The Experts below are selected from a list of 60081 Experts worldwide ranked by ideXlab platform
Henri Seegers - One of the best experts on this subject based on the ideXlab platform.
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Influence of herd structure and type of virus introduction on the spread of bovine viral diarrhoea virus (BVDV) on the spread of bovine viral diarrhoea virus (BVDV) within a dairy herd
Veterinary Research, 2008Co-Authors: Pauline Ezanno, Christine Fourichon, Henri SeegersAbstract:A herd is a population structured into groups not all equally in contact, which may influence within-herd spread of pathogens. Herd structure varies among cattle herds. However, published models of the spread of bovine viral diarrhoea virus (BVDV) assume no herd structure or a unique structure chosen as a representative. Our objective was to identify - for different index cases introduced into an initially BVDV - free dairy herd - risky (favourable) herd structures, which increased (decreased) BVDV spread and persistence compared to a reference structure. Classically, dairy herds are divided into calves, young Heifers, bred Heifers, lactating cows and dry cows. In the reference scenario, groups are all equally in contact. We evaluated the effect of isolating or merging groups. Three index cases were tested: an open persistently-infected (PI) Heifer, an open transiently-infected Heifer, an immune Heifer carrying a PI foetus. Merging all groups and merging calves and lactating cows were risky scenarios. Isolating each group, isolating lactating cows from other groups, and merging calves and young Heifers were favourable scenarios. In most structures, the most risky index cases were the following: first, the entry of a PI Heifer; second, the birth of a PI calf; last, the entry of a transiently-infected Heifer. Recommendations for dairy herds are to raise young animals together before breeding and to isolate lactating cows from others as much as possible. These recommendations will be less efficient if a PI adult enters into the herd.
Jasmeet Kaler - One of the best experts on this subject based on the ideXlab platform.
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short and long term association between individual levels of milk antibody against ostertagia ostertagi and first lactation Heifer s production performances
Veterinary Parasitology, 2018Co-Authors: Camille Bellet, M J Green, A J Bradley, Jasmeet KalerAbstract:Abstract It is agreed that exposure of adult dairy cattle to helminths on pasture can negatively affect production performances as milking herd. Young animals, especially replacement Heifers, represent the future of a dairy farm and are among the most vulnerable to helminth infections in a dairy herd. For this reason, dairy farmers tend to frequently treat Heifers against helminths, although the impact of helminths on Heifers’ production performances is still poorly understood. Using different epidemiological and serological tools, this study examines the relationship between Heifer exposure to helminths on pasture and production performances over time. During a one-year period, 1,454 individual milk samples were collected from first-lactation Heifers in England and tested for Ostertagia ostertagi (O. ostertagi) antibodies. After controlling for other confounders, increasing milk antibody levels against O. ostertagi were significantly associated with decreased milk yield at sampling but not at day 305 of Heifer lactation. We did not observe any relationship between milk antibody levels against O. ostertagi in Heifers and yields in fat and protein. However, Heifers with a high level of milk antibodies against O. ostertagi were more likely to produce dead calf at first calving and present a delay in second calving. Moreover, these Heifers had significantly higher levels of milk antibodies against Mycobacterium paratuberculosis (M. paratuberculosis) during their first lactation and were more likely to die before the end of the study. We argue that epidemiological approaches can be useful but must be complemented by other methodologies to better understand the impact of helminth infections in dairy Heifers. In order to address the complex dynamics of helminth infections in dairy cattle production we require more comprehensive approaches that include triangulation between data sources and interdisciplinary studies.
