View source for Jacob sheep

{{short description|British breed of domestic sheep}}
{{Use dmy dates|date=May 2017}}
{{EngvarB|date=May 2017}}
{{use list-defined references|date=May 2017}}
{{good article}}
{{Infobox sheep breed
| name          = Jacob
| image         = Jacob Ram at Royal Show.jpg
| image_alt     = a piebald sheep with four horns
| image_caption = Ram at the [[Royal Show]] at [[Stoneleigh Park]], [[Warwickshire]]
| status        = {{ubl|[[FAO]] (2007): not at risk{{r|barb|page=147}}|[[Rare Breeds Survival Trust|RBST]] (2017): Category 6{{r|rbst2}}}}
| standard = [http://www.jacobsheepsociety.co.uk/breed_standard.htm Jacob Sheep Society]
| country       = United Kingdom
| altname      = Spanish Sheep
| maleweight    = {{Convert|120|to|180|lb|kg|abbr=on|order=flip}}
| femaleweight  = {{Convert|80|to|120|lb|kg|abbr=on|order=flip}}
| woolcolour     = [[piebald]] – black or grey with white patches 
| facecolour     = badger-faced – black cheeks and [[Snout|muzzle]], white [[Horse markings#Facial markings|blaze]] 
| horns = horned in both sexes; may have two or four horns{{r|jss}}
| note          = 
}}
[[File:Jacob Sheep skull at the Royal Veterinary College anatomy museum.jpg|thumb|Four-horned Jacob skull in the anatomy museum of the [[Royal Veterinary College]] in London]]
The '''Jacob''' is a British [[list of sheep breeds|breed]] of [[domestic sheep]]. It combines two characteristics unusual in sheep: it is [[piebald]]—dark-coloured with areas of white wool—and it is often [[polycerate]] or multi-[[horn (anatomy)|horn]]ed. It most commonly has four horns. The origin of the breed is not known; broken-coloured polycerate sheep were present in England by the middle of the seventeenth century, and were widespread a century later. A [[breed society]] was formed in 1969, and a [[flock book]] was published from 1972.

The Jacob was kept for centuries as a "park sheep", to ornament the large estates of landowners. In modern times it is reared mainly for [[wool]], [[Lamb and mutton|meat]] and [[Sheepskin|skins]].

== History ==

The origins of the Jacob are not known.{{r|Chessa2009|page=4}} It has been bred in the British Isles for several hundred years. Sheep of this kind, little different from the modern breed, were shown in paintings from about 1760 at [[Tabley House]] in [[Cheshire]], and – by [[George Stubbs]] – at [[Wentworth Woodhouse]] in [[Yorkshire]].{{r|roberts|page=77}}

In the de Tabley family, the tradition was that the piebald sheep had come ashore in Ireland from a wrecked ship of the [[Spanish Armada]] in 1588, and been brought to England by Sir John Byrne on his marriage.{{r|elwes|page=33}}

Among the many accounts of ancient breeds of piebald sheep is the story of [[Jacob]] from the [[Book of Genesis]] (Genesis 30:31&ndash;43). Jacob took every speckled and spotted sheep from his father-in-law's ([[Laban (Bible)|Laban's]]) flock and bred them. Due to the resemblance to the animal described in Genesis, the Jacob sheep was named for the Biblical figure of Jacob<ref name="ALBC2009" /><ref name="AJSRHome" /> sometime in the 20th century.<ref name="OKState" />

In 2009, a study which used [[endogenous retrovirus]] [[genetic marker|markers]] to investigate the history of sheep [[domestication]] found the Jacob to be more closely linked to sheep from Africa and South-west Asia than to other British breeds,{{r|Chessa2009|page=4}} though all domestic breeds can be traced back to an origin in the [[Fertile Crescent]].<ref name="npr">[https://www.npr.org/templates/transcript/transcript.php?storyId=507890286 Farmers On Mission To Return 'Old Testament Sheep' To Holy Land]</ref>

Some believe that the modern breed is actually the same one mentioned in the Bible (although there is little genetic evidence) having accompanied the westward expansion of human civilisation through Northern Africa, Sicily, Spain and eventually England.<ref name="JSBAAbout" /> Elisha Gootwine, a sheep expert at the Israeli Agriculture Ministry, says that the resemblance of a British breed to the Bible story is a coincidence, that the breed was not indigenous to ancient Israel, and that "Jacob Sheep are related to Jacob the same as the American Indians are related to India".<ref name="npr" />

