The Effect of Age, Stocking Density and Flooring during Transport on Welfare of Young Dairy Calves in Australia.

Abstract

Simple SummaryYoung calves are vulnerable to the stressful conditions associated with transport. This study examined the effect of age, stocking density and flooring during transport on lying behaviour and some physiological measurements of metabolic state, dehydration and muscle damage in young calves. While physiology and behaviour changed with age, there were no clear effects of transport. More space and straw bedding however was of benefit to calves of all ages, with some indication that straw bedding could ameliorate some of the negative effects of reduced space on lying behaviour.Transport of young (‘bobby’) calves for slaughter is a contentious welfare issue for some sectors of the Australian community. Factors of age, stocking density and flooring need further research to develop appropriate welfare standards for transport of bobby calves. The objective of this study was to identify the space allowance requirements for transport of bobby calves and to understand factors such as age and flooring that minimise risks to calf welfare during transport. Animals aged 3-, 5- and 10-day old were transported for 12 h in a custom-made cattle truck fitted with 9 pens, with movable mesh divisions. Each pen contained 4 calves, with space allowances of 0.2, 0.3 and 0.5 m2 per calf and flooring of solid metal, mesh or straw bedding. A total of 432 male dairy calves were transported in 12 trips during the 2-year study. Behavioural measurements included lying during transport, and lying and drinking for 12 h after transport during recovery. Blood samples were taken prior to transport, immediately after transport and 12 h after transport. Blood samples were analysed for metabolic state (glucose, beta-hydroxy-butyrate (BOHB)), hydration (packed cell volume (PCV)) and exhaustion/bruising (creatine kinase (CK) activity). It was found that several measures were affected by age, which indicates that the physiology and in particular lying behaviour of 3-day old calves is fundamentally different from that of older calves. It is unclear how this affects their ability to cope with the stressors of transport. Space affected the posture changes and CK activity during and after transport and it is concluded that space allowance should be at least 0.3 m2 per calf for calves of average size, while CK activity suggested that providing more space to 0.5 m2 per calf may provide even greater benefits. Straw bedding is of clear benefit to calves during transport, to the extent that it may even reduce some of the negative effects of reduced space on lying behaviour.