Late pregnancy ewe feeding and lamb performance in early life. 2. Factors associated with perinatal lamb mortality

Abstract

Some factors affecting perinatal lamb mortality were studied with 63 Finn × Dorset Horn ewes and 85 Scottish Half bred and Greyface ewes, having an average litter size of 2·26. Total perinatal lamb mortality averaged 29 % of which 44% were stillborn, 1 % attributed to dystocia, 35 % died between birth and 48 h of age, 14 % from 48 h to 10 days, and 5 % after 10 days.For the Finn × Dorset ewes, the 41 viable twin lambs weighed at birth 3·47 kg and 12 twin lambs which did not survive weighed 2·51 kg. Triplet weights were: viable 2·98 kg (34 lambs) and nonsurviving 2·00 kg (14). Quadruplet weights were: viable 2·79 kg (12) and non-surviving 1·90 kg (16). Quintuplet and sextuplet weights were: viable 2·45 kg (2) and non-surviving 1·35 kg (14).In the aggregated Halfbred and Greyface breeds, viable twin lambs weighed 4·5 kg at birth (91) and non-surviving 3·64 kg (11). Viable triplets weighed 3·77 kg (23) and non-surviving 2·68 kg (16).Serum gamma-globulin and total serum protein values were lower in the lambs which failed to survive, and this was particularly marked with triplets. Fractionating the gamma-globulins (IgG) indicated that IgGi was particularly low in non-viable lambs.Litter size, lamb birth weight, and colostrum intake by the lamb had important effects on perinatal lamb mortality.