The Jacob was referred to as the "Spanish sheep" for much of its early recorded history. It has been bred in England for at least 350&nbsp;years,<ref name="AJSRHome" /><ref name="Simmons2009-02" /> and spotted sheep were widespread in England by the mid&ndash;18th century. The British landed gentry used Jacob as ornamental sheep on their estates and kept importing the sheep which probably kept the breed [[Extant taxon|extant]].<ref name="ALBC2009" />

A [[breed society]], the Jacob Sheep Society, was formed in July 1969.{{r|jsc2}} [[Mary Cavendish, Duchess of Devonshire|Mary Cavendish, dowager Duchess of Devonshire]], who had a flock of Jacob sheep at [[Chatsworth House]] in [[Derbyshire]], was the first president of the society.{{r|jss2}} From 1972 onwards, the society published a [[flock book]].{{r|fb}}

Jacobs were first exported to North America in the early 20th century.<ref name="Simmons2009-02" /> Some individuals acquired them from zoos in the 1960s and 1970s, but the breed remained rare in America until the 1980s; registration began in 1985. The first North American association for the breed, the Jacob Sheep Breeders Association, was established in 1988.<ref>[https://www.jsba.org/ Jacob Sheep Breeders Association home page, last viewed 12/18/23]</ref> The Jacob was introduced to Israel in 2016, when a small flock of about 120 head was shipped there from Canada{{r|zz1|zz2|zz3|zz4|zz5}} by a couple who believed the breed is the same one mentioned in Genesis.<ref name="npr" />

=== Conservation status ===

In 2012 the total Jacob population in the UK was reported to the [[DAD-IS]] database of the [[FAO]] as 5638, of which 2349 were registered breeding ewes.{{r|dad}} In 2017, the [[Rare Breeds Survival Trust]] listed the Jacob in Category 6 ("Other UK Native Breeds") of its watchlist, in which categories 1–5 are for various degrees of conservation risk, and category 6 is for breeds which have more than 3000 breeding females registered in the herd-book.{{r|rbst2}} Small numbers of Jacobs are reported from four other countries: the Czech Republic, Germany, the Netherlands and the United States, with conservation status in those countries ranging from critical to endangered-maintained.{{r|dad2}}

== Characteristics ==
[[File:Wildpark Tambach.jpg|thumb|In the {{illm|Wildpark Tambach|de}}, at {{illm|Schloss Tambach|de}} in [[Weitramsdorf]], in [[Coburg (district)|Coburg]], Bavaria]]The Jacob is a small, multi-horned, piebald sheep that resembles a goat in its conformation. However, it is not the only breed that can produce [[polycerate]] or piebald offspring. Other polycerate breeds include the [[Hebridean (sheep)|Hebridean]], [[Icelandic sheep|Icelandic]], [[Manx Loaghtan]], and the [[Navajo-Churro sheep|Navajo-Churro]], and other piebald breeds include the [[Finnsheep]], Shetland Sheep<ref>[http://www.shetland-sheep.org/docs/NASSA-Handbook.pdf North American Shetland Sheepbreeders Association Handbook]</ref> and the [[West African Dwarf (sheep)|West African Dwarf]].

Mature rams (males) weigh about {{Convert|120|to|180|lb|kg|abbr=on|order=flip}}, while ewes (females) weigh about {{Convert|80|to|120|lb|kg|abbr=on|order=flip}}.<ref name=JSBAStandard/> The body frame is long, with a straight back and a [[Rump (animal)|rump]] that slopes toward the base of the tail. The rams have short [[scrotum]]s free of wool which hold the testicles closer to the body than those of modern breeds, while the ewes have small [[udder]]s free of wool that are also held closer to the body than those of modern breeds.<ref name=JSBAStandard/> The head is slender and triangular, and clear of wool forward of the horns and on the cheeks.<ref name=JSBAStandard/> The tail is long and woolly, extending almost to the [[Hock (anatomy)|hock]] if it has not been [[Docking (animal)|docked]]. Jacob owners do not usually dock the tail completely, even for market sheep, but instead leave several inches (several centimetres) to cover the anus and vulva. The legs are medium-length, slender, free of wool below the knees, and preferably white with or without coloured patches. The hooves are black or striped.<ref name=JSBAStandard/> It is not unusual for Jacobs to be [[cow-hocked]]. They provide a lean carcass with little external fat, with a high yield of meat compared to more improved breeds.<ref name=JSBAAbout/>

