I. Horse, dog and cat breeding Flashcards
(109 cards)
Topic 1
– Evolution and domestication of the horse, micro-evolutionary
consequences
- Taxonomy
- Interspecies hybridization
- Evolution
- Domestication
- Consequences of domestication
- Basic Terminology
Topic 1
– Evolution and domestication of the horse, micro-evolutionary
consequences
1. Taxonomy
KPCOFG: KingPopeComeOverFuckGirls
ACMPEE: AnyCuteMayPoopEqualExtra
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Perissodactyla
(non-ruminant, hooved animals) - Family: Equidae
- Genus: Equus
7. Species: • Wild horses – Equus ferus Boddaert • Prewalski horse/Taki – Equus ferus Prewalski • Tarpan – Equus ferus ferus • Domestic horse – Equus caballus Subgenus Asinus (African ass/donkey) Species • Equus asinus/africanus
Topic 1
– Evolution and domestication of the horse, micro-evolutionary
consequences
2. Interspecies hybridization
- Mule
– Male ass (jack) & mare. Usually STERILE - Hinny/jennet
– Female ass (jenny) & stallion. Less common. Also INFERTILE - Zebra mules
- (zorse, zonkey)
Topic 1
– Evolution and domestication of the horse, micro-evolutionary
consequences
3. Evolution
- Evolution is well documented.
- Most important evolutionary forms of horse:
- Eohippus
- Mesohippus
- Mio-, mery-, pliohipps
- Equus
- Most important changes: Size, toe reduction, diet (omnivores ! herbivores),
teeth
Topic 1
– Evolution and domestication of the horse, micro-evolutionary
consequences
4. Domestication
- Occurred ~5000-6000 years ago
1st – Central Asia, later in Persia, Egypt & Europe (3000-4000BC) - Based on mitochondrial examination,
- Tarpan/Tarpan subspecies is main ancestor.
- Wild horses: Przewalkski horse is only remaining wild spp
- Feral horses: Have domestic ancestors but were born & live in wild
- (‘dedomesticated’) ! Mustangs, Bramby
Topic 1
– Evolution and domestication of the horse, micro-evolutionary
consequences
- Consequences of domestication
1• Fusion of chromosomes o Wild horses – 66/64 o Asses – 62 o Domestic horses – 66/64 o Only assumed (has not yet been proved. Chromosome no. of Tarpan is unknown)
2• Mutations & selection
o 200+ breeds, breed groups & types
3• Size variation
o Height at withers (50-180cm) ! Horses & ponies
o Dwarfism – Falabella, Shetland pony
4• Build & conformation
o Draft horses, light horses etc.
o Breed characteristics (Roman nosed, dished face)
5• Weight variation
o 50-1200kg
6• Diet – Less effective feed conversion
7• Accelerated ageing
8• Reduced immune system & increased sensitivity to certain diseases
(e.g. decreased resistance to respiratory diseases)
9• Colour variations
10• Sexual activity
o Poorly expressed sexual dimorphism
o Reduced fertility in some breeds
o Monoestrus ! seasonally polyoestrus
Topic 1
– Evolution and domestication of the horse, micro-evolutionary
consequences
- Consequences of domestication
SHORT
1• Fusion of chromosomes 2• Mutations & selection 3• Size variation 4• Build & conformation 5• Weight variation 6• Diet 7• Accelerated ageing
8• Reduced immune system & increased sensitivity to certain diseases
9• Colour variations
10• Sexual activity
Topic 1
– Evolution and domestication of the horse, micro-evolutionary
consequences
6. Basic Terminology
- FOAL: Horse of either sex <1year old
- YEARLING:
Horse of either sex between 1 & 2 years old - COLT: Male horse <4years old
- FILLY: Female horse <4 years old
- MARE: : Femal horse >4 years old
- STALLION: Entire (non-castrated) male horse >4 years old
- GELDING: Castrated male of any age
- RIG: Stallion with an undescended testicle
Topic 2
–Breeding goals and use in horse breeding, most important performance traits
(race, sport, others)
- Use of horses throughout history
- History of horse breeding
- Breeding systems/methods
Topic 2
–Breeding goals and use in horse breeding, most important performance traits
(race, sport, others)
- Use of horses throughout history
1• Transportation
o Riding – “saddle horse”
o Driving – “harness horse”
2• Work – Farming, carts, ploughing, cavalry, police, ranching etc.
