WEIGHT CHANGES OF PELIBUEY AND BLACKBELLY EWES AND ITS RELATIONSHIP WITH PREWEANING BODY WEIGHT OF THEIR LAMBS

Abstract

Three year data on body weight changes of 382 Pelibuey (Pb) and 156 Blackbelly (Bb) ewes from a flock at the Mocochá Experimental Station in Yucatán, México, were analyzed. Data were sorted according to parity groups (PG) and two body condition levels (BC). Ewe?s body weights, at the start (IBW) and end (FBW) of the mating season and at lambing (LBW) were used to calculate ewe?s weight change from the start to the end of the mating season (CHW1=FBWIBW), from the start of the mating season to lambing (CHW2=LBW-IBW) and from the end of the mating season to lambing (CHW3=LBW-FBW). The effect of mating year, breed, PG and BC on CHW1 was studied, as well as the effect of litter size on CHW2 and CHW3. Lamb birth weights and weaning weights were related to body weight and weight changes of ewes. Mating year and BC had an effect (p0.05) between body weight changes of Pb and Bb ewes at mating, but weight changes during pregnancy was lower (p