A Cohort Study Risk Factor Analysis for Endemic Disease in Pre- weaned Dairy Heifer Calves

Johnson, Kate F; Chancellor, Natalie; Wathes, D Claire

Abstract

Simple Summary: Most dairy heifer calves are removed from their dam and reared on milk from birth until weaning at around nine weeks of age. During this period they are susceptible to diseases which reduce their welfare and later performance in the dairy herd and can cause mortality. This study investigated the risk factors for disease on 11 UK dairy farms. Each calf received a weekly clinical examination. Out of 492 heifers recruited, diarrhoea , bovine respiratory disease (BRD) and umbilical disease were recorded in 48.2%, 45.9% and 28.7%, respectively. This was assessed using a composite disease score (CDS), reflecting severity and duration. The CDS for diarrhoea decreased when more calves were born in the same week, but this increased the risk of umbilical disease. The CDS for BRD was reduced by housing calves in fixed groups and feeding them more milk. Being born at a warmer time of year reduced the severity of BRD but increased it for umbilical disease. Calves acquire their initial immunity by ingesting antibodies in colostrum. Better immunity reduced the severity of BRD but failed to protect against diarrhoea or umbilical disease. Calves with a higher circulating concentration of the metabolic hormone insulin-like growth factor-1 experienced less severe disease. Providing farmers and veterinarians with a better understanding of such risk factors helps them to improve their management practices to reduce disease incidence. Abstract: Dairy heifer calves experience high levels of contagious disease during their pre-weaning period, which may result in poor welfare, reduced performance or mortality. We determined risk factors for disease in a cohort study of 492 heifers recruited from 11 commercial UK dairy farms. Every animal received a weekly examination by a veterinarian from birth to 9 weeks using the Wisconsin scoring system. Multivariable models were constructed using a hierarchical model with calf nested within farm. Outcome variables for each disease included a binary outcome (yes/no), disease duration and a composite disease score (CDS) including both severity and duration. Diarrhoea, bovine respiratory disease (BRD) and umbilical disease were recorded in 48.2%, 45.9% and 28.7% of calves, respectively. A higher heifer calving intensity in the week of birth reduced the CDS for diarrhoea, with a marginal benefit of improved passive transfer (serum immunoglobulin G (IgG) measured at recruitment). The CDS for BRD was reduced by housing in fixed groups, higher mean temperature in month of birth, increasing milk solids fed, increasing IgG, and higher plasma IGF-1 at recruitment. Conversely, higher calving intensity and higher temperature both increased the CDS for umbilical disease, whereas high IGF-1 was Citation: Johnson, K.F.; Chancellor, N.; Wathes, C. A Cohort Study Risk Factor Analysis for Endemic Disease in Pre-weaned Dairy Heifer Calves. Animals

Citation

Johnson, K. F., Chancellor, N., & Wathes, D. C. (in press). A Cohort Study Risk Factor Analysis for Endemic Disease in Pre- weaned Dairy Heifer Calves. Animals, https://doi.org/10.3390/xxxxx

• Journal Article Type: Article
• Acceptance Date: Jan 29, 2021
• Deposit Date: Apr 16, 2021
• Publicly Available Date: Apr 16, 2021
• Journal: Animals
• Print ISSN: 2076-2615
• Electronic ISSN: 2076-2615
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.3390/xxxxx
• Public URL: https://rvc-repository.worktribe.com/output/1443373