=== Horns ===

The most distinguishing features of the Jacob are their four horns, although they may have as few as two or as many as six.<ref name=ALBC2009/><ref name=OKState/><ref name=Simmons2009-02/><ref name=JSCWhat/> Both sexes are always horned, and the rams tend to have larger and more impressive horns.<ref name=ALBC2009/> Two-horned rams typically have horizontal double-curled horns. Four-horned rams have two vertical centre horns which may be {{Convert|2|ft|cm|abbr=on|order=flip}} or more in length, and two smaller side horns, which grow down along the sides of the head. The horns on the ewe are smaller in diameter, shorter in length and appear more delicate than those of the ram.<ref name=JSCWhat/> British Jacobs most often have two horns, while American Jacobs are more often polycerate. [[Polled livestock|Polled]] (hornless) sheep are not registrable, since this trait is considered an indication of past cross-breeding, and as such there is no such thing as a polled purebred Jacob.<ref name=AJSRDesc/>

The horns are normally black, but may be black and white striped; white horns are undesirable. Ideally, horns are smooth and balanced, strongly attached to the skull, and grow in a way that does not impede the animal's sight or [[grazing]] abilities. Rams have larger horns than ewes. The horns in two-horned sheep, and the lower horns in four-horned animals, grow in a spiral shape. The [[Anatomical terms of location#Anterior and posterior|rostral]] set of horns usually extend upwards and outwards, while the [[Anatomical terms of location#Anterior and posterior|caudal]] set of horns curls downwards along the side of the head and neck. On polycerate animals it is preferred that there is a fleshy gap between the two pairs of horns. Partial or deformed horns that are not firmly attached to the skull, often referred to as "scurs", are not unusual but are considered undesirable.<ref name=JSBAStandard/>

=== Markings ===

[[File:Jacob ewe nursing a lamb.jpg|thumb|alt=a piebald ewe suckling a lamb|Ewe suckling her lamb]]
Each Jacob has distinctive markings that enable the shepherd to identify specific sheep from a distance. Desirable colour traits include an animal which is approximately 60% white, with the remaining 40% consisting of a random pattern of black or "lilac" (brownish-gray)<ref name=ALBC2009/> spots or patches.<ref name=JSBAStandard/> The skin beneath the white fleece is pink, while skin beneath coloured spots is darkly pigmented. Both rams and ewes exhibit black markings, some of which are breed specific and some of which are random.<ref name=JSBAStandard/>

Breed specific markings include large, symmetrical dark patches incorporating the ears, eyes and cheeks, and a dark [[cape]] over the dorsal part of the neck and shoulders. The face should have a white [[Horse markings#Facial markings|blaze]] extending from the [[Poll (livestock)|poll]] to the [[Snout|muzzle]]. The muzzle itself should be dark. The classic Jacob face is often referred to as "badger-faced", consisting of black cheeks and muzzle with a white blaze running down the front of the face.<ref name=JSCWhat/> In addition to these markings, random spots may occur on the rest of the body and legs (including the [[knee|carpi]], hocks, and [[pastern]]s). Certain markings are common in particular lines: large muzzle markings, lack of leg markings, lack of muzzle markings, etc.<ref name=JSCWhat/>

The lilac color is caused by a recessive variant of the ''[[Melanophilin|MLPH]]'' gene.<ref name=posbergh2020>{{cite journal|doi=10.3390/genes11060618|doi-access=free |title=A Stop-Gain Mutation within MLPH is Responsible for the Lilac Dilution Observed in Jacob Sheep |year=2020 |last1=Posbergh |first1=Christian J. |last2=Staiger |first2=Elizabeth A. |last3=Huson |first3=Heather J. |journal=Genes |volume=11 |issue=6 |page=618 |pmid=32512769 |pmc=7349772 }}</ref>

=== Diseases ===

Several rare or unusual diseases have been identified in Jacob sheep.

