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Next Gen Exam 1 > Ruminant breeding management > Flashcards

Ruminant breeding management Flashcards

1
Q

Goal of dairy breed management

A

Purpose is year-round production of milk

Lactation follows parturition

Goal is to maintain a 13 month calving interval per cow

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2
Q

The goal in the dairy industry is to maintain a ______ ________ calving interval per cow

A

13 month

2 months Voluntary wait period + ~9m pregnant + ~2m to get pregnant again (ideally less than 30 days) = 13 month calving interval

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3
Q

AI more commonly performed in which type of cow?

A

Dairy
Easy to handle for heat detection and/or estrus synchronization
Don’t require a bull on site
Able to use sexed semen (if need replacement females)

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4
Q

Main factors that affect reproductive performance in dairy cattle

A

Voluntary waiting period (VWP)
Insemination rates
Pregnancy per AI
Pregnancy loss

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5
Q

Voluntary Waiting Period in dairy cows

A

Set amount of time post-partum that an animal is not being bred
Usually around 60-80 days
Factors: herd pregnancy rates, parity, milk production

Allows uterus to recover from infection & involute

Allows cow to achieve positive energy balance and resume cycling

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6
Q

The Voluntary Waiting Period in dairy calves is typically ___-___ days

A

60-80

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7
Q

~90-95% of all cows should be inseminated within 30 days of the VWP if combining….

A

Estrus detection and timed AI

Dairy Records Management System (DRMS) important for tracking

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8
Q

Purpose of Beef Breeding Management

A

Purpose is sale of calves at weaning

Defined breeding seasons – aide with marketing
Spring calving – breed May to August
Fall calving – breed December to January
Easier to identify herd problems (calving distributions)

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9
Q

Beef cattle are commonly bred in the ______ and calve in the _____

A

Spring calving – breed May to August
Fall calving – breed December to January
Easier to identify herd problems (calving distributions)

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10
Q

Breeding methods commonly used in beef breeding management

A

Natural – most commonly used
Limit bull exposure to 60-75 days (3 opportunities to breed)
Can market calves in “groups”

AI (+/- estrus detection) + clean-up bull
Still need to limit bull exposure
Advantages & disadvantages to including AI

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11
Q

Disadvantages of AI use in Beef Herds

A

Requires estrus synchronization for timed AI (labor & drug expenses)

Handeling

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12
Q

Advantages of AI use in Beef Herds

A

Easier introduction of desirable genetics

Shortened calving season (50-60% preg rate)

Increased calf uniformity (calving at same time)
-Earlier births during calving season = heavier weaned calves
–Potential increased return of $25-$40 per calf

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13
Q

Beef Herd Reproductive Profile Components

A

Length of calving season
# days from birth of first calf to the birth of final calf

of calves born in the calving season divided by the # of cows exposed during the previous breeding season
-Total # of calves born in a breeding group, including mortalities
-Total # cows exposed in a breeding group

Distribution of births in the calving season
-Timing of births throughout the calving season aggregated to 21-day intervals

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14
Q

Reproductive Goals for Beef Cows

A

≥ 95% pregnancy success (total)

1st 21 days: 60-65% pregnant (2/3)

2nd 21 days: ~23% pregnant; bull can pick up fertile cows that failed to conceive or maintain pregnancy that have 60-70% chance of getting pregnant still

3rd 21 days: ~7-8% pregnant (remaining cows that have a 60-70% chance of becoming pregnant

% open ≤ 5%

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15
Q

Importance of estrus detection in cattle

A

To determine when to AI (dairy cattle, beef cattle [rarely], small ruminants, swine)

To confirm that females are in heat before performing AI (i.e., if breeding in large groups); assess response to synch protocols
-Beef cattle, small ruminants

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16
Q

How estrus is detected in cattle

A

Direct observation of eligible females showing signs together or with a teaser male (behavior)

Detection aids: heat mount detectors, pedometers, etc.

