Combined Effect of Sow Parity and Terminal Boar on Losses of Piglets and Pre-Weaning Growth Intensity of Piglets

SIMPLE SUMMARY: The production of piglets is influenced by a range of factors; among the most important are parity of sows and genotype, which is half determined by terminal boars. In this study, reproductive performance, losses of piglets, and growth of piglets were compared depending on the parity and effect of terminal boars. The number of reared piglets, which is considered the most important parameter in the breeding of sows, was not affected by the evaluated factors. However, evaluation of pre-weaning losses of piglets clearly showed the lowest values in the third parity sows. Additionally, piglets of purebred Duroc and Large White(sirelinie) boars showed the lowest losses before weaning and the highest growth intensity at the same time. In addition, the importance of studying interactions between factors was emphasized. These interactions revealed differences in some reproductive parameters and growth intensity of piglets in sows of a different parity after insemination with different terminal boars. The results show that the effect of terminal boars is crucial in the production of piglets. Based on the observed evaluation, the terminal boars of Duroc and Large White(sirelinie) breeds can be recommended as optimal for the production of piglets. ABSTRACT: This study analysed the effect of sow parity (P), terminal boars (TB), and their combination on reproductive parameters of sows, losses of piglets, and their individual live-weight (LW) and average daily gain (ADG) from birth to weaning. A total of 120 sows of Large White × Landrace hybrid combination from the first to the fourth parity (30 sows per parity) were included in the observation. The sows were inseminated by terminal boars of Pietrain (Pn), Large White(sireline) (LW(SL)), and Duroc (D) breeds and Duroc × Large White(sirelinie) (D × LW(SL)), Large White(sirelinie) × Pietrain (LW(SL) × Pn), and Duroc × Pietrain (D × Pn) hybrid combinations (20 sows per terminal boar population). The results proved a significant effect of P on the total numbers of piglets (TN), the numbers of stillborn piglets (SB), and the pre-weaning losses of piglets (L) (p ≤ 0.01) with the lowest losses found in the third parity sows. A significant effect of TB was confirmed for TN, the numbers of live-born piglets (LB), SB, the numbers of mummified piglets (M) and non-viable piglets (N), and (L) (p ≤ 0.01). The sows inseminated by D and LW(SL) boars showed the lowest total numbers of piglets but also the highest survivability of piglets until weaning. Significant effects of interaction between P and TB were observed for the TN, SB, N, and L (p ≤ 0.05). Evaluation of growth parameters in piglets (n = 1547) showed that P significantly influenced LW in the first three weeks of life (p ≤ 0.01) and ADG from birth to Day 7 and from Day 15 to Day 21 (p ≤ 0.01). Additionally, a significant effect (p ≤ 0.01) of TB was proven on individual weight and ADG in all the observed time intervals, with the highest growth found in the piglets of the D and LW(SL) boars. Significant interactions (p ≤ 0.01) between P and TB were found for LW and ADG in all the time intervals.