Diagnosis of infertile horse and cattle via cytogenetic and molecular analyses

In this study, we present one case each of a horse and a cattle that underwent chromosomal analysis due to infertility and/or subfertility. We performed PCR (polymerase chain reaction) analysis in conjunction with karyotyping and FISH (fluorescence in situ hybridization) to diagnose potential chromosomal abnormalities in these animals. In the case of the horse, cytogenetic analysis determined that the karyotype is 63, XO female, called X-monosomy. PCR analysis was positive for the androgen receptor (AR) gene and negative for Sex-determining Region Y (SRY) gene, confirming the absence of Y chromosome, female. X monosomy (63,XO) is the most common sex chromosomal abnormality that causes infertility issues in horses. In the case of the cattle, cytogenetic analysis showed a karyotype of 60, XY, consistent with a normal male. PCR analysis was positive for both AR and SRY, confirming male sex determination. However, detailed examination of the karyotype revealed structural abnormalities involving chromosomes 5 and 8. Subsequent FISH analysis confirmed a balanced translocation between these two chromosomes, which likely contributed to infertility in the bull.