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A J Heinrichs - One of the best experts on this subject based on the ideXlab platform.
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effect of forage to concentrate ratio with sorghum silage as a source of forage on rumen fermentation n balance and purine derivative excretion in limit fed Dairy Heifers
Journal of Dairy Science, 2017Co-Authors: Kristina Kljak, F. Pino, A J HeinrichsAbstract:Abstract Sorghum silage has been shown to be a good alternative to corn silage for Dairy cows; however, studies regarding Heifers are insufficiently explored. Therefore, the objective of this study was to evaluate effects of changing forage to concentrate ratio (FOR:CON) in diets based on sorghum silage on N digestibility, rumen fermentation, N balance, C excretion, and microbial N yield in limit-fed Dairy Heifers. A split-plot 4×4 Latin square design with 19-d periods (15 d of adaptation and 4 d of sampling) was conducted with 8 rumen cannulated Dairy Heifers (age 13.7±0.6mo and weight 364.8±17.6kg). Heifers were fed sorghum silage–based diets with 4 FOR:CON (85:15, 75:25, 65:35, and 55:45) balanced for similar metabolizable energy intake per unit of body weight and crude protein concentration. Diets were fed to allow 900 to 1,000g/d body weight gain and were fed once daily. Total collection of feces and urine was completed on d 15 to 19 to determine N, C, urea N, allantoin, uric acid, and creatinine excretion. Rumen contents were sampled on d 19 at 0, 1.5, 3, 4.5, 6, 9, 13, 17, 21, and 23h after feeding to measure pH, volatile fatty acid (VFA), ammonia-N, and free AA concentrations. The pH decreased linearly while ammonia-N and free AA levels increased linearly with decreasing FOR:CON of diets. Although mean total VFA did not differ among treatment diets, molar proportions of VFA did. Acetate proportion decreased while propionate and butyrate increased with decreasing FOR:CON. Intake of N and urea N excretion decreased with decreasing forage proportion in diets while total N excretion, apparent N digestibility, and N retention were not different. Intake of C and excretion in feces (g/d) decreased linearly with decreasing FOR:CON in diets. Creatinine, allantoin, and uric acid excretion were not affected by FOR:CON; however, microbial N yield tended to increase linearly with greater concentrate in diets. Heifers limit fed diets based on sorghum silage demonstrated the effect of available ammonia-N and readily fermentable carbohydrates with subsequent effects on nutrient utilization when different FOR:CON were applied. Based on the presented results, FOR:CON 65:35 had the most suitable balance of available ammonia-N and readily fermentable carbohydrates for the most optimal results.
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precision feeding Dairy Heifers a high rumen degradable protein diet with different proportions of dietary fiber and forage to concentrate ratios
Journal of Dairy Science, 2016Co-Authors: G J Lascano, L E Koch, A J HeinrichsAbstract:The objective of this experiment was to determine the effects of feeding a high-rumen-degradable protein (RDP) diet when dietary fiber content is manipulated within differing forage-to-concentrate ratio (F:C) on nutrient utilization of precision-fed Dairy Heifers. Six cannulated Holstein Heifers (486.98±15.07kg of body weight) were randomly assigned to 2 F:C, low- (45% forage; LF) and high-forage (90% forage; HF) diets and to a fiber proportion sequence [33% grass hay and wheat straw (HS), 67% corn silage (CS; low fiber); 50% HS, 50% CS (medium fiber); and 67% HS, 33% CS (high fiber)] within forage proportion administered according to a split-plot, 3×3 Latin square design (16-d periods). Heifers fed LF had greater apparent total-tract organic matter digestibility coefficients (dC), neutral detergent fiber, and cellulose than those fed LC diets. Substituting CS with HS resulted in a linear reduction in dry matter, organic matter, and cellulose dC. Nitrogen dC was not different between F:C or with increasing proportions of HS in diets, but N retention tended to decrease linearly as HS was increased in the diets. Predicted microbial protein flow to the duodenum decreased linearly with HS addition and protozoa numbers HS interacted linearly, exhibiting a decrease as HS increased for LF, whereas no effects were observed for HF. Blood urea N increased linearly as HS was incorporated. The LF-fed Heifers had a greater ruminal volatile fatty acids concentration. We noted a tendency for a greater dry matter, and a significantly higher liquid fraction turnover rate for HF diets. There was a linear numerical increase in the liquid and solid fraction turnover rate as fiber was added to the diets. Rumen fermentation parameters and fractional passages (solid and liquid) rates support the reduction in dC, N retention, and microbial protein synthesis observed as more dietary fiber is added to the rations of Dairy Heifers precision-fed a constant proportion of rumen-degradable protein.
