Effects of Nutrition and Weaning on Immune Responses in Calves: Implications for Welfare Assessment

Abstract

Calf rearing systems vary greatly in the quantity of milk substitute fed and in the age of the calf at weaning (Webster, 1986). Husbandry conditions can affect disease incidence and welfare of young, bucket-fed calves and Andrews (1979) has suggested a relationship between age at weaning and disease incidence. This experiment was designed to investigate the effects of level of milk substitute powder fed and the age at weaning on the immune responses of bucket-reared calves compared with naturally suckled calves.Two groups of 20 calves were kept at the Veterinary Field Station, University of Liverpool. All calves received pooled mixed-source colostrum at birth and were then randomly allocated to one of five treatment groups. After colostrum, bucket-reared calves were introduced to milk substitute (Volac Easi-Mix) which was reconstituted at 125g ADM per litre of water and fed twice daily. Calves were housed in individual pens arranged in four blocks with wood shavings as bedding. Suckled calves remained with their dams and were housed in the rear of the same building. These calves had access to a calf creep area. All calves were introduced to Keystart Quicklettes (BOCM Silcock) at 7 days of age and fedad libitum. Small quantities of water and silage were also provided from 7 days of age. Table 1 lists the treatment groups, level of milk substitute received (g ADM/day), age of the calf at weaning and at inoculation with antigen (KLH), and also the age of the calf when the skin sensitivity response was measured.