1 GOAT SEMEN COLLECTION AND PROCESSING BY DR. LOUIS ...

The postnatal development of the male reproductive tract has received some attention,
primarily in the bull and ram. Puberty is commonly defined as being the point in time when the male
first produces sufficient sperm to impregnate a female. In many of the domestic species it is
practically defined when an ejaculate is obtained containing 50 million sperm of which 10% are
motile. The pubertal period is associated with rapid testicular growth, changes in LH secretory
pattern, a gradual increase in blood testosterone, and the initiation of spermatogenesis. The
hypothalamus is believed to play a key role in initiating puberty because the pituitary gland, gonads,
and steroid-dependent target tissues are each competent and ready to respond to their respective
tropic hormones prior to puberty. In the boar, bull and ram, and probably the buck, puberty appears
to be the culmination of a continuous and lengthy process of endocrine changes which begin shortly
after birth. The most remarkable early change is an increase in the frequency of pulsatile discharge
of LH. This is followed by altered testicular steroidogenesis, increased circulating levels of
testosterone, differentiation of Sertoli cells and the onset of spermatogenesis.
It has been proposed that puberty occurs when an animal becomes desensitized to the
feedback inhibition imposed on the hypothalamic-pituitary complex by gonadal steroids.
Presumably, the allows an increase in GnRH discharge and a greater response by the pituitary gland
to GnRH.
Spermatogenic Cycle
The spermatogenic cycle begins with a stem cell or A-type spermatogonia, which provides
the starting point of a spermatogenic series. The duration of spermatogenesis, that is from the time it
takes an A-type spermatogia to end up as spermatozoa in the buck is probably very similar to what
has been reported for rams, namely 47 days.
3