POSTPARTUM INTERVAL TO ESTRUS OF SUMATERA CROSSBRED SHEEP UNDER CONFINEMENT

Abstract

A study was conducted to investigate the occurrence of estrus after panuration in
Sumatera x St. Croix x Barbados Blackbelly (Composite Sumatera, COM, n= 42 ) and
Sumatera X Barbados Blackbelly (BC, n=24) crossbred sheep that were housed
intensively. Each pen consisted of 6 ewes. Animals received isoenergy (68% TDN) and isoprotein (16% crude protein) concentrate and chopped King grass, and water was supplied at libitum The study was started on day 20 after the lambing, where ewes were estrus checked twice daily. The onset of estrus was identified as the time where ewes showed full estrus behaviour signs and received rams. The parameters being observed were postpartum estrus (days), ewe weight and lambs weight. The data were analysed using General Linear Model, where the dependent variables were postpartum interval to estrus, ewe and lambs body weight. The independent variables were of ewes genotype, eweage, feeding regimes and litter size. There was no significant effect of sheepgenotype, ewe age, feeding regimes and litter size on the onset of estrus, with the average postpartum interval to estrus of 74.63177 days. The range of postpartum interval to estrus duration for the ewes was 29 - 114 days, with the highest frequency (70.7%) of ewes came to heat on day 63 - 79. The body weight changes of ewes during lactation was significantly affected (P<0.05) by ewe age, but not by breeds of sheep, feeding regimes and litter size with average of — 3.4 kg head'l lactation“ Total birth weight of lambs was significantly affected (P<0.05) by litter size and ewe age, but not by breed and feeding treatment, with average of 3.8 kg. Total weaning weight of lambs was significantly (P<0.05) affected by litter size with average of 15.2 kg. The duration of postpartum interval to estrus will decide the remating of the ewes and overall decide the lifetime production of the ewes.