Effect of maternal intrinsic factors on productivity and efficiency at weaning in commercial flock of Pelibuey ewes in the tropic of Tabasco, Mexico Effect of maternal intrinsic factors on productivity and efficiency at weaning in commercial flock of Pelibuey ewes in the tropic of Tabasco, Mexico

Resumen

Objective: To evaluate maternal intrinsic effects (body weight, body condition score, udder type, litter size, lamb sex) on litter growth traits (litter weight at lambing [LBW] and at weaning adjusted for 70 days [LWW70]) as a criteria of productivity and some indexes of efficiency in Pelibuey ewes.

Design/Methodology/Approach: Data of body weight (BW), body condition scores (BCS), and udder types (UT) were taken at lambing, likewise at weaning BW (WBW), on 48 multiparous Pelibuey ewes. Additionally, litter size, sex, birth and weaning weight, were recorded for each offspring; this information was used to calculate LBW, LWW70, average daily gain (ADG), and the following indexes: Ewe efficiency (EEF) expressed as kg of lamb weaned per kg ewe BW at lambing, EEF^0.75   expressed as kg of lamb weaned per kg ewe metabolic BW (BW^0.75) at lambing, and EEF2 expressed as kg of lamb weaned ± ewe BW gained or lost at waning per kg ewe BW at lambing. For statistical analysis, ewes were classified according to BW (low, medium and high), BCS (low and high) and udder type (I, II, III and IV) at lambing. High BW ewes had greater (P≤ 0.01) LLW and LWW70 than low BW ewes.

Results: Ewe BW at lambing did not affect (P> 0.05) any productivity index. Also, BCS from lambed ewes did not alter (P> 0.05) the productivity parameters. The udder type affected only LWW70 and productivity indexes, being similar among ewes with type-I, II and III udders, but lower in ewes with type-IV udders. Likewise, double litters were heavier at birth and weaning than single litters, affecting EEF and EEF^0.75, but not EEF.

Conclusions: The Pelibuey ewe’s productivity in humid tropic depends on the maternal BW, udder type at lambing and prolificacy, being a better productivity when ewes have a high BW, double lambing and non-misshapen udders.