Why Do Sheep Lose Their Fleece
Why Do Sheep Lose Their Fleece – Alopecia, or hair loss, affects up to 50% of the human population at some stage during their life. In humans, this is usually of cosmetic and psychological concern.
It also is a phenomenon found in many animal species. Sheep is one of few domestic animals bred for the wool, and this could potentially be an important question for both the sheep-owner and the wool production.
15 Main Reasons for Sheep Wool / Fleece Loss / Alopecia
- Nutrition Deficiencies
- Pregnant Sheep with two Lambs/
- Natural Shedding
- Wool Cycles
- Control Length of Hair
- Clean Animal
- Disease in the Follicles
- Specific Breeds more susceptible
- Mechanical – stable/fence/construction
If the wool loss is as frequent in the sheep population as hair loss is in the human population, the phenomenon should be brought into the light.
Study Regarded Why Sheep Have Fleece Loses:
The original idea of this project came from a feed study with sheep. Ewes were divided into two groups when one group was fed only silage started in January. It lasted over the lambing seasons for two years, with lambing from the end of February to the beginning of April. Both years the study was finished in May.
The wool loss was experienced both years and mainly seen on ewes with more than one lamb. Both years most ewes with wool loss were found in the group fed only silage. The wool loss was seen mainly after lambing, but also during pregnancy during the first year of study.
Parameters recorded in the study included weight and body condition, feed intake, beta-hydroxybutyrate, and non-esterified fatty acid in the blood. According to these data, a lack of protein in the diet was not likely the first year but could be a possible cause for the second year. The cause of the wool loss in the first year was believed to be cold stress since the temperature dropped the weeks after shearing the wool.
In our domesticated, sheared sheep, the wool loss is mostly seen as a negative sign. The general health of the animal is reflected by the status and quality of its fiber.
Stress in the form of malnutrition, reproduction, or disease will cause a thinning of the fibers and even a reduction of wool growth that could lead to a wool loss. Apart from it being a cosmetic concern, a disease affecting the fleece will reduce the value of the wool and could also increase the maintenance cost of the sheep in terms of heat loss that needs to be compensated by increased feeding in colder climates.
What are the causes of the loss of fleece in sheep?
There are the following causes of the loss of fleece in sheep:
The Wool Fiber and Natural Shedding:
The wool fiber grows from hair follicles that are formed during three different stages of the development of the fetus. The central primary follicles are the first follicles to develop and spread in the skin of the fetus at 70 days.
At day 85 the lateral primary follicles develop on the sides of the central primary follicles, in a group of three, together with the secondary follicles. At day 105, the secondary-derived follicles develop in between the earlier formed follicles, branching out from the secondary follicles.
One month after birth, all follicles are usually producing wool fibers. The long-wool breeds and the hairs have a greater diameter and grow faster and longer. They form the guard hair. The secondary follicles form thinner fibers that grow slower and make up the under-fur or fleece of the wool.
In sheep, the average number of hairs per centimeter square is 5000-7000. The number of secondary-derived follicles varies between the different breeds of sheep, from derived follicles to every primary follicle. In extreme wool-producing breeds, such as merino, the secondary follicles may branch and form up to 60 secondary fibers per primary fiber.
As the number of secondary follicles increases, they spread out from the primary follicles and form a more homogenous hair coat where the fleece wool is the dominating feature.
During the lifetime of a sheep, the wool follicles go through several cycles, each leading to the shedding of the wool.
The Reason Behind the Cycle Which Goes Through Sheep’s Wool Follicles:
Several Reasons for this Cyclicity has been Suggested;
- To enable the animal to grow.
- To control the length of hairs
- To clean the body by shedding old hairs
- To suit different weather conditions and to protect against a disease that could arise in the follicles.
The cyclicity differs between breeds of sheep and even on different parts of an animal, but all hairs will go through the same phases, even though the length of the phases may vary.
Shedding of the Fleece:
Shedding has been defined as the total loss of the fleece, as observed macroscopically, over the whole or a significant part of the body area.
