Ruminant and Porcine Breeding Management Flashcards
estrous behavior is __ hours in dairy cattle and __ hours in beef
7, 12-18
dairy breeding management aims for year round ___ and a __ month calving interval per cow so __ is more commonly preferred
production of milk, 13, AI
after the voluntary waiting period for dairy cows, insemination should happen within __ if combining estrus detection with timed AI
30 days
__ is the largest energy demand in the dairy cow repro cycle
lactation
_ months breeding + __months pregnant/lactating + __ months pregnant/dry = 13 months
2,9,2
the purpose of beef breeding management is __. Spring calving is bred __ to __ while fall calving is bred __ to __
sale of calves at weaning, may to august, december to January
what is the most common breeding method in beef?
natural
__ pregnancy success is aimed for in beef cows with __ pregnant in the 1st 21 days
> 95%, 60-65%
signs of behavioral estrus
- tail twitching or walking with tails elevated
- clear, thick mucous discharge from vulva
- mounting
what is a teaser male (rams/bucks)?
vasectomized or epididectomized that blocks sperm transport but retains sexual behavior
*can still transmit venereal dz *
what can affect heat detection?
weather, malnutrition, stress
heat detection rate
number of cows bred divided by number of cows eligible to get bred over a 21 day period
conception rate
the percentage of the number of cows that conceive divided by the number bred at the time of pregnancy check
pregnancy rate
the percentage of cows eligible to become pregnant in a given timeframe that actually become pregnant
what is the AM-PM rule for AI? who does it apply to?
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
what are the two options for manipulation of the estrous cycle?
shorten (prostaglandin) or lengthen(progestins) the luteal phase
GnRH agonist __ LH/FSH from the anterior pituitary which does what?
stimulates, resets the follicular wave to trigger LH surge causing ovulation
Does PGF travel systemically?
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
in order for lutalyse to be effective cows must be __ with a __, adequate __ and time postpartum
cycling, CL, nutrition
at what time in the cycle can PGF2alpha be used successfully?
day 5-17 (cow must be in diestrus for it to work)
how is PGF2alpha administered in a herd setting to control estrus?
- 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)
what are progestins and what are they used for?
progesterone analogues (ex. melengesterol acetate, CIDR implants)
mimic the luteal phase (makes the body think a CL is present even if its regressing)
Melengesterol Acetate (MGA)
generally used in feedlot situations to suppress estrus/used for synchronization and increased rate of weight gain/feed efficiency
CIDR implant
intravaginal drug release of progestins that are absorbed through the vaginal mucosa to induce estrus/synchronize estrus
GnRH agonists
admin after dominant follicle selection and resets the follicular wave
OV- Synch
commonly used in dairy cows
- GnRH on Monday
- PGF next monday (d7)
- GnRH wednesday (d9)
- breed 8-18 hours later
CO- Synch Protocol
commonly used in beef cows bc requires less handling
- GnRH on monday
- PGF on following monday (d7)
- GnRH and AI ~54-66 hours later
Select Synch
- GnRH monday
- PGF following monday (d7)
- heat detect and AI day 6-13
why is synchronizing estrus in small ruminants difficult?
small ruminants have 3 to 4 follicular waves
what effects ovulation in small ruminants?
breed, season, nutrition will all affect ovulation rate
estrus cycle manipulation methods in small ruminants
photoperiodic treatments
male effect
dormitory effect
adapted nutrition
hormonal treatments
photoperiodic treatments
altering the daylight length
1. begin with long days
2. decrease day length to trigger melatonin release from the pineal gland
the male effect
- 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
how is the male effect used?
- 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
dormitory effect
introduction of one ewe in estrus to a herd causes most (80%) of ewes to come into estrus within a few weeks
adapted nutrition
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
PG- 600 (what is it and how is it used)
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
how is natural breeding timed/tracked in small ruminants?
male is left with females for 1.5 cycles and wear markers to keep track of which females were bred
why can sheep not be AI’d through transcervical insemination? what must be done instead?
too many cervical ring make it difficult to advance the AI probe
alternative method is laproscopic AI with injection of sperm into the uterus
methods to advance puberty in non-cycling gilts
- mature boar exposure combined with transportation stress
- relocate to group with mature females
- PG-600 (induces estrus in 55% gilts withing 7 days), must be old enough (165 days) and large enough (185lbs)
how can weaning be used to sync estrus in pigs?
wean all females after 21 day lactation –estrus occurs within 4-7 days
altrongest (matrix) in pigs
synthetic progesterone feed additive used for 14 days then stopped – females go into estrus within 4-7 days after withdrawal of the drug
why are prostaglandins not used to sync estrus in pigs? what situation can it be used in?
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
how often should pigs be checked for estrus? when is the best time to AI?
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
