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PubMed2002

Evaluation of three enzyme-linked immunosorbent assays (ELISAs) for the detection of serum antibodies in sheep infected with Echinococcus granulosus.

The aim of this study was to develop an immunological method for the identification of sheep infected with Echinococcus granulosus which would allow the monitoring of animals imported into countries free from hydatidosis and as an aid to countries where control schemes for the disease are in operation. Three enzyme-linked immunosorbent assays (ELISAs) were developed and validated, using as antigen either a purified 8 kDa hydatid cyst fluid protein (8kDaELISA), a recombinant EG95 oncosphere protein (OncELISA) or a crude protoscolex preparation (ProtELISA). Sera used for the assay validations were obtained from 249 sheep infected either naturally or experimentally with E. granulosus and from 1012 non-infected sheep. The highest diagnostic sensitivity was obtained using the ProtELISA at 62.7 and 51.4%, depending on the cut-off. Assay sensitivities were lower for the 8kDaELISA and the OncELISA. Diagnostic specificities were high, ranging from 95.8 to 99.5%, depending on the ELISA type and cut-off level chosen. A few sera from 39 sheep infected with T. hydatigena and from 19 sheep infected with T. ovis were recorded as positive. Western immunoblot analysis revealed that the dominant antigenic components in the crude protoscolex antigen preparation were macromolecules of about 70-150 kDa, most likely representing polysaccharides. This study demonstrated that the ProtELISA was the most effective immunological method of those assessed for detection of infection with E. granulosus in sheep. Because of its limited diagnostic sensitivity of about 50-60%, it should be useful for the detection of the presence of infected sheep on a flock basis and cannot be used for reliable identification of individual animals infected with E. granulosus.

Animals↗
PubMed1997

Host specificity of sheep and cattle nematodes in São Paulo state, Brazil.

The trial was carried out to investigate parasite host specificity and to analyse the dynamics of infection with nematodes parasitizing sheep and cattle raised together or separately in São Paulo state, Brazil, and, also to clarify doubts about the systematics of species of the genus Haemonchus on the basis of cytological and morphological studies. Ten steers and 32 ewes were randomly assigned to three paddocks (P), as follows: P1, 5 steers; P2, 5 steers and 16 ewes; and P3, 16 ewes. The animals remained on these paddocks in continuous grazing throughout the trial (1-yr period). Faecal exams and larvae counting on pasture were performed fortnightly. Once a month two tracer lambs were placed in each paddock, while two tracer calves were also placed, but only in the eighth month of the trial. All these animals were slaughtered for worm identification and counting. At the end of the trial, one steer and one ewe from P2, which showed high faecal egg counts, were also slaughtered for the same purpose. Nematodes identified cytogenetically as H. placei presented spicule hooks longer than those identified as H. contortus. The following distribution of parasites in cattle and sheep was observed: Bunostomum phlebotomum, H. similis, Mammomonogamus laryngeus strongly adapted to cattle, H. placei and Cooperia punctata more adapted to cattle than to sheep, Trichostrongylus axei and C. spatulata apparently more adapted to cattle, T. colubriformis strongly adapted to sheep, H. contortus more adapted to sheep than to cattle and C. curticei apparently more adapted to sheep. Cross-infection was shown to occur involving some species, however, with time the animals apparently eliminate the species that are not well adapted to them. Therefore, grazing management systems using cattle and sheep appear to be promising for worm control in southeastern Brazil.

Animals↗
PubMed1997

Acquisition of resistance against Fasciola gigantica by Indonesian thin tail sheep.

The plasma levels of GLDH and the dynamics of development of the numbers of surface lesions on livers, and numbers of parasites, within two to three weeks of a challenge infection, indicated that the major component of the high resistance of Indonesian thin tail (ITT) sheep against Fasciola gigantica was acquired, and acted against juvenile parasites. Few parasites reached the livers of ITT (exposed) sheep, but many had been inhibited, probably in the wall of the jejunum. ITT (naive) sheep showed some resistance, compared with control Merino sheep, by three weeks after infection. Manifestation of the resistance of ITT (exposed) sheep was suppressed by administration of the immunosuppressant, dexamethasone. Killing of parasites in ITT sheep appeared to have ceased by 21 to 28 days after infection. The basis of the acquired resistance was deemed to be an exceptional immunological capacity of ITT sheep responding to an antigen, or an immunological suppressant, peculiar to F. gigantica. That molecule, produced by juvenile parasites, warrants further study as a candidate for a vaccine.