Increased movement & standing

Hormonal assessment
Not practical in production setting

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17
Q

Behavioral estrus signs in cow

A

Tail twitching or walking with tails elevated
Clear, thick mucous discharge from vulva
Mounting (females in heat should stand to be mounted)

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18
Q

Dairy Cattle: Trained observer should be able to detect heat efficiently by observing the herd for ____-___ min in the morning and evening

A

30-60
(May want to increase frequency with heifers)

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19
Q

Small ruminants/ swine can check for behavioral estrus 1-2x per day with…

A

fence line male exposure

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20
Q

Teaser Male Preparation

A

Vasectomized or Epididectomized
Blocks transport of sperm from testes to urethra/ductus deferens
Advantage: Retains sexual behavior
Disadvantage: Risk of venereal disease transmission

Penile translocation (“Gomer” Bull)
Surgical procedure that transplants the sheath/penis to the fold of the flank to prevent female penetration (usually)
Advantages: Normal erection & behavior; Decreased risk of venereal disease transmission
Disadvantage: bull may become frustrated & lose sexual drive; can “figure out” out to penetrate female (oftentimes performed with a vasectomy)

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21
Q

Factors that affect heat detection in cattle

A

Adverse weather conditions or sudden change in weather
Malnutrition
Stress (rough handling, transportation, noise, overcrowding, heat/cold stress)

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22
Q

two primary causes of poor reproductive performance and low reproductive efficiency in dairy cattle are…

A

Failure to detect heat and errors in heat detection

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23
Q

Results of Inadequate Heat Detection

A

Undetected heats = longer calving intervals, lower lifetime milk production, fewer calves
Breeding cows unsuitable for insemination -> ↓ conception rates and wasted semen and time ($$$)
Combinations of unrecognized estrus and low conception rates may result in inappropriate culling of normal cows
Insemination of pregnant cows mistakenly identified in heat can result in abortion

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24
Q

Heat Detection Rate (HDR) equation

A

Number of cows bred divided by the number of cows eligible to get bred over a 21 day period

100 cows in a herd are eligible for breeding
35 cows submitted for AI
(35)/100=
Heat Detection Rate = 35%

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25
Q

Conception Rate (CR) equation

A

The percentage of the number of cows that conceive (actually get pregnant) divided by the number bred at the time of pregnancy check

35 cows submitted for AI
14 cows that were bred become pregnant
(14/35)=
Conception Rate = 40%

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26
Q

Pregnancy Rate equation

A

The percentage of cows eligible to become pregnant, in a given time frame, that actually become pregnant

Time frame = 21 days (dairy)
Can apply to bull bred herds, AI bred herds, or a combination of both
PR = HDR x CR

14 cows become pregnant
Pregnancy rate = 35% x 40% = 14%
OR
14 cows pregnant/ 100 eligible cows

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27
Q

Artificial Insemination Timing in ruminants

A

AM-PM rule

If a female is observed in estrus in the AM, she should be bred via AI in the PM
Conversely, if observed in the PM, breed in the AM

Females will be bred via AI and semen placed in the uterine body ~ 12-20 h before ovulation occurs

Sperm placed 12-24 h prior to ovulation
Viability of sperm 24-30 h
Egg viability 8-12 h after ovulation

28
Q

Reasons for manipulation of the estrous cycle

A

Convenience (do it all at same time)
Fertility control
Management procedures (know when they calve)
Artificial insemination/embryo transfer techniques

29
Q

2 main options of manipulating estrus cycle

A

Shorten the luteal phase
Lengthen the luteal phase

30
Q

Prostaglandin (PGF2α) agonists can be used to…

A

Lyse the CL and shorted the luteal phase to get animal cycling and in heat faster (estrus ~3days post admin)

Effective 5-17 of the estrous cycle during diestrus (CL MUST be present and have the receptors present)

Lutalyse (dinoprost) & Estrumate (cloprostenol)

Labor intensive- heat detection is required

31
Q

Progestins can be used to…

A

Lengthen the luteal phase (prevent ovulation) - Mimics the luteal phase (makes body THINK there is CL)

(Negative feedback of GnRH)

MGA – oral
Progesterone in oil - injectable
CIDR pessaries – most commonly used

32
Q

GnRH agonists can be used to…

A

Stimulates LH/FSH from anterior pituitary

“Resets” follicular wave OR triggers ovulation
Administration AFTER dominant follicle selection- Ovulation
Emergence of new wave in 1.5-2 days- “Resets” the follicular wave

Administration BEFORE selection
-No effect on progression of existing follicular wave

