Lecture 19 - 20

What is the Thoroughbred birthday?

Set on 1st August. or January 1st in NH

What is the standardbred birthday

1st September

When does breeding season begin usually

September 1st

What type of seasonal breeders are mares

Long day breeders

What is the length of a mare's oestrus cycle? How long does oestrus last

Approximately 21 days. Oestrus lasts 5 days

What is foal heat and the period length

Foal heat = the first heat cycle a mare goes through after foaling

10 days post foaling

Name some common signs of oestrus in mares.

• The mare seeks the presence of a teaser stallion.

• Signs include squealing and vulval "winking."

• Increased frequency of urination can also indicate oestru

What is a key indicator that a mare is ready to breed?

The presence of an ovulatory follicle detected via ultrasound, or increasing uterine oedema or cervix relaxation

What is the optimal breeding condition of mares

• Teasing behaviour is positive.

• Dominant follicle is larger than 30 mm (grows approximately 5 mm/day).

• Uterine oedema is observed (scale of ~2)

What is the desired per cycle fertility rate for thoroughbred mares?

60-85% for thoroughbreds

What are some common causes of infertility or apparent infertility

• Embryonic Death: Up to 40 days post mating.

• Extrinsic Factors:

  • Poor management practices or inadequate condition of the mare.

  • Stallion infertility.

  • Timing of the breeding season relative to daylight.

• Intrinsic Factors:

  • Age-related issues.

  • Hormonal and physical abnormalities (e.g. ovarian or uterine issues).

  • Infectious diseases such as endometritis.

What procedure distinguishes between infectious and non-infectious endometritis?

Uterine Biopsy.

What is a uterine lavage used for for management of mare fertility

Procedure to clear debris, exudates, and treat infections.

What is a caslick vulvoplasty procedure used for for management of mare fertility

Involves the closure of the upper vulva to prevent bacteria from entering the reproductive tract.

How many covers can a stallion cover typically

typically good stallions cover over 100 mares but the really high end stallions can cover more than 200

What is a typical coverage routine for stallions

• One or two covers per day across 6 days with a day of rest.

• Two covers daily for 8 days with a follow-up of 2 days’ rest

What is a shuttle stallion

Stallions that fly across country to breed with mares in different hemispheres, enhancing genetics and extending breeding seasons.

How do you manage stallions well?

• Provide individual paddocks to prevent fighting.

• Maintain large, airy loose boxes to avoid stress and boredom.

• Disease Control Sampling for infections and pathogens (tetanus, strangles EHV, EAV, Hendra

• Good condition 3/5

• Hygiene practices

What are you semen evaluation measurements

• pH: Optimal range is 7.3-7.7.

• Motility: Assessed on a warmed microscope slide on a 0-5 scale.

• Morphology: Live to dead sperm ratio should be evaluated.

• Concentration: Measured using a haemocytometer or automated analyst (target of 30-600 x 10^6/ml).

• Bacteriology: Includes leukocyte counts.

What are the types of breeding permitted in the Thoroughbred industry?

Natural breeding.

What is a significant benefit of Artificial Insemination (AI) in breeding?

A single stallion can breed many mares. Mares and stallions don’t have to be co-located, can reduce risks for handlers and animals, minimises disease transmission

What % of mares produce a live foal, and when do foal losses tend to occur

Approximately 70% of TB mares produce a live foal, with potential losses occurring after day 40 post-conception.

When does pregnancy diagnosis occur ? How do you do it

• Ultrasound: Usable from day 10 post mating (routine around day 14).

• Rectal Palpation: Effective from day 18 but becoming less reliable for twin identification beyond this point.

• Clinical Pathology Samples:

  • Oestrone Sulphate: Detectable from day 60, indicates viable foetus and placenta.

  • Equine Chorionic Gonadotropin (eCG): Present between days 40 and 120, used for viability assessmen

What is the incidence of twins, how is it managed ?