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a longitudinal study of gastrointestinal parasites in english dairy farms practices and factors associated with first lactation Heifer exposure to ostertagia ostertagi on pasture
Journal of Dairy Science, 2018Co-Authors: Camille Bellet, M J Green, A J Bradley, Jasmeet KalerAbstract:The gastrointestinal nematode Ostertagia ostertagi is an important cause of lost production, health, and welfare in cattle. Detailed records were obtained over a 5-yr period (2010–2015) by questionnaires and qualitative interviews to investigate the practices adopted by dairy farmers to control cattle helminth infections and the factors associated with Heifer exposure to O. ostertagi on pasture. In total, 1,454 Heifers' individual milk samples were collected over a 1-yr period (2014–2015) in 43 dairy farms in England and tested for O. ostertagi antibody by ELISA. Multilevel linear regression models were used to investigate the association between individual milk optical density ratio (ODR) against O. ostertagi and Heifer management from birth to time of sampling. Farm and Heifer median ODR against O. ostertagi were 0.98 (interquartile range = 0.76–1.02) and 0.64 (interquartile range = 0.42–0.84), respectively. The majority of Heifers (88%) received an anthelmintic treatment before sampling in this study. After controlling for the effect of anthelmintic treatments, Heifer individual milk ODR against O. ostertagi significantly increased with high stocking rate at first grazing and co-grazing with adult cows before calving. Conversely, Heifer individual milk ODR against O. ostertagi significantly decreased when Heifers had co-grazed with sheep and pasture grass had frequently been mowed. Overall, these results provide evidence to support targeting grazing management toward limiting the use of anthelmintics in dairy young stock to enable sustainable control of cattle helminth infections in England. However, to be accepted and adopted by farmers, these best practices would need to take into account farmers' perspectives and contextual challenges.
Pauline Ezanno - One of the best experts on this subject based on the ideXlab platform.
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Influence of herd structure and type of virus introduction on the spread of bovine viral diarrhoea virus (BVDV) on the spread of bovine viral diarrhoea virus (BVDV) within a dairy herd
Veterinary Research, 2008Co-Authors: Pauline Ezanno, Christine Fourichon, Henri SeegersAbstract:A herd is a population structured into groups not all equally in contact, which may influence within-herd spread of pathogens. Herd structure varies among cattle herds. However, published models of the spread of bovine viral diarrhoea virus (BVDV) assume no herd structure or a unique structure chosen as a representative. Our objective was to identify - for different index cases introduced into an initially BVDV - free dairy herd - risky (favourable) herd structures, which increased (decreased) BVDV spread and persistence compared to a reference structure. Classically, dairy herds are divided into calves, young Heifers, bred Heifers, lactating cows and dry cows. In the reference scenario, groups are all equally in contact. We evaluated the effect of isolating or merging groups. Three index cases were tested: an open persistently-infected (PI) Heifer, an open transiently-infected Heifer, an immune Heifer carrying a PI foetus. Merging all groups and merging calves and lactating cows were risky scenarios. Isolating each group, isolating lactating cows from other groups, and merging calves and young Heifers were favourable scenarios. In most structures, the most risky index cases were the following: first, the entry of a PI Heifer; second, the birth of a PI calf; last, the entry of a transiently-infected Heifer. Recommendations for dairy herds are to raise young animals together before breeding and to isolate lactating cows from others as much as possible. These recommendations will be less efficient if a PI adult enters into the herd.
