Seminal plasma proteins do not consistently improve fertility after cervical insemination of ewes with non-sorted or sex-sorted frozen–thawed ram spermatozoa
T. Leahy A C , G. Evans A , W. M. C. Maxwell A and J. I. Marti BA Faculty of Veterinary Science, University of Sydney, Sydney, NSW 2006, Australia.
B Unidad de Tecnologıa en Produccion Animal, Centro de Investigacion y Tecnologıa Agroalimentaria de Aragon, 50059 Zaragoza, Spain.
C Corresponding author. Email: tamaral@vetsci.usyd.edu.au
Reproduction, Fertility and Development 22(4) 606-612 https://doi.org/10.1071/RD09207
Submitted: 31 August 2009 Accepted: 1 October 2009 Published: 9 March 2010
Abstract
The effect of supplementation of sex-sorted and non-sorted spermatozoa with seminal plasma protein (SPP) on fertility after cervical insemination was examined in the present study. Spermatozoa were sorted into high purity X and Y chromosome-bearing spermatozoa or not sorted and then either supplemented with SPP (>10 kDa) before freezing and/or after thawing (non-sorted only) or processed without supplementation. Inseminations were performed over 2 days with ewes receiving 100 or 25 million motile non-sorted spermatozoa in the cervix or uterus, respectively, or two cervical inseminations of 3.5 million motile sorted spermatozoa. Pregnancy rates in cervically inseminated ewes were unaffected by supplementation of sorted or non-sorted spermatozoa with SPP before freezing compared with no supplementation. The effect of post-thaw supplementation of non-sorted spermatozoa with SPP on pregnancy rates after cervical insemination varied with the day of insemination (P < 0.05); fertility was similar to laparoscopic insemination on Day 1 (56.0 ± 10.2% v. 58.6 ± 10.1%), but not on Day 2 (23.1 ± 7.4% v. 66.7 ± 9.2%). In conclusion, under the conditions of the present study, SPP did not consistently improve pregnancy rates after cervical insemination with frozen–thawed ram spermatozoa. This is the first report of pregnancies (5/56 ewes inseminated) after cervical insemination with frozen–thawed sex-sorted ram spermatozoa. Although the success rate is low, the findings are encouraging because ewes inseminated with the sex-sorted spermatozoa received only 7% of the recommended dose (100 million motile) for cervical insemination of frozen–thawed spermatozoa.
Additional keywords: cryopreservation, pregnancy rate, sex preselection, sheep.
Acknowledgements
The authors acknowledge the support of XY Inc. (Fort Collins, CO, USA) and Sexing Technologies Inc. (Navasota, TX, USA) and a grant from the Spanish Science and Education Ministry (Salvador de Madariaga Programme) (grant no. PR2006–0186). The authors also thank Australian Wool Innovation for providing a scholarship support for TL, Bioniche Animal Health Australasia (Caulfield North, Vic., Australia) for the generous gift of Ova-gest and Pregnecol and the McPhie family (Cottage Creek Pastoral Co., Cooma, NSW, Australia) for the provision of animals, facilities and on-farm assistance.
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