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effect of trace minerals and starch on digestibility and rumen fermentation in diets for Dairy Heifers
Journal of Dairy Science, 2016Co-Authors: F. Pino, A J HeinrichsAbstract:The objective of this study was to evaluate the effect of different forms of trace minerals (TM) and the use of different starch levels in Dairy heifer diets on rumen fermentation and digestibility. Eight rumen cannulated Dairy Heifers (15.4 ± 0.8 mo of age and 438.31 ± 18.08 kg of body weight) were subjected to a split-plot, 4 × 4 Latin square design with 19-d periods: 15d of adaptation and 4d of sampling. The whole-plot factor was type of TM; organic as proteinates (OTM) or inorganic sulfates (ITM), and the subplot was starch level (3.54, 12.95, 22.25, and 31.73%). Total collection of feces and urine was completed on d 15 to 19 to determine digestibility and TM excretion. Rumen contents were sampled on d 18 to 19 at 0, 1, 2, 4, 8, 12, 16, 20, and 22 h after feeding to measure pH and volatile fatty acid (VFA) concentrations. Plasma samples were collected to evaluate TM concentrations and enzymatic activity for ceruloplasmin, glutathione peroxidase, and superoxide dismutase. Starch level affected pH, individual VFA concentrations, and nutrient excretion. Trace mineral intake was lower for OTM compared with ITM. No effect of TM form on dry matter digestibility was detected, but as level of starch increased, diet dry matter digestibility increased. Rumen pH was lower for diets with OTM, which is consistent with higher total VFA production and butyrate proportion observed for Heifers fed OTM diets. These variables may be explained by the higher bioavailability of OTM and faster utilization and fermentation by rumen microorganisms. Heifers that consumed ITM had higher moisture in feces and higher urine excretion, which increased total manure production. Total excretion of TM was not different by treatment. Blood plasma mineral concentration was not different between treatments except for Mn, which was higher for OTM. Enzymatic activity was not affected by treatments. Mineral intake was reduced and blood mineral levels were not different, suggesting enhanced absorption of OTM compared with ITM. In conclusion, based on rumen pH, VFA production, and plasma TM concentration, OTM may be more ruminally bioavailable and absorbed to a greater extent than ITM. Also, TM form affected fecal moisture and urine excretion, suggesting that ITM may stimulate water intake.
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short communication nutrient utilization of fresh sugarcane based diets with slow release nonprotein nitrogen addition for control fed Dairy Heifers
Journal of Dairy Science, 2012Co-Authors: G J Lascano, M Velez, J M Tricarico, A J HeinrichsAbstract:Abstract An experiment was conducted to determine the effect of replacing soybean protein (SBM) with a slow-release urea (SR-U) in control-fed Dairy Heifers in the tropics. Eight Holstein Heifers (237.6 ± 5.45 kg of body weight) were allocated to 2 treatments in a crossover design. Treatments were control (SBM) and SR-U (Optigen II; Alltech Inc., Nicholasville, KY). The forage-to-concentrate ratio was 50:50 [dry matter (DM) basis], and fresh chopped sugarcane was the sole source of forage. Data were analyzed using a mixed-effects model. Compared with the SR-U diet, SBM tended to have greater total tract apparent digestibility of DM and ash. Total tract apparent digestibilities in SBM-fed Heifers were greater than in SR-U-fed Heifers for organic matter (73.9 vs. 71.3 ± 0.6), crude protein (76.9 vs. 75.2 ± 0.7), hemicellulose (50.5 vs. 43.3 ± 0.9), and starch (98.6 vs. 97.1 ± 0.5). However, total tract apparent digestibility of neutral detergent fiber was similar, and digestibility of acid detergent fiber was higher in SR-U Heifers than in SBM (33.3 vs. 27.7 ± 2.6). Water intake and excretion of urine and feces (wet and dry) were similar between treatments. Retained N was similar for all groups, and no differences were observed in the distribution of excreted N. We conclude that when SR-U replaced SBM, it tended to marginally decrease DM and decreased organic matter, crude protein, hemicellulose, and starch total tract apparent digestibility, but did not affect neutral detergent fiber and increased acid detergent fiber digestibility.
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short communication analysis of milk yield and composition for Dairy Heifers limit fed lower forage diets during the rearing period1
Journal of Dairy Science, 2010Co-Authors: G I Zanton, A J HeinrichsAbstract:Methods to improve feed efficiency in Dairy Heifers have been studied that employ limit feeding and high concentrate or highly digestible diet ingredients. To date, the published studies have used differing daily gains, diet components, and management systems. All of these studies have had limited numbers of animals, which limits the power of each study by itself. The objective of this analysis was to evaluate, using all available studies, the overall effect of limit feeding Dairy Heifers during the rearing phase on milk production and composition during the first lactation. To accomplish this objective, responses from published experiments were analyzed using random effects meta-analytic procedures. The results of this analysis confirmed the results of the individual experiments in that no significant differences were found in lactation performance between the limit-fed, lower forage diets and the higher forage control diets. Heterogeneity of results between experiments was low to moderate for the response variables evaluated, indicating that the results were reasonably consistent among the trials. Limit feeding of higher concentrate diets represents a viable alternative to traditional high forage heifer feeding systems when environmental or economic conditions favor these systems.
