breeding horses

mare suitability

puberty 1-2 yo

breed from 2 yo

• optimium 5-6yo

• marked decreas fertility >15yo

optimal BCS = 3/5 at conception

athletic - let down 1 month prior

winter coat - rarely exhibit regular cyclicity

perineal and pelvic conformation

essential - integrity of 3 seals(vulva, vestibule, cervix)

• want at least ¾ of vulva sitting below pelvic floor

• opening of vulva sjould cause air to move in(indicates functioning seal)

• if vulva seal is poor then will aspirate faeces 

cranio-caudal vulva slope < 10 degrees off vertical

at least 80% of vulva ventral to dorsal ischial limit

lighting regime

extend light to 16hrs/ day

at end day - switch on 30 mins before sunset

constant between days

200 W bulb for 12’x12’ box

effect in 60-90 days - start <15 dec for feb-mar breeding 

adjust husbandry - loose winter coat, increase metabolism 

tricks mare into thinking days are already getting longer

gives foal advantage when theyre a few yrs older

• will be born in early jan if bred in feb(need to start 60 days before)

oestrus cycle 

spring transition - irregular oestrus behaviour, ovary=multiple anovulatory follicles 

normal cycle 

• mean 21 days 

• oestrus 3-7 days

• ovulation 24-48hrs before end of oestrus 

• ovulation fossa

clinical aspects 

• CL not palpable as deeply embedded in wall of ovaries

• 2nd follicular wave possible -can make them show behavioural oestrus signs due to amount of oestrogen being produced, dont mate again check levels of oestrogen first 

• ovulatory F >35mm

long day breeders, late winter early spring when they start ovarian activity again

reproductive status

fertilisation rate(healthy young mares) - 90%

pregnanacy rates per cycle - 60%

pregnancy rates per season - 50-90%

foaling rates per breeding season 

• feral horses 23-85%

• domestic horses 50-80%

gestation length variable 

• full term = 320+ days 

• avg thoroughbred = 341 days (± 2 wks)

significance of pregnancy rates

high value of breeding animals

owner expectation for foal

can’t rebreed that season if pregnancy lost after 35 days due to pregnancy cups -

• progesterone levels stay high and prevent her from returning to oestrus, by time returns to oestrus its too late in yr

if infectious - impact future fertility 

reputation loss for stud  

significance of foaling rates

economic viability of commercial studs

• each resident mare foaling annually 

• stallion fees claimed confirmation of pregnancy or production of live foal (NFFR = non-foal free return)

breeding horses maintained for long - value increases as early progeny proven 

pregnancy loss - mare

embryo is up to point where placenta is fully formed and implantation takes place, after this its a foetus

• if then lose pregnancy its abortion 

pregnancy loss rates

outcome of twin pregnancies

20% of ovulations are twins 

of twin conceptions 70% are unicornual 

total loss/survival: 20% abort both, 60% single foal 

ED = embryo death(<day 40)

abort = abortion (day40-300)

fate of bicornual twins

A = one foetus gets more nutrients than the other so 1 dies and the toxic products produced causes the other to die

pregnancy diagnosis

ultrasound - earliest diagnosis = day 11

manual palpatation - earliest diagnosiis = day 20 

blood endocrinology - earliest diagnosis = day 40 

breeding mares factors 

costs - transport to stud, stud fee, groom and in foal fee, veterinary fees(pregnancy diagnosis, vaccinations, if foal has any problems, testing for manurial disease), livery at stud

facilities - foaling box, suitable paddock, expertise 

time - care and management, loss of saddle horse from mid pregnancy

health - HBLB code of practise 

mares certified free of transmissible venereal diseases before arriving at stud 

stud may repeat swabs on arrival or during subsequent oestrus

additional precautions if mare deemed high risk 

culture by approved lab

report on an official lab certificate 

stud procedures

luteolysis - using prostaglandins - short cycles her so she can be serviced

monitor oestrus 

• scan ovaries and uterus to see when ovulation is likely

• teasing = hot, cold, indifferent response ( use a vasectomised male or stallion to do so)

• - indiffernt if has a foal at foot 

• cervical changes 

for AI - order semen/ induce ovulation 

• induce ovulation using GnRH to mimic hypothalamus at ovulation or give LH direct(ECG)

remove shoes 

service

post service check at 24hr - ovulation, mating-induced endometritis( small amount of free fluid in uterine horns)

pregnaancy diagnosis(PD)

monitoring progress - mare

natural service

vulva and penis of breeding pair washed immediately before covering

mare should be adequately restrained(hobble so cant kick and injure stallion) and protected(neck cover) 

breeding rolls to limit penetration - vigorous stallion, small or caslicked( procedure to fix poor vulva conformation) mare 

• placed across peronuem of mare as distance holder 

stallion considerations

puberty at 12-24 months

used typically from 3-5 yrs old - proven competition performance

5 functions of breeding male

• libido(sex drive)

• be able to easily mount and serve

• have good semen quality and quatity

• free from disease

• longetivity and maintain body condition 

nutrition - stallion

consumes 2-3% of BW/day

≥ 50% should be roughage

10% Crude Protein (12-14% for younger)

•Vitamin A if housed inside over breeding season - grass has plenty 

Obesity common problem

• average to serve around 25 mare per season = not alot of activity so doesnt need more than maintanence 

semen collection steps

expected stallion behaviour

immediate interest in mare

erection <2 mins of contact with mare

ready to mount 5-10 secs after erection 

ejaculation after 5-6 pelvic thrusts

foaling prep signs

udder = 3-6 w before

teat fill = 7-10 d before

teat waxing = 6-48h before

ligaments sofetening = 1-3w before

vulva swells and relaxes = 0-24h before

drop in body temp = <4h before

milk electrolytes = 24-48h before

• calcium >10mmol/l

• K+ becomes higher than Na+

milk pH <6.5 = 24h

last weeks = decrease E, increase P4

post-partum procedures

mare

• placenta- fully expulsed - 11% of foals birth weight , normal =inside out

• udder

foal

• vigour - sternal 1-2mins, suckle reflex 20mins, standing 15-120 mins, nurse<4hrs

• navel

• colostrum