Chapter 20: Sheep Flashcards
1
Q
Sheep Rumen Volume
A
- 20-22 L (5 gal)
2
Q
Ram
A
- intact, mature male sheep
3
Q
Wether
A
- male sheep castrated before reaching sexual maturity
4
Q
Stag
A
- male sheep castrated after reaching sexual maturity
5
Q
Ewe
A
- mature female sheep
6
Q
Lamb
A
- 9-15 mo old young sheep
- male: ram lamb
- female: ewe lamb
- hogget: market animal that hasn’t reached full maturity
7
Q
Jug
A
- pen to keep lambing ewe and newborn lamb together
8
Q
calorie
A
- amount of energy needed to raise 1 g of H2O by 1 degree C
- 4.19 J = 1 cal
9
Q
Sheep Dentition
A
- 0/4, 0/0, 3/3, 3/3
- incisors, canines, premolars, molars
- total: 32 teeth
- 1 pair of permanent teeth per year
- only have top teeth at the back (molars)
- dental pad on top of mouth for lower teeth to rest against
10
Q
Diastema
A
- gap where canine teeth should be
- place to eject sticks, stones, seeds, pips, pits in grass
11
Q
Saliva
A
- produced by salivary glands
- provides liquid and enzymes
- sheep produce 10 L (2.5 gal)/day
12
Q
Sheep Taxonomy
A
Class: Mammalia
Order: Artiodactyla
Family: Bovidae
Subfamily: Caprinae
Genus: Ovis
Species: Ovis aries (descended from O. orientalis)
13
Q
Taxonomy Defined
A
- mammals have hair, produce milk
- artiodactyla are even-toed animals (sheep have 2 toes)
14
Q
Chromosomes
A
- 54 (27 pairs)
15
Q
Parturition
A
- process of giving birth
- for sheep: lambing
16
Q
Domestication
A
- 8000 BC for food
- from Mouflon sheep (O. orientalis - Middle East)
- 200 sheep breeds in world
17
Q
Fleece
A
- collective coat of wool
- sheared annually
- avg of 5 kg wool/sheep/shearing (12 lbs)
18
Q
Diameter
A
- measured in micrometers/microns
19
Q
Fine Wool
A
- <20 micrometers
- high-quality
- Merino, Rambouillet
20
Q
Long Wool
A
- > 30 micrometers
- more coarse
- used for rugs, carpets, heavy wool coats
- Border Leicester, Coopworth, Romney
21
Q
Medium Wool
A
- 20 < x < 30 micrometers
- dual purpose
- Dorset, Hampshire, Shropshire
22
Q
Long Wool/Carpet Wool Breeds
A
- > 38 micrometers
- Icelandic, Navajo
- cooler climates
- high yield, poor quality
- used for carpets and rugs
23
Q
Awassi Fat Tail Breed
A
- 25% of world population, esp underdeveloped countries
- big humps and tails full of fat
- 5+ kg of fat in tail
- useful for energy and fuel
- adipocytes - fat cells
24
Q
Katahdin, Barbados Breeds
A
- shed hair
- tropics
25
Q
Dorper
A
- medium wool
- sheds, not good for wool production (hair + wool)
- meat
26
Q
Suffolk
A
- meat production
- sires of offspring to produce fat lambs
27
Q
Jacob Sheep
A
- 4 horns, spotted skin
- genetic alterations in cells that make up hair, horns
- ornamental
- cottage industry
28
Q
Sheep Distribution
A
- TX has highest pop (feedlot ops)
- 2nd is CA (breeding, processed in NorCal, 3rd is Colorado)
- US: 5M sheep(used to be 40-50M)
- China: 130M sheep
- Aus and India: 70M sheep
- NZ: 30M sheep
29
Q
Reasons for US pop
A
- less consumption of lamb
- wool replaced by synthetic fibers
- sheep in Midwest are breeding stock
- offspring shipped to TX and feedlot system
- separate production systems
30
Q
Wool Properties
A
- antibacterial
- insulator (for houses too)
- fire retardant
- sustainable
- durable
- renewable
- biodegradable
- moisture-wicking
31
Q
Wool Today
A
- price of wool decreasing worldwide as popularity drops
- used as house insulator, clothing, and in manufacturing
32
Q
Staple
A
- fiber length/fleece depth
33
Q
Crimp
A
- zigzag pattern on fleece hairs
- affects ability to be woven into textiles
- crimp interlocks w/ next crimp to stick hair fibers together
- caused by cuticular scales
34
Q
Fiber Cuticular Scales
A
- wool grows continuously out of hair follicles
- dead deposited cells push fiber up and cause fibers to grow in certain directions
- paracortical cells and orthocortical cells make up follicles
35
Q
True Hair Fiber
A
- has piloerector muscle
- hair has more primary follicles
- kemp/medullated fibers
36
Q
Secondary Follicles
A
- true wool fibers
- sheep can have these
- more secondary follicles = higher quality wool/finer wool
- Merino: 20 secondary follicles to 1 primary follicle
- more secondary follicles means most of the sheep is wool, not hair
37
Q
Sebaceous Glands
A
- on secondary follicles
- produce lanolin
38
Q
Lanolin
A
- oily, waxy, fatty secretion of sebaceous glands
- on human skin too
- comes onto wool as it grows
- gives wool its oily feeling and unique smell
- repels water
- must be removed before dying/spinning wool in production
39
Q
Wool Contaminants
A
- sticks, stones, burrs
- reduce wool quality
- nutrition, disease, state of sheep in general also affects wool quality
- also why top of sheep produces best wool – not contaminated by dirt, feces, etc., that belly is
40
Q
Lamb Meat
A
- in Aus and other parts of world: < 1 yr old (dentition-determined)
- USA: “lamb” = break joint due to youth of animal
- more challenging bcs break joint presence varies w/ age and nutrition
41
Q
Mutton Meat