M A G Von Keyserlingk - One of the best experts on this subject based on the ideXlab platform.
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Dairy Heifers benefit from the presence of an experienced companion when learning how to graze
Journal of Dairy Science, 2016Co-Authors: Joao H C Costa, Daniel M Weary, W G Costa, L Machado C P Filho, M A G Von KeyserlingkAbstract:Pasture remains important on many Dairy farms, but the age of first contact with pasture varies depending on the month of birth, weaning age, and farm management. Regardless of age, naive Dairy Heifers must learn to graze when first introduced to pasture. This study investigated whether being grouped with experienced Dairy cows would affect the development of grazing behaviors. Sixty-three Holstein Heifers (mean ± SD 14.2 ± 1.3 mo; 546 ± 60.7 kg) and 21 dry Holstein cows (2.6 ± 0.8 lactations; 751 ± 53.9 kg) were assigned into 7 groups of 12 animals (3 dry cows and 9 naive Heifers), and each was divided and assigned to an experienced (3 cows and 3 Heifers) and nonexperienced (6 Heifers) sub-group. Sub-groups were introduced to pasture in different paddocks without visual contact with any other cattle. No difference was found in the time after introduction to the paddock for Heifers to first attempt to nibble grass [experienced: 0:23 (0:17-0:43) vs. nonexperienced 0:40 (0:35-0:46); median (quartile 1 - quartile 3), h:mm]. However, Heifers grouped with experienced cows showed a shorter latency to begin grazing [experienced: 0:47 (0:28-00:52) vs. nonexperienced 2:13 (1:25-2:30)]. During the first hour after introduction to pasture, Heifers in the experienced treatment showed fewer stomping events [experienced: 2.5 (1.25-4) vs. nonexperienced: 6.5 (4-8)] and vocalized less often [experienced: 3.5 (1.25-5.75) vs. nonexperienced: 7 (5-8.75)]. After this initial period, animals in both subgroups began to graze normally; treatments did not differ in grazing behaviors over the 3-d observation period. These results indicate that grouping Heifers with pasture-experienced cows improves grazing behavior of Dairy Heifers in the first hours following introduction to pasture.
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competition for feed affects the feeding behavior of growing Dairy Heifers
Journal of Dairy Science, 2009Co-Authors: T J Devries, M A G Von KeyserlingkAbstract:The objective of this study was to determine how competition for feed influences the feeding behavior of young, growing Dairy Heifers. Thirty-six prepubertal Holstein Heifers (231.5 ± 12.1 d old, weighing 234.7 ± 24.0 kg), consuming a total mixed ration ad libitum, were assigned to 1 of 2 treatments: noncompetitive (1 heifer/feed bin), or competitive (2 Heifers/feed bin). After 7 d of treatment adaptation, dry matter intake and feeding behavior were monitored for 7 d for each animal. Fresh feed and orts were sampled on the last 3 d of the treatment period from each bin and were subjected to particle size analysis. The particle size separator consisted of 3 screens (18, 9, and 1.18 mm) and a bottom pan resulting in 4 fractions (long, medium, short, and fine). Sorting activity for each fraction was calculated as the actual intake expressed as a percentage of the predicted intake. There was no difference in sorting behavior or dry matter intake between the treatments. Overall, the Heifers sorted against long particles (94%), and sorted for medium (102%) and short (103%) particles. The competitively fed Heifers tended to have 10% shorter feeding times, particularly at peak feeding periods. The competitively fed Heifers also consumed 9% fewer meals per day, although the duration of these meals were 10% longer, and tended to be 13% larger. Competition for feed also tended to increase the day-to-day variation in feeding time, meal duration, and meal size. It can be concluded that competition for feed for growing Dairy Heifers alters feeding patterns, reduces access to feed, particularly during periods of peak feeding activity, and tends to increase day-to-day variation in feeding behavior.