Animals↗
PubMed1999

Detection of T. gondii in tissues of sheep and cattle following oral infection.

It has been reported in the literature that cattle are more resistant to toxoplasmosis than sheep. Congenital disease due to T. gondii infection is rarely reported in cattle whereas the parasite is a major cause of abortion and neonatal mortality in sheep. It is believed that sheep remain chronically infected for life. Undercooked meat from infected sheep is an important source of infection for man. In contrast cattle are thought to harbour fewer parasite tissue cysts which may not persist for the lifetime of the host. Therefore, cattle are believed to pose less of a risk for human infection. In this study we examined the presence of T. gondii within a range of tissues in sheep and cattle at 6 weeks and 6 months following oral infection with 10(3) or 10(5) sporulated oocysts of T. gondii. The presence of parasite was determined by bioassay in mice and using polymerase chain reaction (PCR). The results from this study show that T. gondii was more frequently and consistently detected in sheep, in particular within brain and heart tissues, whereas parasites were not detected in the samples of tissues taken from cattle. T. gondii was more frequently detected in sheep given the higher dose of T. gondii. Examination of tissues at either 6 weeks or 6 months after infection did not appear to affect the distribution of T. gondii. The polymerase chain reaction has more specificity and sensitivity when detecting the presence of T. gondii in large animals than histological detection.

Animals↗
PubMed2000

Detection of Oestrus ovis and associated risk factors in sheep from the central region of Yucatan, Mexico.

A cross-sectional epidemiologic study was conducted in order to detect the presence of and to estimate the seroprevalence of Oestrus ovis L. infection in flocks of sheep from the central region of the state of Yucatan, Mexico. The risk factors associated with disease were also identified. A sample size of 10 animals per farm was used to detect seropositive animals, considering a 30% prevalence and 95% confidence level. Blood samples of 689 sheep from 88 flocks were collected and a questionnaire with questions about the flock and the host was applied. The thin layer immune assay test was used. The risk factors were screened using logistic regression procedures. 77% of the flocks had at least one-positive animal with antibodies against O. ovis. The overall seroprevalence and standard error was 30.6 +/- 3.5%. Only flock size and sheep nose color showed association (P < 0.05) with the disease. The odds ratios for flocks with less than 11 and with 11 to 25 sheep, as related to herds with 25 or more sheep, were 0.74 and 1.73, respectively. Sheep with dark noses had a higher risk (OR = 1.46) compared with sheep having light noses (P < 0.05).

Age Factors↗
PubMed2001

Effect of hypomagnesemia and cold exposure on tissue responsiveness to insulin in sheep given a low magnesium and high potassium diet.

Hypomagnesemia in ruminants has been shown to be associated with cold stress and with altered insulin secretion and sensitivity. However, the relationship between hypomagnesemia and tissue responsiveness to insulin in ruminants exposed to cold environment is still unclear. The hyperinsulinemic euglycemic clamps, four insulin infusion rates (1, 2, 4 and 8 mU x kgBW(-1) x min(-1) for four sequential periods of 2-h each) were performed to determine combined effects of hypomagnesemia and cold exposure (0 degrees C) on tissue responsiveness to insulin in sheep. The low magnesium (0.05% Mg) and high potassium (4.20% K) diet and cold exposure decreased (P <.05) plasma Mg levels compared with those of the control diet (0.28% Mg/0.52% K) and the thermoneutral environment (20 degrees C). In the euglycemic clamps, cold exposure increased (P <.01) the pooled glucose infusion rate (GIR) across various insulin infusion rates in both diet treatments, though the increases in GIR were small for the low Mg/high K diet. In the cold environment, the GIR was lower (P <.01) for the low Mg/high K diet-fed sheep than for the control diet-fed sheep. The maximal insulin-induced increase in GIR was lower (P <.01) in the hypomagnesemic sheep than in the control sheep during cold exposure, and the insulin level resulting in half-maximal GIR tended to be higher in the hypomagnesemic sheep than in the control sheep. These results indicated that hypomagnesemia in ruminants depressed the enhanced tissue responsiveness to insulin in the cold environment, and decreased insulin-mediated glucose disposal.

Animals↗
PubMed1976

Immunisation of sheep against Schistosoma mattheei using either irradiated cercariae or irradiated schistosomula.

