Abstract

GALINDEZ, Rafael  and  PULIDO, Félix. Genetics and non-genetics effects on farrowing interval of Duroc, Hampshire sows and their reciprocal crosses. Zootecnia Trop. [online]. 2014, vol.32, n.2, pp.139-148. ISSN 0798-7269.

The object of this investigation was evaluate the effect of breed group and some non-genetic factors on farrowing interval (IEP) in Duroc (D), Hampshire (H) sows and their reciprocal crosses. A total of 4 008 records from a genetic center pig located in the Yaracuy state, were analyzed. An analysis of variance with unequal number of observations using the restricted maximum likelihood procedure was made, including in the model the fixed effects of: breed group of the sow (GR= D, H, D*H and D*H), farrowing period (PP= 1, 2), farrowing month (MP= January, …, December), farrowing number (NP= 1, …, 6 or more), the interactions GR*PP, MP*PP, NP*PP and the covariate lactation length. The adjusted mean for IEP was 148.37 ± EE 0.44 days. D and H*D sows tended to reduce the IEP in the analyzed time period. The interaction farrowing month*farrowing time period and farrowing number*farrowing time period were significant, observing a better reproductive performance trend in the dry month and adult female. On the other hand, the lactation length increased as the IEP also increased (β1= 0.55). In addition, the heterosis was low in magnitude and negative (- 0.20 %). Determined that sows that came of mothers D that had a better performance, however, major variations in the reproductive performance of sows are mainly due to the non-genetic effects.

Keywords : environmental effects; genetics; heterosis; productivity; reproduction.

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