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short communication feeding method affects the feeding behavior of growing Dairy Heifers
Journal of Dairy Science, 2009Co-Authors: T J Devries, M A G Von KeyserlingkAbstract:There is limited information available on what is the most appropriate feeding method for growing Dairy Heifers. The objective of this study was to determine the effect of feeding method on the feeding behavior and diet selection of growing Dairy Heifers. Six prepubescent Holstein Heifers (158.2 ± 4.0 d old, weighing 168.2 ± 15.7 kg), fed once per day for 1.0 kg/d of growth, were subjected to each of 3 treatments in 3 successive 7-d treatment periods using a replicated 3 × 3 Latin square design. Treatments consisted of feeding 2.02 kg/d dry matter of grain concentrate and ad libitum chopped grass hay as: 1) choice (grain concentrate and hay in separate feed bins), 2) top-dressed ration (grain concentrate placed on top of the hay in one feed bin), and 3) total mixed ration (TMR, grain concentrate mixed with hay in one feed bin). Dry matter intake (DMI) and feeding behavior were monitored for 7 d for each animal on each treatment, and feed sorting was monitored for the last 3 d of each treatment period. The provision of grain concentrate and hay in either a choice or top-dressed situation resulted in young Dairy Heifers rapidly consuming the grain concentrate portion of their ration in very few, large meals before consuming the hay portion of their ration. The provision of the 2 ration ingredients as a TMR increased the distribution of DMI over the day and reduced the amount of sorting (against long forage particles, and for short grain concentrate particles) by Heifers. These results suggest that the provision of a TMR to growing Dairy Heifers, as opposed to feeding concentrate and hay as either a choice or top-dressed, promotes a more balanced intake of nutrients across the day.
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nutrient intake and feeding behavior of growing Dairy Heifers effects of dietary dilution
Journal of Dairy Science, 2008Co-Authors: A M Greter, T J Devries, M A G Von KeyserlingkAbstract:The objective of this study was to determine how the addition of straw to a total mixed ration offered to growing Dairy Heifers affects their nutrient intake and feeding behavior. Six prepubescent Holstein Heifers (226.2 +/- 6.3 d old and weighing 250.1 +/- 17.7 kg), fed once per day for 1.0 kg/d of growth, were subjected to each of 3 treatment diets using a replicated 3 x 3 Latin square design. The treatment diets were 1) control (17.0% corn silage, 52.1% grass silage, 30.9% concentrate), 2) control diet with 10% straw, and 3) control diet with 20% straw. Dry matter intake and feeding behavior were monitored for 7 d for each animal on each treatment. Fresh feed and orts were sampled on the last 3 d of each treatment period for each heifer and were then subjected to particle size analysis. The particle size separator contained 3 screens (19, 8, and 1.18 mm) and a bottom pan, resulting in 4 fractions (long, medium, short, and fine). Sorting activity for each fraction was calculated as actual intake expressed as a percentage of the predicted intake. Heifers sorted against long particles and for short particles on all 3 diets. On the 10 or 20% straw diets the Heifers sorted for medium particles. Heifers also sorted for fine particles on the 20% straw diet. There was a linear increase in sorting for medium, short, and fine particles with increased straw in the diet. Dry matter intake linearly decreased with increased straw in the diet. Feeding time and meal duration increased linearly with the addition of straw to the diet, whereas feeding rate, meal size, and meal frequency decreased with the addition of straw. Requirements for maintenance and growth of 1.0 kg/d were sufficiently met when the animals consumed the control and 10% straw diet. On the 20% straw diet the animals consumed sufficient nutrients to achieve a 0.9 kg/d growth rate. These results indicate that the addition of straw to the diet of prepubescent Heifers strongly influences their sorting behavior. Despite this sorting, the results suggest that a low-quality feedstuff may be included in the diet to target nutrient intake and reduce feed costs without negatively affecting feeding behavior or growth potential.
G R Edwards - One of the best experts on this subject based on the ideXlab platform.
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plasma amino acid profiles of Dairy Heifers grazing pasture chicory and plantain
New Zealand Journal of Agricultural Research, 2020Co-Authors: Innocent Rugoho, G R Edwards, D Pacheco, Jeffrey Mccormick, C M Logan, Long ChengAbstract:The objective of this study was to quantify amino acid (AA) profiles in plasma collected from Dairy Heifers grazing swards containing ryegrass/clover, chicory and plantain in autumn and spring. The...
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live weight and growth of holstein friesian jersey and crossbred Dairy Heifers in new zealand
New Zealand Journal of Agricultural Research, 2019Co-Authors: R C Handcock, G R Edwards, N Lopezvillalobos, L R Mcnaughton, P J Back, R E HicksonAbstract:ABSTRACTThe objective of this study was to model the growth of Dairy Heifers to estimate the effects of breed and heterosis on live weight (LWT) and growth from three to 22 months of age. Data comprised of 1,653,214 LWT records obtained from 189,936 Dairy Heifers in 1547 herds. At all ages Holstein-Friesian (F) Heifers were heavier than Holstein-Friesian–Jersey crossbred (F × J) which were heavier than Jersey (J) Heifers. Heterosis effects for LWT were greatest at nine months of age (3.6%) and least at 22 months of age (2.0%). The growth pattern differed, as evidenced by the regression coefficients of the Legendre polynomial. Growth was non-linear and heterosis effects were different throughout the growth period. Friesian, J and F × J Heifers exhibited different growth patterns. These differences in growth pattern should be considered when formulating target LWTs and growth rates for a pasture-based system.
