Variations in immunoglobulin concentrations in Finnish x Dorset Horn lambs

The serum immunoglobulin concentrations in two-day-old Finnish x Dorset Horn lambs, which were born and nursed indoors, were high and unrelated to littersize, except when young ewes had large litters, or when ewes lambed twice in a year. The results contrast sharply with those from Merino and Blackface lambs, examined previously, whose mean concentrations were much lower, and generally fell substantially with increasing litter-size. The superiority of the Finnish x Dorset Horn sheep in this respect is attributed to the ability of the lambs to suck particularly vigorously, shortly after birth, especially when large litters are compared, and to a higher rate of colostrum production by the ewes. The correlations between the immunoglobulin concentrations in the lambs and their growth and survival were significant but slight.