Why Do Sheep Lose Their Fleece / Alopecia


15 Main Reasons for Sheep Wool _ Fleece Loss _ Alopecia

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 breed 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
  • Drugs
  • Stress
  • Infections
  • Parasites
  • Dermatitis
  • Mechanical – stable/fence/construction
  • Ringworm
  • Scab
  • Mite

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 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 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.

World Record Sheep Wool

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 breed 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 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 normal grow. The first step in diagnosing hair loss is to determine whether the hair getting thinner, and therefore easily break, 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 the 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 lesion 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:

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.

Sheep Diseases

Wool Break:

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, can cause wool loss if the animal is scratching the area because of the itch. 

Wiltipol Sheep / Shed their Wool

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 the 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. 

Feed-related Causes:

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

SheepLambs / 3 Per YrSpace Required 20 Sq Feet - EachGrazing Acres .3 / SheepFeed Required / Yr $10015 Lbs Wool / YearAverage Price $ 10 / LB WoolTotal Revenue Possible
1360 sq ft.9 acres$ 30045 lbs$ 450$ 150
26120 sq ft1.80 acres$ 60090 lbs$ 900$ 300
515300 sq ft4.5 acres$ 1,500225 lbs$ 2,250$ 750
1030600 sq ft9 acres$ 3,000450 lbs$ 4,500$ 1,500
20601200 sq ft18 acres$ 6,000900 lbs$ 9,000$ 3,000
30902,700 sq ft27 acres$ 9,0001,350 lbs$ 13,500$ 4,500
401204800 sq ft36 acres$ 12,0001,800 lbs$ 18,000$ 6,000
501503,000 sq ft45 acres$ 15,0002,250 lbs$ 22,500$ 7,500
1003006,000 sq ft90 acres$ 30,0004,500 lbs$ 45,000$ 15,000
20060012,000 sq ft180 acres$ 60,0009,000 lbs$ 90,000$ 30,000
Sheep can give Birth 6+ lambs every Two Years
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

SheepLambs / 3 Per YrSpace Required 20 Sq Feet - EachGrazing Acres .3 / SheepFeed Required / Yr $100Wool $ 15 lb / YearAverage Price $ 10 / LB Wool90 Gallon/ Yr each ewePrice $ 30 per GallonTotal Wool Revenue PossibleTotal Revenue Milk and Wool
1360 sq ft.9 acres$ 30045 lbs$ 4502708100$ 1508,250
26120 sq ft1.80 acres$ 60090 lbs$ 90054016,200$ 30016,500
515300 sq ft4.5 acres$ 1,500225 lbs$ 2,250135040,500$ 75041,250
1030600 sq ft9 acres$ 3,000450 lbs$ 4,500270081,000$ 1,50082,500
20601200 sq ft18 acres$ 6,000900 lbs$ 9,0005400162,000$ 3,000165,000
30902,700 sq ft27 acres$ 9,0001,350 lbs$ 13,5008100243,000$ 4,500247,500
401204800 sq ft36 acres$ 12,0001,800 lbs$ 18,00010,800324,000$ 6,000330,000
501503,000 sq ft45 acres$ 15,0002,250 lbs$ 22,50013,500405,000$ 7,500412,500
1003006,000 sq ft90 acres$ 30,0004,500 lbs$ 45,00027,000810,000$ 15,000825,000
20060012,000 sq ft180 acres$ 60,0009,000 lbs$ 90,00054,0001,620,000$ 30,0001,650,000
Sheep can give Birth 6+ lambs every Two Years
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 SheepCountry OriginPurpose of BreedUseEwe Weight
KatahdinsCaribbean / Maine / AfricaTo Graze Power lines / instead of ChemicalsMeat120 - 160 lbs
DorperSouth AfricaThrive in Africa / Hot ClimateMeat / Fast Growing230 LBs
BlackbellyAmericaHot ClimatesMeat150 LBs
St. CroixCarribeanCame on Ships for Meat for sailorsMeat150 lbs
RomanovsRussiaPrimarily for MeatMeat
Wool - Double Coated
110 lbs
Blackhead PersianAfrica / SomailaBred for High Quanity of FatMeat120 lbs
West African DwarfSouth / Central AfricaMeat55 lbs
Red MaasiEast AfricaBred for Hardiness and parasite ResistanceMeat77 Lbs
Wiltshire HornEngland Do not suffer from FlystrikeMeat149 lbs
Royal WhiteUnited States / TexasBred for Tender Meat and Disease ResistantsMeat175 lbs
California RedNot completely Hair sheep/ Combination of both/ Prod 2 lambs YrMeat140 lbs
DamaraEgyptVigorous with fast growing / in extreme conditionsMeat110 lbs
PelibueyCuba / MexicoTropical SheepMeat75 lbs
AfricanaColumbia / VenezulaMeat110 lbs
MoradaBrazilSurvive ScrubMeat66 lbs
Brazillian SomailaSouth Africa / SomaliMeat
UdaAfricaLong Legged SheepMeat88 lbs
TouabireAfrica Dairy / Meat77 lbs
Breeds - Origin - Purpose - Weight

