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Puberty. The ability to accomplish reproduction successfully. Dependant on:. Development of a threshold body size. Exposure to social and environmental cues. Genetics of the animal. Puberty is a transition from prepubertal to postpubertal that may last for weeks or months.

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Puberty
Puberty

The ability to accomplish reproduction successfully

Dependant on:

Development of a threshold body size

Exposure to social and environmental cues

Genetics of the animal

Puberty is a transition from prepubertal to postpubertal that may

last for weeks or months

“The fundamental requirement for pubertal onset is the secretion

of GnRH at the appropriate frequency and quantities to stimulate

Gonadotropin release by the anterior pituitary lobe”


Development of the Surge Center

in the female and defeminization

in the male


Changes in Hypothalamic sensitivity

Prepubertal female

Low frequency GnRH pulses from the tonic center result in

low stimulation of estradiol resulting in insufficient stimulation

of the surge center

Postpubertal female

Higher frequency GnRH pulses from the tonic center result in

stimulation of estradiol above threshold concentrations to stimulate

the surge center resulting in the preovulatory LH surge

Prepubertal male

GnRH is very sensitive to negative feedback of testosterone/estrogen

Postpubertal male

Decreased GnRH sensitivity to negative feedback results in more GnRH

released producing greater concentrations of testosterone/estrogen


End Points to determine the age of puberty

Female

Age at first estrus

Age at first ovulation

Age at which the female can successfully support a pregnancy

Male

Age when behavioral traits are expressed

Age at first ejaculation

Age at first spermatozoa in the ejaculate

Age at first spermatozoa in the urine

Age when ejaculate has a threshold number of spermatozoa


Factors that influence the age of puberty

Body Size and Degree of Fatness


Factors that influence the age of puberty

Body Size and Degree of Fatness

External and social factors

Genetics


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