Irradiated cercariae, irradiated schistosomula, or heterologous infections were used to vaccinate sheep against Schistosoma mattheei infection. In the first experiment four doses of 10(4) S. mattheei cercariae irradiated at 6Kr were administered to sheep by percutaneous infection at 4 week intervals. This induced a 74% reduction in a challenge infection compared to control sheep while only 13% protection was achieved in a third group of sheep immunised with normal cercariae of the heterologous parasite S. mansoni. No significant differences were seen in histopathology of the liver of any of the sheep but the pathological changes were more severe in the large and small intestines of sheep vaccinated with the heterologous parasite. In the second experiment with irradiated cercariae only one or two immunising exposures were used. The degree of protection in the adult worm load (9-11%) was not significant and no significant differences were noticed in the pathology of the vaccinated and control animals. In the third experiment four doses of irradiated organisms were used to vaccinate five groups of sheep: 3Kr or 6Kr cercariae were administered by percutaneous infection; 6Kr skin-transformed schistosomula were administered by intra muscular injection; the same 6Kr skin-transformed schistosomula were given by intravenous injection and 6Kr syringe transformed schistosomula were administered by intramuscular injection. The degree of protection (determined as the reduction in worm burden) achieved by these different procedures was respectively 72%, 61%, 77%, 56% and 78%. These results indicate the possibility of making a live vaccine against ovine schistosomiasis and show that effective immunisation is not dependent on the presence of a mature worm infection or on cercarial penetration of the skin by the immunising infection.

Animals↗
PubMed1999

Single nucleotide variation in rDNA ITS-2 differentiates Psoroptes isolates from sheep and rabbits from the same geographical area.

Psoroptic sheep scab and psoroptic otoacariasis of domestic rabbits occur in the same geographical regions of Switzerland. To address the question as to whether Psoroptes mites are naturally transmitted between sheep and rabbits, we determined the sequences of the rDNA second internal transcribed spacer (ITS-2) from psoroptic mites from sheep (5 field isolates from Switzerland and 2 laboratory isolates from Ireland and the UK) and from rabbits (8 field isolates from Switzerland). The ITS-2 sequences for all Psoroptes mites originating from sheep were identical and differed at 1 nucleotide position from all the sequences of the rabbit-derived isolates. A statistically significant difference between a rabbit-derived isolate and isolates originating from sheep was also obtained by morphometric analysis of the lengths of the outer opisthosomal setae. For comparative purposes, the ITS-2 sequences from Chorioptes and Sarcoptes collected in Switzerland were also determined. No intraspecies variation was found in 6 sarcoptic isolates from red foxes, with a sequence identity of 41% as compared to Psoroptes. The ITS-2 sequences of 3 chorioptic isolates differed by 24-29% from the Psoroptes sequence. Identical sequences were found for the Chorioptes isolates from sheep and a camel, which differed by 18% from the sequence of an isolate from a cow. These genetic data of psoroptic mites originating from sheep and rabbits from the same geographical area suggest the existence of epidemiologically separated populations.

Animals↗
PubMed1999

The prevalence of coccidian species in sheep in Kars Province of Turkey.

Coccidia were detected in the faeces of 556 out of 592 sheep (93.9%) in sheep in Kars province. The prevalence of coccidiosis was significantly higher (p < 0.01) in young (97.9%) and immature sheep (96.6%) than in adult sheep (90.2%). Mixed infections were widespread (71.5%). Ten species of Eimeria were recognized. These species (and their prevalences) were: Eimeria ovinoidalis (47.7%), E. bakuensis (E. ovina) (46.6%), E. parva (37.1%), E. granulosa (27.7%), E. ahsata (23.4%), E. pallida (23.2%), E. faurei (15.1%), E. intricata (13.9%), E. crandallis (13.7%) and E. punctata (2.3%). Eimeria punctata is reported in sheep from Turkey for the first time. The mean oocyst count from infected animals was 3451 +/- 409 opg (range 50-117,600). The mean was higher (9529 +/- 502) in young sheep. Differences in the counts from young, immature and adult sheep were statistically significant (p < 0.01). However, no clinical cases of coccidiosis were encountered.

Age Factors↗
PubMed2002

Financial implications of rearing sheep and goats under natural trypanosomosis challenge at Galana ranch, Kenya.

