Chromosomal anomalies in dairy cattle as reasons of impaired fertility

Abstract

Aim. The evaluation of animals for the presence of chromosomal anomalies is one of the main tasks of prac- tical selection, aimed at detecting undesired chromosomal anomalies in early age, which may have negative impact on the reproductive and productive capability of cows and lead to considerable economic losses. The aim of the work is a cytogenetic analysis of the chromosome set in cows of Ukrainian Red-and-Motley dairy cattle breed, which will allow assuming a decrease in reproductive functions with chromosomal aberrations. Methods. We examined 53 cows of the Ukrainian Red-and-Motley dairy cattle breed in SE Research Farm Khrystynivske, IABG named after M.V. Zubets, NAAS. The investigation of chromosomal anomalies involved 72-h cultivation of lymphocytes from the peripheral blood of animals using the common methods. During a routine analysis the preparations were stained with 2 % Giemsa staining solution. The induction of G-bands for differential staining of chromosomes was conducted using 0.25 % solution of trypsin. The processing of study results was performed with Microsoft Excel software package. Results. The investigations in the aberration spectrum detected aneuploid and polyploid cells, breaks and fragments of chromosomes, premature chromo- some disjunction in mitosis and translocation. The total number of aberrant cells in cows with decreased fertil- ity was 14.69 ± 0.56 %, the number of aberrations per one investigated cell was 0.144, which was almost twice reliably (Р < 0.999) exceeding the values of similar features for cows which did not have problems with repro- duction. GTG-banding method was used to detect a new RT 13/23 Robertsonian translocation. Conclusions. The cytogenetic analysis of chromosome set of Ukrainian Red-and-Motley dairy breed cows allows assuming the connection between a decrease in the fertility of cows and chromosomal instability. A routine screening of dairy cows allows both evaluating the karyotype saturation with undesired chromosomal aberrations and using the obtained results to forecast the reproductive ability of an animal in the early age.