The efficiency of pig industry is largely influenced by the level of sows’ reproductive performance that determines the amount of growing and fattening pigs for slaughter. Therefore, the study of different factors influence on sow reproductive performance, in particular boars’ genotype, is a topical issue in pig breeding.

The study was conducted in the PAE “Agroprodservice” of Ternopil region in 2014. There were found some differences between the sows’ reproductive performances in the first farrow, paired with boars of different genotypes. In particular, multiple pregnancy (11,8 piglets), milk production (65,2 kg), number and weight of piglets weaned per litter (10,9 piglets and
72,0 kg, respectively) and piglet survival (95,6 %) had sows, paired with boars of American selection. The sows of this group are characterized by higher complex index of reproductive performance (CIRP) – 120,6 points, selection index of sows’ reproductive performance (SISRP) – 98,1 points and survival index – 94,8 %.

Worse reproduction performance had sows, paired with purebred Yorkshire boars. Their multiple  pregnancy was lower by 1,2 heads, milk production – 4,5 kg, number of weaned piglets per litter – 1,5 heads, weight of weaned piglets  per litter – 9,6 kg,
a piglet weaning weight – 0,4 kg, piglet survival –1,6, %, CIRP – 28,8  points, SISRP – 9,8 points, survival index – 11,5 % as compared with sows, paired with boars of American selection.

When analyzed the second farrow it is worth noting the improving of sows reproductive performance, paired with different genotypes boars for all studied parameters compared to the first farrow, except piglet survival, which decreased on average by 2,4 %, and, consequently, survival index, which depends on piglet survival (–1,2 %).

The highest rates of multiple  pregnancy (13,7 piglets), milk production (82,4 kg), number of weaned piglets per litter (12,1 piglets), weight of weaned piglets  per litter (81,3 kg), piglet survival (89,6 %), CIRP (125,1 points), SISRP (118,5 points) and survival index (97,5 %) were observed in sows, paired with boars of American selection.

In the second farrow worse reproductive performance characterized sows, paired with purebred Duroc boars; the sows had significantly lower multiple  pregnancy – by 1,6 piglets (p<0,05), milk production – 26,1 kg (p<0,001), number of weaned piglets per litter – 1,9 piglets (p<0,05), CIRP – 22,2 points (p<0,01), SISRP – 26 points (p<0,01) and survival index –13,8 % (p<0,05) than sows, paired with boars of American selection.

Based on our research results, the best reproduction performance in the third farrow is also characteristic for sows, paired with boars of American selection, yet by milk production, greater piglet weaning weight and SISRP index the sows, paired with Duroc boars were better.

Depending on boars genotypes, the multiple  pregnancy of sows in the third farrow in the studied herd was within 11,0–12,7 heads, milk production – 40,7–62,7 kg, number of weaned piglets  per litter – 9,8–11,7 heads, weight of weaned piglets  per litter – 58,0–74,9 kg, a piglet weaning weight – 6,4–7,1 kg, piglet survival – 86,4–92,0 %, CIRP – 85,6–106,1 points, SISRP – 84,1–98,9 points, survival index – 79,6–94,7 %.

A complex index of reproductive performance of sows (CIRP), which depends on litter size born alive, milk production, number and weight of piglets weaned per litter, regardless of parity were higher in sows, paired with boars of American selection – 106,1–125,1 points and prevailed the litter size born alive of sows, paired with boars of other genotypes, by the first litter – on 24,7–28,8 points, the second – 15,0–22,2 points, the third litter – on 1,8–20,5 points.

Depending on the genotype of boars selection index SISRP at the first farrow was 88,3−118,5 points, at the second – 92,5–118,5 points, the third − 79,6–94,7 points. The greater SISRP at the three farrows had sows, paired with boars of American selection (98,1–118,5 points). Worse selection index SISRP at the first and the second farrows characterized sows, paired with Duroc boars (86,7 and 92,5 points, respectively), for the third farrow – sow, paired with terminal boars (84,1 points).

The sows’ reproductive performance was studied by the survival index, which depends on multiple pregnancy and piglet survival. In the first farrow the survival index was 78,3–94,8 %, the second – 83,4–97,2 %, the third farrow – 79,6–94,7 %. The highest values of survival index regardless of farrow had the sows, paired with boars of American selection – 94,7–97,2 %. On average the greater survival index showed sows in first farrow (89,9 %).

Thus, the CIRP index, the SISRP indexes and survival index, which comprehensively characterize the reproductive performance, where higher in the sows, paired with boars of American selection, that gives grounds to state about boar genotype influence on sow reproductive performance and recommend wide use of American selection boars for foundation stock reproduction in the herd of the PAE “Agroprodservice”.

Key words: genotype, reproductive performance, complex index of reproductive performance (CIRP), selection index of sows’ reproductive performance (SISRP), survival index.