Cystorelin and Factrel most commonly used

33
Q

OV-Synch protocol

A

Commonly used in dairy cows
4 handlings

GnRH on Monday (d 0)
PGF on following Monday (d 7)
GnRH again on Wednesday (d 9)
Breed 8-18 hours later

Alterations:
+ CIDR (between GnRH and PGF) (improve efficacy)

34
Q

CO-Synch protocol

A

Commonly used in beef cows
Less handling (3)

GnRH on Monday (d 0)
PGF on following Monday (d 7)
GnRH and AI ~54-66 hours later

Alterations
+/- CIDR

35
Q

Select-Synch protocol

A

GnRH on Monday (d 0)
PGF on following Monday (d 7)
Heat detect and AI day 6 – 13 (if CIDR not being used)

Alterations
+/- CIDR
Give GnRH and TAI all non-responders 72-84 h after PGF

36
Q

Artificial Insemination techniques in cattle

A

Uterine body deposition: 15 million sperm (most common)

Cornual insemination: 2 million sperm (less common unless high value sperm)

37
Q

Sheep and goats at beginning and ending of breeding season or post-partum will have increased…

A

Frequency of cycles

More commonly seen in goats than sheep
Photoperiod or nutrition

38
Q

Estrus duration in sheep

A

30-36h

39
Q

Estrus duration in goats

A

24-48h

40
Q

Sheep and goat behavior when coming into estrus

A

Expression of immobilization reflex in response to male nudges, including serial mounting and copulation
Swollen vulva, mucoid discharge turning cloudy

41
Q

In goats and sheep, When double ovulations occur, usually derived from…

A

The same follicle wave
Sometimes, can come from two consecutive follicle waves

42
Q

In More prolific breeds of sheep and goats the dominant astral follicle achieves….

A

Smaller maximum sizes

43
Q

Ovulation rate in small ruminants is affected by….

A

Breed
Season
Nutrition

44
Q

Estrous Cycle Manipulation in small ruminants is useful for…

A

Allows for distribution of milk and meat production throughout the year
Labor saving for breeding and kidding
Induction of estrus in transition periods and during winter anestrous
Synchronization for breeding (AI or natural)

45
Q

Estrous Cycle Manipulation in small ruminants

A

Photoperiodic Treatments
Male Effect
Dormitory Effect
Adapted Nutrition
Hormonal treatments
NOTE: most drugs not approved for use in goats in U.S.
Combination of all of these

46
Q

Photoperiodic Treatments in small ruminants

A

Altering the length of the daylight (need facilities)
Begin with long days to prepare for stimulatory effects of short days (otherwise become photo-refractory)
Decreasing day length will trigger melatonin release from the pineal gland
*works best during transition periods not to keep them cycling because they can have a photo refractory period and stop cycling

Field conditions: melatonin implants
Synergistic with progesterone to induce cyclicity and pregnancy in the anestrous animal
Not available in U.S.

47
Q

Goats and sheep are more complicated to synchronize since…

A

They have on average 3-4 waves per cycle

48
Q

The Male Effect

A

Brings sheep/ewes out of anestrus period quicker

Ewe and goat isolated for 30 days (no sight, smell, sound) then male introduced

Male introduced abruptly for 48h

Ewes and does pick up pheromones and trigger LH secretion and induces “silent” ovulation (no estrus behavior since no progesterone priming on hypothalamus has occurred)

Works to up regulate estrogen receptor production on hypothalamus so she can respond and show estrus behavior

Ovulation occurred so there is now a CL present to prime the hypothalamus to create more estrogen receptors

Likely short cycle but after she should be able to show estrus behaviors on next cycle since estrogen receptors formed

49
Q

The Dormitory Effect

A

Introduction of ewe in estrus

25% of other ewes will respond and come into estrus
Remaining 80% will respond in a few weeks
Great to advance breeding season without the expense of drugs or a ram

50
Q

Adapted Nutrition “Flushing”

A

↑ nutrition (energy) before/ early breeding season -> ↑ ovulation rate -> ↑ twinning rate

Feed 1 lb of high-energy supplement (corn, oats, barley etc.) per day @ 2-3 weeks BEFORE BREEDING

Success affected by age, genetics, body condition, time of year
-Best response with marginal body condition

51
Q

Hormone Treatments in ewe/goats- Prostaglandins

A

Lyses the CL
Single or double injections, 11-12 days apart- Estrus in 24-72 hours
2nd dose will result in tighter synchrony
*Must be cycling (i.e., in season)

52
Q

Hormone Treatments in ewe/goats- Progesterone/progestins

A

Sponges – various products
Medroxyprogesterone acetate
Flurogesterone acetate

CIDR (330 mg) progesterone
Most commonly used in the U.S.

