this binding protein inhibits IGF-1 action at the tissue level and therefore may reduce IGF-1 bioavailability. Finally, other endocrine end points (e.g., insulin and thyroid hormones) differed between the 2 groups.
Function of milk polymorphonuclear neutrophil leukocytes in bovine mammary glands infected with Corynebacterium bovis - Corrected Proof M.G. Blagitz, F.N. Souza, B.P. Santos, C.F. Batista, A.C. Parra, L.F.F. Azevedo, P.A. Melville, N.R. Benites, A.M.M.P. Della Libera
ABSTRACT: Corynebacterium bovis is one of the most commonly isolated bacteria from aseptically collected bovine milk samples. The objective of the current study was to characterize the bovine innate immune response by evaluating milk polymorphonuclear neutrophilic leukocytes (PMNL) in mammary glands infected with C. bovis. Twenty quarters infected with C. bovis and 28 culture-negative quarters (with milk somatic cell count <1 × 105 cells/mL) were used. The percentages of milk PMNL and the PMNL expression of L-selectin (CD62L), β2-integrin (CD11b), and one of the endothelial-selectin ligands (CD44), as well as the levels of intracellular reactive oxygen species (ROS) and the phagocytosis of Staphylococcus aureus, were evaluated by flow cytometry. The apoptosis and necrosis rates of the PMNL were quantified using dual-color flow cytometry with fluorescein-labeled annexin and propidium iodide. The present study revealed a higher percentage of PMNL in the milk from C. bovis-infected quarters, although no significant differences were found in levels of CD44, CD62L, or CD11b expression among the PMNL. A lower percentage of apoptotic PMNL was observed in C. bovis-infected quarters, as well as higher percentages of viable PMNL and of PMNL that produced intracellular ROS. However, no alterations were observed in phagocytosis of Staph. aureus by the PMNL or in intensity of intracellular ROS production by PMNL. Thus, results from this investigation of the PMNL function support, at least in part, the fact that intramammary infections by C. bovis may offer protection against intramammary infections by other bacteria.
Long-term detection of Mycobacterium avium subspecies paratuberculosis in individual and bulk tank milk from a dairy herd with a low prevalence of Johne's disease - Corrected Proof J.L. Khol, M. Wassertheurer, E. Sodoma, S. Revilla-Fernández, J. Damoser, E. Österreicher, M. Dünser, U. Kleb, W. Baumgartner
ABSTRACT: Mycobacterium avium ssp. paratuberculosis (MAP) causes Johne's disease (JD) in ruminants and is shed into the milk of infected cows, which contributes to the controversial discussion about a possible link between MAP and Crohn's disease in humans. The aim of the study was to investigate the risk for the entry of MAP in the food chain via milk from dairy farms with subclinical JD. Therefore, the occurrence of MAP in the milk of a dairy herd with a low prevalence of JD was studied in single and bulk tank milk samples over a period of 23 mo and compared with MAP shedding into feces. Milk, fecal, and blood samples were taken from all cows older than 1.5 yr of age at the beginning and the end of the trial and analyzed for MAP or specific antibodies. In addition, 63 cows (33 MAP infected and 30 MAP noninfected) were selected for monthly sampling. Raw and pasteurized bulk tank milk samples were collected on a monthly basis. The milk samples were tested for MAP by real-time quantitative PCR (qPCR), and the fecal samples were tested for bacterial shedding by qPCR or solid culture. Based on the results of the herd investigations, the prevalence of cows shedding MAP was around 5%; no cases of clinical JD were observed during the study period. The results of the ELISA showed high variation, with 2.1 to 5.1% positive milk samples and 14.9 to 18.8% ELISA-positive blood samples. Monthly milk sampling revealed low levels of MAP shedding into the individual milk samples of both MAP-infected and noninfected cows, with only 13 cows shedding the bacterium into milk during the study period. Mycobacterium avium ssp. paratuberculosis was not detected by qPCR in any raw or pasteurized bulk tank milk sample throughout the study. A significant positive association could be found between MAP shedding into milk and feces. From the results of the present study, it can be concluded that MAP is only shed via milk in a small proportion of cows with subclinical JD for a limited period of time and is diluted below the detection level of qPCR within the bulk tank milk of these herds. These findings indicate that dairy herds subclinically infected with JD pose only a minor source for human MAP consumption with milk and milk products.
