Detalle de: 795. Analyses of heat stress effects on the farrowing rate of Iberian sows

Iberian pigs are well-adapted to high temperatures, however, detrimental effects on reproductive traits have been reported. We evaluate the effect of heat stress on farrowing rate (FR) of Iberian sows. Data included 13,290 first insemination records from 3,009 sows. Temperature-humidity index (THI) was calculated using records from the closest weather station. Heat stress was defined trough heat load, as the number of degrees surpassing a particular threshold (THI0) affecting farrowing rate. Cycle number, heat load (THI0=16) and breed sire effects on FR were assessed and heritability using a threshold model was estimated. Heritability of FR was low 0.039 (0.018/0.065) and heat load, cycle number and sire effects were detected. Heat stress affects the farrowing rate of Iberian sows since the liability for this trait was lower with higher heat loads. Therefore, THI has to be taken into account for improving the farrowing rate.