A study to compare the profitability of rearing sheep and goats under natural trypanosomosis challenge was carried out on Galana ranch in south-eastern Kenya between July 1996 and October 1997. Seventy-nine male weaner sheep and 79 male weaner goats were monitored monthly for weight changes and fortnightly for trypanosomosis. The animals of each species were divided into two groups. Group 1 was an untreated control, while group 2 was treated with isometamidium chloride (Samorin) at 0.5 mg/kg body weight every 3 months. In both groups, trypanosome infections were detected by microscopy and treated with diminazene aceturate (Veriben), at 3.5 mg/kg body weight, when the packed cell volume reached 17% or below. The profitability of each drug regime was expressed as the marginal revenue over the cost of trypanosomosis (MOT). There were greater losses occasioned by trypanosomosis in sheep than in goats. Animals of both species on chemoprophylaxis gave higher MOT values than those that received chemotherapy on diagnosis. However, the MOT values for the chemoprophylactic regime were higher for sheep than for goats, suggesting that the greater weight gain by sheep more then compensated for the higher cost of maintaining them under high trypanosomosis challenge. Thus, a Galana rancher would be better off keeping sheep rather than goats, other things being equal. The marginal revenue per dose of Samorin was lower than that of Veriben for both species, suggesting that strategic use of Samorin timed to precede the peak incidence of trypanosomosis might be a better option to raise the overall profitability in sheep and goats.

Animal Husbandry↗
PubMed1978

Immune responses of sheep to the parasitic nematode Trichostrongylus colubriformis: infections in Thiry-Vella loops.

Some aspects of the local immune response to nematode infection were examined by introducing fourth-stage Trichostrongylus colubriformis larvae into Thiry-Vella loops in worm-free and T. colubriformis-resistant sheep. Approximately 15% of the larvae introduced into the worm-free sheep survived and matured into adult worms, whereas less than 1% survival in resistant sheep. The amount of IgG1, IgG2, IgM and albumin discharged from loops in worm-free but not resistant sheep all increased following infection with larvae. Secretions from resistant sheep contained approximately three times as much IgA as secretions from the worm-free group and, in addition, their plasma IgG1 level was significantly higher. Antibodies against T. columbriformis were found in both plasma and intestinal secretions, the highest titres being found in the resistant sheep. During worm expulsion from loops in the resistant sheep neither immunoglobulin levels nor antibody titres in the secretions increased significantly.

Animals↗
PubMed2000

Effect of shearing on the incidence of caseous lymphadenitis in Awassi sheep in Jordan.

A total of 876 sheep from five flocks in north Jordan were selected to study the effect of shearing on the incidence of caseous lymphadenitis (CLA). The animals were divided into two age groups, sheep aged 1-2 years and those aged > or = 3 years. Blood samples were collected from the animals at the time of shearing and again 6 months later. A toxin enzyme-linked immunosorbent assay was used to identify sheep that had been infected with Corynebacterium pseudotuberculosis. The point prevalences of CLA were 6.59% and 21.06% in the 1-2-year and > or = 3-year age groups, respectively, and were significantly higher (P < 0.01) in the > or = 3-year age group. The overall prevalence among all ages was 15.3%. In the shorn sheep, the incidence of CLA was 22.46% and 9.47% in the 1-2-year and > or = 3-year age groups, respectively, and was significantly higher (P < 0.05) in the 1-2-year age group. In the control animals, the incidence was 8% and 5.26% in the 1-2-year and > or = 3-year age groups, respectively, and was different (P < 0.01) between the shorn (22.46%) and control (8%) animals of the 1-2-year age group. An epidemiological survey of 35 sheep farms revealed the prevalence of CLA, shearing wounds and unhygienic conditions during shearing in all farms. In conclusion, the prevalence of CLA increases with age and the incidence increases only in young sheep after shearing. Sheep are sheared under unhygienic conditions, which may be a contributing factor in increasing both the prevalence and the incidence of CLA.

Animal Husbandry↗
PubMed2006

Sensitivity and specificity of the agar-gel-immunodiffusion test, ELISA and the skin test for detection of paratuberculosis in United States Midwest sheep populations.

