Management Systems to Improve the Economic and Environmental Sustainability of Dairy Enterprises (rev. Nc-1119)
It is well established that 25 to 35 % of dairy cows on US dairies must be replaced annually in order to maintain herd size and improve genetics (Harris and Shearer, 2005). Quality dairy heifers must therefore be available to replace the culled cows. The cost of raising dairy heifers increases if inadequate management results in a higher than normal morbidity and/or mortality. Colostrum management has a very large impact on dairy calf health due to the fact that calves are born without significant amount of immunoglobulins (antibodies). Passive transfer is the transfer of immunoglobulins from the cow to the calf and is typically accomplished through colostrum feeding. Failure of passive transfer (FPT) occurs when the level of immunoglobulins G (IgG), which account for 85% of immunoglobulins absorbed, in the calf serum is less than 10 g/L
indicating that the calf did not absorb an adequate quantity of IgG. Low IgG in the calf blood is the result of insufficient colostrum uptake, inadequate intestinal absorption or a combination of both. Newborn calves absorb the immunoglobulins from the small intestine and this absorption is time dependent. With increasing age, the number of intestinal epithelial cells capable of pinocytic activity, efficiency of absorption and transmission of IgG to blood circulation is decreased (Stott at. al., 1979, Besser and Gay, 1985; Kacskovics, 2004). Early studies conducted with calves have demonstrated that most calves deprived from colostrum develop septicemia (Smith, 1962; Gay, 1965). FPT has been associated with increased calf morbidity and mortality as well as reduced growth rate (Donovan et al., 1998). Robison et al. (1988) demonstrated that heifers' mortality increased when serum IgG
levels at 24 to 48 hours were less than 12 mg/ml. Furthermore, FPT has been linked with decreased milk production and an increase in culling rate (DeNise et al. 1989; Faber et al., 2005). Management strategies for maximizing colostrum IgG levels should be identified on modern dairies. Typically dairy calves are housed in individual hutches until one to weeks after weaning. They are then grouped based on age if they are consuming at least a certain amount of starter for 3 consecutive days. Individually housed weaned heifers reach different levels of feed intake, and they vary in their adaptation period once they are moved to weaning pens. Moving calves from individual hutches to group pens adds stress to the animal and may cause a challenge on many dairies. It is unknown whether grouping calves randomly and without any consideration of where they rank in the eating quartile of the group
has any effect on intake, social behavior, performance or health. We will examine the effect of adding a serum derived colostrum supplement to maternal colostrum on serum immunoglobulin in calves, calf health and performance; determine the effect of quantity and frequency of colostrum feeding on serum immunoglobulin concentration, health parameters, and growth in Holstein calves and determine the effects on performance, feeding behavior and intake of weaned calves grouped according to their pre-grouping starter intake.