Abstract
Two hundred and forty six litters from imported purebred guts including Landrace (L), Large White (W), Duroc (D), Hampshire (H) and locally introduced Tauyen (T) natives were used to investigate reproductive performance. The ages at first farrowing were found youngest for L and followed by D, W, T, H in the order. The durations of gestation were longest for T (116.9 days) while D, W, H and L were in the range of 114-115 days. L had the shortest farrowing interval (between the first and second parity) while W and D took approximately 10 days longer and H 15 days longer. The best conception rate was found in T (82.76%), follwed by L, D, H, W in the order. Farrowing rates of W, D, T, L were high while that of H was low. Litter size was large at bornin T, L and W. At three and eight weeks, litter-size of L and W were large while that of T was similar to L, but H and D were smaller at these ages. Survival rates in L, W, D, T were similar but in H poor. L had the heaviest litter weight at born, 3 weeks and 8 weeks, followed by W but T had the lightest litters except at 3 weeks. The average pig weights of L were the heaviest and that of T the lightest. There were similar average pig weights at 3 weeks for all breeds but at 8 weeks T were the smallest of them.