- There are however domesticated breeds that show annual shedding of the wool and thus have a circannual rhythm of the wool follicle cycle.
- Temperature, nutrition, and genetic factors have been suggested to influence this rhythm, but the main factor is believed to be the annual change in daylight.
- The long hair follicle cycles found in domesticated sheep, also found for example in humans and horse manes, are not triggered by the same factors are shedding, and the influence of this is not yet fully known.
- Shedding of individual fibers should be differentiated from annual shedding because the shedding of individual fibers may or may not be sufficiently coordinated and extensive as to cause the loss of parts of the fleece.
General and Localized Fleece Loss:
Alopecia is described as the absence of hair from the area where it normally grow. The first step in diagnosing hair loss is to determine whether the hair getting thinner, and therefore easily breaks, or if the hairs fall off due to shedding.
Hair loss is often divided into localized or general hair loss. Generalized alopecia includes telogen effluvium, hair loss caused by drugs, stress, infections, and injuries. Alopecia areata, infections, and injuries can cause localized alopecia.
Fleece Loss Due to the Mechanical Cause:
Before suspecting a disease, mechanical causes for wool loss should always be considered. Lambs playing and sleeping on the backs of ewes may cause wear of the wool in those areas. The interior of the stable, especially the construction of the feeding areas, could cause wear of the wool mainly around the neck.
Fleece Loss Due to ovine telogen effluvium or Wool Slip:
Ovine telogen effluvium, commonly called wool slip, is identified by the moth-eaten look of the patches and the surrounding wool. The scientific name refers to the loss of telogen effluvium; the normal cyclicity of the wool is disturbed.
Skin biopsies taken from sheep with telogen effluvium showed that the wool follicles were in the anagen phase, compared to the telogen phase in unaffected animals. This finding support that cyclicity has been disrupted and the wool has been shed prematurely and that the wool follicles already are in the anagen phase again.
Ovine telogen effluvium is mainly seen during housing in the winter, especially in connection to shearing, but it has also been reported in the summer. The patches of alopecia commonly appear 3-4 weeks after shearing and are usually found on the back and neck. The cause is believed to be elevated levels of corticosteroid due to the stress of housing and shearing.
Cortisol and glucocorticoid analogs have been shown to decrease wool growth. In a study by Chapman and Bassett plasma cortisol levels above three micrograms per ml caused inactivation of the wool follicle and fiber-growth ceased.
The study included ewes in three different feeding regimes, and the group with the most restricted diet reacted with decreased wool growth at the lowest plasma cortisol levels.
It has been found similar results in the study where three different glucocorticoid analogs were found to make the wool more fragile and prone to break at different degrees from complete wool loss to reduce wool growth without signs of wool loss.
Fleece Loss Due to Bacterial Dermatitis:
The bacterium Dernatophilus congolensis causes mycotic dermatitis or thick wool. It is more common in damp areas where rain or high humidity keeps the wool from drying. Breeds with fine down-type fleece are more prone to infection.
If the bacteria invade the skin, the result is exudative dermatitis, which dries and forms scabs at the base of the fibers. The infection increases the risk of flystrike. After healing, new will grow underneath the scabs that form a hard layer in the fleece.
The back is the most commonly affected, but lesions can also appear in the ear and on the head. Wool loss is present in severe cases, where itching and secondary infections are common. During the lesion stage, the skin is pain-sensitive, and this may restrict the movement of the sheep. A form of this disease is called Strawberry foot-rot with strawberry-like non-exudative dermatitis and scabs localized above the roof.
Dermatitis presents with alopecia or hypotrichosis, redness the skin, hyperpigmentation, superficial ulcers with crusting and exudation, thickening of the skin but no itching. Staphylococcus aureus was found in the exudates and skin biopsies.
Pelodera dermatitis causes wool loss and thickening of the skin in sheep. It is a rare infection caused by the larvae of Pelodera Strongyloides, a free-living saprophytic nematode. The larvae invade the hair follicles and cause an inflammatory response.
