The effect of altrenogest, an oral progestin, on hematologic and biochemical parameters in mares

Twenty mares were assigned to 1 of 4 groups: no altrenogest; altrenogest at 0.044 mg/kg BW; altrenogest at 0.132 mg/kg BW; or altrenogest at 0.220 mg/kg BW. Treatment was administered daily for 86 days. No signs of illness attributable to feeding altrenogest were observed during the trial. Treatment had no effect (P greater than .05) on the following parameters: WBC, differential WBC, platelet number, creatinine, LDH, CPK, total bilirubin, cholesterol, globulin, BSP, and erythrocyte sedimentation rate. When comparing values over time with pretreatment means or among treatment groups, there were differences (P less than .05) in RBC, PCV, Hb, ALT, PT, PTT, P, Na, TP, BUN, Cl and glucose. However, these changes remained within established normal ranges and also occurred in mares in the control group. There was no treatment by time interaction for any of these parameters. Treatment differences (P less than .05) were observed for K, Ca, alkaline phosphatase and AST during the course of the trial. However, only occasional values of these parameters were outside the established ranges. They were only slightly elevated and tended to be either sporadic or also occurred in control mares. Few of the observed changes could be attributed to the feeding of altrenogest.