Puberty

Question 1

Puberty

Answer 1

Ability to accomplish reproduction successfully. “Process” of acquiring reproductive competence.

Question 2

Criteria/definitions for puberty in the female

Answer 2

Age at first ovulation (silent ovulation), age at first estrus, or age at which the female can support pregnancy without deleterious effects.

Question 3

Which of the criteria/definitions for puberty in the female is most applicable practically?

Answer 3

Age at which the female can support pregnancy without deleterious effects

Question 4

criteria/definitions for puberty in the male:

Answer 4

Age when behavioral traits are expressed
Age at first ejaculation
Age when sperm first appear in the ejaculate
Age when sperm appear in the urine
Age when the ejaculate contains a threshold number of sperm

Question 5

What is the most valid criterion/definition for puberty in the male?

Answer 5

Age when the ejaculate contains a threshold number of sperm.

Question 6

Average age of puberty in the female bovine:

Answer 6

11 months

Question 7

Range of puberty age in the female bovine:

Answer 7

9-24 months

Question 8

Average age of puberty in the male bovine:

Answer 8

11 months

Question 9

Age range of puberty in the male bovine:

Answer 9

7-18 months

Question 10

Average age of human male puberty:

Answer 10

13 years

Question 11

Average age of human female puberty:

Answer 11

12 years

Question 12

Is puberty sexual maturity?

Answer 12

No. Just because it can happen does not mean it should.

Question 13

What is the fundamental requirement for the onset of puberty?

Answer 13

Secretion of GnRH at appropriate frequency and quantities to stimulate gonadotropin release form the AP

Question 14

What does the secretion of GnRH at appropriate frequency and quantity, causing release of gonadotropins from the AP result in?

Answer 14

Promotion of gametogenesis, steroidogenesis, and development of reproductive tissues.

Question 15

What are hormone levels like prior to puberty?

Answer 15

Low frequency and amplitude of GnRH, low LH and FSH in both males and females

Question 16

LH pulse frequency and amplitude in the months leading up to puberty in heifers:

Answer 16

Increases months before puberty. It takes about 2 months before the pulse frequency is high enough to achieve puberty. Eventually get GnRH/LH surge

Question 17

Onset of puberty in males and females:

Answer 17

Decreased hypothalamic sensitivity to negative feedback to testosterone/estrogen.

Question 18

Puberty is associated with:

Answer 18

changes in feedback sensitivity of hypothalamus to estradiol.

Question 19

The first LH surges after puberty are:

Answer 19

not always associated with estrus

Question 20

What sensitizes the hypothalamus to estradiol to get behavioral estrus?

Answer 20

Progesterone

Question 21

What happens after the first LH surge?

Answer 21

“Silent” ovulation

Question 22

When does the first estrus begin, “silent” ovulation or first real ovulation?

Answer 22

First real ovulation

Question 23

When does sensitization to hypothalamus estradiol occur?

Answer 23

When progesterone increases after “silent” ovulation

Question 24

Changing features in peripuberal bulls:

Answer 24

Body conformation, increased aggressiveness and sexual desire, rapid growth of the penis and testicles, and separation of the penis from prepuce so extension is possible.

Question 25

Testes size =

Answer 25

sperm production

Question 26

Factors affecting age at puberty:

Answer 26

Genetics, metabolic/nutritional status, environment (seasonal breeders), and social cues (group housing)

Question 27

Example of genetics influencing age at puberty:

Answer 27

Breed
Holstein female age (months): 8.5, male age: 9
Brahman female age (months): 19, male age: 17

Question 28

Threshold of body size before puberty can be achieved means:

Answer 28

certain degree of “fatness” required for females

Question 29

How does availability of energy change with growth?

Answer 29

In growing animals: food goes to growth, very little body fate, no excess energy
In animals close to maturity: excess energy, glucose, fatty acids, fat deposition

Question 30

In seasonal breeders, _____________ influences age of puberty.

Answer 30

month of birth

Question 31

Age of puberty in spring born ewe lambs:

Answer 31

6 months

Question 32

Age of puberty in fall born ewe lambs:

Answer 32

12 months

Question 33

Group housing in males (effects on puberty onset):

Answer 33

Large groups: normal onset
Smaller groups: delayed onset

Question 34

Male exposure effect on puberty onset:

Answer 34

accelerated

Question 35

Detrimental factors affecting puberty age:

Answer 35

Any factor that slows growth rate and reduces mature size of animal
Ex) nutritional stress, heat stress, poor sanitation, poor health

Question 36

Minimizing age at puberty for males is _____ advantageous for females.

Answer 36

more

Question 37

How is minimizing age at puberty in males more advantageous?

Answer 37

Reduces reproductive “down time” and reduces generation interval

Question 38

Physiological demands of pregnancy/parturition/lactation limit:

Answer 38

benefits of hastening puberty in females