3• Food – Meat, milk
4• Companionship (pleasure riding, pleasure driving)
5• Therapeutic purposes
6• Sport – Hunting, racing, eventing
7• Medicine – Globulin & eCG (equine choriogonadotropin) production
8• Housing, instruments – Horse hair
Topic 2
–Breeding goals and use in horse breeding, most important performance traits
(race, sport, others)
- History of horse breeding
1• ARABIAN horse ! Earliest documentation of breeding of horses by Bedouin
people in Middle East
2• Akhal-Teke ! Bred for war & racing in West-Central Asia
3• NOMADS of Mongolian Steppes have bred horses for several thousand years
4• MEDEVIAL Europe ! Specific breeding of horses for war
5• North Africa & Middle East ! Muslim warriors bred lighter horses for
speed & agility
- Later, in Europe, Europeans incorporated genetic traits of oriental horses to
improve the speed of native breeds. - Renaissance period: “Haute ecole” riding
Popular with the nobility
- Development of breeds such as Lipizanner - Thoroughbred: “Ultimate racehorse”
Warmblood: Developed during the 17th & 18th centuries for use as carriage
horses
Easily adapted to modern use as competition horses
Topic 2
–Breeding goals and use in horse breeding, most important performance traits
(race, sport, others)
3. Breeding systems/methods
Selection of animals to be mated depends on intended use of animal
Must have a clear breeding goal
Knowledge of basic genetics:
1• Mendelian genetics – colour
2• Population/quantitative genetics
– polygenic traits, performance, speed,
strength, conformation
- Understanding of reproductive cycle & fertility
- PURE BREEDING
• Inbreeding: Inbreeding coefficient should NOT EXEED 0.1-0.3
• Line breeding: Repeated BACK CROSSING used for character fixation
- CROSSBREEDING
a• Blood refreshment:
Crossing of individuals of same breed but
different familial lines to increase vigour
b• Single crossing: One-time crossing
c• Grading up:
Regular crossings throughout more generations to improve breed/produce new breed
d• Synthetic breeds:
A planned gene pool of a horse breed
e• Terminal crossings: Utilises heterosis
- INTERSPECIES HYBRIDS
- Mules etc.
Topic 3
– Marking and identification of the horses, principal coat colours and inheritance, the behavioral vices
SHORT
- Monogenic (qualitative) characteristics of the horse – Coat colours
- DNA colour test
- Behavioural Vices
Topic 3
– Marking and identification of the horses, principal coat colours and inheritance, the behavioral vices
1. Coat colours
Monogenic (qualitative) characteristics of the horse – Coat colours
- Basic colours:
- Black, bay (brown), chestnut - Modified variants:
- Grey, roan
- Rules of Mendelian inheritance are valid for coat colour
- Roan ! Intermediate inheritance
- Coat colour may be a breed characteristic (Suffolk Punch, Cleveland Bay, Fresian
etc. ) - Some colour genes are molecular genetically UNDETECTABLE
(dun, chestnut, tobiano, overo spotted)
Topic 3
– Marking and identification of the horses, principal coat colours and inheritance, the behavioral vices
1. Coat colours
COAT COLOUR LOCUS
A – Agouti
• Distribution of black coloured hair
E – Melanin extension/non-extension
• Extension of RED pigments
(red, chestnut, sorrel !
ee = ability to produce BLACK pigment in SKIN, but appears RED in HAIRS)
G - Grey
• Exclusion of pigment from hair over time (born dark, lightens with age ! progressive greying)
R – Roan • Mixing of dark & light hairs • Black-, blue-, bay- & red roan • Appaloosa characteristics may be related to the roan gene D – Dilution/dominant • Dun horses
W – White
• Inability to form pigment
• WW homozygotes ! Embryonic lethal
C - Colour • S – Spotting (Appaloosa; blanket, marble, leopard, snowflake, spot) • P – Piebald/skewbald • O – Ovaro spotted • T – Tobiano
Topic 3
– Marking and identification of the horses, principal coat colours and inheritance, the behavioral vices
2. DNA colour test
Basic colour is determined by the
- white (W),
- grey (G),
- extension (E) &
- agouti (A) genes.
W, G ! Dominant
In absensce of W or G, the colours of: - bay, - black, - chestnut & - sorrel = are controlled by variations at the E & A locus.
