[Chromosome aberrations in the peripheral lymphocytes in breeding sheep stock]

The health of animals depends not only on the level of hygiene on the farms but also on the ability of the individual to withstand diseases and to face various unfavourable effects of the environment. On the cellular level, chromosome analysis in the peripheral lymphocytes of farm animals is used to determine the effects of various environmental factors. According to present knowledge the frequency of chromosome aberrations is considered to be a quantitative index of genetic damage. The present work reports on in-vitro observations of structural aberrations in the peripheral lymphocytes of Merino and crossbred sheep kept under good hygienic conditions. Comparison of the incidence of aberrant cells (AB.C.) was carried out in two seasons of the year (Tab. I). There was not a significant difference (P > 0.05) between the spring (0.96%-AB.C.) and autumn findings (1.59% AB.C.). In these seasons, chromatid breaks (B1) were the most frequently recorded structural aberrations. Comparison of the three age groups (comprising animals aged 1-2, 3-4 or 5-9 years) did not reveal any significant differences in the AB.C. percentage (P > 0.05, Tab. II).