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positive relationships between body weight of Dairy Heifers and their first lactation and accumulated three parity lactation production
Journal of Dairy Science, 2019Co-Authors: R C Handcock, G R Edwards, N Lopezvillalobos, L R Mcnaughton, P J Back, R E HicksonAbstract:This study investigated the relationships between body weight (BW) and milk production of 140,113 New Zealand Dairy Heifers. Heifers were classified into 5 breed groups: Holstein-Friesian, Holstein-Friesian crossbred, Jersey, Jersey crossbred, and Holstein-Friesian-Jersey crossbred. Body weights were assessed at intervals of 3 mo from 3 to 21 mo of age and their relationships with first-lactation and accumulated milk production over the first 3 lactations (3-parity) were analyzed. We found positive curvilinear relationships between BW and milk production. The response to an increase in BW was greater for lighter Heifers compared with heavier Heifers, indicating possible benefits of preferentially feeding lighter Heifers to attain heavier BW. Within the age range and BW range studied, an increase in BW was always associated with an increase in first-lactation energy-corrected milk (ECM) and milk solids (milk fat plus milk protein) yield for breed groups other than Holstein-Friesian. For Holstein-Friesian Heifers, there was a positive relationship between BW and ECM and milk solids yields for all ages except for 3 mo of age, when no relationship existed. These results show the potential to increase first-lactation milk production of New Zealand Dairy Heifers by increasing heifer BW. Likewise, for 3-parity accumulated yields, the BW at which maximum ECM and milk solids yields occurred were at the heavier end of the BW range studied. The costs of rearing a heifer are incurred regardless of how long she remains in the herd. Potential bias exists from considering only cows that survived to lactate each year if particular cows had better survival than others. Therefore, the data in the current study for 3-parity production includes all Heifers that were old enough to have completed 3 lactations, regardless of whether they did or not. Including the Heifers that did not complete all 3 lactations describes the effect that BW of replacement Heifers has on accumulated milk yields without discriminating whether the increased milk yield came from greater survival or from greater production per surviving cow. Further research on the relationships between BW and survival of Heifers is required to confirm whether the heavier Heifers survived longer than the lighter Heifers, but could explain why the relationship between BW and 3-parity milk yields was more curvilinear than the relationship between BW and first-lactation milk production. Holstein-Friesian Heifers that were 450 kg in BW at 21 mo of age were estimated to produce 168 and 509 kg more ECM than 425-kg Holstein-Friesian Heifers in first-lactation and 3-parity accumulated yields, respectively. A further increase in BW at 21 mo of age, from 450 to 475 kg, was estimated to result in 157 and 409 kg more ECM in first-lactation and 3-parity accumulated yields, respectively. Consequently, for Heifers that were average and below average in BW, considerable milk production benefits would occur over the first 3 lactations by improving rearing practices to result in heavier Heifers throughout the precalving phase.
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live weight gain animal behaviour and urinary nitrogen excretion of Dairy Heifers grazing ryegrass white clover pasture chicory or plantain
New Zealand Journal of Agricultural Research, 2018Co-Authors: Long Cheng, Jeffrey Mccormick, C M Logan, Omar Almarashdeh, Xuefeng Guo, Ao Chen, Jing Zhong Tao, Hazel Carr, G R EdwardsAbstract:The objective of this study was to assess live weight gain, animal behaviour and N excretion in the urine of Dairy Heifers fed herbs during autumn and spring. Sixty Heifers were allocated into five...
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live weight gain urinary nitrogen excretion and urination behaviour of Dairy Heifers grazing pasture chicory and plantain
The Journal of Agricultural Science, 2017Co-Authors: Long Cheng, D Pacheco, Jeffrey Mccormick, C M Logan, A N Hussein, Miriam Hodge, G R EdwardsAbstract:The objective of the present study was to investigate live weight (LW) gain, urinary nitrogen (UN) excretion and urination behaviour of Dairy Heifers grazing pasture, chicory and plantain in autumn and spring. The study comprised a 35-day autumn trial (with a 7-day acclimation period) and a 28-days spring trial (with a 7-day acclimation period). For each trial, 56 Friesian × Jersey Heifers were blocked into five dietary treatments balanced for their LW and breeding worth (i.e. genetic merit of a cow for production and reproduction): 1·00 perennial ryegrass–white clover pasture (PA); 1·00 chicory (CH); 1·00 plantain (PL); 0·50 pasture + 0·50 chicory (PA + CH); and 0·50 pasture + 0·50 plantain (PA + PL). A fresh allocation of the herbage was offered every 3 days with allowance calculated according to feed requirement for maintenance plus gain of 1·0 kg LW/day. In both trials, LW gain was lower on CH than other treatments. In the spring trial, UN concentration and UN excretion were lower in CH and PL than other treatments. In autumn, a higher urination frequency was observed over the first 6 h after forage allocation in CH and PA + CH than other treatments. Data from the present study indicate that feeding CH alone limited heifer LW gain. However, Heifers grazing swards containing chicory (CH and PA + CH) and plantain (PL and PA + PL) had the potential to lower nitrous oxide emissions and nitrate leaching from soil compared with Heifers grazing PA, by reducing N loading in urine patches.
