Breeding horses

Question 1

At what age do mares and stallions go through puberty?

Answer 1

1-2 years old

Question 2

At what age can you breed mares? What is the optimum age?

Answer 2

2 years old

Optimum = 5-6

Question 3

What is the optimal BCS at conception?

Answer 3

3

Question 4

What should be done to athletic horses before conception and why?

Answer 4

‘Let down’ 1 month before conception

Athletic fitness suppresses regular ovarian function

Question 5

Why may horses with a winter coat struggle to conceive?

Answer 5

Winter coat = rarely exhibits regular cyclicity

Question 6

It is essential for horses to have integrity of the 3 seals in the caudal repro tract. What are these?

Answer 6

Vulva seal
Vestibule seal
Cervical seal

Question 7

What happens if the seals of the caudal repro tract are insuffiecient?

Answer 7

Air borne contamination

Causes endometritis

Question 8

What degree should the craniocaudal vulva slope be? What can be done to alter this?

Answer 8

10 degrees of vertical

Vulvo-plasty

Question 9

What type of breeders are horses?

Answer 9

Seasonal, long day polyoestrus breeders

Ponies very seasonal

Question 10

When is horse repro status maximal?

Answer 10

During longest day length - Spring to early Summer

Question 11

How can lighting be used for breeding mares?

Answer 11

Extend light to 16 hours a day - switch on just before sunset
Effect in 2-3 months

Question 12

In Spring, horses have irregular oestrus behaviour and multiple follicles on the ovary. How long is the normal cycle in a horse?

Answer 12

21 days

Question 13

How long is oestrus in a horse?

Answer 13

3-7 days

Question 14

When does ovulation occur in a horse? Where do horses ovulate from?

Answer 14

24-48 hrs before end of oestrus

Ovulator fossa

Question 15

Are the corpus luteum palpable on a horse? How many follicular waves do they have?

Answer 15

No

Usually one follicular wave but can have two

Question 16

How long is diestrus (not receptive) in a horse?

Answer 16

14-17 days

Question 17

When does spontaneous luteolysis occur in a horse? What hormone causes this and where is it released from?

Answer 17

13-16 days after ovulation

PGF2a - from endometrium

Question 18

Superovulation is the drug induced production of multiple eggs for IVF. What anatomical fetaure of the horse stops super ovulation from being possible?

Answer 18

Ovulatory fossa

Question 19

At what ages does an embryo become reabsorbed if it dies?

Answer 19

0-40 days

Question 20

At what age does an embryo become stillborn/premature if it dies?

Answer 20

300-335 days

Question 21

If a horse has a uni-cornual twin pregnancy, what is the outcome for the foetuses?

Answer 21

Usually one survives

Question 22

If a horse has a bicornual twin pregnancy, what is the most likely outcome for the foetuses?

Answer 22

One foetus aborts

physically destroy smaller twin

Question 23

What causes a foetus to die in a twin pregnancy?

Answer 23

Placental insuffficiency

Question 24

How can pregnancy diagnosis be carried out in a horse?

Answer 24

Rectal ultrasound
Rectal palpation
Blood endocrinology

Question 25

At what day of the pregnancy can ultrasound be used? What about rectal palpation? What about blood endocrinology?

Answer 25

Ultrasound from day 11 Manual from day 30 eCG in blood from day 40

Question 26

What is the HBLB code of practice?

Answer 26

Mares certified free of transmissible ventral disease before arriving for swabs (Clitoral and endometrial swabs)

Question 27

What hormone can be given if corpus luteum are minimum, and you are preparing a mare for stud? What does this cause?

Answer 27

PGF2a | Luteolysis

Question 28

How can teasing be done for mares?

Answer 28

Vasectomised stallion

Question 29

What size should corpus luteum and follicles be?

Answer 29

>35mm for CL | Follicles 2x10mm

Question 30

What needs to happen before a natural service with a mare?

Answer 30

Wash vulva and penis immediately before Restrain mare with twice and hobbles Protect mares neck with neck cover Breeding rolls to limit penetration

Question 31

At what age do stallions usually become used for natural service?

Answer 31

3-5 years old

Question 32

What are the 5 function requirements for a stallion?

Answer 32

``` Libido Mount and serve Semen quality and quantity Free from disease Longevity ```

Question 33

How does exercise and access to the outside affect a stallions hormone levels?

Answer 33

Increases testosterone

Question 34

What should the scrotal witdth of a stallion be and at what age?

Answer 34

81 mm at 2-3 y/o 85 mm at 4-6 y/o 95 mm at 7+ y/o

Question 35

What % of their BW should stallions consume? And what proportion should be roughage and protein?

Answer 35

2-3% of BW per day 50% should be roughage 10% should be protein

Question 36

What is a common nutritional problem with stallions?

Answer 36

Obesity - mating is not intensive like sheep (do not need high BCS)

Question 37

What vitamin do they require and how is this supplied?

Answer 37

Vitamin A | Leafy greens

Question 38

In which horses is AI prohibited in?

Answer 38

Thorough bred

Question 39

What is the normal behaviour leading up to semen collection in stallions?

Answer 39

Immediate interest and erection in 2 mins Ready to mount straight after erection Ejaculate after 5-6 pelvic thrusts

Question 40

How long does sperm survive when fresh, chilled and frozen?

Answer 40

``` Fresh = 72 hrs Chilled = 36 hrs Frozen = 12 hrs ```

Question 41

When should insemination take place?

Answer 41

48hrs before to 6 hrs after ovulation (fresh) 24hrs before to 6 hrs after ovulation (chilled) 12 hrs before to 6 hrs after (frozen)

Question 42

When does the udder develop prior to foaling?

Answer 42

3-6 wks prior

Question 43

What is teat waxing? When does it occur?

Answer 43

A way to tell she will give birth - droplets form at bottom of each teat = colostrum 6-48hrs prior to birth

Question 44

What happens in preparation of foaling?

Answer 44

``` Udder preparations Teat waxing Ligaments soften Drop in body T Milk electrolytes ```

Question 45

Horses are unique in the way their oestrogen and progesterone levels change prior to foaling. Describe how the hormone levels change

Answer 45

Oestrogen decreases | Progesterone increases for few weeks then rapidly declines in days before parturition

Question 46

What is different about the placenta of the horse?

Answer 46

It is 'inside out' | Has a calcified remnant of the yolk sac

Question 47

What happens to the navel of a foal?

Answer 47

Ruptures within minutes of birth