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Fecal consistency as related to dietary composition in lactating Holstein cowsIreland-Perry, Rebecca L. 07 April 2009 (has links)
Two trials were designed to study the relationships of dietary fiber (ADF) and protein level and source to fecal consistency in lactating cattle. In Experiment 1, 30 cows (12 multiparous, 18 primiparous) were randomly assigned to one of six total mixed diet treatments through four 21 d periods. For Experiment 2, six primiparous cows were used in two 6 x 6 Latin squares to evaluate water consumption, apparent digestibilities of DM, AOF, NOF, and starch, and to quantitate whole corn kernel passage. Total mixed diets for both trials were formulated to contain 17% (LF) or 25% AOF (HF) with CP levels of: 15% (S15) and 22% (S22) with soybean meal (SBM) supplementation, or 22% (G22) with combination of 50% corn gluten meal (eGM) and 50% SBM. Two forage sources were evaluated: corn silage (e) and alfalfa/corn silage (Ae) (50:50 on OM basis). Fecal consistency was evaluated using a 4 point scale (l-most fluid to 4-least fluid).
Experiment 1 demonstrated that lower dietary fiber reduced fecal pH (LF=6.65, HF=7.11) and fecal score (LF=2.18, HF=2.41), but increased fecal DM (LF=16.1%, HF=13.2%). Supplementing SBM (S22) decreased fecal DM (S22=14.1%, G22=15.5%) and fecal score (S22=2.01, G22=2.48). Forage source affected fecal DM (C=14%,AC=15.3%), but not pH or score. HF=13.2%). Supplementing SBM (S22) decreased fecal DM (S22=14.1%, G22=15.5%) and fecal score (S22=2.01, G22=2.48). Forage source affected fecal DM (C=14%,AC=15.3%), but not pH or score.
Results of Experiment 2 support major conclusions of Experiment 1. High supplementation of SBM increased daily water consumption (S22=80.2 kg, G22=74.5 kg), and reduced fecal score (S22=1.9, G22=2.4). Forage source affected apparent corn kernel (C=21.1% ,AC=33.9%) and starch (C=96%, AC=93%) digestibilities. High protein diets resulted in greater apparent DM digestibility (S15=68.2%, S22=71.8%, G22=71%). In prediction of fecal score from dietary components and animal parameters, dietary DM percent and 4% fat corrected milk (r²=.09, Experiment 1), and DM intake (r²=.12, Experiment 2) were variables most related to fecal score.
Dietary effects on fecal consistency were primarily due to ADF level and type of protein supplement. Accurate prediction of fecal consistency score from the dietary and animal parameters identified was not possible. Further study is suggested to evaluate different protein sources, the contribution of water consumption, and to clarify interactions of protein, forage source and fiber level in relation to fecal consistency. / Master of Science
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Relationships between survival and linear type traits in Quebec Holsteins and AyrshiresPhilpot, Jill C. January 1998 (has links)
No description available.
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Analyses épigénétique et transcriptomique sur embryons bovins obtenus à partir d'ovocytes de donneuses péri-pubèresMorin-Doré, Léonie 18 April 2019 (has links)
Avec l'arrivée des techniques de reproduction assistée et de la génomique, le progrès génétique chez les bovins laitiers est plus rapide que jamais, favorisant maintenant l'utilisation d'animaux de plus en plus jeunes pour la reproduction. Cette situation aurait possiblement un impact sur la qualité des embryons, affectant potentiellement la génisse de la génération suivante. Ce projet vise à documenter l'effet de l'âge sur la qualité de l'embryon et, en l'occurence, à identifier des pistes pour corriger la situation. Dix jeunes femelles Holstein ont subi trois cycles de stimulation ovarienne (8, 11, 14 mois). Les ovules ont ensuite été fécondés in vitro (semence d'un même taureau adulte), générant trois lots d’embryons par animal. Grâce à la plateforme EmbryoGENE, il fut possible de mesurer l'expression génique ainsi que l'état de méthylation de l'ADN au stade blastocyste. En premier lieu, l'analyse transcriptomique des contrastes selon l'âge (8 vs 14 mois et 11 vs 14 mois) a permis de dénombrer 242 gènes différentiellement exprimés pour le premier contraste et 296 pour le deuxième. Parmi les voies géniques affectées par l'âge, on retrouve notamment les voies mTOR et PPAR, ainsi que la voie de réponse au stress oxydatif médiée par NRF2. Pour sa part, l'analyse épigénétique a permis d'identifier 5787 régions différentiellement méthylées pour le premier contraste et 3658 pour le deuxième. Il est possible d'observer une tendance à l'hyperméthylation chez les embryons obtenus à partir de donneuses de 8 mois, alors qu'une hypométhylation du génome plus marquée est notée chez les embryons provenant des donneuses de 11 mois. Le premier constat est que les embryons sont marginalement affectés par l'âge de la donneuse et que la qualité s’avère très bonne dès 8 mois. Les résultats suggèrent une causemétabolique pour expliquer les différences observées, trahissant un impact plus grand des conditions in vitrosur les embryons produits par les plus jeunes donneuses.