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, Katrijn Peeters, H W Barkema, 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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Heifer and quarter characteristics associated with periparturient blood and milk neutrophil apoptosis in healthy Heifers and in Heifers with subclinical mastitis
Journal of dairy science, 2009Co-Authors: Sofie Piepers, Geert Opsomer, A. De Kruif, Herman W. Barkema, Evelyne Meyer, Kristel Demeyere, S. De VliegherAbstract:Polymorphonuclear neutrophilic leukocytes (PMNL) play an important role in the first line cell-mediated immune defense of the body in general and of the mammary gland against mastitis pathogens in particular. Reduced viability of PMNL close to parturition may explain the high incidence of infectious diseases and the high prevalence of intramammary infections (IMI) in periparturient dairy Heifers. Apoptosis of blood PMNL 1 wk before the expected calving date and of blood and milk PMNL at 1 to 4 d in milk was determined using flow cytometry. Information on Heifer and gland characteristics was collected before calving and in early lactation. Data were analyzed using multivariable, multilevel regression analysis. Supplementation of a commercial mineral/vitamin mix before calving was associated with less blood (14.4 +/- 2.9 vs. 22.4 +/- 2.1%) and milk PMNL apoptosis (19.0 +/- 1.1 vs. 26.4 +/- 0.9%) near calving, presumably related to higher blood selenium concentrations. Both blood and milk PMNL apoptosis showed seasonal variation with the highest proportion of apoptotic cells between January and March (32.0 +/- 6.1 and 34.6 +/- 2.7%, respectively) and April and June (31.3 +/- 5.7 and 37.8 +/- 2.3%, respectively). Heifers losing 0.25 points or more of their body condition in the periparturient period had higher proportions of apoptotic blood PMNL in early lactation compared with Heifers losing less than 0.25 points (24.0 +/- 2.8 vs. 16.6 +/- 1.7%). Milk PMNL apoptosis was less pronounced in quarters having teat orifices colonized with non-aureus staphylococci before calving (18.9 +/- 1.0 vs. 29.4 +/- 1.0%). The variation in blood PMNL apoptosis before and after calving mainly resided at the Heifer level (71.4 and 98.4% of the total variation, respectively), whereas the variation in milk PMNL apoptosis mainly resided at the Heifer (45.7% of the total variation) and quarter levels (45.5% of the total variation). These data imply that the impaired blood and milk PMNL viability in periparturient Heifers can be reduced by optimization of certain Heifer management practices such as supplementation of minerals/vitamins, and pasture and feeding strategies.
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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, Hans Laevens, Herman W. Barkema, 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.
A J Heinrichs - One of the best experts on this subject based on the ideXlab platform.
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symposium review strategies to improve the efficiency and profitability of Heifer raising
Journal of Dairy Science, 2020Co-Authors: Peter S Erickson, J L Anderson, K F Kalscheur, G J Lascano, M S Akins, A J HeinrichsAbstract:ABSTRACT Regional Research Project NC-2042 has a main objective to study calf and Heifer nutrition. Within this objective, feeding the postweaned Heifer is considered a major priority to improve the profitability and sustainability of US dairy farms. Through optimizing nutrient utilization by precision feeding, using alternative feeds, high-fiber diets, and feed additives, this research group has worked to enhance dairy Heifer nutrition. Research has focused on precision feeding Heifers and incorporating high- and low-fiber diets into this system of feeding. This is accomplished by meeting the nutrient needs of the Heifer for a desired rate of growth while enhancing total-tract nutrient digestibility, reducing waste and improving profitability. High-fiber forages have been studied as a means of controlling ad libitum dry matter intakes and thus weight gain in Heifers. These results provide producers with a means of feeding Heifers while reducing costs. Similarly, utilizing alternative feedstuffs in Heifer diets has also been a major research area for this group including comprehensive research on distillers co-products, and new protein sources such as camelina and carinata meals. Results indicated that these products can be satisfactorily incorporated into Heifer diets. Studying feed additives has also been a function of the research group. Research with Ascophyllum nodosum and cinnamaldehyde indicated that calves find these additives unpalatable and that supplementing cinnamaldehyde to postweaned Heifers showed no benefit. However, sodium butyrate and yeast supplementation proved to be beneficial in the growth and feed efficiency of Heifers. Research from this group has an effect on Heifer feeding, resulting in new information that can aid in the sustainability of dairy farms. This review will focus on the area of postweaned Heifer nutrition.
