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Seasonal Changes In Sexual Activity And Serum Levels Of Lh And Testosterone In Finnish Landrace And Suffolk Rams, B. D. Schanbacher, D. D. Lunstra
Seasonal Changes In Sexual Activity And Serum Levels Of Lh And Testosterone In Finnish Landrace And Suffolk Rams, B. D. Schanbacher, D. D. Lunstra
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
A procedure for assessing sexual activity (libido) in individual rams is described. Mating activity measured by this procedure and serum levels of luteinizing hormone (LH) and testosterone in Finnish Landrace and Suffolk rams was determined at 8-week intervals from October, 1974 through October, 1975. Seasonal changes were observed for serum LH, testosterone and libido index scores. Mating activity in rams was highest for both breeds during the peak breeding season (October) and declined 50% by late spring and summer before it increased the next October.
Serum LH concentrations were lowest in May (.54 ng/ml) and increased abruptly in July ( …