S. De Vliegher - One of the best experts on this subject based on the ideXlab platform.
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pathogen group specific risk factors at herd heifer and quarter levels for intramammary infections in early lactating Dairy Heifers
Preventive Veterinary Medicine, 2011Co-Authors: S Piepers, Geert Opsomer, Herman W. Barkema, Katrijn Peeters, K Frankena, S. De VliegherAbstract:Risk factors for intramammary infections caused by coagulase-negative staphylococci, contagious major pathogens and environmental major pathogens in early lactating Heifers were evaluated at the herd, heifer and quarter levels. In total, 764 quarters of 191 Dairy Heifers in 20 randomly selected farms in Flanders (Belgium) were sampled. Quarter milk samples were collected between 1 and 4 days in milk and between 5 and 8 days in milk for bacteriological culture. Data were analyzed using multivariable, multilevel logistic regression analysis. Higher average herd milk somatic cell count (>200,000 cells/mL), not having an effective fly control strategy, contact with lactating cows prior to calving and moderate to severe udder edema prior to calving increased the odds of intramammary infections caused by contagious major pathogens. Poor heifer hygiene and lack of mineral/vitamin supplementation prior to calving were risk factors for intramammary infection caused by environmental major pathogens. Teat apex colonization with coagulase-negative staphylococci prior to calving seemed to protect quarters against intramammary infections caused by major pathogens. Poor heifer hygiene before calving, a non-clipped udder and not practicing of teat dipping prior to calving increased the odds of intramammary infection with coagulase-negative staphylococci. Although management is important in the prevention and control of intramammary infections in early lactating Heifers, most variation in the prevalence of intramammary infections resided at the heifer and quarter levels, indicating that the susceptibility for intramammary infections around calving is mainly determined by heifer and quarter characteristics.
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impact of intramammary infections in Dairy Heifers on future udder health milk production and culling
Veterinary Microbiology, 2009Co-Authors: S Piepers, S. De Vliegher, Geert Opsomer, A. De Kruif, H W BarkemaAbstract:Dairy Heifers represent the future of a Dairy herd, and are expected to freshen with a healthy and well-developed udder, capable of producing an optimal amount of high quality milk. A high proportion of Heifers have infected mammary quarters at calving, with coagulase-negative staphylococci (CNS) being the most common cause. Staphylococcus aureus and environmental pathogens are also found. The aim of this paper is to summarize how intramammary infections during (late) gestation and early lactation impair the development of the mammary gland and negatively affect future udder health and milk production. Heifers calving with either subclinical or clinical mastitis are also at a higher risk to be culled in first lactation. The magnitude of the effect is most likely related to the virulence of the causative pathogen, the persistence of the infection when milk production has started, and the time of onset of infection. Histological changes in udder tissue from quarters infected with S. aureus are more pronounced than those in udder tissue from CNS-infected quarters. The longer the infections exist and the longer they persist into lactation, the larger the impact on Heifers' future udder health and milk production will be. In general, CNS infections are cleared early in lactation and some studies show that CNS do not have a large impact on future milk production and udder health. Future research should elucidate to what extent pathogen-specific as well as host-related factors affect the persistence of IMI in early lactating Heifers.
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association between somatic cell count in early lactation and culling of Dairy Heifers using cox frailty models
Journal of Dairy Science, 2005Co-Authors: S. De Vliegher, Geert Opsomer, A. De Kruif, H W Barkema, Luc DuchateauAbstract:The association between somatic cell count (SCC) of Dairy Heifers in early lactation [SCCel; measured between 5 and 14 d in milk (DIM)] and the culling hazard during the first lactation was studied using Cox frailty models. Udder health problems were the culling reason for 10% of the culled Heifers in this study. For each unit increase in the log-transformed SCCel (LnSCCel), the culling hazard increased by 11% [Hazard ratio (HR) = 1.11]. The strength of the association depended on 5 factors. Firstly, the association was stronger when SCCel was recorded after 10 DIM than at an earlier DIM. Secondly, the association was stronger if only culling events for udder disorders were considered (HR = 1.32) instead of all culling events (HR = 1.11). Furthermore, for each unit increase of test-day LnSCC after 14 DIM, modeled as a time-varying covariate, the culling hazard in the first lactation increased by 26% (HR = 1.26). Including LnSCC in the model already containing LnSCCel, reduced the estimate of LnSCCel slightly. Fourth, a higher test-day milk yield, modeled as a time-varying covariate, protected against culling and reduced the magnitude of the effect of LnSCCel as well when taken into account. Finally, the association between LnSCCel and culling was still present, although smaller, in the group of Heifers with a second test-day SCC ≤50,000 cells/mL.
