Learning Objectives

1
Learning Objectives
To understand what puberty is, how it occurs,
when it occurs and what factors influence it
2
Puberty Onset of reproductive competence,
i.e., both behavior and
function
Age at Puberty (months)

Female Male
Sheep-Goats 7-10
4-6 Swine
4-7 4-8
Cattle
8-11 10-12
Brahman type cattle 15-18
Horses 15-18
13-18
Swine (gilts) can be induced into puberty by boar
exposure, mixing pens and transport close to
5-7months of age
3
Onset of puberty more related to development than
age
Mature weight at puberty Dairy
Cattle 30-40
Beef cattle 55-65
Sheep 40- 63
When to Breed Heifer 15 months (65
mature BW) Bull 15 natural mating,
12 months AI Filly 2-3 years Colt
2 years Boar 9 months
4
Changes associated with puberty Male
Gonocytes located in center of seminiferous
tubule. The migrate to periphery and
differentiate into spermatogonia
Spermatogenesis starts Rapid testicular
growth begins
Female Tertiary follicles
start to form in prepubescent period.
Eventually LH surge causes ovulation get 1st
corpus luteum cycles initiated.
5
Stimulates sperm production and testosterone
from Ledig cells
Bull
Causes negative feedback which lowers LH
Sperm in ejaculate
Spermatogonia start dividing