Semen yield, mass motility of spermatozoa, semen spermatozoa concentration, total number of spermatozoa per ejaculation and percentage of abnormal and dead spermatozoa were studied in 11 Fulani and Tuareg adult rams. With one and two successive emissions in Fulani rams, average sperm volume was 0.895±0.31 ml and 0.93±0.53 ml, respectively; mass motility was 31.3 and 3.2±1.2 units; spermatozoa mean concentration was 3777 x 106 ± 1245 x 106 per ml and 3694 x 106±1345 x 106 while total number of spermatozoa per emission was 3614 x 106 ± 1758 x 106 and 3723 x 106 ± 2854 x 106. In Tuareg rams, for one and two emissions, average sperm volume was 1.13±0.31 ml and 1.78±0.48, respectively; mean mass motility was 3.4±0.09 and 3.1±0.1 ml; mean spermatozoa concentration was 4156 x 106±791 x 106 and 3580 x 106±406 x 106 while total number of spermatozoa per emission was 4805 x 106±1631 x 106 and 6414 x 106±2119 x 106. Breed x number of emissions had a significant effect (P<0.05) on volume of sperm and total number of spermatozoa in semen but not on mass motility and spermatozoa concentration (P>0.05). Depending on the breed, it is therefore better to use two emissions per "yield" to determine sperm volume and total number of spermatozoa. Percentage of abnormal spermatozoa was similar in both breeds. It varied from 4.5 (0.5) to 11 (0.43) and was within normal limits for fertility. Percentage of dead spermatozoa varied from 18.5 (4.15) to 41.25 (4.8)% for both breeds, which is rather high. However, this should be related to other environmental and individual factors, including temperature, individual biological parameters, number of emissions etc. Regression between semen spermatozoa concentration and optical density was studied using a spectrocolorimeter. For Fulani rams, the equation of the regression line was Y = 8225.2 X + 18.2 (where Y is the spermatozoa concentration and X is the optical density). The highly significant (P<0.01) correlation coefficient (r = 0.97) indicated a strong relationship between the two variables. For Tuareg sperm, the equation of the regression line was Y = 7590.6 X + 317.7 and the correlation coefficient (r = 0.86) was also highly significant (P<0.05). These results suggest that morphological characteristics of the sperm of Tuareg rams are different from those of Fulani rams semen when collection frequency is greater than 1. Taken together these parameters indicate the quality of sperm. It is concluded that studies of various environmental factors should be carried out in relation with seasons.
