Resumen

DICKSON-URDANETA, L; TORRES-HERNANDEZ, G; DAUBETERRE M, R  y  GARCIA B, O. Growth performance of West African sheep on a limited grazing system in Venezuela. Rev. Fac. Agron. [online]. 2004, vol.21, n.1, pp.59-67. ISSN 0378-7818.

With the objective of studying the factors affecting pre and post weaning growth of a West African sheep herd in Lara state of Venezuela, 10 years of data on 613 births, 587 weaning and 443 sheep of six months were subjected to analysis under a fixed effects model. Means for birth weight (BW), weaning weight (WW) and average pre-weaning daily gain (ADG) of lambs were: 2.8 ± 0.58, 11.9 ± 3.3 kg and 101 ± 0.03 g/day, respectively. Analysis showed a significant effect of sex of lamb on BW (P<.01) and WW (P<.05), male lambs were heavier than female. Significant differences (P<.01) in BW for primiparous and multiparous ewes were found. Lambs from multiparous ewes were heavier than lambs from primiparous ewes. Lambs from multiple births also had significantly (P<.01) lower values than single births lambs for all variables under study. A significant interaction (P<.01) between year of lambing and lambing season was found for WW and ADG. Means for weight at six months (W6M) and average post-weaning daily gain (APWDG) were: 18.04 ± 4.5 kg and 0.69 ± 0.03 kg/day, respectively. The interaction parturition year x season was significant (P<.01) for both post-weaning variables studied. Results showed that growth performance is influenced by environmental and individual factors. Knowledge of these factors could be useful in developing production strategies so overall weight averages can be improved.

Palabras clave : Birth weight; Weaning Weight; Average Daily Gain; West African Sheep.