Some effects of testosterone propionate and thyroprotein in rams.

M cKENZIE and Berliner (i937) have shown that under Missouri conditions rams decline in semen production during summer months, or when exposed to high environmental temperatures during other seasons. The deleterious effects of the summer season upon semen quality and pro. duction of rams has been found by Green (I94o), Phillips et al. {I943) and upon that of dairy bulls by Erb, Andrews, and Hilton (i94~). Similar results have been obtained through scrotal insulation of rams by Phillips and McKenzie (i934). Berliner and Warbritton (I937) suggested that a hypothyroid condition may account for impaired semen quality during the summer months: Bogar t and Mayer (i946) at Missouri obtained beneficial results by feeding thyro. protein to rams which were showing this so.called "summer sterility." However, Warwick et al. (i948) at Washington obtained both deleterious and beneficial results while Eaton et al. (~948) at Beltsville found no improvement at all. In view of the conflicting results obtained by these workers, the present study was undertaken to determine the action of thyroprotein upon sexual behavior and semen production under Wisconsin conditions. Testosterone propionate was also included in this study since the action of exogenous androgen in farm animals has received only slight attention, even though its effect in laboratory animals is well known. In rabbits Cheng and Casida (I949) found increased libido and semen volume, decreased sperm concentration, and no change in total sperm production with testosterone propionate treatment. However, preliminary trials at this Station have failed to show pronounced changes in semen production and libido of rams given testosterone. The possible existence of an interaction between testosterone and thyroprotein in alleviating the symptoms of "summer sterility" was also considered.