They thrive in humid, decaying organic matter, such as dirty bedding. This disease has been described in a flock of crossbreed Rasa Aragonesa ewes. The symptoms were found in areas in contact with the bedding material when the ewes were lying down.
The clinical examination showed large areas of thick and leathery exfoliating skin with a lesion in 74% of the ewes. After complete removal of the bedding cleaning and disinfection of the stable, the problems disappeared.
The wool break is when the wool fibers are thinned and eventually break, causing parts of the wool fleece to loosen. This could be secondary effects caused by malnutrition or disease such as mastitis.
A wool break can also have infectious causes such as in Johne’s disease caused by Mycobacterium avium ss, Paratuberculosis, Ringworm, Trichophyton verrucosum, which can cause wool loss if the animal is scratching the area because of the itch.
External Parasites Cause Fleece Loss:
The sheep scab mite, Psorptes ovis, causes symptoms such as restlessness and irritation. Scratching and biting the wool leads to wool loss and yellow pustules and crusts are seen at the edge of the lesions.
In heavily infected sheep, the mites can be seen with bare eyes around the lesions. In heavily infected multiply rapidly and only a few mites that infect a sheep can in 8-12 weeks lead to a severe infection. This mite is not found in Sweden.
Chorioptes ovis, foot scab, can be found in Sweden and mainly affects the distal parts of the hind legs and the scrotum. It can cause wool loss, and it is common to get a secondary infection with allergic dermatitis in the area after treatment, making it difficult to evaluate if the treatment of scab is effective or not.
Scrapie Causes Fleece Loss:
Scrapie is transmissible spongiform encephalitis. The symptoms include severe itching, which leads to self-inflicted damages all over the body, wool loss, and a decline in overall health.
Neurological signs are present in some cases, for example, changed behavior, fine tremor, oversensitivity for light, sound, and touch, and unsteadiness. Death occurs two to six weeks after infection. Prions probably cause scrapie, and the diagnosis is confirmed by autopsy.
Mineral deficiency and protein deficiency are commonly stated as causes of wool loss in sheep. Deficiencies of copper, zinc, cobalt, calcium, phosphorus, sodium chloride and manganese are all connected to wool plucking. Wool plucking or pulling is partner-directed in sheep, and ewes mostly perform the behavior. The most commonly affected area is the back.
Genetic Causes Fleece Loss:
Georgian semi-fine wooled fat-tailed sheep that some breeds are more disposed to suffer from alopecia than others due to a hereditary increase in metabolism. The Georgian semi-fine wooled fat-tailed sheep show heavy shedding in the spring, but wool loss appears earlier in winter and spring when feed is at its scarcest.
Sheep Farming for Wool Profitability Table
|Sheep||Lambs / 3 Per Yr||Space Required 20 Sq Feet - Each||Grazing Acres .3 / Sheep||Feed Required / Yr $100||15 Lbs Wool / Year||Average Price $ 10 / LB Wool||Total Revenue Possible|
