Jovanka Krnjaić

Heritability and repeatability estimates of reproduction traits in purebred pigs

Research was performed on four farms, on 2434 highly fertile females Landrace and Yorkshire, and 28 boars of Danish origin, or 7684 consecutive parities, in period 2009 - 2012. Study of genetic parameters of conventional breeds Landrace and Yorkshire were conducted on 3964 females who mated with 49 males or 15764 litters in the same period. Estimates of genetic parameters for litter size show the same tendency as the legality of the purebred sows that produce 11-14 weaned piglets less per sow per year. Environmental factors, HYS, food technology and management expressed no significant effect on traits. Heritability and repeatability of live and still born piglets, litter size and the live at day 5 after birth and the number of piglets weaned in category of low hereditary traits whose values vary within the limits of 0.07 to 0.12 for the heritability and from 0.15 to 0.19 for the repeatability. There was tendency of lower values of genetic parameters in the conventional compared to highly fertile sows, which is considered to be the effect of selection on gene frequency for the observed traits.

Growth intensity of the fertile breed gilts in the nucleus pig farm

Production in the farm directly depends on the quality of gilts. For this reason it would be necessary to replace non-productive sows. By monitoring and control of the growth intensity in the performance test make possibility to provide selection effect and get gilts adequate age and weight at insemination. The present paper analyses of growth traits from birth until the end of the performance test. The investigations included 205 gilts, of which 104 Landrace and 101 Yorkshire, which were obtained from 7 sires (4 of Landrace and 3 of Yorkshire breed). The gilts that had a smaller weight at birth, showed a smaller daily gain and body weight realized at the end of the test. Lactation duration of 32 days, weight at weaning was not less than 7 kg. During the test of 85 days, the realized average weight was 76 kg, with a gain of 0.90 kg for Landrace gilts, while Yorkshire had smaller one (71 kg) and so smaller daily gain (0.84 kg). With an average age of gilts of 160 days, Landrace gilts reached weight 108 kg, with an average life gain of 0.67 kg, while the Yorkshire gilts reached weight of 101 kg, with an average life gain of 0.62 kg. Tests of significance showed that the sire, breed and weight at birth have a highly significant impact on most of the observed traits and represent a significant source of phenotypic variability in growth traits of tested gilts.

The effect of parental genotype and parity number on pigs litter size

The aim of this study was to investigate the effect of parental genotype and parity number on the litter size properties of sows (number of live born, stillborn and weaned piglets). The investigation was conducted on a farm in Vojvodina. The analysis included 65535 litters that originated from five genotypes of dams (sows with unknown origin, n = 20980; Yorkshire, n = 3189; Landrace, n = 22426; F1(YxL), n = 14251; F1(LxY), n = 4689) and five genotypes of sires (Yorkshire, n = 21641; Landrace, n = 26623; Pietrain, n = 485; Duroc, n = 13463; Hampshire, n = 3323). Based on the obtained results it can be concluded that the genotypes of the dams had statistically significant (p<0.01) influence on the observed litters properties. Landrace sows achieved the highest average number of born alive piglets (10.12) with a statistically significant difference (p<0.01) compared with sows of other genotypes. The observed effect of sire genotype on litter size properties was statistically significant (p<0.01), where the terminal genotypes were superior when it comes to the number of live born and weaned piglets. Regression analysis of dependence between parity and litter size recorded positive regression coefficients: number of live born (b = 0.007), stillborn (b = 0.09) and weaned piglets (b = 0.07). Influence of parity on the observed traits of litter size was highly statistically significant (p<0.01). [TR 31032]