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Hindgut fermentation in ruminating Holstein calvesLoveland, Jennifer January 1986 (has links)
The effects of quantity of dietary starch and type of dietary protein on hindgut fermentation were evaluated. Thirty-two Holstein bull calves were fed diets containing variable amounts of orchardgrass hay and a grain mixture. The amount of starch and types of protein were: [L1] low starch, soybean meal (SBM); [L2] low starch, fishmeal plus dried brewers' grains (FBG); [Hl] high starch and SBM; [H2] high starch, FBG. The percentages of acid detergent fiber (ADF) and crude protein were: [L1] 19.2%, 15.1%; [L2] 18.0%, 15.6%; [H1] 9.5%, 14.9%; [H2] 9.6%, 15.4%. After calves were fed the diets for 17 days, they were slaughtered to obtain their intestinal tracts. Ileal, cecal, and colonic digesta and feces of calves fed Hl and H2 versus Ll and L2 contained less water and ADF. Concentration of nitrogen in digesta and feces did not differ. Ileal, cecal, and colonic digesta from calves fed H1 and H2 had significantly greater numbers of viable anaerobic bacteria and lower pH._ Cecal digesta from calves fed high fiber diets (L1 and L2) had lower total VFA, propionate, and buytrate concentrations than calves fed high starch diets. Colonic and cecal digesta of calves fed diets H1 and H2 contained less ammonia. Acetate and propionate flux across cecal epithelium ro vrtro was faster for diets H1 and H2. Results indicate that high dietary starch stimulated anaerobic bacterial growth and fermentation in the hindgut, and enhanced acetate and propionate flux across the cecal epithelium. Acetate and propionate transport across the cecal wall probably is not due solely to passive diffusion, but it may involve a carrier. Replacement of SBM by FBG also altered cecal fermentation to a lesser extent. Calves fed H2 had significantly greater numbers of viable anaerobic bacteria in cecal and ileal digesta and 2 to 10 times the number of bacteria associated with cecal epithelium than calves fed the other diets. Butyrate cecal concentration and production was significantly increased when calves were fed diets containing FBG. Cecal VFA production may account for approximately 3 to 5% of digestible energy intake. / Ph. D. / incomplete_metadata
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Preference and acceptability of four protein sources by ruminating Holstein calvesWampler, Susan Anderson 01 August 2012 (has links)
Four successive groups of four calves each (~ 4 mo old) were individually penned and observed during a 14 d trial period for choice of concentrate. Prior calf diets contained soybean meal (SBM) (for two groups and distillers grains in place of SBM for two groups. Concentrates contained approximately equal amounts of corn with either SBM, peanut meal (PNM), fish meal (FSM), or corn gluten meal (CGM). Each day of four trials, .45 kg of each concentrate was randomly assigned to one of four equal feed box sections. Calf feeding position was recorded every 30 sec for no more than 50 min or until calves stopped eating. In addition, 1.36 kg of first cutting orchardgrass hay was offered twice per day. Measurements of amount of each feed consumed, order of consumption and length of time spent eating each feed were analyzed statistically to determine preference. Overall preference was for SBM, closely followed by PNM, both over FSM and CGM, with the l preference status of FSM showing the most change over time by decreasing throughout the trial periods. Neither section in which feed was offered nor previous experience with SBM significantly influenced preference. In addition, twenty calves ranging in age from 4 mo to 7 mo were divided and housed in four groups of five and observed during a 30 d trial period for acceptability of the protein feeds tested for preference. Acceptability, measured subjectively as length of time required by calves to eat each feed, was greatest for SBM, closely followed by PNM and CGM, and least for FSM. Analysis of calf weight gain showed no differences between feeds. / Master of Science
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Nutritional and endocrine aspects of the lactation cycle of Holstein and Jersey cows: nutrient balances, response to supplemental dietary fat, rib composition and rib histologyBallantine, Holly Taylor January 1989 (has links)
Eight mature Holstein and Jersey cows beginning their third or later lactation were used throughout this study to evaluate various aspects of the lactation cycle. The lactation (control) diet consisted of 28.8% corn silage, 22.4% alfalfa haylage, and 48.8% concentrate dry matter. Breeds responded differently to the stress of calving. Jerseys had higher plasma somatotropin on day after calving, but Holsteins had higher glucose on day of and day after calving. Plasma parathyroid hormone did not differ between breeds, but Jerseys had higher 1,25-dihydroxyvitamin D₃ than Holsteins on both days after calving. Plasma total calcium and ionized calcium concentrations were lower for Jerseys on both days. Holsteins and Jerseys had similar concentrations of hormones and calcium at 4 and 8 wk. Ionized calcium as a percent of total calcium was elevated at calving, as compared to other times in the lactation cycle, in both breeds.
