Abstract

Failure of passive transfer of immunity in calves is associated with poor-quality colostrum, determined by Immunoglobulin G (IgG) concentration. Another quality problem of colostrum is bacterial contamination, which can impair IgG absorption by the calf. Thirty-five samples from daily pooled first-milking colostrum collected over a period of six weeks were tested for IgG concentration and bacterial contamination. Seventeen of 35 first-milking colostrum samples (49%) had bacterial counts above a 100,000 CFU/ml threshold. Twenty-nine of the 35 pooled colostrum samples were fed to 63 newborn heifer calves, of which 12 (41%) had bacterial loads above 100,000 CFU/ml and were fed to 36 calves. Only eight samples (28%) had Brix values >22% and five samples (17%) fed to nine calves met the criteria of low bacterial load and high Brix (>22%). Twelve of the 63 calves (19%) had serum IgG concentrations <10 mg/ml so were classified as having failure of passive transfer, of which 10 of these calves were offered colostrum with high bacterial counts. However, there was no association of level of bacterial contamination with subsequent growth. There were no differences in serum IgG concentrations of calves which were fed colostrum that exceeded the quality threshold and those that were not. Calves with greater serum IgG concentrations grew faster (P<0.05).

PJ, Back, RE Hickson, NW Sneddon, LW Coleman, and RA Laven

New Zealand Journal of Animal Science and Production, Volume 79, Palmerston North, 149-152, 2019