The present study was conducted to determine the trace mineral profile in fertile, subfertile and pregnant mares kept under different management conditions. For this purpose the blood samples were collected without anticoagulant from 100 field mares and 100 farm mares for serum separation. All animals were grouped according to their history and rectal examination. Serum manganese levels in pregnant mares were significantly (P<0.05) higher than all other mares. Serum iron levels showed no significant difference between the groups and within the groups. Pregnant mare in field conditions showed significantly (P<0.05) higher serum copper level than farm animals. Serum zinc levels in estrual group of mares under field conditions showed significantly (P<0.05) lower levels compared with rest of the three groups and from farm maintained groups. Serum zinc levels in estrual mares under farm condition were significantly (P<0.05) higher as compared to their counterparts under field conditions. Fertile, subfertile and pregnant mares under field conditions differed significantly (P<0.05) from one another, pregnant mares showed significantly (P<0.05) higher levels compared with rest of three groups under same condition. Pregnant mares under field conditions showed significantly (P<0.05) higher serum selenium levels when compared with the farm animals. It can be concluded that deficiency of manganese, iron, zinc, copper and selenium might be possible causes of infertility in mares.

Key words: Fertile, Mare, Micro minerals, Serum biochemistry