The paper presents the results of a comparative analysis of the adaptive properties of Welsh and Landrace pigs based on three key economically useful traits: the number of piglets in the litter at weaning, piglet pre-weaning mortality during the suckling period, and piglet survival during the suckling period. The purpose of the study was to determine the level of stability and plasticity of the analysed economically useful traits in changing conditions of housing and feeding. In this case, the values of the studied traits in these six generations of piglets were used as environmental indices. The research was based on data on 822 litters of suckling piglets obtained in 2015-2024 from six generations of pigs. The animals were kept under traditional feeding and breeding conditions at Shubske Farming Enterprise LLC. The variability of the environment was formed under the influence of changes in feeding, technological, and organisational factors in the farm. To estimate the adaptive parameters, the Eberhart-Russell method was used, which determined the plasticity coefficient (bi) and the stability index (S2di) of the studied traits. Statistical processing was performed using the SPSS Statistics-22 package. The results obtained showed significant breed differences. Thus, Landrace pigs showed the best average values of all the indicators considered, in particular, a significantly higher survival rate of piglets (p < 0.001). However, Welsh pigs showed significantly greater plasticity in terms of survival (bi = 1.36), indicating their increased sensitivity to changes in housing and feeding conditions, while in Landrace pigs this indicator was only bi = 0.57. In terms of survival stability, Welsh pigs were also inferior, characterised by a higher residual variance (S2di = 58.48 vs. 34.03 in Landrace). Based on the obtained data, a statistically significant regression model for assessing the survival of Welsh piglets was constructed (p = 0.005). The results of the study can be used to optimise breeding programmes and select breeds for specific production conditions
Tsereniuk et al. (Mon,) studied this question.