Physiological status and productivity of boars of foreign breeding during acclimatization in Siberia

The aim of the study was to investigate the effect of acclimatization on the physiological status indices of phenotypically healthy boars of PIC selection imported from abroad in the conditions of an industrial complex. The biochemical indices of the blood serum of boars aged 5 months upon import and 2 months later, as well as the indices of sperm production at the age of 1,5 years were assessed. The high level of cortisol in the blood serum of boars (92.3 nmol/l) upon import reflected the manifestation of acclimatization stress. At the end of the acclimatization period, a statistically significant decrease in this index was observed (80.5 nmol/l). At the same time, multidirectional changes in the content of thyroid hormones were registered an increase in the level of triiodothyronine and a tendency to decrease thyroxine in the blood serum were noted. The indicators of the biochemical status of boars of foreign breeding during import were mainly within the reference limits established by other authors. However, at the beginning of acclimatization, the animals were characterized by a lower content of total protein in the blood serum of imported animals (P < 0.001) compared with the post-adaptation period. After quarantine, all boars showed an increase in the content of total protein (by 42 %), albumin and chlorides (by 47 %), phosphorus (by 61 %). Depending on the initial serum cortisol content, the boars were classified into groups of conditionally stable (group 1) and susceptible (group 2). The cortisol level in the second group (126.0 nmol/l) was 2 times higher than in the first group (61.3 nmol/l). At the end of the acclimatization period, the indices in the groups leveled off. The indices of sperm production of boars in both groups were within the reference values established by other authors, which shows the absence of the influence of individual differences in the reaction to acclimatization stress on subsequent sperm production of boars.