Influence of growth hormone on growth and onset of puberty ofRahmani ewe lamb

摘要

Objective:To study the effect of somatotropin administration on growth and puberty attainment of Rahmani ewes -lamb.Methods:TwelveRahmani ewes–lamb of6-7 months of age and average body weight(24.75±0.16) kg were randomly allotted into two equal groups.The first group served as control and the second group was somatotropin-treated.The ewe-lambs were weighed at the start and at the end of the experiment.In addition, the body condition score, withers height and heart girth were determined at the end of the study.Blood samples were collected weekly till the end of experiment(Twelve weeks).Sera samples were assayed for progesterone, insulin-like growth factor-1(IGF-1) glucose, total cholesterol, high density lipoprotein and urea.Results:It indicated that the somatotropin-treated group attained puberty2.5 weeks(18 days) earlier than control one.Somatotropin-treatedRahmani ewe lambs had higher body weight, and body condition score than those of the control one.A similar tendency was observed in average daily gain, withers height and heart girth.Somatotropin administration had a beneficial effect on blood born metabolites as indicated by increased serum glucose, total lipids, cholesterol,IGF-1 and decreased urea ofRahmani ewes- lamb as compared to control one.Conclusion:Somatotropin administration enhanced puberty inRahmani ewe lambs.This is due to increased provision of trophic signals(represented by increasedSerumIGF-1 secretions) and/or blood-borne metabolites(glucose, cholesterol and lipid).