equine reproduction

Question 1

TF of all domestic livestock species horses are the least successful

Answer 1

T

Question 2

how long is a horses gestation length

Answer 2

11 months

Question 3

what is the management of a mare and foal

Answer 3

• one foal per mare per year (in the wild theres 2 foals every 2 years)

Question 4

what type of breeders are horses

Answer 4

• seasonal breeders
• due to the horses birthdays, jan 1st a year after birthday
• so they want foals born- jan and feb, so they can be old as possible (feb 14 is the orine day)

Question 5

how long is an estrous cycle

Answer 5

• 21 day average
• 3-16 cycles/yr
• changes because of breeds and geographical location
• horses closer to the equater are likely to have more cycles
• horses farther from equater are likely to have less
• 4-7 day average

Question 6

what is a problem with insemination

Answer 6

• timing for insemination and breeding
• 24-48 hours before ed of estrous
• egg viable for 6-8 hours - decreases over time, as does concentration and motility

Question 7

how can you manipulate a breeding season

Answer 7

• march and feb are optimal breeding times
• increases with daylight increase
• because horses are daylight breeders, they need to think its daytime
• they also need hormones

Question 8

what are reproductive disfunctions of the mare

Answer 8

• aberrant estrous cycles
• endometritis

Question 9

cycling abnormalitites

Answer 9

• peristent CL prolonged diestrus
• peristent cl results from defective PGF2 secretion

Question 10

what is peristent estrus

Answer 10

• granulosa theca cell tumours

Question 11

what is split estrus

Answer 11

• 2-4 days of sexual receptivity
• stops 24-48 hours
• restarts

Question 12

what is silent heat

Answer 12

• during egg maturation they display no signs of being in heat

Question 13

failure to maintain pregnancy

Answer 13

• accelerated regeneration of post ovulation CL
• egg might have been fertilized, it will be lost
• no uncommon especially in thoroughbreds probably because they are watched more then other breeds

Question 14

what is endometritis

Answer 14

• inflammation of uterine lining
• primary cause of subfertility or infertility

Question 15

what are reproductive dysfunction

Answer 15

• defective perineal conformation
• pneumovagina - air is asperated in the vagina because of conformation
• caslicks surgery - sew part of it up, to reduce contamination

Question 16

gestation timeline

Answer 16

• implantation (8 weeks)
• penetration of uterine mucosa by chrionic villi (10 weeks)
• attachment complete (14 weeks)
• average 330-345 days
• range can be 310-370 days

Question 17

what can influence legnth of gestation

Answer 17

• age
• breed
• parity
• health status
  -fetal = gender, weight, twin/single

Question 18

what envionmental fator length of gestation

Answer 18

• climate/location
• month of breeding/foaling
• nutritional status
• housing : indoor vs outdoor

Question 19

causes of abortion

Answer 19

• uterine body pregnancy
• infection/ disease
• twinning
• uterine torsion
• twisted umbilicus
• abnormal fetus (genetic/toxic/spontaneous)
• mare malnutrition

Question 20

parturition stages

Answer 20

stage 1= dilation of the cervix (1-4 hours)
stage 2= expulsion of fetus (5-30 minutes)
stage 3 = expulsion of membranes (1 hour, retained fetal membrane is it takes longer then the hour)

Question 21

what is dystocia

Answer 21

• atypical or pathologic labour
• premature prolonged or arrested
• malpresentation (top cause of tough labour)

Question 22

steps for the neonate

Answer 22

• 20 minutes suckling reflex
• 1 hour standing
• 2 hours nursing

Question 23

reasons for neonatal losses

Answer 23

• failure of passive transport
• neonatal isoerythrolysis
• meconium impaction