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Theriogenology > Intro To Breeding Programs > Flashcards

Intro To Breeding Programs Flashcards

1
Q

Length of estrus and when ovulation occurs in relation to it for MARES

A

4-7 days
24-48hr BEFORE end

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2
Q

Length of estrus and when ovulation occurs in relation to it for COWS

A

12-18 hours
4-16 hours AFTER end

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3
Q

Length of estrus and when ovulation occurs in relation to it for EWES/DOES

A

36 +/- 12 hours
during last half

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4
Q

Length of estrus and when ovulation occurs in relation to it for SOWS

A

2-3 days
24-40 hours after onset

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5
Q

Length of estrus and when ovulation occurs in relation to it for BITCHES

A

5-10 days
6 days before 1st day of diestrus

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6
Q

Length of estrus and when ovulation occurs in relation to it for QUEENS

A

3-6 days
25-50 hours after breeding

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7
Q

When is the best to get sperm into a cow?

A

-BEFORE ovulation or within 6 hours after because of how short it is
-Best to inseminate in the last half of standing hear

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8
Q

What is the AM/PM rule for AI in cows?

A

If cow is seen in estrus this morning, AI in the evening and again the next morning

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9
Q

What are some issues with estrus detection in cows? (4)

A

-Staffing is very costly
-Short estrus duration
-70% of activity happens overnight
-~25% of heats are low intensity

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10
Q

What % of cows are detected in heat on average?

A

30-40%, very poor average detection

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11
Q

When should you breed a mare with AI?

A

Best to get sperm in BEFORE ovulation, once she has been in estrus for about 2 days

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12
Q

What happens if you breed a mare on the first day of estrus?

A

If you breed/inseminate on the first day, the sperm must live 4-6 days before ovulation happens which is too long

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13
Q

What happens if you breed a mare on the last day of estrus?

A

If you breed on the last day it might be after ovulation and too late

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14
Q

When to breed a mare when using natural cover?

A

breed every other day when she will stand for the stallion

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15
Q

When to breed a mare when using frozen semen?

A

as close to ovulation as possible

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16
Q

What are some challenges in equine breeding? (4)

A

-Most farms dont have a stallion
-Many owners arent knowledgable about signs of estrus
-Many mares dont show strong signs
-Vets use results of repro exams to time breeding

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17
Q

What are some advantages of using estrous synchronization programs? (4)

A

-Use multiple sires
-Shorten the breeding season = shorter calving season
-Produce uniform groups of calves/lambs/kids
-In horses; it results in better planning for the stallion especially early in the year

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18
Q

What are some reasons to manipulate the cycle? (6)

A
  • Assist producers in achieving their goals!
  • Manipulate to allow out of season breeding (mares, ewe)
  • Induce estrus (alone or in groups of females)
    ~Planned breeding
    ~Shorter breeding/calving season
    ~Uniform groups of calves/kids/lambs
  • Timed breeding
  • Synchronize cycles (embryo transfer)
  • Keep out of estrus (performance mares)
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19
Q

What are some disadvantages of breeding programs? (4)

A

-Not all animals will respond to the program
~Genetics, BCS, nutrition, management factors
-In some programs the expressed estrus is weak, low intensity
-Cost of drugs and manpower for giving injections or oral medications
-Stress to animals if handling multiple times

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20
Q

What are four approaches to controlling the estrus cycle?

A
  1. Management techniques
  2. Control the luteal phase
  3. Control of the follicular phase
  4. Combination programs (both phases)

2-4 are hormonal manipulation

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21
Q

Four management techniques for estrous cycle control

A

A) Manipulate daylength by controlling environmental lighting
B) Male Effect
C) Short Term Weaning
D) Increasing Plane of Nutrition

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22
Q

What is the effect of melatonin and GnRH for mares when days are short?

A

short days = increased melatonin = SUPPRESSES GnRH

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23
Q

What is the effect of melatonin and GnRH for sheep when days are short?

A

shortening days = increased melatonin = STIMULATES GnRH

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24
Q

How do you fool mares into thinking its spring?

A

Expose them to artificially long days starting in the Fall

25
Q

How do you fool small ruminants into thinking its fall?

A

Expose them to increasing darkness beginning in late summer

26
Q

What does male exposure do?

A

will induce release of GnRH and LH, stimulating cyclicity and ovulation in virtually all spaces

27
Q

How long must males be out of sight, sound, and smell before reintroduction to induce cycling?

A

More than 30 days.

28
Q

How does daily exposure to a boar affect gilts?

