Utilisation of artificial insemination has led to the increased role of male animals. They significantly contribute to the efficiency of productivity; therefore, sperm quality has been emphasised. The aim of this study was to analyse changes in the boar sperm morphology during the year in forty-two Duroc, Landrace and Large White boars in the Czech Republic. For each boar, a spermiogram was evaluated every month in 2018. The number of morphologically abnormal spermatozoa was recorded every month to evaluate the morphology. The abnormalities were categorised as abnormalities of the head, abnormalities of the acrosome, proximal cytoplasmic droplets and abnormalities of the tail. Throughout the study, the temperature in the stable was monitored. Changes in the sperm morphology were recorded in all breeds during the year, the changes were different for each breed. In the Landrace boars, the highest concentrations of morphologically abnormal spermatozoa were observed in July and August (P < 0.05). In this period, the concentration of the tail defects increased (P < 0.05), while, in October, a higher concentration (P < 0.05) of spermatozoa with defects of the acrosome was recorded in the Landrace boars. In the Duroc and Large White boars, the highest morphologically abnormal spermatozoa values were observed in September and October (P < 0.05). In the Duroc boars, the increase in the morphologically abnormal spermatozoa in this period was mainly caused by an increased occurrence of proximal cytoplasmic droplets (P < 0.05). On the contrary, in the Large White boars, the increase was related to a higher incidence of tail defects (P < 0.05). These results show that changes in the sperm morphology are influenced by the ambient temperature and the breed.

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 Whitesireline (LWSL), and Duroc (D) breeds and Duroc × Large Whitesirelinie (D × LWSL), Large Whitesirelinie × Pietrain (LWSL × 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 LWSL 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 LWSL boars. Significant interactions (p ≤ 0.01) between P and TB were found for LW and ADG in all the time intervals.

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