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Management Practices and Heifer Characteristics Associated with Early Lactation Somatic Cell Count of Belgian Dairy Heifers
Journal of dairy science, 2004Co-Authors: S. De Vliegher, Geert Opsomer, Herman W. Barkema, Hans Laevens, Ian R. Dohoo, Henrik Stryhn, A. De KruifAbstract:Abstract Associations between somatic cell counts (SCC) from Heifers between 5 and 14 d in milk (DIM) and both herd-management practices and heifer characteristics were studied for 1912 Heifers in 159 Dairy herds in Flanders (Belgium). In higher-producing herds and in herds with an average calving age of Heifers >27 mo, SCC of Heifers was lower than in less-producing herds or in herds with an average calving age ≤27 mo. Heifers raised in herds with a higher bulk-milk somatic cell count had higher SCC. In herds in which Heifers calved on slatted floors, Heifers had lower SCC compared with herds in which Heifers calved on nonslatted floors. A significant difference in SCC was observed between provinces. At the heifer level, SCC decreased with increasing DIM. On average, Heifers calving in April to June had higher SCC, compared with those calving in the other months of the year. In the multilevel regression models, nearly all the variations of SCC resided at the heifer level, indicating that preventive measures against udder health problems in freshening Dairy Heifers should, in the short term, focus more on factors that vary between Heifers than on factors that vary between herds. However, for the long term, the need to identify new, and to implement known, herd-level strategies is important.
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Prepartum teat apex colonization with Staphylococcus chromogenes in Dairy Heifers is associated with low somatic cell count in early lactation.
Veterinary microbiology, 2003Co-Authors: S. De Vliegher, Luc Devriese, Geert Opsomer, Herman W. Barkema, Hans Laevens, J.l.m.r. Leroy, A. De KruifAbstract:Abstract A high number of Dairy Heifers freshen with udder health problems. The prevalence of teat apex colonization (TAC) with Staphylococcus chromogenes , one of the most widespread coagulase-negative staphylococci (CNS) in milk samples from freshly calved Dairy Heifers, was measured cross-sectionally in non-lactating Heifers on eight commercial Dairy farms in Belgium. The influence of age on this prevalence, and the association between teat apex colonization with S. chromogenes prepartum and quarter milk somatic cell count (SCC) in early lactation were studied. In total, 492 teat apices were sampled from 123 Heifers. The age of the Heifers varied from 8 to 34 months. Overall, 20% of the Heifers had at least one teat apex colonized with S. chromogenes . Of all teats sampled, 10% were colonized with S. chromogenes . The chance of having at least one teat apex colonized with S. chromogenes increased with age of the heifer. The presence of prepartum teat apex colonization with S. chromogenes was not associated with intramammary infection (IMI) early postpartum with the same bacterium. On the contrary, teat apex colonization with S. chromogenes prepartum appeared to protect quarters in the first few days of lactation from having somatic cell count ≥200,000 cells/ml milk, commonly accepted as the threshold for intramammary infection.
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impact of intramammary infections in Dairy Heifers on future udder health milk production and culling
Veterinary Microbiology, 2009Co-Authors: S Piepers, S. De Vliegher, Geert Opsomer, A. De Kruif, H W BarkemaAbstract:Dairy Heifers represent the future of a Dairy herd, and are expected to freshen with a healthy and well-developed udder, capable of producing an optimal amount of high quality milk. A high proportion of Heifers have infected mammary quarters at calving, with coagulase-negative staphylococci (CNS) being the most common cause. Staphylococcus aureus and environmental pathogens are also found. The aim of this paper is to summarize how intramammary infections during (late) gestation and early lactation impair the development of the mammary gland and negatively affect future udder health and milk production. Heifers calving with either subclinical or clinical mastitis are also at a higher risk to be culled in first lactation. The magnitude of the effect is most likely related to the virulence of the causative pathogen, the persistence of the infection when milk production has started, and the time of onset of infection. Histological changes in udder tissue from quarters infected with S. aureus are more pronounced than those in udder tissue from CNS-infected quarters. The longer the infections exist and the longer they persist into lactation, the larger the impact on Heifers' future udder health and milk production will be. In general, CNS infections are cleared early in lactation and some studies show that CNS do not have a large impact on future milk production and udder health. Future research should elucidate to what extent pathogen-specific as well as host-related factors affect the persistence of IMI in early lactating Heifers.
