A study to establish methods for improvement of the reproductive management of dairy cows using milk progesterone enzyme immunoassay

Dradjat, Adji Santoso (1990) A study to establish methods for improvement of the reproductive management of dairy cows using milk progesterone enzyme immunoassay. PhD thesis, Murdoch University.

Abstract

Studies were undertaken to develop suitable methods of improving the reproductive efficiency and management of dairy cows by the use of oestrus synchronization and monitoring reproductive activity using milk progesterone enzyme-immunoassay. The milk progesterone enzyme immunoassay technique (Munro and Stabenfeldt, 1984) is simple and reliable and enables the monitoring of ovarian activity of large herds of dairy cows. The assay was evaluated as a technique for detecting oestrus, judging the timing of insemination and diagnosing pregnancy, with the aim of synchronizing cows for a batch breeding management system.

Progesterone profiles were used to determine the stage of the oestrus cycle. The basal progesterone level associated with oestrus was found to be < 2.27 ng/ml and the progesterone level associated with luteal activity > 4 ng/ml.

The accuracy of the screening test for detection of oestrus (milk progesterone concentration < 2.27 ng/ml) was 93.22%. This was 4.5% better sensitivity than was obtained by observing standing oestrus behaviour to detect oestrus. The accuracy of the screening test (milk progesterone concentration > 4 ng/ml) for diagnosing pregnancy on days 21 to 24 was 100%, but with 6 10% false positive diagnoses .

A number of treatments for synchronizing oestrus were compared. They were; Two injections of prostaglandin 11 days apart; CIDR, (Cloprostenol, ICI, Sydney), an intravaginal device for the slow release of progesterone, inserted for 15 days; CIDR inserted for 9 days; CIDR inserted for 9 days with an injection of prostaglandin on day 8; CIDR inserted for 9 days with an injection of prostaglandin on day 9 and Gonadotrophin Releasing Hormone on day 10; Synchromate B implanted for 9 days; Synchromate B implanted for 9 days with injections of oestradiol benzoate on days 5 and 7. and Synchromate B implanted for 9 days with an oestradiol benzoate injection on day 5 and prostaglandins injection on day 7.

CIDR treatment for 9 days gave the highest degree of synchrony amongst treated cows. CIDR treatment for 9 days with cloprostenol injected on day 8 resulted in higher pregnancy rates than other hormone treatment regimes. By this method, 80% of cows were found to be pregnant. The time of CIDR treatment (whether initiated in the luteal or follicular stage) had no effect on the in the luteal or follicular stage) had no effect on the onset of oestrus.

Overall, the results of this study suggest that, of the methods used, the best way to synchronize oestrus is to use ClDR treatment for 9 days with prostaglandin injection on day 8. Screening tests involving estimation of progesterone levels were found to be the most accurate means of detecting oestrus and diagnosing pregnancy.

Item Type:	Thesis (PhD)
Murdoch Affiliation(s):	School of Veterinary Studies
Notes:	Note to the author: If you would like to make your thesis openly available on Murdoch University Library's Research Repository, please contact: repository@murdoch.edu.au. Thank you.
Supervisor(s):	Williamson, Peter
URI:	http://researchrepository.murdoch.edu.au/id/eprint/53190

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