The condition known as ''split eyelid'' is a [[congenital defect]] common to several polycerate British breeds, and is [[Genetic linkage|genetically linked]] to the multi-horned trait. In mild cases, the eyelid shows a "peak" but does not impair vision or cause discomfort. Extreme cases (Grade 3 or higher) result in a complete separation of the upper eyelid in the middle.{{r|JSBAStandard|ark}}

In 1994, an unusual form of asymmetric [[occipital condylar dysplasia]] was found in two Jacob lambs; a possible link to the multi-horn trait has been suggested.{{r|cornell}}

In 2008, researchers in Texas identified the [[hexosaminidase A]] deficiency known in humans as [[Tay–Sachs disease]] in four Jacob lambs.{{r|Porter2011|ALBC2009a}} Subsequent testing found some fifty [[Genetic carrier|carriers]] of the genetic defect among Jacobs in the United States.{{r|ALBC2011}} The discovery offers hope of a possible pathway to effective treatment in humans.{{r|Torres2010}} In 2022, two babies diagnosed with the disease were treated with gene therapy developed from this research and further follow up studies are being conducted. {{r|SenaEstevez}}

==Husbandry==
{{See also|Sheep husbandry}}

The Jacob is generally considered to be an "unimproved" or "heirloom" breed (one that has survived with little human selection).<ref name=Wooster2005/> Such breeds have been left to mate amongst themselves, often for centuries, and therefore retain much of their original wildness and physical characteristics. American breeders have not subjected Jacobs to extensive cross-breeding or selective breeding, other than for fleece characteristics.<ref name=ALBC2009/> Like other unimproved breeds, significant variability is present among individuals within a flock. In contrast, the British Jacob has been selected for greater productivity of meat, and therefore tends to be larger, heavier and have a more uniform appearance. As a result, the American Jacob has retained nearly all of the original [[Phenotype|phenotypic]] characteristics of its Old World ancestors while its British counterpart has lost many of its unimproved physical characteristics through cross-breeding and selective breeding. The British Jacob has thus [[Genetic divergence|diverged]] from the American Jacob as a result of artificial selection.<ref name=ALBC2009/>

Jacobs are typically hardy, low-maintenance animals with a naturally high resistance to [[Parasitism|parasites]] and hoof problems.<ref name=JSBAAbout/> Jacobs do not show much [[Flocking (behavior)|flocking behaviour]]. They can be [[Anxiety|skittish]] if not used to people, although with daily handling they will become [[Domestication|tame]] and make good [[pet]]s. They require shelter from extreme temperatures, but the shelter can be open and simple. They tend to thrive in extremes of heat and cold and have good or excellent [[foraging]] capabilities. They can secure adequate nutrition with minimal to no supplementation, even in the presence of suboptimal soil conditions.<ref name=Wooster2005/><ref name=Simmons2009-03/>

Due to their low tail dock and generally unimproved anatomy, Jacob ewes are widely reputed to be easy-lambing.<ref name=JSCWhat/> Jacobs are [[seasonal breeder]]s, with ewes generally cycling in the cooler months of the autumn. They will begin to cycle during the first autumn following their birth and most often the ewe's first lamb is a single. Subsequent [[Pregnancy (mammals)|gestations]] will typically bear one or two lambs in the spring, and triplets are not unusual. The lambs will exhibit their spotting and horn characteristics at birth, with the horn buds more readily apparent on ram lambs. Lambs may be weaned at two months of age, but many shepherds do not separate lambs and allow the ewe to wean the lamb at about 4&nbsp;months of age.<ref name=JSCWhat/> Jacob ewes are instinctively attentive mothers and are protective of their lambs. They are included in commercial flocks in England because of their ease of lambing and strong mothering instincts.<ref name=JSBAAbout/><ref name=AJSRHome/>

== Use ==

=== Wool and skins ===
[[File:Jacob ewe.jpg|thumb|alt=Photograph of a Jacob ewe in full fleece|Ewe in full fleece near [[Ewhurst, East Sussex|Ewhurst]] in [[Sussex]]]]
Jacobs are [[Sheep shearing|shorn]] once a year, most often in the [[Spring (season)|spring]]. The average weight of the fleece is {{Convert|2|–|2.5|kg|lb|abbr=on|0}}. The wool is medium to coarse: [[Staple (wool)|staple length]] is about {{Convert|8|–|15|cm|in|0|abbr=on}} and fibre diameter about {{nobreak|32–34 [[micron]]s}} ([[Bradford count]] {{nobreak|48s–56s}}).{{r|cabi|page=830}}

