Superovulatory response of zebu cows treated with pFSH in a single subcutaneous injection followed by an additional intramuscular sub-dose 48 h later

Reprod Domest Anim. 2010 Jun;45(3):421-4. doi: 10.1111/j.1439-0531.2008.01209.x. Epub 2008 Dec 12.

Abstract

The aim of this study was to evaluate whether an additional intramuscular (im) injection of pFSH would increase the embryo production in zebu cows superovulated with a single subcutaneous (sc) pFSH injection. Twenty-one Nelore cows were treated with a progesterone vaginal implant (Controlled Internal Drug Relased - CIDR B) and injected im with 2.5 mg estradiol benzoate. Four days later, cows were assigned randomly into three groups and superovulated with pFSH. Groups A and B received single sc injections of 400 and 320 IU, respectively; Group C received multiple im injections of 400 IU in decreasing doses at 12-h intervals over 4 days. In the morning (07:00 am) of day 3 after starting superovulation, cows received im 150 mcg cloprostenol and Group B was additionally injected im with 80 IU of pFSH. CIDR-B was withdrawn in the afternoon (07:00 pm). Cows were inseminated 48 and 62 h after the cloprostenol injection. Embryo collection and corpora lutea (CL) estimation were done 7 days after insemination. Alternation of treatments (crossover design) occurred at a 60-day interval. There was no significant difference (p > 0.05) of CL counts among treatments. The total (transferable and no transferable) number of recovered embryos from Group A (6.9 +/- 1.5) was not different from Group C (9.8 +/- 1.2), whereas Group B (5.7 +/- 1.5) was lower than Group C (p < 0.05). The number of transferable embryos from Groups A (2.4 +/- 0.7) and B (1.7 +/- 0.6) was lower (p < 0.05) than Group C (4.6 +/- 1.2). Lesser (p < 0.05) embryo production from Group B was related to lower recovery rate (46.4%), compared with Groups A (65.1%) and C (81.7%). It was concluded that an additional im subdose of pFSH, injected 48 h after a single subcutaneous (sc) dose of pFSH, does not improve the embryo production in zebu cows.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle / embryology
  • Cattle / physiology*
  • Embryo Transfer / veterinary
  • Estradiol / administration & dosage
  • Estradiol / analogs & derivatives
  • Female
  • Follicle Stimulating Hormone / administration & dosage*
  • Injections, Intramuscular / veterinary
  • Injections, Subcutaneous / veterinary
  • Insemination, Artificial / methods
  • Insemination, Artificial / veterinary
  • Pregnancy
  • Progesterone / administration & dosage
  • Superovulation*
  • Tissue and Organ Harvesting / veterinary

Substances

  • estradiol 3-benzoate
  • Progesterone
  • Estradiol
  • Follicle Stimulating Hormone