1. Domestication of small ruminant 양과 염소의 가축화

A16 Origin and domestication of small ruminants (sheep and goat), their species characteristics

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Species groups:

Sheep (ovis)	Wild sheep Diff. chromosomes number 54-58 Typical centric fusion of chromosomes when crossing	Wild goat (Capra, caprini)	Wild goat  twirl horned, capra falconeri. 60 chromosomes
	oriental wild sheep (mouffloans) ovis ammon musimon, 54 chromosomes		Prisca goat  capra prisca
	Asiatic wild sheep (argali)  ovis ammon ammon (56) & ovis vignei arkal (58)		Rock goat  capra ibex
	Snow sheep  Ovis Nicola Thick horn sheep  ovis dalli Big horn wild sheep  ovis Canadensis		Bezoar goat  capra aegagrus
	Domesticated sheep  ovis aries		Domesticated goat  capra domestica

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Domestication of sheep and goats

• Sheep domestication is believed to have occurred 9-11,000 BC
• Goat domestication: 10 000 BC.
• Sheep and goats were the 2nd to be domesticated after the dog! in SW asia
• Semi domestication: hunting, natural selection, flocks, herding with dog
• Full domestication: production, selection, shelter, meat, milk, fleece wool production
• White fine wool sheep appeared (north African): merino sheep, roman colonization, about 100 BC
• The fine wool- sheep developed in Islamic spain (750- 1000 A.D)
• Breeding in England: long wool and short wool mutton breeds! (Bakewell and Ellman, 19 and 20 century)
• Dispersion of merino breeds throughout the world “super- production” after 19 century
• Intensive milk & mutton / chevon breeds ​

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Major milestone in the historical development in sheep breeding

• ​Very early domestication typical (8-10k BC)
• Ancestry (partly confusion, disagreement, polyphyletic?).
• Breed differences, large, extremes.
• Important domestication changes (coat!)
• Dependence on human civilization (sheep!)
• De-domestication (returning to wild life) not typical or rarely (goats return easily): feral sheep and goat populations on islands.
• successful Crossing (hybridization) of wild and domesticated sheep and wild goats, despite diff. chromosome number.
• Interspecies-hybridization of sheep and goat means some problems:
• ram (male sheep) × doe (female deer) possible
• bock × ewe (female sheep) never.

​2n chromosome number:

- sheep: 54, (wild sheep: 54- 58);

- all goats: 60

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Important goat breeds:

• ​Milk, meat breeds- Saanen and its breed derivatives
• Meat (but also milk) producing breeds- boer goat, Anglo- Nubian goat
• Mohair and pashmina (goatwool) producing goat breeds- Angora, American cashmere
• Local, rare, special breeds- African dwarf goat. Genetic preservation, resources, pets, expirimantion

​Microevolutionary consequence

Phenotype (body shape, form, conformation):	Range of heights & weights according to breed Typical weight: Ewes 45-100kg (female sheep) Rams 45-160kg (male sheep)
Coat & wool:	continuous growth, fiber length and diameter, 1st 2nd hair follicle
Wool color	Brown, black, white, agouti
Tail length	Long, short & fat-tailed breeds Fat- rumped breeds Goat: no tail changes
Horns	May be horned, polled, have horns in one sex or both sexes Also variability in size & shape of horns (if present) Sex influenced expression
Ears	Long/ dropping, less/ well developed
Reproduction, prolificacy	Mono / polyestrous Increased testicular size Seasonal polyestrous Higher fertility
Milk production	different udder size & form (significant changes in goat)
Muscle hypertrophy	Can happen In sheep  Callipyge (round buttock)

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Diff between seep and goat

	sheep	Goat
Preferred environment	Temperate & lowland areas Steppes (grassland) Savannah Varied soils  Medium rainfall	Tropics Highland & forest areas Sandy, well-drained soils
Nutrition	Grazers Less selective	More selective and preference Tree leaves Higher digestion efficiency
Body characteristics	More uniform horns No split in upper lips Wooly Tails hang downwards No male caudal scent glands	Mobile, split upper lip Tails point upwards Highly intelligent Beards common Male caudal scent glands present
Horns	More uniform horns Sheep breeds are often naturally polled (no horns)	Heteronymous horns (not uniform) polled goats are rare
Intelligence & behavior	Flocking instinct (together as a herd) Calm Less susceptible to stress	No flocking instinct (they are not going together as a band) docile Intelligent Active temperament Great susceptibility to stress
Reproduction	Twinning common in both
Fiber	Mainly woolly, rarely hairy	Rarely wooly, mostly hairy
Milk production		Goat milk is more commonly produced !