Ruminant and Porcine Breeding Management

Question 1

estrous behavior is __ hours in dairy cattle and __ hours in beef

Answer 1

7, 12-18

Question 2

dairy breeding management aims for year round ___ and a __ month calving interval per cow so __ is more commonly preferred

Answer 2

production of milk, 13, AI

Question 3

after the voluntary waiting period for dairy cows, insemination should happen within __ if combining estrus detection with timed AI

Answer 3

30 days

Question 4

__ is the largest energy demand in the dairy cow repro cycle

Answer 4

lactation

Question 5

_ months breeding + __months pregnant/lactating + __ months pregnant/dry = 13 months

Answer 5

2,9,2

Question 6

the purpose of beef breeding management is __. Spring calving is bred __ to __ while fall calving is bred __ to __

Answer 6

sale of calves at weaning, may to august, december to January

Question 7

what is the most common breeding method in beef?

Answer 7

natural

Question 8

__ pregnancy success is aimed for in beef cows with __ pregnant in the 1st 21 days

Answer 8

> 95%, 60-65%

Question 9

signs of behavioral estrus

Answer 9

• tail twitching or walking with tails elevated
• clear, thick mucous discharge from vulva
• mounting

Question 10

what is a teaser male (rams/bucks)?

Answer 10

vasectomized or epididectomized that blocks sperm transport but retains sexual behavior

*can still transmit venereal dz *

Question 11

what can affect heat detection?

Answer 11

weather, malnutrition, stress

Question 12

heat detection rate

Answer 12

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

Question 13

conception rate

Answer 13

the percentage of the number of cows that conceive divided by the number bred at the time of pregnancy check

Question 14

pregnancy rate

Answer 14

the percentage of cows eligible to become pregnant in a given timeframe that actually become pregnant

Question 15

what is the AM-PM rule for AI? who does it apply to?

Answer 15

applies to ruminants only, a female observed in estrus in the AM should be bred by AI in the PM which is about 12-20 hours before ovulation occurs

Question 16

what are the two options for manipulation of the estrous cycle?

Answer 16

shorten (prostaglandin) or lengthen(progestins) the luteal phase

Question 17

GnRH agonist __ LH/FSH from the anterior pituitary which does what?

Answer 17

stimulates, resets the follicular wave to trigger LH surge causing ovulation

Question 18

Does PGF travel systemically?

Answer 18

NO, it is picked up by the ovarian artery through countercurrent exchange and delivered back to the ovary where it causes lysis of the CL

Question 19

in order for lutalyse to be effective cows must be __ with a __, adequate __ and time postpartum

Answer 19

cycling, CL, nutrition

Question 20

at what time in the cycle can PGF2alpha be used successfully?

Answer 20

day 5-17 (cow must be in diestrus for it to work)

Question 21

how is PGF2alpha administered in a herd setting to control estrus?

Answer 21

1. single injection – gives cows one injection on monday; 60-70% of cows will go into estrus, need to start watching for heat on wednesday (heat is 2-5 days post inj)

Question 22

what are progestins and what are they used for?

Answer 22

progesterone analogues (ex. melengesterol acetate, CIDR implants)

mimic the luteal phase (makes the body think a CL is present even if its regressing)

Question 23

Melengesterol Acetate (MGA)

Answer 23

generally used in feedlot situations to suppress estrus/used for synchronization and increased rate of weight gain/feed efficiency

Question 24

CIDR implant

Answer 24

intravaginal drug release of progestins that are absorbed through the vaginal mucosa to induce estrus/synchronize estrus

Question 25

GnRH agonists

Answer 25

admin after dominant follicle selection and resets the follicular wave

Question 26

OV- Synch

Answer 26

commonly used in dairy cows 1. GnRH on Monday 2. PGF next monday (d7) 3. GnRH wednesday (d9) 4. breed 8-18 hours later

Question 27

CO- Synch Protocol

Answer 27

commonly used in beef cows bc requires less handling 1. GnRH on monday 2. PGF on following monday (d7) 3. GnRH and AI ~54-66 hours later

Question 28

Select Synch

Answer 28

1. GnRH monday 2. PGF following monday (d7) 3. heat detect and AI day 6-13

Question 29

why is synchronizing estrus in small ruminants difficult?

Answer 29

small ruminants have 3 to 4 follicular waves

Question 30

what effects ovulation in small ruminants?

Answer 30

breed, season, nutrition will all affect ovulation rate

Question 31

estrus cycle manipulation methods in small ruminants

Answer 31

photoperiodic treatments male effect dormitory effect adapted nutrition hormonal treatments

Question 32

photoperiodic treatments

Answer 32

altering the daylight length 1. begin with long days 2. decrease day length to trigger melatonin release from the pineal gland

Question 33

the male effect

Answer 33

- isolated female from the sight, smell and sound of males for 30 days - introduce ram or buck to a group of transitional period females abruptly - can activate LH secretion and induce ovulation in 48 hours

Question 34

how is the male effect used?

Answer 34

- initial ovulation induction is often silent, female does not display estrous behavior because the hypothalamus does not have receptors for it yet-- female is not bred with initial ovulation - abnormal CL development and premature luteolysis occur in most females then they have a normal estrus with typical estrus behaviors

Question 35

dormitory effect

Answer 35

introduction of one ewe in estrus to a herd causes most (80%) of ewes to come into estrus within a few weeks

Question 36

adapted nutrition

Answer 36

feeding high energy supplement increases ovulation rate, making twins more likely in small ruminants; success affected by environment and other factors, works best on lean females

Question 37

PG- 600 (what is it and how is it used)

Answer 37

combo equine chorionic gonadotropin hCG combo use: acts directly on the ovary to stimulate ovulation by increasing follicle selection --increases twinning rate in small ruminants

Question 38

how is natural breeding timed/tracked in small ruminants?

Answer 38

male is left with females for 1.5 cycles and wear markers to keep track of which females were bred

Question 39

why can sheep not be AI'd through transcervical insemination? what must be done instead?

Answer 39

too many cervical ring make it difficult to advance the AI probe alternative method is laproscopic AI with injection of sperm into the uterus

Question 40

methods to advance puberty in non-cycling gilts

Answer 40

1. mature boar exposure combined with transportation stress 2. relocate to group with mature females 3. PG-600 (induces estrus in 55% gilts withing 7 days), must be old enough (165 days) and large enough (185lbs)

Question 41

how can weaning be used to sync estrus in pigs?

Answer 41

wean all females after 21 day lactation --estrus occurs within 4-7 days

Question 42

altrongest (matrix) in pigs

Answer 42

synthetic progesterone feed additive used for 14 days then stopped -- females go into estrus within 4-7 days after withdrawal of the drug

Question 43

why are prostaglandins not used to sync estrus in pigs? what situation can it be used in?

Answer 43

PGF2alpha is not effective in pigs until after day 12 of the cycle ( day 5 in other species) ---so it only shorts the luteal phase by 3-4 days use: administered 14 days after boar exposure to terminate pregnancy

Question 44

how often should pigs be checked for estrus? when is the best time to AI?

Answer 44

can be checked once or twice daily Gilts: AI twice, 12 and 24 hours after estrus is detected Sows: AI twice, 24 and 36 hours after estrus is detected