Topic 3
– Marking and identification of the horses, principal coat colours and inheritance, the behavioral vices
3. Behavioural Vices
Crib biting
Weaving
Windsucking
Topic 4 – Main reproduction features and traits of the horse
(breeding season, AI, raising foals)
SHORT
Reproductive traits of horse (polygenic/quantitative characteristic)
- Puberty:
- General reproductive features
- Breeding season:
- Ovarian cycle of mare
- Cycle length:
- Ovulation:
- Corpus luteum (CL)
- Heat (oestrus)
- Practical heat detection - Frequent disorders:
- Covering
- Gestation
- Gestation period
- Fertilization:
- Implantation:
- Pregnancy diagnosis
- Pseudopregnancy: - Environmental effects/factors
- Photoperiod:
- Condition
- Hormones
9- Advanced reproductive techniques
• Embryo transfer
• Gamete intrafallopian transfer (GIFT)
• Egg transfer
Topic 4 – Main reproduction features and traits of the horse
(breeding season, AI, raising foals)
Reproductive traits of horse (polygenic/quantitative characteristic)
- Puberty:
Occurs btw 16-18 months
Full sexual maturity reached by:
2+ years (ave btw 3-5 years)
Topic 4 – Main reproduction features and traits of the horse
(breeding season, AI, raising foals)
Reproductive traits of horse (polygenic/quantitative characteristic)
- General reproductive features
- Uniparous
- Low reproductive potential
- Late puberty
- Seasonal sexual activity
o Mares are seasonally polyoestrus, except Camargue horse
(v. short season, essentially monoestrus)
• Frequent miscarriages
• Low pregnancy rate
Topic 4 – Main reproduction features and traits of the horse
(breeding season, AI, raising foals)
Reproductive traits of horse (polygenic/quantitative characteristic)
- Breeding season:
Feb-August
Fertility highest in March-June
Topic 4 – Main reproduction features and traits of the horse
(breeding season, AI, raising foals)
Reproductive traits of horse (polygenic/quantitative characteristic)
- Ovarian cycle of mare
1• CYCLE LENGTH: 20-21 days
Biphasic with luteal phase
2• OVULATION: Normally spontaneous
Occurs during last phase of heat
(4th/5th day)
One (occasionally two) egg(s) per ovulation
o TWIN ovulations rarely occurs
▪ Consequences of twin ovulations ! resorption, abortion 30%
▪ Twin-pregnancy is rare & undesirable (pathological trait)
3• CORPUS LUTEUM (CL)
o Persistency may occur causing anoestrus & missing cycles
o Heat can be induced in mares with a mature CL
4• HEAT (oestrus) o Lasts 3-5 (7) days o Foal heat (9th day after foaling) ▪ May be used for mating ▪ Fertile in 50% of cases
o Heat signs ▪ Relaxed, hyperaemic external genitals ▪ Frequent urination ▪ Raising tail ▪ Mucous discharge ▪ Desire for company ▪ Presenting to teaser stallion ▪ Teasing of other mares
o Practical heat detection
▪ LIVE COVER ! Mare is ‘teased’ several times with a teaser stallion.
Mares in heat will generally tolerate teaser or present herself to him
▪ VETERINARY determination ! - Ultrasound - Palpation; - Measuring hormone levels (LH, progesterone)
Topic 4 – Main reproduction features and traits of the horse
(breeding season, AI, raising foals)
Reproductive traits of horse (polygenic/quantitative characteristic)
- Frequent disorders:
- Anovulatory cycle (only follicular phase)
- Persistency & atresia of follicles
- Prolonged cycles
• Short, “split” & silent heat
(common in early & late season, signs of
sterility)
Topic 4 – Main reproduction features and traits of the horse
(breeding season, AI, raising foals)
Reproductive traits of horse (polygenic/quantitative characteristic)
- Covering
• LIVE COVER
(required for all Thoroughbreds)
• AI
o Semen is collected using an artificial vagina (AV) & processed in a
laboratory before freezing/chilling & transporting
o Plastic catheter is used intrauterine deposition of semen
o Semen motility of 50% + is successful
o Conception rate is 60-80%
o Advantages of AI
1▪ No contact between mare & stallion
• No accidents
• Reduces spread of venereal disease
2▪ International breeding programs are possible
▪ Less stress to animals (no travel required)
▪ More mares can be mated to a valuable stallion
3▪ Allows linebreeding !
Semen can be stored long after death
of a valuable stallion