A study of the impact of general and specific combinative ability on reproductive performance of pigs with different genotypes among maternal and sire forms were evaluated (polyfetus, milk production, quantity of piglets, litter weight and one piglet at weaning and piglet survival). The study was conducted in the PSC “PK Podillia” of Vinnytsia region in 2015.

It was established that the heterosis power depends on the maternal and sire forms of genotype.

Effects of general combinative ability (GCA) among maternal forms for polyfetus varied from –0.80 to 0.50 piglets, milk production –1.20+1.30 kg, quantity of piglets at weaning –0.30+0.50 and litter weight and one piglet at weaning –5.40+5.60 kg, and –0.30+0.50 kg, piglets survival –4.30+4.60 %.

Pure bred sows had positive values for GCA on polyfetus (+0.50 piglets), litter weight (+5.60 kg) and weaning weight (+0.50 kg). However, these sows had worse GCA for the quantity of piglets at weaning (–0.30 piglets) and piglets survival (–4.30 %). Two-breed sows proved themselves the best in milk production (+1.30 kg) and in the quantity of piglets at weaning (+0.50 piglets), sows with genotype purebred father × hybrid mother was the best in piglet survival (+4.60 %).

Among the sire forms higher GCA effects on polyfetus at birth (+2.40 piglets) and the quantity of piglets at weaning (+0.70 piglets) had Yorkshire boars, milk production (+10.10 kg) and litter weight at weaning (+5.60 kg) – Pietrain boars, weaning weight (+0.40 kg) and piglets survival (+8.50 %) – hybrid boars with genotype Pietrain × Duroc. On average for the researched reproductive performance higher GCA effects were observed in boars with genotype Pietrain × Duroc.

It was established that the higher specific combinative ability (SCI) effects on reproductive performance was in combination ♀(purebred father × hybrid mother) × ♂ (Pietrain × Durok)– positive in all cases except piglet survival and high enough for polyfetus at birth (+0.70 piglets), litter weight at weaning (+10.10 kg) and weaning weight (+0.90 kg). Negative values SCI for researched reproductive parameters were observed in combinations purebred sow × Duroc (except piglet survival), two-breed sow × Duroc (except weaning weigh) and sow with genotype purebred father × hybrid mother× Large White (except litter size at birth). Thus, in PSC “PK Podillia” these combinations of maternal and sire forms are undesirable.

With the use of mathematical models it was calculated theoretical average values of reproductive performance studied combinations of maternal and sire forms.

Deviation of the calculated values of reproductive performance from the actual values varied from 0.3 to 27.3 %. Calculated values differ from the actual polyfetus at birth varied from –0.09 to +1.4 piglets, milk production –8.9 to +6.6 kg, litter size and litter weight at weaning –0.08 to +0.6 piglets and –14.5 to +5.4 kg, weaning weight –0.4 to +0.4 kg and piglets survival –4.8 to +6.3 %.

Thus, the parameters of mixed mathematical model give opportunity of prediction of different genotypes sows’ reproductive performance. It is established that in PSC “PK Podillia” sows with genotype purebred father × hybrid mother had the most accurate forecast.

Results of calculated values of maternal forms reproductive performance comparing to the actual values have some differences.

On average in the group of purebred sows greatest deviation between calculated values and actual values was observed by litter weight at weaning (–5.9 %) and polyfetus  at birth(–2.9 %), in the group oftwo-breed sows – by milk production (–2.7 %), in sows with genotype purebred father × hybrid mother – by piglet survival (–1.4 %), polyfetus at birth and litter weight at weaning (+1.3 %in both cases).

Among the sire forms calculated values of reproductive performance had wider deviation comparing with maternal forms.

The greatest deviation of calculated values of sows reproductive performance characterized boars Yorkshire and Duroc. For example, Yorkshire – by polyfetus at birth (+8.0 %), milk production (–9.8 %) and piglet survival (–7.9 %), Duroc – by milk production (–9.7 %), litter weight at weaning and weaning weight (–13.1 % and –4.5 %, respectively).

The lowest deviation by researched reproductive performance has shown Landrace boars (on average 0.3 %); Pietrain, Large White and hybrids Pietrain × Durok which have deviation by 0.9–1.1 %, Yorkshire – 1.5 % Duroc – on average 5.3 %.

Thus, the accuracy of sows reproductive performance predicting depends on the genotype of maternal and boars forms. In PSC “PK Podillia” calculated values of maternal forms reproductive performance varied in narrower range (0.1–5.9 %, on average 1.5 %) compared with boars forms (0.5–13.1 % on average 3.5 %).

Key words: pigs, genotype, maternal and sire (boars) forms, reproductive performance, combinative ability.