A

It induces estrus in gilts within 10-20 days.

29
Q

What effect does the sight, smell, and suckling of a calf have on LH levels postpartum?

A

It decreases LH levels, inhibiting cycling and ovulation (lactational anestrus).

30
Q

What is a recommended practice for weaning calves to enhance reproductive cycling?

A

Wean calves for 48 hours at the beginning of the breeding season

31
Q

What effect does weaning calves have on LH levels and estrus onset?

A

It increases LH levels and leads to the onset of estrus

32
Q

How does improving nutrition affect cycling rates in cattle after weaning?

A

It increases the cycling rate from 40% to over 75%

33
Q

What is the combined effect of weaning sows and boar exposure?

A

Approximately 90% of sows will be in estrus within 10 days after weaning

34
Q

What is flushing?

A

When you increase level of prebreeding nutrition

35
Q

When does flushing work best?

A

Start 2-3 weeks ahead of breeding season

Works better in thin compared to fat ewes/cows

36
Q

Why is the luteal phase P4 dominant?

A

due to the CL

37
Q

What happens when estrus ends in the cow? (Overview of the rest of the cycle)

A

-When estrus ends and the cow ovulates, she forms a CL that produces P4 through the luteal phase of the cycle.
-When she isnt pregnant, the endometrium releases prostaglanin which will lyse the CL, P4 levels will drop and she will come into estrus
-Estradiol and LH levels increase when shes in estrus and developing follicles and ovaries (follicular phase)

38
Q

How do you shorten the luteal phase and what point does it mimic?

A

shorten by inducing luteolysis by giving a prostaglandin shot

mimics what happens naturally at day 16-17 of eyes

39
Q

what are some disadvantages of prostaglandins

A

-only works on a mature CL
-not all animals will response
-some dise effects like sweating, diarrhea, colic, crampiness

40
Q

Can you use lower than label doses of prostaglandins to try and avoid side effects?

A

Yes, results are just as effective

41
Q

Why doesnt prostaglandin injections work in anestrus animals?

A

because it only works if you give it to animals with a mature CL (>6 days post ovulation)

42
Q

Do prostaglandin injections synchronize ovulation

A

Nope. just induces estrus. range of 2-5 days after injection that animal will come into estrus

43
Q

How can you prolong the luteal phase?

A

administer progesterone or synthetic progestagens

44
Q

What happens when you provide an exogenous P4?

A

It mimics CL presence = suppresses LH release during treatment which suppresses estrus and ovulation = LH builds up in the pituitary gland and when the P4 source is taken away = surge of LH = estrus = ovulation

45
Q

What are some available forms of progesterone? (5)

A

-Intravaginal devices
-Oral preparations (MGA or altrenogest)
-Daily injections of P4
-Long acting injections of altenogest or P4
-Ear implants

46
Q

What are some hormones that we can use to control the follicular phase? (6)

A

-PMSG (eCG)
-HCG
-GnRH (or synthetic deslorelin)
-estrogens
-FSH
-LH

47
Q

What happens when you use GnRH to control the follicular phase?

A

It stimulates LH and FSH. Mostly its used for its LH activity to induce ovulation though

48
Q

Wha are some examples of GnRH products and what it does in MARES

A

deslorelin to induce ovulation in mares

49
Q

Wha are some examples of GnRH products and what it does in CATTLE

A

cystorelin, fertiline

depending on when its given, GnRH will induce ovulation OR emergence of a new follicular wave in cows

50
Q

What does hCG do in mares?

A

Acts like LH. Used to induce ovulation in mares

51
Q

What do estrogens do in cattle?

A

Its used to induce estrus, ovulation or emergence of new follicular wave. Banned from food producing animals in USA and Europe

52
Q

How can you increase the number of follicles? when is it normally used

A

Give folltropin; FSH which stimulates follicular growth and development

often used for superovulation im embryo transfer programs

53
Q

where is PMSG produced naturally in the mare?

A

produced by the endometrial cups from day 35-120 of pregnancy in the mare

54
Q

What is the difference in the effect of PMSG is mares vs ruminants

A

Mares = mostly LH activity during pregnancy

Ruminants = acts like FSH which stimulates follicular development

55
Q

what is PMSG used for in sheep

A

out of season breeding

56
Q

what is PMSG used for in cows and sheep

A

superovulation

57
Q

What is a combination program? example in mares

A

use of multiple hormones for specfic reasons. programs are species specific

P4 and estradiol in mares

58
Q

What does control of follicular waves allow for?

A

More precision for timed AI

Theriogenology (25 decks)

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