Isolation and characterization of Staphylococcus aureus strains from a Paso del Norte dairy - Corrected Proof S.A. Matyi, J.M. Dupre, W.L. Johnson, P.R. Hoyt, D.G. White, T. Brody, W.F. Odenwald, J.E. Gustafson
ABSTRACT: The primary purpose of this study was to determine if methicillin-resistant Staphylococcus aureus (MRSA) strains could be identified in the milk of dairy cattle in a Paso del Norte region dairy of the United States. Using physiological and PCR-based identification schemes, a total of 40 Staph. aureus strains were isolated from 29 raw milk samples of 133 total samples analyzed. Pulsed-field gel electrophoresis after digestion with the SmaI enzyme revealed that the 40 confirmed strains were represented by 5 pulsed-field types, which each contained 3 or more strains. Of 7 hospital strains isolated from cows undergoing antibiotic therapy, 3 demonstrated resistance to 3 or more antimicrobial classes and displayed similar pulsed-field gel electrophoresis patterns. A secondary purpose of this study was to belucidate the evolutionary relationships of strains isolated in this study to genomically characterized Staph. aureus strains. Therefore, Roche 454 GS (Roche Diagnostics Cor., Dallas, TX) pyrosequencing was used to produce draft genome sequences of an MRSA raw milk isolate (H29) and a methicillin-susceptible Staph. aureus (PB32). Analysis using the BLASTn database (http://blast.ncbi.nlm.nih.gov/) demonstrated that the H29 draft genome was highly homologous to the human MRSA strain JH1, yet the β-lactamase plasmid carried by H29 was different from that carried by JH1. Genomic analysis of H29 also clearly explained the multidrug resistance phenotype of this raw milk isolate. Analysis of the PB32 draft genome (using BLASTn) demonstrated that this raw milk isolate was most related to human MRSA strain 04-02981. Although PB32 is not a MRSA, the PB32 draft genome did reveal the presence of a unique staphylococcal cassette mec (SSCmec) remnant. In addition, the PB32 draft genome revealed the presence of a novel bovine staphylococcal pathogenicity island, SaPIbovPB32. This study demonstrates the presence of clones closely related to human and (or) bovine Staph. aureus strains circulating in a dairy herd.
Short communication: A genetic study of mortality in Danish Jersey heifer calves - Corrected Proof E. Norberg, J.E. Pryce, J. Pedersen
ABSTRACT: The aim of this study was to estimate genetic parameters for mortality of Jersey heifer calves during the first 6 mo after birth, calculate the genetic trend of the trait, and estimate breeding values of widely used Jersey sires. More than 260,000 heifer calves were included in the study. The mortality traits included in the analysis were defined as mortality in 8 different periods from 24 h after birth to age 180 d (d 1–14, d 15–30, d 31–60, d 61–90, d 91–120, d 121–150, and d 151–180) and mortality over the entire period. A linear model was used for estimation of genetic parameters, breeding values of sires, and genetic trend. Fixed effects included in the model were herd-year class, month of birth, parity of mother, and whether the calf was sold to another farm in the first 6 mo. Both direct and maternal genetic effects were included in the model; however, the maternal genetic effect was very small and not significant. The mortality rate was highest in the first month after birth (7.8%). Total mortality in the first 180 d was 12.5%. Direct heritabilities of mortality were quite low, ranging from 0.002 to 0.03 on the observable scale and 0.025 to 0.076 on the underlying scale. Maternal heritabilities were even lower. The genetic correlation between mortality from d 1 to 14 and d 1 to 180 was estimated to be 0.88, although by definition, these 2 traits share the same observations for many records. No clear genetic trend existed over the last 20 yr; however, considerable genetic variation exists. The best and the worst sires differed by about 8% in their estimated breeding values of mortality in the first 180 d. Based on the results obtained in this study, genetic selection for reducing calf mortality should be possible.
