Estrous cycle and anestrus Flashcards

1
Q

Estrous cycles:

A

Time period between periods of estrus (sexually receptive to male), physiological events occurring between successive periods of estrus

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2
Q

Average estrous cycle length in cow (include range):

A

Average length: 21 days
Range: 17-24 days

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3
Q

Average estrous cycle length in ewe (include range):

A

Average length: 17 days
Range: 13-19 days

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4
Q

Average estrous cycle length in sow (include range):

A

Average length: 21 days
Range: 17-25 days

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5
Q

Average estrous cycle length in mare (include range):

A

Average length: 21 days
Range: 15-26 days

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6
Q

Reproductive cyclicity importance:

A

Provides the female with repeated opportunities to become pregnant.

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7
Q

Estrous cycles begin and end with:

A

estrus

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8
Q

Menstrual cycle:

A

Predictable reproductive events beginning and ending with menses

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9
Q

Estrus is commonly referred to as:

A

heat

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10
Q

Estrus is a ______.
Estrous is an _______.
Estrual is an ________.

A

noun
adjective
adjective used to identify a condition related to estrous

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11
Q

Different types of reproductive cyclicity:

A

Polyestrus, seasonally polyestrus, monoestrus

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12
Q

Estrus causes a dramatic increase in:

A

estradiol

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13
Q

Domestic canids have about ____ estrous cycles every two years. Estrus lasts _______.

A

three
several days

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14
Q

The four periods of the estrous cycle:

A

Estrus, metestrus, diestrus, proestrus

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15
Q

Estrus

A

Period of sexual receptivity and mating

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16
Q

Estrus length:

A

12-18 hours in cow

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17
Q

Dominant hormone in estrus and its function:

A

Estradiol
Behavior changes (receptive rather than disinterested), changes in reproductive tract

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18
Q

Metestrus

A

Period between ovulation and formation of a functional corpus luteum

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19
Q

Events of metestrus:

A

Ovulation occurs 27-30 hours after start of estrus or 12-18 hours after end of estrus. CH to CL formation. Progesterone rises. Metestrus bleeding

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20
Q

Metestrus bleeding:

A

Noticed 35-45 hours after estrus. Capillary breakage causes blood in mucus. Occurs in 90% of heifers and 45% of cows. If seen, you have missed the window for breeding.

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21
Q

Diestrus

A

Period for preparing the uterus for pregnancy

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22
Q

What is present during diestrus?

A

A functional corpus luteum

23
Q

Diestrus ends with (when pregnancy does not occur):

A

Luteolysis

24
Q

Proestrus:

A

Begins with CL destruction and terminates at beginning of estrus

25
Q

Proestrus is a major:

A

endocrine transition

26
Q

Proestrus events:

A

Progesterone declines. Recruitment and rapid follicle growth. Estradiol increases (prepares estrus, positive feedback)

27
Q

Proestrus only happens if:

A

progesterone decreases

28
Q

Estrous cycle order:

A

Estrus -> metestrus -> diestrus -> proestrus -> estrus

29
Q

What happens because of the GnRH-LH surge:

A

Ovulation, CL formation

30
Q

Tonic LH secretion function:

A

CL function, follicle growth and turnover

31
Q

When estradiol decreases, inhibin _______, resulting in an ______.

A

decreases, FSH surge

32
Q

FSH surge results in _______ inhibin, _______ inhibin, resulting in ________.

A

increases, decreased, decreased, secondary surge

33
Q

The bitch is receptive to the male during:

A

declining estrogen and rising progesterone

34
Q

Anestrus length in bitch:

A

5 months

35
Q

Proestrus length in bitch:

A

9 days

36
Q

Estrus length in bitch:

A

9 days

37
Q

Diestrus length in bitch:

A

2 months (pregnancy does not alter length)

38
Q

In the bitch, ovulation occurs:

A

2-3 days after LH surge

39
Q

In the bitch, fertilization is delayed _______ after ovulation because:

A

48-72 hours, ovum is not ready

40
Q

Estrous cycle in the queen:

A

Proestrus -> estrus -> postestrus -> diestrus -> anestrus

41
Q

In the queen, unless induced:

A

ovulation will not occur, so hormonal changes will not occur, P4 levels remain low.

42
Q

In the queen, estrus lasts __ days and occurs every __ days.

A

9, 17

43
Q

In the queen, during lactation:

A

cycling continues

44
Q

What occurs after parturition in the queen?

A

Lactation and anestrus

45
Q

Induced ovulators:

A

Alpaca, llama, queen

46
Q

Anestrus

A

When cyclicity stops

47
Q

Normal reasons for anestrus:

A

Pregnancy, parturition, uterine involution, lactation, offspring presence, season of the year.

48
Q

Abnormal reasons for anestrus:

A

Stress, pathological conditions

49
Q

Another name for pregnancy:

A

Gestational anestrus

50
Q

Progesterone during pregnancy:

A

Negative feedback

51
Q

After pregnancy, anestrus:

A

continues

52
Q

Another name for lactation:

A

induced anestrus

53
Q

Induced anestrus purpose:

A

Prevents new pregnancy before weaning young