Metabolic changes during the perinatal period in dairy sheep in relation to level of nutrition and breed. II. Early lactation

Abstract

SummaryThe effect of level of nutrition during pregnancy was investigated on various plasma parameters, on energy intake, body weight, energy balance and milk yield, after parturition in two Greek dairy breeds. Thirteen Chios (CH) and 17 Karagouniko (K) pregnant ewes were assigned to groups A and B, which received 110% of their energy requirements for maintenance plus pregnancy for two foetuses and 90% of their maintenance energy requirements, respectively. After parturition all ewes were fed ad libitum. Body weights of group A and K ewes were higher (p 0.05) compared with group B and CH ewes, during lactation, although daily energy intakes tended to be greater in group B than in A ewes, during the first 3 weeks and in CH than K ewes (p 0.05), after the second week post‐partum. Total mean milk production was 114 ± 11 l and 82 ± 10 l for groups A and B (p 0.05) and 120 ± 12 l and 70 ± 7 l for CH and K ewes (p 0.001), respectively. Positive energy balance appeared after the day 15 and 7 of lactation, for groups A and B ewes and after the day 15 and 5 of lactation, for CH and K ewes, respectively. The group B and K ewes tended to have higher mean plasma glucose concentrations than group A and CH ewes, during early lactation. There were no significant differences in free fatty acids, β‐hydroxybutyric acid, insulin and T4 concentrations between A and B ewes. CH had higher free fatty acids (p 0.05) and β‐hydroxybutyric acid (p 0.05), and lower T4 (p 0.01) and insulin (p 0.05) concentrations than K ewes. It was concluded that under‐nutrition during pregnancy results in low milk yields of ewes fed ad libitum in early lactation, due to the poor development of the udder during late gestation.