Assessment of different selection criteria for reproduction rate in Dormer and S.A. Mutton Merino sheep. 3. Prepubertal testis

Author: N.M. Kritzinger, H.W. Stindt & J.M. van der Westhuizen
Year: 1984
Issue: 2
Volume: 14
Page: 88 - 90

Data of all the ram lambs born to the Elsenburg Dormer (n = 144)and SA Mutton Merino (n = 166) flocks during the 1977 and 1978 lambing seasons as well as that of their female relatives were used to study various aspects regarding the use of testis size as a possible selection criterion for reproduction rate in sheep. The prepubertal testis diameter of ram lambs was found to be a highly repeatable character, positively correlated with either live mass or plasma LH levels. No significant differences between breeds could be found, while considerable within-breed variation was observed for both breeds. No positive association between testis diameter of ram lambs and the reproductive performance of their female relatives could, however, be demonstrated for anyone of the two breeds.



Keywords: reproduction rate, selection criterion, sheep, Testis size
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