Our objective was to estimate the sensitivity and specificity of the agar-gel-immunodiffusion test (AGID), the ELISA, and the skin test for the detection of Mycobacterium avium subspecies paratuberculosis (MAP) in sheep using Bayesian methods without a gold standard. Fourteen flocks (2 465 sheep) were used. Five flocks (450 sheep) were considered MAP non-infected and 9 flocks (2 015 sheep) had sheep infected with MAP. Sheep were skin tested and blood was collected for AGID and ELISA testing. Results were analyzed using a Bayesian 3-test in 1-population model fitted in WinBUGS. The model allowed for dependence (correlation) between the two serologic tests, but these two tests were assumed to be conditionally independent of the skin test. The estimated specificity was 99.5% (95% PI of 98.9-99.9%) for the AGID; 99.3% (98.4-99.8%) for the ELISA using an optical density measured cutoff of 0.20; 99.2% (98.1-99.8%) using a cutoff of 0.15; 97.5% (95.8-98.7%) using a cutoff of 0.10; and 98.7% (97.3-99.5%) for the skin test. The estimated sensitivities were 8.3% (6.2-10.7%) for the AGID; 8.0% (6.0-10.4%), 10.6% (8.3-13.1%), and 16.3% (13.5-19.4%) for the ELISA using the cutoffs 0.20, 0.15, and 0.10 respectively; and 73.3% (62.3-85.8%) for the skin test. The skin test was specific in non-infected populations and sensitive in infected populations, although in some cases a positive skin test might represent MAP exposure rather than infection. The AGID and ELISA were specific but lacked sensitivity. The AGID and ELISA consistently identified two different populations of infected sheep with only moderate overlap between positive test results.

Animals↗
PubMed2005

Inherited chondrodysplasia in Texel sheep.

CASE HISTORY: A skeletal disease characterised by dwarfism, limb deformity and sometimes sudden death occurred over a period of 5 years in lambs born on a commercial sheep farm in Southland. The disease showed variable expression and occurred in crossbred sheep. A genetic aetiology was supported by the birth of affected lambs over two seasons in a flock of putative carrier and affected sheep transported to Massey University. CLINICAL FINDINGS: Affected lambs appeared normal at birth but showed evidence of dwarfism, wide-based stance and exercise intolerance as early as 1 week of age. Most died within the first 3 months of life, often after developing bilateral varus deformity of the forelimbs. Some severely-affected lambs died suddenly of respiratory embarrassment, probably due to tracheal collapse. Mildly-affected individuals had a short, blocky stature and some survived to breeding age. PATHOLOGICAL FINDINGS: Gross and microscopic lesions of variable severity were present in the tracheal, articular, epiphyseal and physeal cartilages. In severe cases, articular cartilage in major joints was eroded from weight-bearing surfaces. The trachea was flaccid, abnormally kinked, and had thickened cartilaginous rings and a narrow lumen. Affected sheep that survived to breeding age eventually developed severe degenerative joint disease. Histologically, chondrocytes were disorganised, surrounded by concentric rings of abnormal fibrillar material, and the matrix often contained focal to coalescing areas of chondrolysis. DIAGNOSIS: Inherited chondrodysplasia of Texel sheep. CLINICAL RELEVANCE AND CONCLUSIONS: This chondrodysplasia differs from those previously described in sheep and is considered to be a newly-recognised, recessively-inherited genetic disease of the Texel breed. A defect in the synthesis of glycosaminoglycans in cartilage matrix is suspected. This disease of sheep may provide a suitable model for studying various forms of therapy for human chondrodysplasias.

Animals↗
PubMed1983

Antigenic drift in visna: virus variation during long-term infection of Icelandic sheep.

A group of 20 Icelandic sheep were infected intracerebrally with visna virus strain 1514, and 209 virus isolates were obtained from the blood, cerebrospinal fluid, and central nervous system (CNS) over a period of 7 years, during which eight animals developed clinical signs of visna necessitating sacrifice. (i) Using type-specific antisera, it was found that 12 (16%) of 76 isolates tested escaped neutralization. These 12 variant viruses were distributed randomly among animals and over time, and did not replace the infecting strain even though all sheep developed homotypic antibody within 3 months of infection. The one exception was sheep no. 1557 (an animal without clinical visna), where the last six isolates were variants. (ii) A total of 35 blood and CNS isolates from seven of these sheep (including five with clinical visna) were tested against serial samples of their own sera. Autologous antisera neutralized all isolates tested with the exception of isolates from sheep 1557. None of the isolates obtained at sacrifice from the five sheep with clinical visna escaped neutralization with autologous antisera. These data suggest that although variant viruses are encountered at considerable frequency during long-term infection of Icelandic sheep, the variants usually do not replace the infecting strain. Antigenic drift does not appear to be essential for virus persistence or for the development of clinically evident CNS lesions.