Up to 10%

• Intervention is manageable prior to day 16 while embryos are still movable, allowing for separation.

• If pregnancy is terminated before day 35, the mare can resume cycling and further attempts for a single pregnancy can be initiated

  • After this period, endometrial cups form and produce eCG, sustaining di-oestrus state regardless of the embryo viability

What is the gestation length of mares

Typically between 320 to 365 days, average around 340 days

What are the 3 stages of parturition ?

1. Stage I (1-4 hours): Signs include restlessness, sweating, and laying down.

2. Stage II (5-20 minutes): Rapid delivery of the foal; longer than 60 minutes could be fatal for the foal.

3. Stage III (1-3 hours): Expulsion of the placent

What is a stud owned mare vs a client owned mare

A client-owned mare is a mare owned by a third party, who pays a stud fee to breed it with the stud's stallion. A stud-owned mare is a female horse owned by the breeding operation itself

How long should you isolate new or infected horses for

At least 2 weeks

How should you swab mares for infections and what are you testing for

• Most mares:

  • Swab from clitoral fossa prior to oestrus covering

  • Swab from endometrium at the oestrus of covering

• For walk-in, high-risk mares:

  • Must have swab negative before arriving at stud

Test for

• Contagious Equine Metritis (Taylorella equigenitalis)

• Klebsiella pneumoniae and Pseudomonas aeruginosa (and occasionally other bacteria)

When should weaning of foals typically occur?

Around 6 months of age.

What does the term 'coprophagic behaviour' in foals refer to?

Foals consuming their own feces, necessitating regular worming starting from 2-3 months

When do you typically vaccinate foals

3-4 months of age once mAb start waning

What is creep feed and when do you introduce for foals

Creep feed = High energy and high protein (15%) feed

Introduce creep feed starting from 4-6 weeks, aiming for up to 1 kg per day by 3-4 months

What causes Developmental Orthopaedic Disease (DOD).

Contributing factors include trauma, rapid growth rates, large body size, hormonal variations, and genetic predispositions

Nutritional Influence:

• Excess energy intake, inadequate protein, imbalance of calcium and phosphorus, and trace minerals deficiency are critical factors

What is 'foal management' focused on immediately after birth?

Monitoring for standing and suckling and colostrum intake and conditions such as neonatal isoerythrolysis

What are the three categories of brood mares?

• Maiden: Not previously had a foal

• Barren: Previously had a foal but not currently pregnant

• Brood Mare: Currently pregnant, may or may not have a foal at foot

What nutritional management should be followed for brood mares?

• Rising plane of nutrition (flushing) at least 4-6 weeks prior to covering

• Maintain body condition score (BCS) not exceeding 3 out of 5 to avoid obesity

What are some common veterinary vaccinations recommended for young horses?

Tetanus and Strangles vaccines. But also hendra in north east australia

When do yearling sales typically occur

February, March, April, and May

How are vets involved in pre-purchase examinations

• Routine veterinary attendance at all major thoroughbred yearling sales

• Typical components:

  • Soundness/conformation examination

  • Clinical examination (may be limited during sales)

  • Pre-sale endoscopic examination of laryngopharynx

  • Interpretation of repository radiographs

What are horse repository radiographs

36 radiographic views of limbs and joints obtained within six weeks of sale enabling vets to view prior to auction for informed decision making

What is an example of DOD

• Osteochondrosis (OC): Failure or abnormal maturation of cartilage

• Osteochondrosis Dissecans (OCD): Progressed OC resulting in cracks and fissures in cartilage

• Physitis (Epiphysitis): Inflammation of the physis or metaphyseal growth plate

• Angular Limb Deformities (ALD): May be congenital or acquired, commonly requiring correction

• Flexural Deformities: Impediment in the ability to straighten or extend legs, resulting in knuckling appearance

• Subchondral Cystic Lesions: Secondary to OCD or trauma to weight-bearing joints

• Cuboidal Bone Malformation: Delay in endochondral ossification of cuboidal bones in the knee