Ovarian Follicle Atresia In Dairy Cows In Relation To The Body Condition

The aim of the study was to define types of atresia in cow ovarian follicles in relation to their body condition. The ovaries were recovered from slaughtered cyclic Czech Fleckvieh dairy cows of three body condition scores: BCS1 (emaciation), BCS2 (tendency to emaciation) and BCS3 (average body condition status), classified according to a 5-point scale of BCS. The ovarian tissue sections were processed for histological analysis and stained with basic fuchsine and toluidine blue. For acidic mukopolysacharides a combination of PAS-technique with Alcian blue was used. In cows with BCS 1 the percentage of ovulated follicles was decreased up to 19% compared to the BCS 2 (76.6%) or BCS 3 (68.7%) animals. Among the non-ovulated follicles the ratio of cystic atresia was highly increased in cow with BCS 1 and 2 compared to the BCS 3. Also, the ratio of atresia associated with luteinization was substantially higher in cows with lower BCS grade (BCS 1), when compared with cows with average body condition status (BCS 3). No significant differences in the occurrence of obliterative atresia among cows with different BCS grades were observed. Higher occurrence of acidic mukopolysaccharides in small and large antral follicles from cows with lower BCS (1 and 2) was revealed. Our observations indicate that in emaciated dairy cows the most frequent forms of follicle degeneration are cystic atresia and atresia with luteinization.