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Michigan State University, East Lansing
Abstract
Previous research has shown that a high percentage of ram sperm survives freezing. The successful application of frozen ram semen to sheep breeding depends on the fertility achieved after insemination of thawed, frozen semen. The fertility reported thus far has been low.
Smirnov ( 1951) achieved 42 % conception after inseminating ewes with thawed frozen ram semen. Graca (1955) reported 31.2% conception, Emmens and Blackshaw (1955) reported 5%, and Kuznetsov (1956) reported 19.3% and 33.5% in two different studies.
This paper presents the data of five breeding trials conducted to study the fertility of frozen ram semen.
Experimental
Ram semen was collected with either an artificial vagina or by means of electrical stimulation. Dilution, freezing and microscopic examination were according to the procedures of First et al. (1961).
For insemination, in experiments 1 through 4, the rear quarters of ewes in estrus were elevated in a breeding crate. The cervix was located with the aid of a head lamp and a glass or a spreading speculum. Semen was then deposited in the cervix with a 2 ml syringe and a drawn glass pipette. In experiment 5 ram semen was deposited in the anterior vagina near the cervix. All ewes were inseminated at one estrus only.
1 Published with the Approval of the Michigan Agricultural Experiment Station Under Journal Article No. 2644.
2 Present address: Department of Animal Husbandry, University of Wisconsin, Madison 6, Wisconsin.
3 Present address: Ankara Universitesi, Zootekni, Kursusu, Ankara, Turkey.
4 Present address: Director of Short Courses, Michigan State University.
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