|1||3||60 sq ft||.9 acres||$ 300||45 lbs||$ 450||$ 150|
|2||6||120 sq ft||1.80 acres||$ 600||90 lbs||$ 900||$ 300|
|5||15||300 sq ft||4.5 acres||$ 1,500||225 lbs||$ 2,250||$ 750|
|10||30||600 sq ft||9 acres||$ 3,000||450 lbs||$ 4,500||$ 1,500|
|20||60||1200 sq ft||18 acres||$ 6,000||900 lbs||$ 9,000||$ 3,000|
|30||90||2,700 sq ft||27 acres||$ 9,000||1,350 lbs||$ 13,500||$ 4,500|
|40||120||4800 sq ft||36 acres||$ 12,000||1,800 lbs||$ 18,000||$ 6,000|
|50||150||3,000 sq ft||45 acres||$ 15,000||2,250 lbs||$ 22,500||$ 7,500|
|100||300||6,000 sq ft||90 acres||$ 30,000||4,500 lbs||$ 45,000||$ 15,000|
|200||600||12,000 sq ft||180 acres||$ 60,000||9,000 lbs||$ 90,000||$ 30,000|
Sheep can Produce 2 - 30 lbs of wool per year depending on Breed
Raw washed Wool Runs $ 6 - $ 14 using average $ 10
Feed 5 Months Buying Hay $ 100 rest Grazing
Please Check my Numbers
Sheep Farming for Milk Profitability Table
|Sheep||Lambs / 3 Per Yr||Space Required 20 Sq Feet - Each||Grazing Acres .3 / Sheep||Feed Required / Yr $100||Wool $ 15 lb / Year||Average Price $ 10 / LB Wool||90 Gallon/ Yr each ewe||Price $ 30 per Gallon||Total Wool Revenue Possible||Total Revenue Milk and Wool|
|1||3||60 sq ft||.9 acres||$ 300||45 lbs||$ 450||270||8100||$ 150||8,250|
|2||6||120 sq ft||1.80 acres||$ 600||90 lbs||$ 900||540||16,200||$ 300||16,500|
|5||15||300 sq ft||4.5 acres||$ 1,500||225 lbs||$ 2,250||1350||40,500||$ 750||41,250|
|10||30||600 sq ft||9 acres||$ 3,000||450 lbs||$ 4,500||2700||81,000||$ 1,500||82,500|
|20||60||1200 sq ft||18 acres||$ 6,000||900 lbs||$ 9,000||5400||162,000||$ 3,000||165,000|
|30||90||2,700 sq ft||27 acres||$ 9,000||1,350 lbs||$ 13,500||8100||243,000||$ 4,500||247,500|
|40||120||4800 sq ft||36 acres||$ 12,000||1,800 lbs||$ 18,000||10,800||324,000||$ 6,000||330,000|
|50||150||3,000 sq ft||45 acres||$ 15,000||2,250 lbs||$ 22,500||13,500||405,000||$ 7,500||412,500|
|100||300||6,000 sq ft||90 acres||$ 30,000||4,500 lbs||$ 45,000||27,000||810,000||$ 15,000||825,000|
|200||600||12,000 sq ft||180 acres||$ 60,000||9,000 lbs||$ 90,000||54,000||1,620,000||$ 30,000||1,650,000|
Sheep can Produce 1/2 Gallon Milk per day / 180 Day Lactation
Raw Sheep Milk $9 - $25 per Quart - Used $ 30 per Gallon for Table
Feed 5 Months Buying Hay $ 100 rest Grazing
Please Check my Numbers
18 Breeds of Hair Sheep FAQ Table
|Hair Breeds of Sheep||Country Origin||Purpose of Breed||Use||Ewe Weight|
|Katahdins||Caribbean / Maine / Africa||To Graze Power lines / instead of Chemicals||Meat||120 - 160 lbs|
|Dorper||South Africa||Thrive in Africa / Hot Climate||Meat / Fast Growing||230 LBs|
|Blackbelly||America||Hot Climates||Meat||150 LBs|
|St. Croix||Carribean||Came on Ships for Meat for sailors||Meat||150 lbs|
|Romanovs||Russia||Primarily for Meat||Meat|
Wool - Double Coated
|Blackhead Persian||Africa / Somaila||Bred for High Quanity of Fat||Meat||120 lbs|
|West African Dwarf||South / Central Africa||Meat||55 lbs|
|Red Maasi||East Africa||Bred for Hardiness and parasite Resistance||Meat||77 Lbs|
|Wiltshire Horn||England||Do not suffer from Flystrike||Meat||149 lbs|
|Royal White||United States / Texas||Bred for Tender Meat and Disease Resistants||Meat||175 lbs|