In general, the fleece is light, soft, springy and open, with little [[lanolin]] (grease);<ref>[https://flippityfelts.com/the-wool-review/core-wools/jacob/  Flippity Felts Jacob Sheep Wool Review]</ref>  there may be some [[Kemp (wool)|kemp]].<ref>[https://site.jacobsheepsociety.com/breed-standard/ Jacob Sheep Society breed standard]</ref> In some sheep (particularly British Jacobs, which have denser fleeces), the black wool grows longer or shorter than the white wool. This is called "quilted fleece", and is an undesirable trait.<ref name=JSBAShow/>

While other British and Northern European multi-horned sheep have a fine inner coat and a coarse, longer outer coat,<ref name=Dyrmundsson2009/> Jacobs have a [[Wool#Quality|medium-grade]] fleece and no outer coat.<ref name=JSBAAbout/><ref name=JSCWhat/> Lambs of the more primitive lines are born with a coat of guard hair that is protective against rain and cold; this birth coat is shed at 3&ndash;6&nbsp;months.<ref name=JSCWhat/>

Some individual sheep may develop a natural "break", or marked thinning, of the fleece in springtime, which can lead to a natural [[Moulting|shedding]] of the fleece, particularly around the neck and shoulders. The medium-fine-grade wool has a high lustre, and is highly sought after by [[Spinning (textiles)#Hand spinning|handspinners]].<ref>[https://jsba.org/guidebook/information.pdf Jacob Sheep Breeders Association Jacob Sheep Information Booklet]</ref> The colours may be separated or blended after shearing and before spinning to produce various shades of yarn from a single fleece, from nearly white to nearly black.<ref name=JSCWhat/> Tanned Jacob [[sheepskin]]s also command high market prices.<ref name=Simmons2009-02/>

==References==

{{Reflist|45em|refs=

<ref name=AJSRDesc>{{cite web|title=Description of the Jacob Sheep|author=American Jacob Sheep Registry|publisher=American Jacob Sheep Registry|location=McKean, Pennsylvania|year=2005|url=http://jacob.sheepregistry.com/descrip.htm|access-date=5 May 2011}}</ref>

<ref name=AJSRHome>{{cite web|title=About the Jacob Sheep...|author=American Jacob Sheep Registry|publisher=American Jacob Sheep Registry|location=McKean, Pennsylvania|year=2006|url=http://jacob.sheepregistry.com/|access-date=5 May 2011}}</ref>

<ref name=ALBC2009>{{cite web|title=Jacob Sheep|author=American Livestock Breeds Conservancy|author-link=American Livestock Breeds Conservancy|publisher=American Livestock Breeds Conservancy|location=Pittsboro, North Carolina|year=2009|url=http://www.albc-usa.org/cpl/jacob.html|access-date=5 May 2011|archive-date=10 August 2011|archive-url=https://web.archive.org/web/20110810165333/http://www.albc-usa.org/cpl/jacob.html|url-status=dead}}</ref>

<ref name=ALBC2009a>{{cite web|title=Jacob Sheep Shed Light on Tay Sachs Disease|author=Horak F|work=ALBC Newsletter|publisher=American Livestock Breeds Conservancy|location=Pittsboro, North Carolina|year=2009|url=http://www.albc-usa.org/Newsletter/newsletterJanFeb2009.html|access-date=5 May 2011}}</ref>

<ref name=ALBC2011>{{cite web|title=Jacob sheep breeders find more Tay-Sachs carriers|vauthors=Kolodny E, Horak F, Horak J|work=ALBC Newsletter|publisher=American Livestock Breeds Conservancy|location=Pittsboro, North Carolina|year=2011|url=http://www.albc-usa.org/Newsletter/newsletterJanFeb2011.html|access-date=5 May 2011|archive-date=20 March 2012|archive-url=https://web.archive.org/web/20120320074643/http://www.albc-usa.org/Newsletter/newsletterJanFeb2011.html|url-status=dead}}</ref>

<ref name=SenaEstevez>{{cite web|title=First Gene Therapy for Tay-Sachs Disease Successfully Given to Two Children|first=Miguel |last=Sena-Estevez |url=https://singularityhub.com/2022/02/18/first-gene-therapy-for-tay-sachs-disease-successfully-given-to-two-children/|access-date=23 June 2024}}</ref>

<ref name=ark>Elizabeth Henson (1981). A Study of the Congenital Defect 'Split Eyelid' in the Multi-Horned Breeds of British Sheep. ''ARK'' '''VIII''': 84–90.</ref>

