Resumen

HINOJOSA-CUELLAR, JA et al. Factors that affect pre-weaning growth of pelibuey lambs in the Humid Tropics of Mexico. Universidad y ciencia [online]. 2012, vol.28, n.2, pp.163-171. ISSN 0186-2979.

The objective of this study was to determine the effects of the season (BS) and type of birth (BT), the sex (SX) and the lamb's sire (S) on the weight at birth (BW; n = 394), the pre-weaning daily weight gain (DGW; n = 218) and the weaning weight (WW; n = 218) in a flock of Pelibuey sheep located in the humid tropics of Mexico. For BW, WW and DWG, fixed effects linear models were used that included the BS (dry, rainy and northers seasons), the BT (single and multiple), the SX of the lambs (male and female) and the lamb's sire (nine brown Pelibuey rams for BW and seven for DGW and WW). The model for WW also included the effect of the BW as a co-variable. The BS affected the BW and the WW (p < 0.01), the BT affected (p < 0.01) the BW and the GDW, the SX did not affect any of the three variables that were analysed (p > 0.05) and the lamb's sire affected the variation in the GDW and the WW (p < 0.01). The BW, as a co-variable, affected the WW (p < 0.01). It is concluded that the BS and the BT of the lambs had an important effect on the pre-weaning growth characteristics. The lambs that were born in the rainy season had a lower pre-weaning weight compared with those that were born in the dry and northers seasons. The lambs from multiple births had a lower pre-weaning DWG than those from single type births. The sire lamb affected the pre-weaning DWGD and WW. The BW is an important variable in the determination of the WW.

Palabras llave : Pre-weaning growth; Pelibuey lambs; humid tropics.