Last update: August 16, 2011 02:39:19 PM E-mail Print

 

PLASMA TESTOSTERONE LEVELS IN RONDERIB AFRIKANER AND MERINO RAMS

 

P R King, W A Coetzer*, E Roux & Annalida van Loggerenberg

Grootfontein College of Agriculture, Middelburg Cape, 5900

*Department of Human and Animal Physiology, University of Stellenbosch,

Stellenbosch, 7600

 

From results obtained it is evident that the sexual activity of the Ronderib Afrikaner ram among ewes is significantly higher than that of the Merino ram. Testosterone produced by the testis is responsible for the sexual behaviour and libido in the male. In an attempt to explain the difference in sexual activity between Ronderib Afrikaner and Merino rams, blood samples were collected hourly from four Ronderib Afrikaner and four Merino rams for a twenty-four hour period during autumn and during spring. The plasma testosterone level was determined in all samples. The mean plasma testosterone levels of the Ronderib Afrikaner rams (6.2 ± 4.8 ng\ml) did not differ significantly from that of the Merino rams (6.0 ± 5.0 ng\ml) during spring. During autumn, however, the mean plasma testosterone level of the Ronderib Afrikaner rams (3.3 ± 3.4 ng\ml) was significantly lower (P<0.01) than that of the Merino rams (6.8 ± 5.5 ng\ml). These results are contrary to what was expected. Currently the testosterone turnover rate in Ronderib Afrikaner and Merino rams are being determined in an attempt to explain the above mentioned results.

 

Published

Proceedings 31st SASAP congress