The effect of a low dose of cadmium on spermatogenesis in rams

Spermatogenesis in five rams that were fed 7.5 mg Cd daily, a quantity typi cal of levels in the vicinity of a pollution source, was compared with five rams that received no cadmium supplement. Cadmium was added to their conce ntrate supplement and the rams grazed a perennial ryegrass and cocksfoot pa sture. Semen from each ram was collected weekly into an artificial vagina f or 7 weeks from days 20-69, a period that was deliberately short to minimis e the possibility that effects of cadmium on intake and other physiological processes might indirectly affect spermatogenesis. There were no treatment effects on the spermatozoa concentration in the semen or output per ejacul ate, the proportion of live spermatozoa, their progressive linear or vertic al motility, wave motion at the periphery of the semen sample or testis cir cumference. Of 13 different measurements taken of behaviour, cadmium affect ed only 3; cadmium-treated rams grazed longer, ruminated less and had fewer Flehman responses. Since there were only 5 rams/treatment for a 2-day peri od, these apparent effects of cadmium on behaviour need to be treated with caution. It is concluded that cadmium concentrations of feed that are typic al of a polluted area pose no risk in the short term to spermatogenesis in rams, but there are effects on behaviour that warrant further investigation . (C) 1999 Published by Elsevier Science B.V. All rights reserved.