Effect of genotype and order of farrowing on variation of fertility traits in pigs

Abstract

Investigations were carried out in single pig herd. It included 9 genotypes of sows (4 breeds and 5 groups of crosses of different crossing combinations) and 25.040 of their litters. Traits such as size of litter of Swedish Landrace sows (18.511 litters) and crosses of Fl generation (4651 litters) obtained by crossing of Swedish Landrace (SL) sows and boars of Large White breed (LW) were especially investigated. Second part of the investigation related to effect of sire (SL, LW and D) and dam breed (SL and SLxLW) on average demonstration and variability of number of live born piglets in first seven farrowings. Standard mathematical-statistical methods were applied in order to evaluate average demonstration and variability of the trait litter size. Effect of parent genotype and order of farrowing on variability of traits was evaluated using the variance analysis. Testing of differences in average values was carried out using t-test. Results of the variance analysis (table 2) show that sow genotype and order of farrowing had highly significant effect (P (lt) 0,01) on investigated traits. In investigated herd and between investigated sow-genotypes average number of live born piglets (from 8.50 to 10,37), still born piglets (from 0,30 to 0,79) and reared piglets (from 6,75 to 8,44). Only the difference of average values for number of still born piglets between sows SL and SLxLW had no statistical significance. Investigation of the effect of dam and sire breed on average demonstration and variability of number of live born piglets per farrwoings (table 4) indicates that sows of SL breed mated with boars of LW breed produced more liveborn piglets compared to sows of SL breed mated with SL boars in all farrowings (from +0,30 to +0,69 piglets). These sows, from fourth to seventh farrowing farrowed more than 11 live piglets, which means that individual heterosis effect was displayed (3 to 7%). Mating of sow crosses of F1 generation (SLxLW) with boars of Durroc breed caused no increase of number of live born piglets in litter compared to rearing in pure breed (except in 3rd farrowing) or two breed crossing.

U cilju utvrđivanja varijabilnosti nekih osobina plodnosti kod različitih genotipova i prašenja po redu izvršena su ispitivanja na 25.040 legala. Dobijeni rezultati pokazuju da su genotip krmača i prašenje po redu (starost krmača) uticali (P (lt) 0,01) na variranje broja živorođene, mrtvorođene i odgajene prasadi. Krmače rase švedski landras oprasile su i odgajile prosečno više prasadi od krmača F1 generacije bez obzira na genotip nerasta. Međutim krmače rase ŠL parene sa nerastovima rase VJ proizvele su veći broj živorođene prasadi od krmača ŠL parenih sa nerastovima ŠL u svim prašenjima (od 0,30 do 0,69 prasadi). Parenjem krmača meleza F1 generacije (ŠLxVJ) i nerastova rase durok (D) nije postignuto povećanje broja žive prasadi u leglu u poređenju sa odgajivanjem u čistoj rasi i dvorasnim ukrštanjem.