fertility management of the Friesian mare

Abstract

The practical experiences with fertility management of the Friesian mare can be supported in some measure by the results of this study. In Friesian mares, the threshold follicle size, by which ovulation can be expected at 36-48 hours after hCG treatment, appears to be greater, than the threshold follicle size of the Dutch Warmblood- and Thoroughbred mares. With a diameter of ≥ 43,9 mm in comparison with a diameter of ≥35 mm, this parameter differs from that of the Dutch Warmblood- and Thoroughbred mares in their estrus cycle. The development and reduction of the uterus edema, in the estrus cycle, follows a different pattern in Friesian mares than in Dutch Warmblood - and Thoroughbred mares. Instead of the characteristic peak on day 3 before ovulation, it shows a plateau between day 6 and day 2 before ovulation. Not only can an uterus edema ‘score 3’ be found in the beginning, but also in the end of this plateaufase. According to this study of the Friesian mare, the time in between the PGF2a analogue treatment and the ovulation is 8 days. This parameter does not differ in comparison to the 7-12 days interval seen at the Dutch Warmblood - and Thoroughbred mares. In this study, the PGF2a analogue treatment is in all cases interpreted as a treatment to hasten the onset of the estrus period. In reality a PGF2a treatment might also be given for another purpose. A proper comparison can thereby not been made with this study of Dutch Warmblood - and Thoroughbred mares.