Pregnancy Rates in Repeat-breeder Heifers Following Multiple Artificial Inseminations during Spontaneous Oestrus
Open Access
- 31 March 2005
- journal article
- Published by Springer Science and Business Media LLC in Acta Veterinaria Scandinavica
- Vol. 46 (1), 1-12
- https://doi.org/10.1186/1751-0147-46-1
Abstract
Hormonal asynchronies during oestrus, related to the presence of suprabasal plasma-progesterone (P4) concentrations and a delayed ovulation, interfere with the fertility of repeat-breeder heifers (RBH). Since tubal dysfunction can occur in connection with hormonal asynchronies and constrained availability of fertile spermatozoa at the time of ovulation, the present study tested the hypothesis that frequent sperm deposition from onset of oestrus to ovulation may improve pregnancy rates in RBH. Five RBH and five virgin heifers (VH; controls) were repeatedly artificially inseminated (AI) at 6 h intervals from onset of oestrus to spontaneous ovulation. Hormone analyses revealed suprabasal P4 concentrations and a delay in the occurrence of the luteinising hormone (LH) surge, but a normal cortisol profile in RBH. Compared with controls, RBH presented longer interval from onset of oestrus to ovulation, and therefore, received more AIs. Pregnancy rates in RBH reached control levels (60%; NS), indicating that the hypothesis might be correct. Pregnancy rates in VH were below the expected range, presumably attributed to a deleterious influence of the frequent handling. The study suggests that pregnancy rates can be improved in RBH by frequent AI in relation to spontaneous ovulation. However, this practice of repeated manipulations, while seeming not to show adverse effects, lacks practicality for routine use.Keywords
This publication has 31 references indexed in Scilit:
- Repeat breeding in dairy heifers: follicular dynamics and estrous cycle characteristics in relation to sexual hormone patternsTheriogenology, 2002
- Deviant peri-oestrual hormone patterns affect the epithelium of the uterine tube in repeat-breeder heifersReproduction, Fertility and Development, 2002
- What is stress, and how does it affect reproduction?Animal Reproduction Science, 2000
- Standing Oestrus, Ovarian Function and Early Pregnancy in Virgin and Repeat Breeder HeifersJournal of Veterinary Medicine Series A, 1991
- Effect of various veterinary procedures on plasma concentrations of cortisol, luteinising hormone and prostaglandin F2 alpha metabolite in the cowVeterinary Record, 1986
- Characteristics of embryos from repeat breeder and virgin heifersTheriogenology, 1985
- Relationship between LH and cortisol in acutely stressed beef cowsTheriogenology, 1984
- Effects of Hyperadrenal States on Luteinizing Hormone in CattleBiology of Reproduction, 1983
- Fertilisation and embryonic survival rates in dairy cows culled as repeat breedersVeterinary Record, 1983
- Reproductive wastage following artificial insemination of heifersVeterinary Record, 1981