Hostname: page-component-77c89778f8-sh8wx Total loading time: 0 Render date: 2024-07-18T06:55:05.813Z Has data issue: false hasContentIssue false

An evaluation of the use of synchrony technology in beef breeding herds

Published online by Cambridge University Press:  02 September 2010

A. B. Pleasants
Affiliation:
Mathematical Biology Unit, AgResearch, Ruakura Research Centre, Private Bag 3123, Hamilton, New Zealand
K. L. Macmillan
Affiliation:
Department of Veterinary Clinical Sciences, University of Melbourne, Werribee, Victoria 3030, Australia
Get access

Abstract

A model which was originally developed to derive the probability density of a calving distribution for beef cows under natural breeding has been modified to incorporate the effects of using oestrous synchronization at the beginning of the breeding period.

The model has been used to investigate five oestrous synchronization strategies over four herds, each with differing calving patterns: no synchronization; every cow in the herd is synchronized; every anoestrous cow is synchronized; every cow calving more than 20 days after the date of the planned start of calving is synchronized; every cow calving 30 days after the date of the planned start of calving is synchronized. Two of the herds previously had long calving periods and two previously had short, compact calving periods.

Model results showed that synchronization improved average herd calf live weight by 21 kg in the two herds with long prior calving periods but showed little effect in the two herds with compact prior calving periods. Synchronizing cows which calved more than 20 days after the start of calving in the herd showed similar results to synchronizing every cow in the herd and thus would be more cost effective. Synchronizing cows which calved more than 30 days after the start of calving in the herd showed a smaller advantage but only in the herds with long prior calving periods. The optimal strategy for oestrous synchronization in a herd will depend on the prior calving distribution and the average duration ofanoestrus in that herd as well as the relative costs of the treatment.

Type
Research Article
Copyright
Copyright © British Society of Animal Science 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Day, M. L., Burke, C. R., Taufa, V. K., Day, A. M. and Macmillan, K. L. 1997. The strategic use of oestradiol benzoate to enhance fertility and submission rates of progestin-based synchronisation programmes in lactating dairy cows. Proceedings of the Australian Society for Reproductive Biology 28:101.Google Scholar
Fike, K. E., Day, M. L., Inskeep, E. K., Kinder, J. E., Lewis, P. E., Short, R. E. and Hafs, H. D. 1997. Estrus and luteal function in suckled beef cows that were anestrous when treated with an intravaginal device containing progesterone with or without a subsequent injection of estradiol benzoate. Journal of Animal Science 75:20092015.CrossRefGoogle ScholarPubMed
Macmillan, K. L. and Burke, C. R. 1996. Effects of oestrous cycle control on reproductive efficiency. Animal Reproduction Science 42:307320.CrossRefGoogle Scholar
Macmillan, K. L. and Peterson, A. J. 1993. A new intravaginal progesterone releasing device for cattle (CIDR-B) for oestrous synchronisation, increasing pregnancy rates and the treatment of post-partum anoestrus. Animal Reproduction Science 33:125.CrossRefGoogle Scholar
Macmillan, K. L., Taufa, V. K., Barnes, D. R. and Day, A. M. 1991. Plasma progesterone concentrations in heifers and cows treated with a new intravaginal device. Animal Reproduction Science 26:2540.CrossRefGoogle Scholar
Mauleon, P. 1974. New trends in the control of reproduction in the bovine. Livestock Production Science 1: 117131.CrossRefGoogle Scholar
Morris, C. A. 1984. Calving dates and subsequent intercalving intervals in New Zealand beef herds. Animal Production 39: 5157.Google Scholar
Pleasants, A. B. 1997. Use of a stochastic model of a calving frequency distribution for beef cows for formulating optimal mating strategies. Animal Science 64:413421.CrossRefGoogle Scholar
Pleasants, A. B. and Barton, R. A. 1992. Observations on the length of the postpartum oestrous cycles and their relationship to other reproductive parameters in mature Angus cows calving in the spring of two consecutive years. New Zealand Journal of Agricultural Research 35:5962.CrossRefGoogle Scholar
Pleasants, A. B. and McCall, D. G. 1993. Relationships among post-calving anoestrous interval, oestrous cycles, conception rates and calving date in Angus and Hereford × Friesian cows calving in six successive years. Animal Production 56:187192.Google Scholar
Ryan, D. P., Snijders, S., Yaakub, H. and O'Farrell, K. J. 1996. An evaluation of estrus synchronisation programs in reproductive management of dairy herds. Journal of Animal Science 73: 36873695.CrossRefGoogle Scholar