Exam 2 - Livestock Reproduction

Question 1

puberty in bovine
age?
bos taurus vs indicus?
season?
body weight?

Answer 1

4mo - 2 yr
bos taurus before indicus
autumn births before spring births
40-50% mature weight

Question 2

bovine seasonal or non-seasonal breeders

Answer 2

non-seasonal
polyestrous

Question 3

bovine estrous cycle?
estrus length?
ovulation?

Answer 3

21 days
12-18hrs
30hrs after estrus onset

Question 4

what is a clinical significance in cows that means it is too late to breed

Answer 4

bloody vaginal mucus

Question 5

how many follicular waves do cattle most commonly have

Answer 5

2 follicular waves

Question 6

how many ovulations do cows have per cycle? do beef or dairy cattle have double ovulations more commonly?

Answer 6

1 ovulation

double ovulation more common in dairy cows

Question 7

what is a definitive sign of estrus in cows?

Answer 7

standing to be mounted

Question 8

methods of estrus detection in cows

Answer 8

1. pressure sensitive mount detectors and tailhead markings
2. estrus detector animals
3. electrical resistance of repro tissue fluids
4. pedometer
5. electric pressure-sensitive mount detectors

Question 9

OV synchronization is good for what in cows

Answer 9

improves preg rates
reduces days open in lactating dairy cows

Question 10

caprine (goats) puberty
age?
weight?

Answer 10

6-8 mo
60% body weight

Question 11

caprine seasonal or non-seasonal breeders?

Answer 11

seasonally polyestrous “short day breeders”
august-march (esp Oct-Dec)

Question 12

caprine estrous cycle

Answer 12

21 days

Question 13

what is the buck effect

Answer 13

intro of a buck will synchronize a group of doelings in breeding season

Question 14

what is unique about a caprines estrus

Answer 14

no progesterone priming

Question 15

difference between a cow and goat in metestrus

Answer 15

goats refuse to mate until CL formation
goats do not have vulvar hemorrhage

Question 16

how to detect estrus in goats

Answer 16

1. teaser or breeding buck
2. buck jar
3. side/side or up/down tail flagging
4. cervix speculum exam

Question 17

how can you extend the luteal phase/delay estrus & ovulation?

Answer 17

progesterone products

Question 18

how can you shorten the luteal phase/induce luteolysis?

Answer 18

prostaglandin products

Question 19

puberty in sheep
dependent on?
what must they experience?
suffolk & western white face…
what may be seen?

Answer 19

depends on nutrition, adequate rate of growth & photoperiod
experience long days then decreasing daylength
30 weeks
silent ovulation or short luteal phase

Question 20

sheep seasonal or non-seasonal breeders?

Answer 20

seasonally polyestrous “short day breeders”
july-march

Question 21

sheep estrous cycle

Answer 21

17 days

Question 22

what do sheep and goats have in common about metestrus?

Answer 22

refuse to mate until CL formation

Question 23

what is the most powerful stimulus of estrus detection in sheep?

Answer 23

novel ram introduction

Question 24

what is the star system in sheep

Answer 24

5 lambs in 3 years

Question 25

camelid puberty age? weight?

Answer 25

12 mo 65% adult weight

Question 26

what is different about camelid estrous cycles, coitus and ovulation?

Answer 26

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)

Question 27

how can you induce ovulation in camelids?

Answer 27

GnRH, LH or hCG breed with vasectomized male

Question 28

porcine puberty age? depends on?

Answer 28

5-8mo (165 days) season, social environment, nutrition & boar exposure

Question 29

what is the primer effect in pigs?

Answer 29

stimulation of puberty due to boar pheromones

Question 30

what is the signaler effect in pigs?

Answer 30

elicitation of lordosis (standing heat) due to boar exposure

Question 31

ideal environment for pigs?

Answer 31

pens 6-12 ideal

Question 32

pigs estrous cycle

Answer 32

21 days

Question 33

what is a pigs ovulation rate affected by

Answer 33

age breed nutrition

Question 34

estrus detection in pigs

Answer 34

boar for detection lordosis

Question 35

why do you house a boar away from females?

Answer 35

cannot maintain lordosis due to muscle exhaustion

Question 36

why is it impractical to induce luteolysis with PGF2alpha in pigs?

Answer 36

unlike other LA, pigs are not responsive until late in estrous cycle (days 12-14)

Question 37

pig mating systems

Answer 37

1. insemination not more than 24 hr before ovulation or 4 hr after 2. pen mating (boar:sow 1:8) 3. hand mating 4. AI (majority, 1:150 boar:sow)