engleski

Estimates of litter size traits in two local pig populations in the Mediterranean region

Local pig populations such as Black Slavonian (BS) and Nero di Parma (NP) contribute to genetic diversity and represent a unique genetic material of the Mediterranean region. The objective of this study was to evaluate differences between the two genotypes in reproductive efficiency, as one of the most important factors for biological and economic sustainability of breeding. Data were collected from 1835 parities of 685 sows (264 BS and 421 NP). The following parameters were included in the analysis: total number of born (TNB), number of born alive (NBA), number of stillborn (NSB), number of weaned (NW) piglets. The effects included in the model were analyzed (GLM procedure in SAS), separately for each parity (from 1st to ≥4th) and for all parities taken together. The following fixed effects were tested: breed (BR), herd (HD), interactions breed*herd (BR*HD), year-month of farrowing (YMF) and parity order (PO) ; boar (BO) was added as a random effect. Primiparous BS vs. NP sows showed 5.9±1.9 vs.7.3±2.1 TNB and 5.6±2.1 vs. 6.9±2.3 NBA, with 0.25±0.96 vs. 0.38±1.20 NSB and 5.0±2.4 vs. 5.5±2.7 NW, respectively. BR, BO and YMF had a significant effect (P<0.05) on litter size traits. Higher values in litter size traits were recorded in 2nd parity sows, with 6.7±2.4 vs. 8.3±2.1 TNB, 6.3±2.4 vs. 7.9±2.2 NBA, 0.34±1.20 vs. 0.32±1.80 NSB and 6.1±2.4 vs. 6.3±2.6 NW for BS and NP, respectively. A significant effect (P<0.05) was found for BR, BO, BR*HD and YMF. No significant effects (P>0.05) were found in 3rd parity sows, with 7.1±2.1 vs. 8.1±2.1 TNB and 6.6±2.4 vs. 7.8±2.4 NBA, 0.40±1.13 vs. 0.29±1.10 NSB and 6.4±2.4 vs. 6.3±2.6 NW, for BS and NP, respectively. Fourth and >4th parity sows showed 7.4±2.4 vs. 8.3±2.4 TNB, 6.9±2.6 vs. 8.1±2.5 NBA, 0.53±1.31 vs. 0.31±0.91 NSB and 6.2±2.9 vs. 6.8±2.7 NW, for BS and NP, respectively, with a significant effect (P<0.05) of YMF and BO. The analysis of all parities together yielded significant effects (P<0.05) of BR, BO, BR*HD, YMF and PO. Reproductive parameters of the two local populations showed interesting results, probably related to both genetic and environmental effects. Future investigations of prolificacy are expected to establish genetic variation between the two local populations of pigs by use of the genetic markers that are involved in physiological process controlling reproduction. Knowing the variability between the two local populations of pigs will contribute to better preservation of local pig genetic types.

local pig; litter size; genetic diversity

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