Effect of the level of maternal energy intake prepartum on immunometabolic markers, polymorphonuclear leukocyte function, and neutrophil gene network expression in neonatal Holstein heifer calves - Corrected Proof J.S. Osorio, E. Trevisi, M.A. Ballou, G. Bertoni, J.K. Drackley, J.J. Loor
ABSTRACT: A conventional approach in dairy cow nutrition programs during late gestation is to feed moderate-energy diets. The effects of the maternal plane of nutrition on immune function and metabolism in newborn calves are largely unknown. Holstein cows (n = 20) were fed a controlled-energy (CON) diet (1.24 Mcal/kg) for the entire dry period (∼50 d) or the CON diet during the first 29 d of the dry period followed by a moderate-energy (OVE) diet (1.47 Mcal/kg) during the last 21 d prepartum. All calves were weighed at birth before first colostrum intake. Calves chosen for this study (n = 6 per maternal diet) had blood samples harvested before colostrum feeding (d 0) and at 2 and 7 d of age. Blood samples were used to determine metabolites, acute-phase proteins, oxidative stress markers, hormones, phagocytic capacity of polymorphonuclear leukocytes (PMN) and monocytes, and total RNA was isolated from PMN. Calves from OVE dams weighed, on average, 5 kg less at birth (44.0 vs. 48.6 kg) than calves from CON dams. Blood glucose concentration in OVE calves had a more pronounced increase between 0 and 2 d than CON, at which point phagocytosis by PMN averaged 85% in OVE and 62% in CON. Compared with CON, calves from OVE had greater expression of TLR4, but lower expression of PPARA and PPARD at birth. Expression of PPARG and RXRA decreased between 0 and 2 d in both groups. Concentrations of leptin, cholesterol, ceruloplasmin, reactive oxygen metabolites, myeloperoxidase, retinol, tocopherol, IgG, and total protein, as well as expression of SOD2 and SELL increased markedly by 2 d in both groups; whereas, cortisol, albumin, acid-soluble protein, NEFA, insulin, as well as expression of IL6, TLR4, IL1R2, LTC4S, and ALOX5 decreased by 2 d. By 7 d of age, the concentration of haptoglobin was greater than precolostrum and was lower for OVE than CON calves. Our data provide evidence for a carry-over effect of maternal energy overfeeding during the last 3 wk before calving on some measurements of metabolism in the calf at birth and the phagocytic capacity of blood neutrophils after colostrum feeding. It might be feasible to design nutrient supplements to fortify colostrum in a way that metabolic and immunologic capabilities of the calf are improved.
A mild pulsed electric field condition that improves acid tolerance, growth, and protease activity of Lactobacillus acidophilus LA-K and Lactobacillus delbrueckii subspecies bulgaricus LB-12 - Corrected Proof N. Najim, Kayanush J. Aryana
ABSTRACT: Pulsed electric field (PEF) processing involves the application of pulses of voltage for less than 1 s to fluid products placed between 2 electrodes. The effect of mild PEF on beneficial characteristics of probiotic bacteria Lactobacillus acidophilus and Lactobacillus delbrueckii ssp. bulgaricus is not clearly understood. The objective of this study was to determine the influence of mild PEF conditions on acid tolerance, growth, and protease activity of Lb. acidophilus LA-K and Lactobacillus delbrueckii ssp. bulgaricus LB-12. A pilot plant PEF system (OSU-4M; The Ohio State University, Columbus) was used. The PEF treatments were positive square unipolar pulse width of 3 μs, pulse period of 0.5 s, electric field strength of 1 kV/cm, delay time of 20 μs, flow rate of 60 mL/min, and 40.5°C PEF treatment temperature. Both Lb. acidophilus LA-K and Lb. bulgaricus LB-12 subjected to mild PEF conditions were acid tolerant until the end of the 120 min of incubation, unlike the Lb. bulgaricus control, which was not acid tolerant after 30 min. The mild PEF-treated Lb. acidophilus LA-K and Lb. bulgaricus LB-12 reached the logarithmic phase of growth an hour earlier than the control. Mild PEF conditions studied significantly improved acid tolerance, exponential growth, and protease activity of both Lb. acidophilus LA-K and Lb. bulgaricus LB-12 compared with the control. The mild PEF conditions studied can be recommended for pretreating cultures to enhance these desirable attributes.