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Effects of norethisterone acetate on the performance of female racing Greyhounds

Payne, Richard M.



A comparison between the performance of spayed female racing Greyhounds and those suppressed with norethisterone acetate (NTA) was made. Previous work by the author has shown that the racing performance of spayed bitches is the same as that of entire bitches in anoestrus, i.e. spaying is just a permanent anoestrus. The aim was to assess any performance difference between suppression and anoestrus, and thus to determine the effect of norethisterone acetate on race performance. The study was designed as a retrospective case-control. Raceform data was obtained for female racing Greyhounds which had raced, and which were either spayed or suppressed with norethisterone acetate. Analysis showed that suppressed bitches run on average 0.049 to 0.061 s slower over 480 m (centralised models). Since endogenous progesterone (P4) has been linked with reduced race performance, it is logical that progesterone analogues like NTA should have a similar effect. It is likely that the depression in performance is dose-related, but not quantifiable with the current dataset.


Payne, R. M. (2023). Effects of norethisterone acetate on the performance of female racing Greyhounds. Research in Veterinary Science, 155, 1-5.

Journal Article Type Article
Acceptance Date Dec 24, 2022
Online Publication Date Dec 26, 2022
Publication Date Feb 1, 2023
Deposit Date Jan 12, 2023
Publicly Available Date Jan 13, 2023
Journal Research in Veterinary Science
Print ISSN 0034-5288
Electronic ISSN 1532-2661
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 155
Pages 1-5
Keywords Greyhound; Suppression; Oestrus; Performance; Norethisterone
Public URL
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Additional Information This article is maintained by: Elsevier; Article Title: Effects of norethisterone acetate on the performance of female racing Greyhounds; Journal Title: Research in Veterinary Science; CrossRef DOI link to publisher maintained version:; Content Type: article; Copyright: © 2022 The Author. Published by Elsevier Ltd.


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