<ref name=barb>Barbara Rischkowsky, D. Pilling (eds.) (2007). [ftp://ftp.fao.org/docrep/fao/010/a1250e/annexes/List%20of%20breeds%20documented%20in%20the%20Global%20Databank%20for%20Animal%20Genetic%20Resources/List_breeds.pdf List of breeds documented in the Global Databank for Animal Genetic Resources]{{dead link|date=May 2025|bot=medic}}{{cbignore|bot=medic}}, annex to [ftp://ftp.fao.org/docrep/fao/010/a1250e/a1250e.pdf ''The State of the World's Animal Genetic Resources for Food and Agriculture'']. Rome: Food and Agriculture Organization of the United Nations. {{ISBN|9789251057629}}. Accessed May 2017.</ref>

<ref name=cabi>Valerie Porter, Lawrence Alderson, Stephen J.G. Hall, D. Phillip Sponenberg (2016). [https://books.google.com/books?id=2UEJDAAAQBAJ ''Mason's World Encyclopedia of Livestock Breeds and Breeding''] (sixth edition). Wallingford: CABI. {{ISBN|9781780647944}}.</ref>

<ref name=Chessa2009>{{cite journal |vauthors=Chessa B, Pereira F, Arnaud F, Amorim A, Goyache F, Mainland I, etal |title=Revealing the History of Sheep Domestication Using Retrovirus Integrations|journal=Science|volume=324|issue=5926|pages=532–6|year=2009|issn=0036-8075|pmid=19390051|doi=10.1126/science.1170587|url=http://www.research.ed.ac.uk/portal/files/7605567/EPMCFG_2009_Pemberton.pdf|access-date=9 June 2017|pmc=3145132|bibcode=2009Sci...324..532C}}</ref>

<ref name=cornell>Gayle C. Johnson, James R. Turk, Terry S. Morris, Dennis O'Brien, E. Aronson (1994). [https://babel.hathitrust.org/cgi/pt?id=coo.31924073505483;view=1up;seq=469 Occipital condylar dysplasia in two Jacob sheep]. ''The Cornell Veterinarian'' '''84''' (1): 91–98.</ref>

<ref name=dad>[http://dad.fao.org/cgi-bin/EfabisWeb.cgi?sid=c8bf34a590a3ed92561e8507ae19e4bc,reportsreport8a_50013151 Breed data sheet: Jacob/United Kingdom]. Domestic Animal Diversity Information System of the Food and Agriculture Organization of the United Nations. Accessed May 2017.</ref>

<ref name=dad2>[http://dad.fao.org/cgi-bin/EfabisWeb.cgi?sid=0b1613ebf16355cf65f6a05b9a65fe25,reportsreport16_50000918 Transboundary breed: Jacob]. Domestic Animal Diversity Information System of the Food and Agriculture Organization of the United Nations. Accessed May 2017.</ref>

<ref name=Dyrmundsson2009>{{cite journal|last1=Dýrmundsson|first1=ÓR|last2=Niżnikowski|first2=R|title=North European Short-tailed Breeds of Sheep: a Review|journal=Animal|volume=4|pages=1275–1282|year=2009|issn=1751-7311|doi=10.1017/S175173110999156X|issue=8|pmid=22444647|doi-access=free}}</ref>

<ref name=elwes>Henry John Elwes (1913). [https://books.google.com/books?id=Kd4ODQAAQBAJ&pg=PT25 ''Guide To The Primitive Breeds Of Sheep And Their Crosses On Exhibition At The Royal Agricultural Society's Show, Bristol 1913'']. Edinburgh: Printed by R. & R. Clark.</ref>

<ref name=fb>[Jacob Sheep Society] (1972). [http://explore.bl.uk/primo_library/libweb/action/display.do?doc=BLL01008531539 ''Flock book / Jacob Sheep Society'']. Ringwood: The Society.</ref>

<ref name=JSBAAbout>{{cite web|title=About Jacob Sheep|author=Jacob Sheep Breeders Association|publisher=Jacob Sheep Breeders Association|location=Dexter, Oregon|year=2009|url=http://www.jsba.org/history.htm|access-date=5 May 2011|archive-date=2 August 2012|archive-url=https://archive.today/20120802200917/http://www.jsba.org/history.htm|url-status=dead}}</ref>

<ref name=JSBAShow>{{cite web|title=Jacob sheep in the show ring: information for judges|author=Jacob Sheep Breeders Association|publisher=Jacob Sheep Breeders Association|location=Dexter, Oregon|year=2006|url=http://www.jsba.org/JudgesPacket.pdf|access-date=5 May 2011}}</ref>

