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Cryptorchidism in North Ronaldsay sheep
K C Smith1, P J Brown, J Morris
1School of Clinical Veterinary Science, University of Bristol, Langford House, Langford, Bristol.
The Veterinary Record
|November 13, 2007
Summary
Cryptorchidism, the failure of one or both testes to descend, affected 7.4% of North Ronaldsay ram lambs between 1998-2005. Unilateral retention, particularly of the right testis, was most common.
Area of Science:
- Veterinary Science
- Animal Reproduction
- Sheep Genetics
Background:
- Cryptorchidism is a common congenital condition in male animals.
- North Ronaldsay sheep are a rare indigenous breed with unique genetic traits.
- Understanding breed-specific incidence is crucial for conservation and breeding programs.
Purpose of the Study:
- To determine the incidence of cryptorchidism in North Ronaldsay ram lambs.
- To analyze the laterality and frequency of cryptorchidism over an eight-year period.
- To provide data for genetic management and conservation of the North Ronaldsay breed.
Main Methods:
- Retrospective analysis of breeding records from 1998 to 2005.
- Recording all cases of cryptorchidism in ram lambs.
- Calculating the overall incidence and year-to-year variations.
Main Results:
- The overall incidence of cryptorchidism was 7.4% (range: 2.4%–18.2%).
- In 87.3% of cases, only one testis was retained (unilateral cryptorchidism).
- The right testis was affected in 78.5% of unilateral cases.
Conclusions:
- Cryptorchidism occurs with notable frequency in North Ronaldsay ram lambs.
- Unilateral, right-sided testicular retention is the predominant form.
- These findings highlight the need for monitoring and potential genetic selection against cryptorchidism in this breed.
