Effect of Altrenogest Treatment to Early Postpartum Mares on Reproductive Performance of the Mare and Health, Growth and Development of the Foal

Abstract

Kesler, D.J. and Lock, T.F. 1998. Effect of altrenogest treatment to early postpartum mares on reproductive performance of the mare and health, growth and development of the foal. J. Appl. Anim. Res., 14: 51–56. Fourteen mares were included in a study to determine the effect of altrenogest treatment to early postpartum mares on the reproductive performance of the mares and health, growth and development of the foals. Mares were assigned to one of three groups: group 1- no treatment (control group), group 2- orally administered altrenogest for the first 7 days postpartum and group 3- orally administered altrenogest for the first 15 days postpartum. On days 1–30 postpartum, mares were tested daily with a stallion to determine estrus. Foals were monitored daily for general health and weighed and bled for serum chemistry concentrations on days 1, 5, 10, 15, 20, 25 and 30 of age. Foals nursing mares orally administered altrenogest grew as rapidly as foals suckling untreated mares (P>.20). Furthermore, serum chemistry of foals nursing mares orally administered altrenogest were not adversely affected and none of the foals became ill during the first 30 days of age. As anticipated, the foal heats were delayed (P<0.05) in the mares orally administered altrenogest for the first 15 days postpartum. No adverse effects on the reproductive performance of the mares were detected. In summary, administration of altrenogest to early postpartum mares had no adverse effects on the reproductive performance of the mares and on the health, growth and development of the suckling foals.