Selection index of reproductive qualities of sows (SIRQS): calculation algorithm and mechanism for selecting highly productive animals

The article presents the results of a study of the reproductive qualities of sows of the Large White breed of French selection by absolute indicators and using SIRQS; based on the data obtained, the direction and strength of correlations between quantitative characteristics were determined, as well as the economic efficiency of using sows of the experimental groups. The experimental part of the research, biometric data processing, and their analysis were carried out in the conditions of a breeding reproducer for breeding pigs of the Large White breed of the State Enterprise “Research Farm of the Institute of Agriculture of the North-East of the NAAS”, the animal husbandry laboratory of the State Institution Institute of Grain Crops of the NAAS, the Department of Genetics and Breeding of the Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies Lviv and the Laboratory of Animal Husbandry and Feed Production of the Institute of Agriculture of the North-East of the NAAS. Generally accepted zootechnical, statistical, and economic research methods were used to achieve the goal. The research results and the analysis of the primary zootechnical documentation indicate that sufficiently high indicators of reproductive qualities characterize the sows of the controlled population. Regarding multiparity and litter weight at the time of weaning at 60 days, the minimum requirements for the elite class prevail by 0.6 goals and 15.9 kg or 5.57 and 8.15 %, respectively. A significant difference between animals of the I–II and I–III experimental groups was established in terms of multiparity (1.0–2.4 goals), milk yield (2.5–4.0 kg), the number of piglets at the time of weaning at the age of 30 days (0.7–1.2 goals), and litter weight at the time of weaning at the age of 30 (2.7–3.7 kg) and 60 days (8.7–13.4 kg). The maximum indicators of high fertility and piglet survival to weaning are characterized by sows of the III experimental group (SIRQS ranges from 64.07 to 89.57 points). The pairwise correlation coefficient between SIRQS and the reproductive qualities of sows ranges from –0.618 (tr = 9.38; P > 0.001) to +0.935 (tr = 69.73; P < 0.001); the number of reliable connections between the indicated pairs of signs is 100.0%. It was established that the maximum increase in additional production was obtained from sows of the I experimental group (+2.48 %), and its cost is +101.34 UAH/head/farrowing. The criterion for selecting highly productive sows for a given controlled population according to the complex indicator SIRQS is its value at 97.59–115.40 points.