EQUINE ANTISPERM ANTIBODIES (EASA) - PRELIMINARY-STUDY OF THE CLINICAL-RESPONSE FOLLOWING BREEDING IN IMMUNIZED MARES

Maiden mares (n=6), previously injected with stallion sperm cells (SC group, n=2), stallion seminal plasma (SP group, n=2), or phosphate-buf fered saline as a control (C group, n=2) were followed through 5 conse cutive estrous cycles to evaluate their clinical response when exposed to stallion sperm cells via breeding. Management was similar to that expected on typical breeding farms. The mares were teased daily and br ed by artificial insemination (AI) in all 5 cycles. Differences in ser um and uterine flushing equine antisperm antibody (EASA) levels, endom etrial culture and cytology results, endometrial biopsy score and fert ility were evaluated between treatment groups. An enzyme-linked immuno sorbant assay (ELISA) was used to determine serum and uterine IgG and IgA levels specific for sperm cell or seminal plasma antigens. Serum I gG specific for sperm cell antigen was higher in the SC group than in the SP and C groups following exposure to sperm cells via breeding (P< 0.05). All other EASA levels were not different between groups (P>0.05 );however, uterine IgA levels in one of the SC treated mares did rise over all 5 cycles. No differences were detected in culture, cytology, biopsy or fertility results between groups (P>0.05). Changes in EASA l evels were detected after breeding mares previously immunized with sta llion sperm cells, however an associated clinical response was not app arent.