Minature Breeds of Sheep

BreedHeightWeight / Full GrownFood Per DayLifespanWool / Hair SheepCost
Quessant Sheep!8"28 - 30 Lbs1/2 - 1lb 10 - 12 YrsWool$ 350 - 450
Baby Doll Southdown18"75 lbs2 - 3 Lbs10 - 12 YrsWool$ 350 -450
Southdown Sheep18" - 24"130 lbs6 - 6 lbs10 - 12 YrsWool$ 180 - $ 600
Cheviot Sheep 20"130 Lbs6 - 6 lbs10 - 12 YrsWool$ 180 - $ 600
Border Cheviot20"130 lbs6 - 6 lbs10 - 12 YrsWool$ 180 - $ 600
Shetland Sheep24"75 - 100 lbs6 - 6 lbs10 - 12 YrsWool$ 50 - $100
Navajo - Churro20"110 lbs6 - 6 lbs10 - 12 YrsWool$ 200
Breed of Sheep and Physical Charistics
Amount of Food they Need
Lifespan
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 SheepCountry OriginPurpose of BreedUseEwe Weight
Suffolk SheepBritian / SuffolkFast GrowingMeat250 - 350 Lbs
Merino SheepSpainSoftest WoolWool100 - 200 Lbs
HampshireBritainBest Tasting MuttonWool / Meat200 Lbs
RomneyEngland / Romney MarshDisease ResistanceWool / Meat225 - 275 Lbs
Lincoln SheepEnglandProduce Longest Fleece In WorldWool250 - 350 Lbs
Dorper SheepSouth AfricanFast Growing MeatMeat230 Lbs
Turcana SheepRomainiaAdapted Alpine PastureWool / Milk / Meat175 - 200 Lbs
Rambouilette SheepFranceStrong / Hearty / All ClimatesWool / Meat300 Lbs
Leicester LongwoolUnited KingdomFast growing / Good FleeceWool200 Lbs
Breeds - Origin - Purpose - Weight

Sheep Associations 10 Breeds of Sheep

Breeds of SheepCountry OriginPurpose of BreedUseEwe WeightAssociation For Info
Suffolk SheepBritian / SuffolkFast GrowingMeat250 - 350 LbsUnited Suffolk Sheep Association
Merino SheepSpainSoftest WoolWool100 - 200 LbsAmerican and Delane Merino Sheep Association
HampshireBritainBest Tasting MuttonWool / Meat200 LbsAmerican Hampshire Sheep Association
RomneyEngland / Romney MarshDisease ResistanceWool / Meat225 - 275 LbsAmerican Romney Breeders Association
Lincoln SheepEnglandProduce Longest Fleece In WorldWool250 - 350 LbsNational Lincoln Sheep Breeders Association
Dorper SheepSouth AfricanFast Growing MeatMeat230 LbsAmerican Droper Sheep association
Turcana SheepRomainiaAdapted Alpine PastureWool / Milk / Meat175 - 200 Lbs?
Rambouilette SheepFranceStrong / Hearty / All ClimatesWool / Meat300 LbsAmerican Rambouilette Sheep Breeders Association
Leicester LongwoolUnited KingdomFast growing / Good FleeceWool200 LbsLeicester Longwool Sheep Breeders Association
Breeds - Origin - Purpose - Weight

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