Melengesterol acetate (MGA) in feed
0.25 mg/hd once per day x 14 days
-Legality concerns (extra-label usage)

Length of time is usually 5 or 14 days
Estrus shown in 24 to 96 hours after withdrawal (varies with other components in protocol)

53
Q

Ovulation Induction during in small ruminants

A

eCG/PMSG (equine chorionic gonadotropin/ pregnant mare serum gonadotropin)
**FSH-like activity (superovulation)
Acts directly on the OVARY to stimulate ovulation
PG-600: eCG/hCG combined
Longer half-life (36 h) compared to GnRH agonists (0.5-1 h)

GnRH agonists
Acts on the anterior PITUITARY to stimulate LH/FSH activity
Short half-life

54
Q

eCG in the ewe/sheep acts on the ________ while GnRH agonists act on the _________ _______.

A

eCG- Acts directly on the ovary FSH like activity (longer T1/2)

GnRH agonist- Acts on anterior pituitary to stimulate LH and FSH (shorter T1/2)

55
Q

Ovulation Induction during Early Seasonal Transition

A

Early Transition
Progestin for >14 d (18-21) + PG600® on the day of or 24-48 h before progestin removal
Ewes – 5 day progestin treatment

56
Q

Ovulation Induction during later Seasonal Transition

A

Late Transition
Ram/Buck Effect
Progestin treatment similar to early transition
Photoperiod manipulation (begin during summer)

57
Q

Ovulation Induction Outside of Breeding Season

A

Progestin for >14 d (18-21)+ PG600® the day of or 24-48 h before progestin removal – sheep 5 days

Artificial lighting programs
Mimic long days for ~ 60 d followed by short days for 60 days or natural light
(Administration of melatonin (not available in U.S.))

58
Q

Sheep Reproduction Goals

A

easy management to provide lambs for year-round marketing and increasing production per ewe

Cornell star system- peak efficiency (not done in small settings)
There are three groups of ewes during any 73-day period. The groups of ewes are those that are:
Lambing (first 30 days) and lactating ewes.
Breeding (first 30 days) and gestating ewes.
In the last half of gestation.

59
Q

Small Ruminant Natural Breeding most commonly used for production of…

A

Meat and fiber

60
Q

Small Ruminant Natural Breedings should be planned around desired date(s) of…

A

Parturition
Male should be left in for 1.5 cycles (32 days in goats or 27 days in sheep)

61
Q

Male-to-female ratios in small ruminant natural breeding will vary based on…

A

Age/SC of male
size of mating area
whether females are synchronized (higher male to female if all sync)

Markers useful to keep records for lambing/kidding

62
Q

Small Ruminant Artificial Insemination deposition

A

Natural- semen deposited in Vagina

For AI usually use frozen, thawed semen and smaller dose so uterine body deposition preferred

Used mostly for breeding stock producers, hobby farms, and show animals

Fresh semen can be deposited intravaginal, cervical, or transcervical intrauterine

Laparoscopic intrauterine insemination recommended for frozen semen (though acceptable rates can be obtained in goats with transcervical; NOT SHEEP)

Recommended to check quality of frozen semen before use due to lack of standards for quality control

63
Q

Advantages of AI in small ruminants

A

Maximal use of superior sires
Elimination of need for males on farm
Inexpensive semen costs
Decreased risk for venereal diseases
Improved herd management

64
Q

Disadvantages of AI in small ruminants

A

Cost for AI and semen equipment (LN2)
Increased labor for estrus detection/synchronization/ insemination
Lack of standardized procedures for cryopreservation of semen
Lack of suitable sire proofs for production traits (risk of spreading less desirable traits)

65
Q

In small ruminants (esp. sheep) need to use _________ for intrauterine insemination

A

Laparoscopy

Goats may be able to get acceptable rates but not in sheep (cervical ring)

Cervical Rings:
Ewe: 2-7 (avg.5)
Doe: 4

Next Gen Exam 1 (16 decks)

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