A11: Technology of race horse breeding. Traits, and genetic improvement of race horses. Flashcards
what are the 2 types of horse racing?
Flat Racing: Usually retire earlier. Good stallions → more valuable as stud animals.
Jump Racing:
-> Fit horses may continue racing up to 12 years.
-> Primary trait is speed at gallop (basic TB selection), although has low heritability (h^2 = 0.2-0.3) → No great correlation with sire performance & offspring performance. Problem in that TBs often bred more for name/pedigree rather than actual
ability. Time, cumulated prize, amount of money, handicap number, etc. are also considered as racehorse traits
-> Secondary Traits: Stamina, Persistence in performance, Early maturity Sex is also important (colts).
When does the TB breeding season take place?
Thoroughbred breeding season in northern hemisphere runs from Feb - June/July → aim to ensure foals are born in the earliest months of year to ensure as much time to mature before racing (if TB is born in northern hemisphere are considered 1 year older on January 1st vs in southern hemisphere they are considered 1 year old on August 1st).
What type of insemiantion must be used?
Must Use Live Cover (stallion physically covers the mare).
* Artificial insemination lead to further narrowing of gene pool (if 1 stallion could cover thousands of
mares).
* Dramatic fall in covering fees (bad for stud farms).
* More difficult recorded keeping/pedigree documentation.
When can a breeding stallion cover a mare?
may cover 4 mares per day (7 AM, midday, 4 PM, 8 PM & midnight if absolutely necessary).
Must allow some flexibility for when mares are ovulating.
What is the process to prepare mares for covering?
Checked for inoculations (venereal diseases, etc.), tail bandaged, washed down, covered with leather cape (to prevent being bitten by stallion) & back hooves booted (a kick in the b*lls could put a stallion out of action for ~ 10 days).
What is race horse breeding based on?
Pedigree,
Conformation,
Performance
What is the ‘speed gene’?
Identified via MAS (marker assisted selection).
MYOSTATIN (MSTN) is a strong inhibitor of muscle growth. it has been identified in several species (belgian blue cattle).
It has been isolated and sequenced from TBs.
A genetic code that substituted a cytosine ‘C-allele’ to a thiamine ‘T-allele’ within the MSTN gene can determine racing performance.
What are the 3 distinct genotype groups?
C/C genotype: short distance races (sprinter).
C/T genotype: middle distance races
T/T genotype: long distance races (longer stamina).
how does selection and testing for the speed gene improve TB horse breeds?
crossing a heterozygote (C/T) mare yo a C/T stallion can produce: C/C (25%), C/T (50%), T/T (25%).