<ref name=JSBAStandard>{{cite web|title=JSBA Breed Standard|author=Jacob Sheep Breeders Association|publisher=Jacob Sheep Breeders Association|location=Dexter, Oregon|year=2009|url=http://www.jsba.org/standard.htm|access-date=5 May 2011}}</ref>

<ref name=JSCWhat>F. Horak, J. Horak (2010). [https://web.archive.org/web/20110726201032/http://www.jacobsheepconservancy.org/jsc_about.htm What is a Jacob Sheep?]. Lucas, Texas: Jacob Sheep Conservancy. Archived 26 July 2011.</ref> 

<ref name=jsc2>[http://www.jacobsheepconservancy.com/history History of the Jacob Sheep] Jacob Sheep Conservancy. Accessed May 2017.</ref>

<ref name=jss>[http://www.jacobsheepsociety.co.uk/breed_standard.htm Breed Standard] {{Webarchive|url=https://web.archive.org/web/20170116154737/http://www.jacobsheepsociety.co.uk/breed_standard.htm |date=16 January 2017 }}. Exeter, Devon: Jacob Sheep Society. Accessed May 2017.</ref>

<ref name=jss2>[https://web.archive.org/web/20090814173702/http://www.jacobsheepsociety.co.uk/the_society_history_function.htm The Society: History & Function]. Exeter, Devon: Jacob Sheep Society. Accessed May 2017.</ref>

<ref name=OKState>{{cite web|url=http://www.ansi.okstate.edu/breeds/sheep/jacob/index.htm|work=Breeds of Sheep|title=Jacob|publisher=Oklahoma State University|access-date=5 May 2011|url-status=dead|archive-url=https://web.archive.org/web/20110608011849/http://www.ansi.okstate.edu/breeds/sheep/jacob/index.htm|archive-date=8 June 2011|df=dmy-all}}</ref>

<ref name=Porter2011>{{cite journal|vauthors=Porter BF, Lewis BC, Edwards JF, Alroy J, Zeng BJ, Torres PA, Bretzlaff KN, Kolodny EH |title=Pathology of GM2 Gangliosidosis in Jacob Sheep|journal=Veterinary Pathology|volume=48|issue=3|pages=807–13|year=2011|issn=0300-9858|pmid=21123862|doi=10.1177/0300985810388522|s2cid=6106101|doi-access=free}}</ref>

<ref name=rbst2>[http://www.rbst.org.uk/content/download/4571/65927/version/1/file/Watchlist+2017+A3+pg+1+-+FINAL+VERSION.pdf Watchlist 2017–18]. Stoneleigh Park, Warwickshire: Rare Breeds Survival Trust. Accessed May 2017.</ref>

<ref name=roberts>J.A. Fraser Roberts (1926). [http://www-old.ias.ac.in/jarch/jgenet/17/77.pdf Colour Inheritance in Sheep, II: The Piebald Pattern of the Piebald Breed]{{Dead link|date=September 2024 |bot=InternetArchiveBot |fix-attempted=yes }}. ''Journal of Genetics'' '''17''' (1): 77–83. {{doi|10.1007/BF02983308}}.</ref>

<ref name=Simmons2009-02>Simmons and Ekarius, ''Chapter 2: Breeding and Breeds'', pp. 30–98 in Simmons and Ekarius (2009)</ref>

<ref name=Simmons2009-03>Simmons and Ekarius, ''Chapter 3: Pasture, Fences, and Facilities'', pp. 99–134 in Simmons and Ekarius (2009)</ref>

<ref name=Torres2010>{{cite journal|vauthors=Torres PA, Zeng BJ, Porter BF, Alroy J, Horak F, Horak J, Kolodny EH |title=Tay-Sachs disease in Jacob sheep|journal=[[Molecular Genetics and Metabolism]]|volume=101|issue=4|pages=357–63|year=2010|issn=1096-7192|pmid=20817517|doi=10.1016/j.ymgme.2010.08.006}}</ref>

<ref name=Wooster2005>Wooster and Hansen, ''Chapter 2: Choosing a Flock'', pp. 11–28 in Wooster and Hansen (2005)</ref>

