Ovarian Responses to Treatment of Non-Lactating Cycling Holstein Cows with a Combination of Progesterone and Either GnRH or Oestradiol Benzoate, Injected at Diestrus

Authors

  • B. V. E. Segwagwe Botswana College of Agriculture, Private Bag 0027, Gaborone, Botswana
  • K. L. Macmillan Faculty of Veterinary Science, The University of Melbourne, 250 Princess Highway, Werribee, Victoria, 3030, Australia
  • P. D. Mansell Faculty of Veterinary Science, The University of Melbourne, 250 Princess Highway, Werribee, Victoria, 3030, Australia

DOI:

https://doi.org/10.21423/aabppro20064659

Keywords:

GnRH, conception rates, estrus, ovulation

Abstract

Treatment of cycling cows with GnRH or ODB at the time of CIDR device insertion during diestrus (day 13) caused follicular turnover and a synchronized emergence of a new follicular wave. This
follicular wave emerged earlier in GnRH than in ODBtreated cows. Following the synchronized emergence of a new wave, there was a synchronized onset of estrus and ovulation. The onset of estrus and ovulation were not influenced by treatment. ODB caused atresia of every second dominant follicle, while GnRH could not consistently ovulate this second dominant follicle. The inability of GnRH to consistently cause follicular turnover may be a limitation to its use.

Cover image of the 39th Conference Proceedings: Three calves lying down in a pasture next to a white fence. Behind them, a rainbow spans over the distant hills. Yellow background.

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Published

2006-09-21

Issue

2006

Section

Posters