From 9 to 21 wk, 4 of 8 Holsteins and 4 of 8 Jerseys were fed a diet supplemented with tallow. Holsteins fed tallow had lower somatotropin than Holsteins fed control diet at 14 and 18 wk. Plasma glucose, parathyroid hormone, and 1,25-dihydroxyvitamin D₃ were similar between tallow- and control-fed cows in both breeds. Plasma total calcium and ionized calcium were higher at 20 wk for Holsteins and Jerseys fed tallow. Dry matter intake was not influenced by diet in either breed. However, Holsteins, but not Jerseys, fed tallow produced more milk and higher body weights than Holsteins fed the control diet.
Balance trials results indicated dietary tallow addition increased energy intake, energy digestibility, and metabolizable energy, but it decreased partial efficiency of metabolizable energy utilization for lactation. Although digestibility of calcium and magnesium was unchanged, tallow-fed cows were in greater positive calcium and magnesium balance than control-fed cows.
Stage of lactation had little effect on specific gravity, shear stress, percent mineral, and histological measurements of biopsied rib samples. However, Jersey rib had higher specific gravity than Holstein rib. All cows had similar bone histological features throughout lactation. / Ph. D.
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Heterogeneity of within-herd variances for conformation and its relationship to various herd parameters in the U.S. Holstein populationSmothers, Clark David January 1989 (has links)
Two data sets of first-parity classification records were analyzed to examine heterogeneity of variances for conformation in the U. S. Holstein population. Data set I included records for final score and linear descriptive traits on cows scored from 1983 through 1986. Results indicated a strong negative correlation (r = -.59) between within-herd standard deviation for final score and herd-mean final score.
Regression analysis suggested a curvilinear decrease (concave up) in within-herd standard deviation for final score with increasing herd-mean final score. Within-herd standard deviations for linear descriptive traits demonstrated a linear decline with increases in herd-mean final score.
Daughter contemporary deviation for final score was regressed on her sire’s Predicted Difference type within 25 mean/standard deviation subclasses. Response to selection was greatest in high-mean/variance herds and least in low-mean/variance herds.
Restricted maximum likelihood estimates of sire and error variance were approximated within each of 5 herd-mean subclasses of the data. Regressions revealed environmental variance for final score decreased curvilinearly (concave up) with increasing herd-mean final score. Genetic variance declined linearly. Heritability demonstrated no significant trend. For most linear traits, environmental variance decreased linearly with increasing herd-mean final score. Linear decreases in genetic variance were noted for foot angle, udder depth and rump angle, Heritability had positive trends for body depth, angularity, rear udder height, udder support, and teat placement.
Data set II included first-parity final scores on cows classified from 1967 to 1986. Relationships estimated between herd mean and within-herd variance for final score on recent data were confirmed. Positive trends over time were noted for: within-herd standard deviation for final score, the antagonistic relationship between herd mean and within-herd variance, the antagonistic relationship between average Predicted Difference type and within-herd variance, and average herd-mean Predicted Difference type.
Results indicate selection for final score was occurring in the population. Differences in within-herd selection differentials accounted for 24% of the differences in within-herd variance for final score. / Ph. D.
