Metabolic changes in ewes shorn during mid-pregnancy

摘要: Previous work has shown that, under appropriate circumstances, mid-pregnancy shearing results in an increase of both the birth and weaning weights multiple-born lambs. However, physiological mechanisms for this response are poorly understood. This paper attempts to clarify link between heavier lamb by investigating metabolic changes that occur ewes shorn mid-pregnancy. Twenty-four twin-bearing were assigned one two treatment groups; (70 days after mid-point mating: P70) or unshorn. Groups balanced ewe age weight. Blood samples collected from all animals on P53, P69, P81, P84, P90, P109 P130, measurement concentrations triiodothyronine (T3), thyroxine (T4), cortisol, glucose, non-esterified fatty acids (NEFA) ‚-hydroxybutyrate. Lamb weight, girth crown-rump length (CRL) measurements within 24 hrs birth. Lambs weighed at weaning. Mid-pregnancy increased girths 0.43 kg (P<0.05) 2.18 cm respectively although these differences not significant once adjusted date There was no effect CRL. Plasma T3 T4 significantly higher mid-pregnancy-shorn relative unshorn P81 (P<0.01) P84 (P<0.01 P<0.05 respectively) tended be P90 (P<0.10). a plasma NEFA (P<0.05). post-shearing mean glucose β-hydroxybutyrate concentrations. The study proposes most likely mechanism which is increasing maternal thyroid hormone concentrations, resulting fat mobilisation causing blood supply, turn improves placental nutrition and, thus,