Animals↗
PubMed2002

Quantities of infectious virus and viral RNA recovered from sheep and cattle experimentally infected with foot-and-mouth disease virus O UK 2001.

The profiles of virus production and excretion have been established for sheep experimentally infected with the UK 2001 strain of foot-and-mouth disease (FMD) virus by inoculation and by direct and intensive contact. Virus replicated rapidly in the inoculated sheep, from which a peak infectivity of airborne virus of 10(4.3) TCID(50) per sheep per 24 h was recovered. Around 24 h later, contact-infected sheep excreted airborne virus maximally. Similar amounts of airborne virus were recovered from cattle. The excretion of virus by the sheep under these conditions fell into three phases. First, a highly infectious period of around 7-8 days. Second, a period of 1-3 days soon afterwards when trace amounts of viral RNA were recovered in nasal and rectal swabs. Third, at 4 weeks after exposure, the demonstration, by tests on oesophageal-pharyngeal samples, that 50% of the sheep were carriers. The implications of the results and the variable role that sheep may play in the epidemiology of FMD are discussed.

Aerosols↗
PubMed2006

Monitoring for bovine spongiform encephalopathy in sheep in Great Britain, 1998-2004.

Bovine spongiform encephalopathy (BSE) may have been transmitted to British sheep via contaminated feed in the 1980s. Strain-typing techniques based on immunohistochemical (IHC) detection of abnormal protein (PrP(d)) and the molecular analysis of proteinase-resistant protein (PrP(res)) by Western blotting (WB) can discriminate between natural or experimental scrapie and experimental BSE in sheep. Between 1 January 1998 and 31 October 2001, 1247 sheep, clinically suspected of scrapie, were found to be positive by statutory tests in Great Britain. Archived brain tissue from these cases was retested by using these discriminatory methods. Twelve brain samples showed PrP(res) WB patterns that were unlike those found in natural or experimental scrapie. Prospective screening of fresh tissue from a further 1121 scrapie cases was also carried out between 1 November 2001 and 31 May 2004. Two samples gave WB results with similarities to the results found for experimental BSE in sheep. When all 14 unusual cases were tested by IHC, no match to experimental BSE in sheep was found. There were uncertainties within the retrospective study, where some equivocal results were obtained due to poor tissue quality or the unavailability of the optimum brain region. However, for the samples where tissue condition was optimum, our results provide no evidence for the presence of BSE in sheep. Epidemiological interpretation of the 450 flocks sampled indicates that the maximum proportion of sheep transmissible spongiform encephalopathy cases that could be BSE is 0.66%. This estimate is lower than calculated previously (5%), when the analysis was based on the results of strain typing in mice.

Animals↗
PubMed2006

Globally dispersed Y chromosomal haplotypes in wild and domestic sheep.

To date, investigations of genetic diversity and the origins of domestication in sheep have utilised autosomal microsatellites and variation in the mitochondrial genome. We present the first analysis of both domestic and wild sheep using genetic markers residing on the ovine Y chromosome. Analysis of a single nucleotide polymorphism (oY1) in the SRY promoter region revealed that allele A-oY1 was present in all wild bighorn sheep (Ovis canadensis), two subspecies of thinhorn sheep (Ovis dalli), European Mouflon (Ovis musimon) and the Barbary (Ammontragis lervia). A-oY1 also had the highest frequency (71.4%) within 458 domestic sheep drawn from 65 breeds sampled from Africa, Asia, Australia, the Caribbean, Europe, the Middle East and Central Asia. Sequence analysis of a second locus, microsatellite SRYM18, revealed a compound repeat array displaying fixed differences, which identified bighorn and thinhorn sheep as distinct from the European Mouflon and domestic animals. Combined genotypic data identified 11 male-specific haplotypes that represented at least two separate lineages. Investigation of the geographical distribution of each haplotype revealed that one (H6) was both very common and widespread in the global sample of domestic breeds. The remaining haplotypes each displayed more restricted and informative distributions. For example, H5 was likely founded following the domestication of European breeds and was used to trace the recent transportation of animals to both the Caribbean and Australia. A high rate of Y chromosomal dispersal appears to have taken place during the development of domestic sheep as only 12.9% of the total observed variation was partitioned between major geographical regions.

Alleles↗