Analysis of long-term dynamics of reproductive characteristics of sows of the large white breed

Abstract

In the field of pig breeding, the main goal is to increase the level of fertility and survival of piglets in order to maximize the size of the nest both at birth and at weaning per sow per year. The purpose of this study was to determine the features of the long-term dynamics of the main reproductive features of sows of the large white breed using time series analysis, as well as the role of climatic factors (primarily, temperature) in the manifestation of these dynamics. For the analysis, we used primary data on sows of the large white breed, which were kept in the conditions of Tavriyski svini LLC (Skadovsky district, Kherson region, Ukraine) during 2007-2017. The presence of a trend was determined using the Spearman rank correlation coefficient. In addition, autocorrelation coefficients were estimated for lags from 1 to 45 months. to detect the presence and duration of cycles. It was established that during the research period there was a negative trend in relation to the total number of piglets at birth and, conversely, a positive trend in relation to the average weight of one piglet at birth and weaning. In addition, pronounced cyclicity of changes was revealed for the time series of the average weight of one piglet at birth and the average weight of one piglet at weaning. It was established that a higher temperature in the winter months led to a decrease in the average weight of one piglet at birth, but contributed to an increase in the number of piglets at weaning. Significant temperature deviations from the optimum (in either direction) in March-May led to a decrease in the fertility of sows due to an increase in the number and proportion of stillborn piglets in the nest. Finally, higher summer temperatures contributed to an increase in the number of stillborn piglets, and there was a tendency for the mean birth weight of one piglet to decrease with increasing air temperatures in summer. Thus, the role of three processes was established in the formation of features of long-term dynamics of reproductive characteristics of sows: a) long-term trend; b) cyclic processes; c) random seasonal fluctuations associated with the reaction of animals to heat stress