Effect of protected methionine supplementation in late lactation on blood metabolites of twin-bearing ewes pre- and post-lambing

BACKGROUND: The rearing of large body size and high ability to twinning by genetic selection and nutritional strategies is expanding. However, lambs’ performance and decreased losses related to the multiple-bearing around lambing can affect the efficiency of multi-bearing. Recognition and control of changes in metabolic factors priparturient have vital importance. Pre-lambing and immediately after lambing could be considered as the most important and critical period of ewe life which affects heath and performance of ewes and lambs. Objectives: This experiment was carried out in order to evaluate the effects of protected methionine supplementation during pre-lambing period on metabolic factors of twin-bearing ewes through priparturient period and their lambs as well. Methods: Sixteen pregnant Afshari ewes weighting 91.5 ± 5.3 kg and  117 ± 1.5 days of pregnancy were randomly assigned to two dietary treatments containing no methionine supplementation and 3gr/kg DM of protected methionine. They were individually fed total mixed ration twice a day. Dry matter intake was recorded daily; the blood samples were drawn on days -30, -15, +1 and +30 related to lambing; ewes’ BWs were measured on days -40, -20, -10, +1, +10 and +20 related to lambing; lambs were weighted on days of birth, +15, +30 and +60. Results: The BW of lambs of ewes supplemented with protected methionine was greater than the control group (p<0.05), protected methionine affected pre-lambing blood urea and albumin concentration (p<0.05), plasma cholesterol was higher in control group (p<0.05) and total protein and albumin tended to be significant (p<0.1) and other blood factors were not influenced by treatments. Conclusions: These results show that blood metabolites are influenced as animals approach  the lambing time. In addition, rumen protected methionine resulted in improved birth weight of multi-bearing ewes’ lambs and caused improved blood metabolites related to N, considering the interaction between time and treatment.