A
USA: no break joint in foreshanks, spool joint instead
42
Q
Dentition Uses
A
- once sheep >5-6yo, they start losing teeth
- can tell disease w/ dentition
- allows you to decide which range/pasture they belong to
43
Q
Food and Water Needs
A
- 2.5 kg DM/day
- 0.5-2 L H2O/day
44
Q
Reticulum Volume
A
- 1.8 L (2 qt)
45
Q
Omasum Volume
A
- 0.9 L (1 qt)
46
Q
Abomasum Volume
A
- 2.7 L (4 qt)
47
Q
Seasonally Polyestrous
A
- start to cycle in fall
- short day breeders –> breed when photoperiod/day length is short
48
Q
Pregnancy Length
A
- 150 days (5 mo)
- lambing in April (more food available in spring)
49
Q
Manipulate Breeding
A
- artificial lighting to induce cycle
- hormone administration (endocrinology)
50
Q
Pregnancy
A
- ewe usually about 18 mo old when first bred
- body condition score (BCS): ewes have to have some fat, be in good shape
51
Q
Fecundity
A
- number of lambs per ewe
- might select for 2 offspring by breeding ewes and rams who give birth/sire more than 1 offspring
- can’t select for too many offspring
- increases efficiency, and flock grows faster generation by generation
52
Q
Puberty
A
- hypothalamus releases hormones to ovaries to begin cycling in the fall
- hypothalamus helps sheep sense shortening daylight
53
Q
Cycling Hormones
A
- luteinizing hormone (LH)
- follicle stimulating hormone (FSH)
54
Q
Follicle Stimulating Hormone
A
- is present and plays its role before replaced by rising estrogen levels and ovulation
55
Q
Estrous Cycle
A
- 16 days long
- FSH develops follicles containing ovum
- follicle ripens in ovary
- estrogen leaves ovary - key for receptivity
- if no ram, ovum is not fertilized and cycle restarts every 16 days
56
Q
Ovulation/Heat
A
- ovum leaves ovary, released into fallopian tubes
- high levels of estrogen in body
- ovulation timed w/ behavioral changes to be receptive to ram
57
Q
Heat Detection
A
- marking harness that ram wears and shows up on ewe’s back when he mounts
58
Q
Lordosis
A
- standing still to be mounted/being receptive to male
- refers to mounting behavior in animals like sheep
59
Q
Bicornuate Uterus
A
- two equal tubes connected to 2 ovaries
- stock of oocytes in ovary - all the eggs ewe has in her life
60
Q
Cotyledonary Placenta
A
- sheep have cotyledonary placenta just like cattle
- placenta has 100 cotyledons (mushroom-like structures) on surface of placenta where nutrient transfer from mom’s circulation to fetus’s circulation takes place
- placenta arises from uterus
61
Q
Caruncle
A
- maternal side of placenta
62
Q
Cotyledon
A
- fetal side of placenta
63
Q
Finnish Landrace
A
- sheep breed famous for high prolificacy
64
Q
Corpus Luteum (CL)
A
- cells in ovary that form scar tissue where ovum released from ovary
- CL cells release progesterone into blood
- ovum goes down and is fertilized
65
Q
Progesterone
A
- pregnancy hormone
- high levels needed to maintain pregnancy
66
Q
Flehmen Response
A
- rams smelling ewes’ pheromones
- smell activates vomeronasal organ –> upper lip curls back
67
Q
Penile Structure
A
- fibrous, not glandular
- stays in body
- penis controlled by retractor muscle that also acts on sigmoid flexure
- pizzle
68
Q
Ejaculate
A
- 1 mL that contains 1B spermatozoa
- spermatogenesis in testes (meiosis) and sperm delivered thru vas deferens
- check that sperm are alive, functional, not defective; keep pizzle clean
69
Q
Gametes
A
- sperm or ovum
- haploid cells (1n)
- rest of body cells are diploid (2n)
70
Q
Finnish Landrace
A
- known for high prolificacy
71
Q
Estrous Cycle Stages
A
- diestrus/proestrus/follicular phase: folliculogenesis (forming of follicles that ripen and release ovum); blood estrogen levels rising
- estrus: ovulation/heat
- metestrus: blood progesterone levels stay elevated if pregnant, and lower if not pregnant to restart cycle
72
Q
Lamb Management
A
- separate lambs and ID w/ ear tags
- dock tails to avoid getting it matted w/ manure and urine
73
Q
Fly Strike
A
- external parasite
- flies land on matted manure-covered fleece, lay eggs, and maggots eat the broken, damaged skin
- maggots release ammonium, which is toxic and potentially deadly to animals
- might cause pizzle strike and affect backend of females
74
Q
Tapeworms
A
- internal parasite
- lives in gut and extracts nutrients
- affects animal growth and can be shed through feces to infect dogs, humans
75
Q
Liver Flukes
A
- internal parasite
- populate liver and detrimental to health and growth of sheep
76
Q
Other Sheep Diseases
A
- STDs
- viruses, bacterial diseases
- tetanus
- can be vaccinated
77
Q
Sheep Predators
A
- coyotes
- mountain lions
- birds of prey (large eagles)
78
Q
Prime Lambs
A
- commercial market lambs
- 50 kg (110 lbs)
79
Q
ADG
A
- average daily gain
- (ending bodyweight) - (start bodyweight) / (# of days)
80
Q
Wean, Feedlot ADG
A
- 0.3 kg/day
81
Q
Wool Breeds
A
- shearing
- health management
- mating
82
Q
Mature Sheep Weight
A
- 140 kg
- rams up to 200 kg
83
Q
Sheep Lifespan
A
10-12 yrs
