EFFECT OF SEASONALITY ON LITTER SIZE TRAITS IN BLACK SLAVONIAN AND “NERO DI PARMA” PIGS

The aim of this study was to analyse the litter size traits in two genotypes of pig population with black coat: Black Slavonian (BS) and “Nero di Parma” (NP). Data analysis included records from the 1st to 4th parity separately, and all parities (from 1st to 11th) for the following traits: Total Number of Born (TNB), Number of Born Alive (NBA), and Number of Weaned (NW) piglets, collected from 296 BS and 421 NP sows. Litter size traits from 1st to 4thparitywas analysed separately for each breed and ANOVA Repetead Measure test was used to calculate the difference between parities. The analysis of seasonality in all parities was performed using the General Linear Model.Significant differences (P<0.05) between-parity in BS were observed in the 1st and 3rd as well in the 1st and 4th parities for TNB and NW. Only for the NBA difference (P<0.05) was found between 1st and 3rd parities.Differences (P<0.05) in NP pigs were reported between the 1st and 3rd as between 1st and 4th parity for TNB and NBA. First-parity sows for NW shows significant differences (P<0.05) in relation to 2nd, 3rd and 4th parity. In all parities analysed according to the seasons significant differences was recorded between summer and autumn period for TNB (P<0.05) in BS. Difference (P<0.05) was also obtained for NBA between spring and autumn, as well as for summer and autumn season. In all parity analysis in BS pig, the NW (P<0.05) showed differences only between spring and summer period. Season in all parity analysis had a significant impact on litter size traits in NP pig. Differences (P<0.05) was obtained for TNB, NBA and NW among spring-winter, summerwinter and autumn-winter period