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Effets de Bacillus subtilis et de Bacillus Licheniformis utilisés comme probiotiques sur la concentration en acides gras à chaîne ramifiée du lait et sur les performances des vaches laitièresLamontagne, Jérome 27 January 2024 (has links)
L’objectif de ce projet de recherche était de déterminer les effets d’une supplémentation de probiotiques du genre Bacillus sur les performances de production de vaches de race holstein en mi-lactation et sur le profil en acides gras de leur lait. Pour ce faire, six vaches multipares porteuses d’une canule ruminale ont été utilisées selon un dispositif en chassé croisé répliqué et randomisé. Les vaches ont ainsi reçu soit 200 g/j de poudre de lactosérum comme traitement témoin ou 200 g/j de BioPlus 2B (Chr Hansen, Milwaukee, WI), un probiotique commercial de Bacillus subtilis et de Bacillus licheniformis, représentant un apport quotidien de 6,4 × 10¹¹ UFC et utilisant la poudre de lactosérum comme diluant. La production laitière, la composition du lait et son profil en acides gras, les paramètres de fermentation ruminale et le microbiote ruminal ont été évalués. Les traitements n’ont pas affecté les performances laitières. L’utilisation du probiotique a cependant augmenté la concentration relative d’anteiso 13:0 et d’anteiso 15:0 et tendait à augmenter la concentration totale d’acides gras à chaîne ramifiée dans les matières grasses du lait lorsque comparé au traitement témoin. Les traitements n’ont pas modifié le pH, l’azote ammoniacal ou les concentrations en acétate, propionate et butyrate du rumen. Cependant,le probiotique a augmenté la concentration ruminale d’isovalérate et tendait à augmenter celle de l’isobutyrate. Cette expérience a permis d’observer la sensibilité du profil en acides gras du lait face aux modifications du microbiote ruminal. Les bactéries probiotiques du genre Bacillus pourraient donc être utilisées dans un protocole de maximisation des acides gras à chaîne ramifiée du lait pour permettre une augmentation du niveau de ces acides gras dans les produits laitiers. / The aim of the study was to determine the effect of a Bacillus-based direct-fed microbial on dairy performance of mid-lactating Holstein dairy cows and on their milk fatty acid composition. To this end, six multiparous cows fitted with a rumen cannula were used in a randomized replicated crossover design. Cows received 200 g/d of either whey powder, as a control, or BioPlus 2B (Chr Hansen, Milwaukee, WI), a commercial direct-fed microbial providing Bacillus subtilis and Bacillus licheniformis, representing a daily dose of 6.4 ×10¹¹ cfu, and using whey powder as a carrier. Milk production, composition and fatty acid profile, as well as ruminal parameters and microbiota were evaluated. Bacillus concentrationin the rumen increased with the addition of the direct-fed microbial supplement. Treatmentdid not affect ruminal pH, NH3-N and concentrations of acetate, propionate, and butyrate.However, direct-fed Bacillus increased ruminal concentration of isovalerate and tended to increase the concentration of isobutyrate. Treatments did not affect milk performance. The direct-fed Bacillus increased the relative concentration of anteiso 13:0 and anteiso 15:0 in milk fat, and tended to increase total concentration of branched-chain fatty acids as compared with control. This trial indicates that milk fatty acid composition is sensitive to ruminal microbiota modifications. Direct-fed Bacillus could be used as part of a standard protocol aiming to produce milk enriched in branched-chain fatty acids.