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association between somatic cell count in early lactation and culling of Dairy Heifers using cox frailty models
Journal of Dairy Science, 2005Co-Authors: S. De Vliegher, Geert Opsomer, A. De Kruif, H W Barkema, Luc DuchateauAbstract:The association between somatic cell count (SCC) of Dairy Heifers in early lactation [SCCel; measured between 5 and 14 d in milk (DIM)] and the culling hazard during the first lactation was studied using Cox frailty models. Udder health problems were the culling reason for 10% of the culled Heifers in this study. For each unit increase in the log-transformed SCCel (LnSCCel), the culling hazard increased by 11% [Hazard ratio (HR) = 1.11]. The strength of the association depended on 5 factors. Firstly, the association was stronger when SCCel was recorded after 10 DIM than at an earlier DIM. Secondly, the association was stronger if only culling events for udder disorders were considered (HR = 1.32) instead of all culling events (HR = 1.11). Furthermore, for each unit increase of test-day LnSCC after 14 DIM, modeled as a time-varying covariate, the culling hazard in the first lactation increased by 26% (HR = 1.26). Including LnSCC in the model already containing LnSCCel, reduced the estimate of LnSCCel slightly. Fourth, a higher test-day milk yield, modeled as a time-varying covariate, protected against culling and reduced the magnitude of the effect of LnSCCel as well when taken into account. Finally, the association between LnSCCel and culling was still present, although smaller, in the group of Heifers with a second test-day SCC ≤50,000 cells/mL.
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Management Practices and Heifer Characteristics Associated with Early Lactation Somatic Cell Count of Belgian Dairy Heifers
Journal of dairy science, 2004Co-Authors: S. De Vliegher, Geert Opsomer, Herman W. Barkema, Hans Laevens, Ian R. Dohoo, Henrik Stryhn, A. De KruifAbstract:Abstract Associations between somatic cell counts (SCC) from Heifers between 5 and 14 d in milk (DIM) and both herd-management practices and heifer characteristics were studied for 1912 Heifers in 159 Dairy herds in Flanders (Belgium). In higher-producing herds and in herds with an average calving age of Heifers >27 mo, SCC of Heifers was lower than in less-producing herds or in herds with an average calving age ≤27 mo. Heifers raised in herds with a higher bulk-milk somatic cell count had higher SCC. In herds in which Heifers calved on slatted floors, Heifers had lower SCC compared with herds in which Heifers calved on nonslatted floors. A significant difference in SCC was observed between provinces. At the heifer level, SCC decreased with increasing DIM. On average, Heifers calving in April to June had higher SCC, compared with those calving in the other months of the year. In the multilevel regression models, nearly all the variations of SCC resided at the heifer level, indicating that preventive measures against udder health problems in freshening Dairy Heifers should, in the short term, focus more on factors that vary between Heifers than on factors that vary between herds. However, for the long term, the need to identify new, and to implement known, herd-level strategies is important.
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Prepartum teat apex colonization with Staphylococcus chromogenes in Dairy Heifers is associated with low somatic cell count in early lactation.
Veterinary microbiology, 2003Co-Authors: S. De Vliegher, Luc Devriese, Geert Opsomer, Herman W. Barkema, Hans Laevens, J.l.m.r. Leroy, A. De KruifAbstract:Abstract A high number of Dairy Heifers freshen with udder health problems. The prevalence of teat apex colonization (TAC) with Staphylococcus chromogenes , one of the most widespread coagulase-negative staphylococci (CNS) in milk samples from freshly calved Dairy Heifers, was measured cross-sectionally in non-lactating Heifers on eight commercial Dairy farms in Belgium. The influence of age on this prevalence, and the association between teat apex colonization with S. chromogenes prepartum and quarter milk somatic cell count (SCC) in early lactation were studied. In total, 492 teat apices were sampled from 123 Heifers. The age of the Heifers varied from 8 to 34 months. Overall, 20% of the Heifers had at least one teat apex colonized with S. chromogenes . Of all teats sampled, 10% were colonized with S. chromogenes . The chance of having at least one teat apex colonized with S. chromogenes increased with age of the heifer. The presence of prepartum teat apex colonization with S. chromogenes was not associated with intramammary infection (IMI) early postpartum with the same bacterium. On the contrary, teat apex colonization with S. chromogenes prepartum appeared to protect quarters in the first few days of lactation from having somatic cell count ≥200,000 cells/ml milk, commonly accepted as the threshold for intramammary infection.