Expression of X chromosome fragility in Holstein-Friesian cattle: A preliminary study

Abstract

Twenty Uruguayan Holstein-Friesian cows were cytogenetically examined focusing on Xq 3.1 fragility manifestation (Fra Xq). Comparative culture media studies were carried out by simultaneously culturing blood samples in TC 199 and RPMI 1640 media. Taking into account that X chromosome aberrations may be interfering with fertility, the cattle population were also evaluated for their reproductive performance. One thousand metaphase spreads were studied in each culture media and showed normal chromosome constitution in most cells. Frequency of Xq fragility detected in TC 199 was 0.9% while in RPMI 1640 it was 1.8% (0.05 > P) 0.01). According to reproductive performance, repeat breeders manifested 92% of all Fra Xq detected. The differences in expression in both tissue culture media and the frequencies of the Xq fragility observed in cattle with reproductive problems are discussed.