Milanko Stupar

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.

Selection criteria in relation to pork carcasses quality.

The paper presents the effect of various selection criteria (Landrace, Yorkshire - productive dairy breed and Hampshire - terminal) on the carcasses quality, as well as differences between sex in regard to distribution of meat, fat and bones. The study included 210 randomly selected pig carcasses at commercial farms, classified by breed and sex. Carcass dissection was carried out according to the model of EU 1992. The percentage of meat in fertile breeds carcasses was 2.04% lower (55.02%), compared to the terminal breed (57.06%). Comparing the proportion of muscle tissue in carcasses of male and female animals, there was determined a statistically significant difference (P<0.05). Within the breeds there was no statistically significant difference (P>0.05) in percentage of meat between two fertile breeds (Landrace and Yorkshire). A statistically significant difference (P<0.05) between fertile and terminal Hampshire breeds was determined. Sex and breed had highly significant impact on the amount of meat in the carcasses. Also, sex had a significantly influenced the amount of fat, while breed significantly influenced the amount of bone in carcasses. The largest and most important part of the carcass is a leg with a share of 29.17% in male and 29.17% in female animals. Data collection on the slaughter line as well as knowledge of slaughterhouses properties are basic conditions for work on genetic improvement of pig carcass quality. Quality rating of pigs on the slaughter line and price formation is a prerequisite for establishing trust between farmers and slaughterhouses. Mutual interest lies also in profit, so farmers will earn more carrying out meatiness selection while slaughterhouses will buy cattle with more meat of optimal quality.