Produetivity of Dorset x Merino, Border x Merino y Merino ewes mated to Suffolk and Merino rams

Ximena Garcia F.1, David Rodriguez S.2 y Alejandro de Kartrow G.3

In 1982/83 season, the productive and reproductive performance of 71 Merino Precoz (M), 108 Dorset x Merino (DM) and 129 Border Leicester x Merino (BM) ewes, of two to six lambing, was compared. These females were mated with 2% of Suffolk (S) and Merino rams. The study was carried out at the Hidango Subexperimental Station (INIA, VI Region, Chile). BM ewes were heavier than DM (6 to 8%) and these, heavier than M (5 to 14%). BM females were superior to M in 12 to 21%. There were no differences in fertility between the genotypes analized. Hybrids females (BM and DM) were, on average, consistently more prolific than M x M (25.4%), produced more market lambs (43.5%) and more kilograms of market lambs per ewe mated (69.4%) and per kilogram of ewe mated (48.3%). Its progenys showed higher viability (13.6%) and total survival rate (14.9%), mainly due to a better performance of hybrids twins lambs. Growth rate of MM lambs (173 g/day) was lower than S x DM (198 g/day), S x BM (198 g/day) and SM (195 g/day) lambs. M x BM and M x DM lambs had an intermediate performance. It was concluded that, under this trial conditions, hybrid females are more productive than M and its lambs have higher growth rateo

1 Facultad de Ciencias Agrarias y Forestales, Depto. Prod. Animal, Univ. de Chile, Casilla 1004, Santiago, Chile.
2 Estación Experimental La Platina (INIA), Casilla 439, Correo 3, Santiago, Chile.
3 Univ. Católica de Valparaiso, Casilla 4, Quillota, Chile.