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a 100 year review a century of dairy Heifer research
Journal of Dairy Science, 2017Co-Authors: A J Heinrichs, G J Lascano, G I Zanton, C M JonesAbstract:The years 1917 to 2017 saw many advances in research related to the dairy Heifer, and the Journal of Dairy Science currently publishes more than 20 articles per year focused on Heifers. In general, nutrition and management changes made in rearing the dairy Heifer have been tremendous in the past century. The earliest literature on the growing Heifer identified costs of feeding and implications of growth on future productivity as major concepts requiring further study to improve the overall sustainability of the dairy herd. Research into growth rates and standards for body size and stature have been instrumental in developing rearing programs that provide Heifers with adequate nutrients to support growth and improve milk production in first lactation. Nutrient requirements, most notably for protein but also for energy, minerals, and vitamins, have been researched extensively. Scientific evaluation of Heifer programs also encouraged a dramatic shift toward a lower average age at first calving over the past 30 yr. Calving at 22 to 24 mo best balances the cost of growing Heifers with their production and lifetime income potential. Increasingly, farms have become more progressive in adopting management practices based on the physiology and nutrient needs of the Heifer while refining key economic strategies to be successful. Research published in the Journal of Dairy Science has an integral role in the progress of dairy Heifer programs around the world.
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identifying efficient dairy Heifer producers using production costs and data envelopment analysis1
Journal of Dairy Science, 2013Co-Authors: A J Heinrichs, C M Jones, S M Gray, P A Heinrichs, S A Cornelisse, R C GoodlingAbstract:Abstract During November and December 2011, data were collected from 44 dairy operations in 13 Pennsylvania counties. Researchers visited each farm to collect information regarding management practices and feeding, and costs for labor, health, bedding, and reproduction for replacement Heifers from birth until first calving. Costs per Heifer were broken up into 4 time periods: birth until weaning, weaning until 6 mo of age, 6 mo of age until breeding age, and Heifers from breeding to calving. Milk production records for each herd were obtained from Dairy Herd Improvement. The average number of milking cows on farms in this study was 197.8±280.1, with a range from 38 to 1,708. Total cost averaged $1,808.23 ± $338.62 from birth until freshening. Raising calves from birth to weaning cost $217.49±86.21; raising Heifers from weaning age through 6 mo of age cost $247.38±78.89; raising Heifers from 6 mo of age until breeding cost $607.02±192.28; and total cost for bred Heifers was $736.33±162.86. Feed costs were the largest component of the cost to raise Heifers from birth to calving, accounting for nearly 73% of the total. Data envelopment analysis determined that 9 of the 44 farms had no inefficiencies in inputs or outputs. These farms best combined feed and labor investments, spending, on average, $1,137.40 and $140.62/Heifer for feed and labor. These Heifers calved at 23.7 mo of age and produced 88.42% of the milk produced by older cows. In contrast, the 35 inefficient farms spent $227 more on feed and $78 more on labor per Heifer for animals that calved 1.6 mo later and produced only 82% of the milk made by their mature herdmates. Efficiency was attained by herds with the lowest input costs, but herds with higher input costs were also able to be efficient if age at calving was low and milk production was high for Heifers compared with the rest of the herd.
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Growth of Holstein Dairy Heifers in the United States
Journal of Animal Science, 1998Co-Authors: A J Heinrichs, Willard C LosingerAbstract:Data were collected on the heart girth (n = 8,565; a measure of body weight) and height at withers (n = 8,568) of Holstein dairy Heifers from 659 dairy farms as part of the National Dairy Heifer Evaluation Project during 1991 and 1992. Means and standard deviations for weight and height were determined for ages .5 to 23.5 mo. Third-order polynomial regression equations were derived to study the relationship of weight and height to age. Stepwise mixed-model regression, using REML estimation, was used to identify factors associated with Holstein Heifer growth and to build a multivariate model describing Holstein Heifer growth across the United States. Holstein Heifers on the sample of dairy farms in this study were heavier and taller at the withers than standards published 30 to 50 yr ago. Increased rolling herd average milk production was associated with a greater rate of growth in Holstein Heifers. Holstein Heifers in the West and Midwest were larger at a given age than those in the Northeast and Southeast.
