EWE PRODUCTIVITY OF COMPOSITE GENOTYPE RESULTING FROM CROSSBRED AMONG LOCAL SUMATRA SHEEP AND ST. CROIX AND BARBADOS BLACBELLY HAIR SHEEP

Abstract

Genetics improvements through crossbreeding are one method that relatively
faster to increase sheep productivity. Increasing productivity through crossbreeding,
usually by exploiting the effect of heterosis. The crossbreeding of Sumatera Sheep
(STT) with the hair sheep of St. Croix (SC) and Barbados Blackbelly (BB) have
been conducted at the Research Institute for Animal Production (RIAP), in order to
create new composite breed with genotype composition of 50% STT, 25% SC and
25% BB. The study was conducted at the Cilebut Research Station, of RIAP. The
ewe productivity compared in this study were Barbados Cross (BC) resulting from
inter se mating between BC x BC; the first generation of composite breed (K-F1)
resulting from mating between St. Croix Cross ram with BC ewes; the second
generation composite breed (K-F2) resulting from mating between K-Fl ewes with
K-Fl rains. Results of the study showed that ewe production indicated by litter
weight at weaning were no significantly difierent (P>0.05) among genotypes (BC,
K-Fl, K-F2). Litter weight for BC, K-F1, and K-F2 were 16.22; 16.21; and 16.8 kg,
respectively. Lambing interval there were no significantly different among genotype,
and respectively for BC, K-Fl, and K-F2 were 273, 279, and 272 days. Litter sizes
at birth and at weaning for BC, K-Fl, K-F2 were 1.47; 1.47 and 1.46, respectively,
for litter size at birth and there were 1.32; 1.26; and 1.29, respectively, for litter size
at weaning. Ewe Productivity Index (EPI) that calculated based on litter weight at
weaning divided by lambing interval in year and then divided by ewe weight for BC,
K-Fl, and K-F2 were 0.72; 0.68; and 0.72, respectively. These showed that the
performances of K-F1, K-F2 and BC were still comparable.