Seasonal variations in the semen quality of young British goats.

Physical characteristics of semen quality were studied over a 12 month period in 10 post pubertal, young male goats (7-19 months of age) maintained under the naturally prevailing climatic conditions characteristic of the South of England (latitude N 51 degrees 46'). Semen was collected fort-nightly using an artificial vagina and an ovariectomized, oestrogenized teaser doe. The physical appearance of the ejaculates varied from a yellow or whitish-yellow colour during September-December to a creamy-white colour during the remainder of the year. Ejaculate volume decreased from 0.96 +/- 0.06 ml in October to the minimum value of 0.39 +/- 0.03 ml in April and 0.38 +/- 0.02 ml in July, after which there was a sharp increase to the highest value, 1.04 +/- 0.05 ml, in September. Sperm cell concentration per ml was lowest (3.66 +/- 0.16 x 10(9)), during November and highest (6.56 +/- 0.29 x 10(9)) during May. However, the total sperm per ejaculate were highest during the September and lowest in December. The mass and individual motilities were higher during August-December than in the remainder of the year. The percentages of dead and morphologically abnormal spermatozoa were highest during May. The effect of the months and seasons of the year on all parameters of semen quality were significant (P < 0.01).