Exam 2 - Livestock Reproduction Flashcards
puberty in bovine
age?
bos taurus vs indicus?
season?
body weight?
4mo - 2 yr
bos taurus before indicus
autumn births before spring births
40-50% mature weight
bovine seasonal or non-seasonal breeders
non-seasonal
polyestrous
bovine estrous cycle?
estrus length?
ovulation?
21 days
12-18hrs
30hrs after estrus onset
what is a clinical significance in cows that means it is too late to breed
bloody vaginal mucus
how many follicular waves do cattle most commonly have
2 follicular waves
how many ovulations do cows have per cycle? do beef or dairy cattle have double ovulations more commonly?
1 ovulation
double ovulation more common in dairy cows
what is a definitive sign of estrus in cows?
standing to be mounted
methods of estrus detection in cows
- pressure sensitive mount detectors and tailhead markings
- estrus detector animals
- electrical resistance of repro tissue fluids
- pedometer
- electric pressure-sensitive mount detectors
OV synchronization is good for what in cows
improves preg rates
reduces days open in lactating dairy cows
caprine (goats) puberty
age?
weight?
6-8 mo
60% body weight
caprine seasonal or non-seasonal breeders?
seasonally polyestrous “short day breeders”
august-march (esp Oct-Dec)
caprine estrous cycle
21 days
what is the buck effect
intro of a buck will synchronize a group of doelings in breeding season
what is unique about a caprines estrus
no progesterone priming
difference between a cow and goat in metestrus
goats refuse to mate until CL formation
goats do not have vulvar hemorrhage
how to detect estrus in goats
- teaser or breeding buck
- buck jar
- side/side or up/down tail flagging
- cervix speculum exam
how can you extend the luteal phase/delay estrus & ovulation?
progesterone products
how can you shorten the luteal phase/induce luteolysis?
prostaglandin products
puberty in sheep
dependent on?
what must they experience?
suffolk & western white face…
what may be seen?
depends on nutrition, adequate rate of growth & photoperiod
experience long days then decreasing daylength
30 weeks
silent ovulation or short luteal phase
sheep seasonal or non-seasonal breeders?
seasonally polyestrous “short day breeders”
july-march
sheep estrous cycle
17 days
what do sheep and goats have in common about metestrus?
refuse to mate until CL formation
what is the most powerful stimulus of estrus detection in sheep?
novel ram introduction
what is the star system in sheep
5 lambs in 3 years
camelid puberty
age?
weight?
12 mo
65% adult weight
what is different about camelid estrous cycles, coitus and ovulation?
sexual receptivity up to 36 days - female in “cushing” position
prolonged coitus 10-50min
induced ovulators - ovulation inducing factor (OIF) in semen (nerve growth factor beta)
how can you induce ovulation in camelids?
GnRH, LH or hCG
breed with vasectomized male
porcine puberty
age?
depends on?
5-8mo (165 days)
season, social environment, nutrition
& boar exposure
what is the primer effect in pigs?
stimulation of puberty due to boar pheromones
what is the signaler effect in pigs?
elicitation of lordosis (standing heat) due to boar exposure
ideal environment for pigs?
pens 6-12 ideal
pigs estrous cycle
21 days
what is a pigs ovulation rate affected by
age
breed
nutrition
estrus detection in pigs
boar for detection
lordosis
why do you house a boar away from females?
cannot maintain lordosis due to muscle exhaustion
why is it impractical to induce luteolysis with PGF2alpha in pigs?
unlike other LA, pigs are not responsive until late in estrous cycle (days 12-14)
pig mating systems
- insemination not more than 24 hr before ovulation or 4 hr after
- pen mating (boar:sow 1:8)
- hand mating
- AI (majority, 1:150 boar:sow)
