Lecture 7: Maturation of Reproductive Organs and Puberty in the Male and Castration

Question 1

Puberty in Males

Answer 1

acquisition of reproductive competence (gradual process)
depends on the maturation of the reproductive tract
- GnRH secretion increases over time with the maturation of the hypothalamus
- sensitivity of HPG cells to hormonal stimulation changes overtime until consistent regulation is achieved

Influence by

• genetics
• environment

Question 2

Definition of Puberty

Answer 2

ejaculate contains threshold spermatozoa for fertilization

- species differences for threshold values

Question 3

Genetics affect on puberty

Answer 3

early maturing breeds have an earlier onset of puberty than late-maturing breeds

maternal breeds reach puberty earlier than meat-type breeds

other clusters of neurons in the hypothalamus sense metabolic molecules and influence GnRH secretion

Question 4

Nutrition influences:

Answer 4

low plane of nutrition - delays puberty

high plane of nutrition - hastens puberty

Question 5

Social cues effect on puberty

Answer 5

olfactory recognition of pheromones
- pheromones: volatile chemical compounds secreted by the body and detected by the olfactory system of other individuals of the same species

Question 6

Effects of photoperiod on puberty

Answer 6

some species are seasonal breeders
sheep = short day
horses= long day

pineal gland - melatonin secretion

Question 7

Castration

Answer 7

removal or destruction or impairment of testicular function

methods: surgical, elastic band, burdizzo, immunocastration, chemical castration
normally performed at young age- quicker recovery