Late pregnancy ewe feeding and lamb performance in early life. 1. Pregnancy feeding levels and perinatal lamb mortality

Abstract

ABSTRACTOne hundred and thirty-nine Scottish Half bred ewes were studied during the last 8 weeks of pregnancy, through parturition and early lactation. They were divided, on the basis of their metabolizable energy intake during this period, into low (483 MJ/ewe; L), medium (742 MJ/ewe; M) or high (974 MJ/ewe; H) feeding groups.Ewe weight change (from mating to 12 h post lambing) was directly related to nutritional level and the number of lambs born, e.g. L ewes with triplets lost a mean 13·8 kg, while H ewes with single lambs gained 14·3 kg.Lamb birth weight and perinatal lamb mortality levels were affected by ewe nutrition and litter size. L twins weighed 19% less at birth than H twins; L triplets weighed 26% less than H triplets. The mortality rate of L twins was 23% greater than M twins; L triplets exceeded the H triplet mortality rate by 87%.Ewe energy feeding during late pregnancy affected the mean daily weight gain of lambs for at least 3 weeks after birth. H single, twin and triplet lambs grew 12%, 15% and 16% faster than M lambs and 19%, 31 % and 31 % faster than L lambs respectively.The H group produced 33 % more lamb live weight at 3 weeks of age for every lamb born than did the L group.Lamb serum immunoglobulin levels were related to litter size but did not reflect the differences in ewe feeding during late pregnancy.