Sheep and goat Flashcards
sheep domestication, feral
ovis aries = entirely domesticated sheep dep. on human for health and survival! mediterranian wild sheep is main ancestor! 2n= 54
Among the first to be domesticated around 9-11k years ago, small feral populations exist where there are no predators
microevolutionary consequences
phenotype according to breed, 45kg -100(female) /160kg(male), !! increased fiber length and decreased fibre diameter !!, white color was selected when breeding since they can be dyed, darker exist. varied tail length/thickness, no change in goat!, horns or polled in both sexes or one, varied shape
reproduction in microevolutionary changes
- went from mono to (seasonal) polyestrus, testicular size increased.
- significant changes in udder size and form in goat esp.
chromosome no. in sheep
domestic sheep: 2n = 54
wild sheep: 2n = 54-58 -> centric fusions in crosses
crosses are successful btw. domestic and wild sheep even with different no.!
goat ancestor and chromosome nr.
the bezoar goat is the main ancestor, all goats have 2n=60 ⇒ interspecies crosses are successful.
interspecies hybridization of sheep and goat
problems: ram*doe is possible occur naturally too! (male sheep, female goat), bock*ewe never!
GEEP, 1984
callipyge
mutation in sheep giving “beatutiful buttocks”, muscular hypertrophy (not in goat!)
sheep vs. goat environment
- sheep: temperate and lowlands, steppes, savannah
- goat: tropics, highlands, forest areas (mountain goat)
nutrition goat vs. sheep
- sheep: grazers, less selective
- goat: browsers, selective
body characteristics sheep vs. goat
- sheep: wooly, downward tail, no split upper lip, more uniform horns(often polled), flocking together(not very intelligent - just follows the one in front - herding!!)
- goat: split upper lip, hairy, inwards pointing tail, beard is common, very intelligent, rarely polled
twinning
twinning is common in both
sheep milk comp to other breeds
- (79.9) less water content than (around 90)goat, cattle and horse
- (7.2)more fat and (6.5)protein content than –=–(eq very little protein and fat! 1-2)
- (5.4)more lactose than goat and cattle, less (5.5) than horse
general about cows milk
rich in protein and Ca²⁺ source
general goat milk characteristics
similar to human milk (A2 protein, oligosacchrose), probiotics (gut flora), medium chain length makes it a quick energy source and not stored in the body as fat. lower lactose makes it easier to digest.
sheep milk general characteristics
less common since low production. Rich in fats and proteins -> cheese, yoghurt, more fat means more product per gallon of milk. good energy source (medum FA), high in A2, B12 and folate (B9)
basic mating systems of sheep and goat
flock/mass mating
harem mating
→natural sex ratio is 1:50
stud/hand mating - controlled by breeder
AI: cervical, transcervical, lapascopic
breeding value of goat and sheep
pedigree not so important, production, conformation and progeny testing is most important
sheep and goat breeding imp criteria
- lamb and muttom: meat prod (muscling, fat dceposition, gain)
- wool quality is the most important, cashmere (making pashmina) and angora goats(making mohair)
- milk prod: lactation, fertility, udder shape
- fur production in certain breeds e.g. karakul
purebreeding in sheep and goat
in smaller populations! inbreeding and line breeding (sheep is a sensitive species - inbreeding depression)
(improving and preserving breeds)
crosses in sheep
- *two-breed cross** is typical in e.g. southdowns ram and romney ewe.
- *rotational cross!**
optimize heterosis for meat production
lamb for meat, by products of sheep prod
new lamb crop: 15kg
light lamb: 25kg
heavy lamb: 40kg
tallow(talg) is a byproduct used for candles and soaps, gelatine
carcass traits of sheep
weight will be at 40-50%, quality, back fat thickness, fat around kidneys and loins=tallow
cuts: shoulder, rack, loin, legs
wool and fur traits in sheep
(fleece) grease vs. (clean fleece) wool weight: about 2-5kg
* *thickness**, primary(hair):secondary(wool) ratio, length and diameter of the fibers, wrinkles of skin fold: incr. fleece prod. surface!
milk production of sheep and goat: lactation performance, length, other
- *sheep**: 80-300L (600)
- *goat**: 60-1200L
- *length**: 100-300 in goat, 100-180 in sheep
(daily milk yield, fat and protein %, ease of milking, udder size and form
products of the goat
meat, milk(cheese) and wool (angora and cashmere goat)
alternative products: goat milk soap, leather, mohair and cashmere in fine garnments
breeding goals for goat
meat and fiber products, genetic variation across herd and continue with genetic diversity
the traits of milk sheep
- *prolific** (prod. lamb), early puberty, twinning rate 60-70%, 50-500kg/lactation lasting 150-200 days,
- *protein**: 5-6%
- *fat**: 6-7%
fur producing sheep
hairy sheep have little or no wool. no fleece means no shearing as hair will shed of (winter coats) -> can thrive in hot climates that wooly sheep cannot, save money.
2 types:
- *true hair sheep:** natural breeds from hairy ancestors.
- *improved hair sheep:** crossed with wool breeds to produce larger meat animals who grew wool in cold weather but shed it in the summer. many has large horns -> trophy huntig
goats milk nutrition and use
More (170)calories, protein and fat than (150cal)cow, less carbs and lactose
- coat cheese, since it has less lactose it is earier to digest than cows cheese
wool defects
- *dry wool:** less greasy and easy to pull out caused by chronic parasitosis intoxication e.g. arsenic, lack of phosphorus
- *greyish, mat wool:** lack or copper, zinc, vit. A
- *bad wool quality**: flourine poisening, chronic parasitosis
- *lighter streaks in pigmented wool:** sub clinical chronic lack of copper
reproduction traits of sheep and goat
seasonally polyoestrus, sexual activity is breed dependant, puberty is 6-15 months, breeding season is aug-feb(higher fertility) and jan-feb. Sexual pheromones are important! flushing (better nutrition bf. breeding) incr. no. of ovulations and more twinning/triplets.(1-4 eggs) laproscopic AI (right into uterine horns through abdomen, low success rate!) easy pregnancy detection - palpation from d90.
manegment systems
- (less input)*extensive: lambing once a year in spring (mating in august)
- (more input)*semi-intensive: lambing 3 times every 2yrs (flushing, short inactive/transitional period, biostimulation, heat detection
- (lots input)*intensive: continous oestrus activity and lambing, breeding out of season, regulated reproduction, inensive care, oestrus detection, intensive feeding, high quality managment
define sheep husnbandry
the raising and breeding of domestic sheep
shelter
paddocks, pens, barn (pasture - rage band flocks).
need to be kept dry 1-2d before shearing
water food and air
food: hay, grains and grasses - sheep are active grazers. usually fed twise a day or allowed to graze on pasture. need fans in hot weather, sheep like moderate temperature.