<ref name=zz1>{{Cite web|url=http://www.jpost.com/Diaspora/Canadian-couple-aiming-to-bring-biblical-Jacob-Sheep-to-Israel-407499|title=Canadian Couple Aiming to Help Jacob Sheep 'Make Aliyah|last=Udasin|first=Sharin|date=29 June 2015|website=Jerusalem Post}}</ref>

<ref name=zz2>{{Cite web|url=https://www.reuters.com/article/us-canada-israel-sheep-idUSKCN0W35QM|title=Israeli Couple Bringing Home Biblical Sheep from Canada|last=Lou|first=Ethan|date=2 March 2016|website=Reuters}}</ref>

<ref name=zz3>{{Cite web|url=https://www.nytimes.com/2016/03/04/world/middleeast/biblical-nomads-will-return-to-the-holy-land-thank-a-canadian-farm.html?_r=0|title=Biblical Nomads will Return to the Holy Land Thanks to a Canadian Farm|last=Levin|first=Dan|date=4 March 2016|website=New York Times}}</ref>

<ref name=zz4>{{Cite web|url=http://www.friendsofthejacobsheep.com/about.html|title=About|last=Friends of the Jacob Sheep|date=1 April 2016|website=Friends of the Jacob Sheep|access-date=6 April 2016|archive-date=16 April 2016|archive-url=https://web.archive.org/web/20160416153717/http://www.friendsofthejacobsheep.com/about.html|url-status=dead}}</ref>

<ref name=zz5>{{Cite web|url=http://www.timesofisrael.com/baa-baa-biblical-sheep-have-you-an-israeli-passport/|title=Baa Baa Biblical Sheep, Do you have an Israeli Passport|last=Lidman|first=Melanie|date=28 December 2015|website=Times of Israel}}</ref>

<!---ref>{{Cite news|url=http://www.timesofisrael.com/barreling-down-the-highway-with-120-sheep/|title=Barreling down the highway with 120 sheep|newspaper=The Times of Israel|access-date=8 December 2016}}</ref>

<ref>{{Cite news|url=http://www.timesofisrael.com/biblical-sheep-in-israel-for-first-time-in-millennia/|title=Biblical sheep in Israel for first time in millennia|newspaper=The Times of Israel|language=en-US|access-date=2 February 2017}}</ref>

<ref>{{Cite news|url=http://www.abbynews.com/news/408629105.html|title=Flooding threatens band of Jacob sheep transported from Abbotsford to Israel - Abbotsford News|newspaper=Abbotsford News|access-date=2 February 2017}}</ref>

<ref>{{Cite news|url=http://www.timesofisrael.com/after-bleating-a-path-to-israel-jacobs-sheep-frolic-in-new-home/|title=WATCH: After bleating a path to Israel, Jacob's sheep frolic in new home|newspaper=The Times of Israel|language=en-US|access-date=2 February 2017}}</ref--->

}}

==Further reading==
* L. Heise & C. Christman (1989). ''American Minor Breeds Notebook''. Pittsboro, North Carolina: The American Minor Breeds Conservancy.
* Ólafur R. Dýrmundsson & Roman Niznikowski, (2008). [https://web.archive.org/web/20120323144033/http://www.eaap.org/Previous_Annual_Meetings/2008Vilnius/Papers/published/33_Dyrmundsson%20Presentation.pdf "North European short-tailed breeds of sheep: a review]. 2008 Annual Meeting of the European Federation for Animal Science. Vilnius, Lithuania: EAAP Sheep and Goat Commission: 1–24.
* M. L. Ryder (2007). [https://books.google.com/books?id=S4_yPQAACAAJ ''Sheep and Man'']. London: Gerald Duckworth & Company. {{ISBN|9780715636473}}.
* P. Simmons & Carol Ekarius (2009). [https://books.google.com/books?id=80eYTaMcPGMC ''Storey's Guide to Raising Sheep'']. North Adams, Massachusetts: Storey Publishing. {{ISBN|9781603424592}}.

==External links==
{{Commons category|Jacob sheep}}
* [http://jacob.sheepregistry.com/ American Jacob Sheep Registry]
* [http://www.jsba.org Jacob Sheep Breeder's Association]
* [https://web.archive.org/web/20150407060900/http://www.jacobsheepconservancy.org/ Jacob Sheep Conservancy]
* [http://www.jacobsheepsociety.co.uk/ Jacob Sheep Society]

{{British livestock|R.1}}

[[Category:Conservation Priority Breeds of the Livestock Conservancy]]
[[Category:Sheep breeds originating in England]]