Gonadal and extragonadal sperm reserves of indigenous Central African bulls.

Abstract

The relationship between testis size, sperm reserves, ejaculate volume and sperm concentration are well established, (Ortavant, 1956; Almquist, Amann & O'Dell, 1958; Hale & Almquist, 1960; Hahn, Foote & Seidel, 1969). In a another report, Igboeli & Rakha (1971) showed that the ejaculate volume and the number of spermatozoa per ejaculate of mature Angoni bulls (Central African Zebu) are less than those values reported for breeds from more temperate areas. No previous reports appear to be available on the testis size, and gonadal and extra-gonadal sperm reserves of indigenous Central African bulls. Thirty, sexually mature, indigenous breeding bulls\p=m-\tenAfricander, ten Angoni, and ten Barotse\p=m-\wereslaughtered, and the reproductive organs were removed. The left and right testes and epididymides were trimmed and weighed. After careful removal of the tunica albuginea, each testis was homogenized at 6000 rev/min for 2 min. After recording the homogenate volume, a sample of the homogenate was diluted 1:40 v/v using physiological saline containing antibiotics. The caput, corpus, and cauda of the epididymis were minced separately with sharp pointed scissors in individual beakers containing 20 ml of physiological saline and the volume was noted. The suspensions were then strained through two layers of sterile cheese-cloth into graduated test tubes. All samples were then stored for 24 hr at 5\s=deg\C before diluting and counting in the haemocytometer. The gonadal sperm reserve was estimated as the total number of late spermatids and spermatozoa in the homogenized testicular tissue. Data were subjected to standard statistical analysis. The results are summarized in Table 1. The testicular weights of Barotse bulls (140 g) were statistically significantly smaller than those ofeither the Africander (190 g) or the Angoni (200 g) breeds, which in turn, did not differ significantly (P>0-05). The epididymal weights