Variation in serum concentrations of immunoglobulins G, A, and M in Canadian Holstein-Friesian calves.

摘要: Radial immunodiffusion was used to quantify Ig concentrations (mg/100 ml) in the sera of 74 male and 82 female Holstein calves whole colostrum from their dams. Calves were progeny 15 AI bulls. Blood samples collected by jugular puncture at birth, 24 36 h post first ingestion, then weekly 3 7 wk age. Colostrum sampled within 6 parturition. Mean calf serum profiles showed peak all isotypes d 1 age, which declined greatly 4 wk, followed gradual increases wk. Within isotype, there highly significant positive correlations between colostral up 5 depending on isotype. Effects season location isotype important, but effects ease calving twinning small. Paternal half-sib heritability estimates computed restricted maximum likelihood ranged 0 .20 for IgG, .45 IgA, .26 IgM, sampling period, .07, .08, averaged over periods. Although standard errors large, passive (24 h) onset active (3 wk) immunity suggested a moderately important additive genetic component that these could possibly be manipulated produce more disease-resistant dairy calves.