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Comparaison du comportement de génisses laitières Holstein nourries avec du lactoremplaceur selon la recommandation canadienne ou en ad libitumMagassa, Ousmane 27 January 2024 (has links)
L'objectif du présent mémoire était de comparer, en situation commerciale, le comportement de génisses laitières Holstein nourries selon la recommandation canadienne (20 % du poids à la naissance) et ad libitum au pic de la consommation lactée, pendant le sevrage et après le sevrage. Pour ce faire, 114 génisses de deux fermes laitières commerciales ont été réparties aléatoirement entre les régimes d'alimentation lactée et étaient logées en groupe avec un distributeur automatique de lactoremplaceur du 7ième au 76ième jour de vie (sevrage). Des accéléromètres ont été utilisés pour déterminer le temps passé couché, la durée des épisodes passés couchés et la fréquence des épisodes passés couchés. Des observations comportementales directes par un observateur en continu (tétée entre veaux, veau qui déplace un autre veau à la louve) et en discontinu (comportement alimentaire, d'abreuvement en eau et de couchée) ont été réalisées pendant deux fois une heure dans chacune des trois périodes de consommation visées par l'étude. Indépendamment du régime lacté, le temps passé couché était plus élevé au pic de la consommation lactée alors que la durée des épisodes passés couchés variait en fonction de la période et du traitement lacté. La fréquence des épisodes passés couchés diminuait en post-sevrage et elle était plus élevée pour les animaux du traitement ad libitum que ceux du traitement suivant la recommandation canadienne au pic de la consommation. Les comportements d'alimentation et d'abreuvement étaient plus fréquent en post-sevrage alors que le comportement de couchée était le plus élevé en présevrage, indépendamment du traitement lacté. Il y avait une tendance à plus de tétée entre veaux en post-sevrage pour les veaux nourris en ad libitum. Cependant, pour les deux traitements, les nombres moyens d'évènements de tétée entre veaux et de déplacement d'un veau par un autre étaient dans des plages considérés acceptables. Malgré les différences observées, les deux traitements ont été adéquats en ce qui a trait aux comportements des veaux. / The objective of this study was to compare, on commercial farms, the behaviour of Holstein dairy calves fed milk replacer equivalent to the current Canadian recommendation or ad libitum at peak milk replacer intake, during the weaning period and after weaning. To do so, 114 heifers from two commercial dairy farms were randomly assigned to the two milk replacer feeding regimes and were group-housed, fed with an automatic milk replacer from day 7 to day 76 of age (weaning). Accelerometers were used to determine lying time, lying bouts, and bouts duration. Direct visual behavioural observations by an observer (feeding behaviour, drinking behaviour, and lying behaviour) were also assessed discontinuously while redirect behaviour (displacement of one calf by another at the automated milk feeder, and cross-suckling) were observed continuously for two one-hour periods of live observations for each of the three selected periods. Daily lying time increased at the peak of milk replacer intake relative to the other observational periods. Mean bout duration varied between periods and treatments. Lying bouts were more frequent after weaning and under the ad libitum treatment during peak milk replacer intake. Feeding and drinking behaviours were more frequent in the post-weaning period while lying time was higher at the peak milk replacer intake period. There was a tendency for more suckling between calves at postweaning when calves were fed ad libitum. Overall, all behavioral observations remained acceptable for both treatments. Therefore, despite the difference observed, both treatments appeared to be adequate in terms of calf behaviour
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Impact de la configuration des stalles sur le confort des vaches laitières en stabulation entravéeBouffard, Véronique 24 April 2018 (has links)
Ce mémoire porte sur la configuration des stalles et le confort des vaches. Cent troupeaux laitiers ont été visités au Québec (n=60) et en Ontario (n=40). La configuration des stalles, les dimensions corporelles, les blessures, la boiterie, la propreté et le temps de repos ont été mesurés pour 40 vaches Holstein en lactation. Plus de 50 % des vaches étaient logées dans une stalle trop petite, 79 % des vaches avaient au moins une blessure et 25 % étaient boiteuses, mais seulement 15 % étaient sales. Outre la hauteur de la barre d’attache, lorsque les dimensions des stalles étaient augmentées pour se rapprocher des recommandations, les risques de blessures et de boiteries diminuaient et le temps de repos ainsi que le nombre de changements de position debout/couchée augmentaient. Toutefois, une stalle plus grande augmentait les chances d’avoir des vaches sales. Ces résultats suggèrent, entre autres, qu’une barre d’attache bien positionnée et une chaine suffisamment longue améliorent le confort des vaches. / This thesis focuses on tie-stall configuration and cow comfort. One hundred dairy herds were visited in Quebec, (n = 60) and in Ontario (n = 40). Stall configuration, body dimensions, injuries, lameness, cleanliness and lying time were measured for 40 lactating Holstein cows. Over than 50% of the cows were in a stall too small, 79% of cows had at least one injury and 25% were lamed, but only 15% were dirty. Except for tie-rail height, every time the size of the stalls was increased closer to the recommendations, the risk of injuries and lameness decreased, and the lying time and the number of lying bouts increased. However, a larger stall size increased the chances of the cows to be dirty. These results suggest, among other, that a tie-rail forward position and a chain length that meet current recommendations would improve cow welfare.
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