|California Red||Not completely Hair sheep/ Combination of both/ Prod 2 lambs Yr||Meat||140 lbs|
|Damara||Egypt||Vigorous with fast growing / in extreme conditions||Meat||110 lbs|
|Pelibuey||Cuba / Mexico||Tropical Sheep||Meat||75 lbs|
|Africana||Columbia / Venezula||Meat||110 lbs|
|Morada||Brazil||Survive Scrub||Meat||66 lbs|
|Brazillian Somaila||South Africa / Somali||Meat|
|Uda||Africa||Long Legged Sheep||Meat||88 lbs|
|Touabire||Africa||Dairy / Meat||77 lbs|
Minature Breeds of Sheep
|Breed||Height||Weight / Full Grown||Food Per Day||Lifespan||Wool / Hair Sheep||Cost|
|Quessant Sheep||!8"||28 - 30 Lbs||1/2 - 1lb||10 - 12 Yrs||Wool||$ 350 - 450|
|Baby Doll Southdown||18"||75 lbs||2 - 3 Lbs||10 - 12 Yrs||Wool||$ 350 -450|
|Southdown Sheep||18" - 24"||130 lbs||6 - 6 lbs||10 - 12 Yrs||Wool||$ 180 - $ 600|
|Cheviot Sheep||20"||130 Lbs||6 - 6 lbs||10 - 12 Yrs||Wool||$ 180 - $ 600|
|Border Cheviot||20"||130 lbs||6 - 6 lbs||10 - 12 Yrs||Wool||$ 180 - $ 600|
|Shetland Sheep||24"||75 - 100 lbs||6 - 6 lbs||10 - 12 Yrs||Wool||$ 50 - $100|
|Navajo - Churro||20"||110 lbs||6 - 6 lbs||10 - 12 Yrs||Wool||$ 200|
Amount of Food they Need
Wool - They Need to be Sheared Hair Sheep - Do not Grow Woll but shed Hair once a year
Pricing Depend whether you just want Sheep Or you want to Breed
10 Breeds of Sheep FAQ Table
|Breeds of Sheep||Country Origin||Purpose of Breed||Use||Ewe Weight|
|Suffolk Sheep||Britian / Suffolk||Fast Growing||Meat||250 - 350 Lbs|
|Merino Sheep||Spain||Softest Wool||Wool||100 - 200 Lbs|
|Hampshire||Britain||Best Tasting Mutton||Wool / Meat||200 Lbs|
|Romney||England / Romney Marsh||Disease Resistance||Wool / Meat||225 - 275 Lbs|
|Lincoln Sheep||England||Produce Longest Fleece In World||Wool||250 - 350 Lbs|
|Dorper Sheep||South African||Fast Growing Meat||Meat||230 Lbs|
|Turcana Sheep||Romainia||Adapted Alpine Pasture||Wool / Milk / Meat||175 - 200 Lbs|
|Rambouilette Sheep||France||Strong / Hearty / All Climates||Wool / Meat||300 Lbs|
|Leicester Longwool||United Kingdom||Fast growing / Good Fleece||Wool||200 Lbs|
Sheep Associations 10 Breeds of Sheep
|Breeds of Sheep||Country Origin||Purpose of Breed||Use||Ewe Weight||Association For Info|
|Suffolk Sheep||Britian / Suffolk||Fast Growing||Meat||250 - 350 Lbs||United Suffolk Sheep Association|
|Merino Sheep||Spain||Softest Wool||Wool||100 - 200 Lbs||American and Delane Merino Sheep Association|
|Hampshire||Britain||Best Tasting Mutton||Wool / Meat||200 Lbs||American Hampshire Sheep Association|
|Romney||England / Romney Marsh||Disease Resistance||Wool / Meat||225 - 275 Lbs||American Romney Breeders Association|
|Lincoln Sheep||England||Produce Longest Fleece In World||Wool||250 - 350 Lbs||National Lincoln Sheep Breeders Association|
|Dorper Sheep||South African||Fast Growing Meat||Meat||230 Lbs||American Droper Sheep association|
|Turcana Sheep||Romainia||Adapted Alpine Pasture||Wool / Milk / Meat||175 - 200 Lbs||?|
|Rambouilette Sheep||France||Strong / Hearty / All Climates||Wool / Meat||300 Lbs||American Rambouilette Sheep Breeders Association|
|Leicester Longwool||United Kingdom||Fast growing / Good Fleece||Wool||200 Lbs||Leicester Longwool Sheep Breeders Association|