Reproductive Capacity of Dairy Bulls. I. Technique for Direct Measurement of Gonadal and Extra-Gonadal Sperm Reserves

Abstract

Sperm were liberated from the epididymis by thoroughly tearing apart the tissue in 50 ml of 0.9% NaCl and grinding the tissue suspension in 200 to 500 ml of saline for a total of 2.5 min. in a Waring Blendor. After removing the tunica albuginea, testicular sperm were liberated by cutting the testis into small pieces and grinding in 1000 ml. of saline for 2 min. Sperm were liberated from the ductus deferens and ampulla by flushing with distilled water to remove most of the sperm and then grinding in a blendor. Soaking the sperm suspensions for 48 hr. before counting did not result in higher values; differences between 0 and 48 hr. counts were relatively small. Sampling the sperm suspension is the major source of error; therefore, replicate counts should be made on separate subsamples of the entire suspension. Extra-gonadal reserves of 35 mature bulls averaged 72.6 billion sperm and gonadal reserves averaged 54.8 million sperm per gram of testicular tissue.