Resumo

RIOS-UTRERA, Ángel; CALDERON-ROBLES, René; LAGUNES-LAGUNES, Juvencio  e  OLIVA-HERNANDEZ, Jorge. Preweaning weight gain in Pelibuey lambs and their crosses with Blackbelly, Dorper and Katahdin. Nova scientia [online]. 2014, vol.6, n.12, pp.272-286. ISSN 2007-0705.

In the tropical region of Mexico, the study of preweaning and postweaning productive peformance of lambs generated by crossbreeding, needs to be carried out in order to determine the productive and economic convenience of using specialized meat sheep breeds in commercial farms. The impact on the preweaning weight gain of lambs from crosses between Pelibuey and Blackbelly ewes and rams from specialized meat breeds (Dorper and Katahdin) was studied through the analyses of data collected from the production records (n= 727) of a commercial sheep flock located in the humid tropical region of Puebla, Mexico. In addition to the breed group, the model included the effects of sex of the lamb (male and female), year of birth (2010, 2011 and 2012), birth season (high and low rainfall), birth type (single, twins and triple) and number of parity (primiparous and multiparous). The variables studied were birth weight (BW), weaning weight (WW) and preweaning daily weight gain (DWG). BW, WW and DWG were adjusted to 90 days of age. PN was affected by all environmental factors (P<0.01). Birth season had not effect (P>0.05) on WW and DWG. Nevertheless, the rest of the environmental factors in the models had a significant effect (P<0.05) on WW and DWG.With respect to the preweaning productive performance of the Pelibuey lambs, the use of Dorper and Katahdin as paternal breeds in crossbreeding with Blackbelly and Pelibuey as maternal breeds allowed to increase the preweaning daily weight gain of F1 lambs.

Palavras-chave : Lambs; preweaning growth; crossbreeding; tropic.