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1.
SUMMARY The decrease in the prevalence of Corynebacterium pseudotuberculosis after two generations of vaccination against the disease it causes, was used to estimate the rate of control of caseous lymphadenitis (CLA). Three groups of 150 sheep, of which 50 in each group were artificially infected with C pseudotuberculosis and 100 in each group were uninfected sheep, were run separately for 40 months and shorn 5 times to promote the spread of CLA. One lot of 50 infected sheep and 2 lots of 100 uninfected sheep were vaccinated against CLA. The rate of spread of CLA was recorded. Sheep vaccinated against CLA and naturally exposed to infection had a 74% lower infection rate than unvaccinated sheep. Sheep vaccinated against CLA and exposed to only vaccinated infected sheep had a 97% lower infection rate. Unvaccinated sheep had a 76% infection rate, with 77% of the transmission occurring at the 4th and 5th shearings, without any discharging CLA abscesses being observed. This study supports the view that in Australian wool producing flocks, CLA spreads mainly from sheep with discharging lung abscesses to sheep with shearing cuts. Vaccinated sheep infected with CLA have 96% fewer lung abscesses compared with unvaccinated infected sheep and are therefore less likely to spread this disease to other sheep .  相似文献   

2.
The wool production of 20 Merino sheep, artificially infected with Fasciola hepatica, was compared with that of 20 uninfected controls. Sheep of two different ages, 6 months and 4 years, were fed in pens ad lib on two different diets giving high and low planes of nutrition. The midside tatooed patch technique was used to measure the wool production over periods of 6 weeks prior to the infection date, and 0–6, 6–12, 12–18 and 18–24 weeks after this date. Infection with F. hepatica caused a significant reduction of 20–39% in wool production from 6 weeks after infection, irrespective of the age of the sheep or the plane of nutrition. It was found that a reduction in wool production may occur without symptoms of fasciolosis being apparent.  相似文献   

3.
Two hundred Merino wether hoggets were used to examine the effect of Corynebacterium pseudotuberculosis infection (caseous lymphadenitis) on wool production and bodyweight. Sheep which were challenged with C. pseudotuberculosis (artificially infected) and not vaccinated against this disease produced 0.20 kg less clean wool than unchallenged controls during the following 12 months. The incidence of sheep with lesions in the group that was vaccinated prior to challenge was 55% lower than in unvaccinated challenged sheep but their wool production was not significantly different from either the controls or the unvaccinated challenged sheep. Vaccinated sheep were also heavier than unvaccinated sheep 12 months after challenge. These results indicate that caseous lymphadenitis infection may reduce wool production.  相似文献   

4.
High glycine–tyrosine keratin‐associated proteins (HGT‐KAPs) are predominantly present in the orthocortex of wool fibres. They vary in abundance in different wools and have been implicated in regulating wool fibre properties, but little is known about the functional roles of these proteins in the fibre matrix. In this study, we used polymerase chain reaction – single‐strand conformational polymorphism (PCR‐SSCP) analysis to screen for variation in a gene encoding the ovine HGT‐KAP6‐1 protein. We identified three gene variants (A, B and C). Variants A and B were similar to each other, with only three nucleotide differences occurring downstream of the coding sequence. However, variant C had a 57‐bp deletion that would notionally result in a loss of 19 amino acids in the protein. The presence of C was found to be associated with an increase in mean fibre diameter (MFD), fibre diameter standard deviation (FDSD), coefficient of variation of fibre diameter (CVFD) and prickle factor (percentage of fibres over 30 microns; PF). Sheep of genotype BC produced wool of greater MFD, FDSD and PF than sheep of genotypes AA, AB and BB. The CVFD was greater in the BC sheep than the AB sheep. The results suggest that variation in ovine KRTAP6‐1 affects wool fibre diameter‐associated traits and that the 57‐bp deletion in this gene would lead to coarser wool with greater FDSD, CVFD and PF.  相似文献   

5.
Caseous lymphadenitis (CLA) infection was established experimentally in a total of 30, 2-tooth merino wethers. In the first experiment a broth culture of the causative organism, Corynebacterum pseudotuberculosis was placed directly on to a freshly shorn area on the right shoulder of 21 sheep after pretreatment with a defatting agent, water or 4 different commercial sheep dips. Within 6–13 days focal skin lesions appeared on 7 sheep and these were followed by abscessation of the right prescapular lymph node. Lung lesions of CLA developed in 6 sheep; 5 of which had skin lesions. In the second experiment C. Pseudotuberculosis broth culture was applied over the right shoulder region of 14 sheep, 24 hours post shearing. The 7 animals had only 1 application of the culture and the remaining 7 had 4 applications on consecutive days. A total of 9 of the 14 sheep developed skin lesions and subsequent CLA in the right prescapular lymph nod but there was no significant difference between the 2 methods of application. As part of the second experiment a broth culture of C. pseudotuberculosis was added to a commercial arsenical sheep dip and 2 hours later sprayed on to the right side of sheep shorn 24 hours or 2 weeks previously. Within 6–13 days all 14 sheep treated in this way developed skin lesions from which C. pseudotuberculiosis was recovered in dense pure growth. Healing time of skin lesions in all affected sheep ranged from 17–72 days post inoculation. A serological test to detect the presence of C. pseudotuberculosis antitoxin was used at regular intervals on all experimental sheep. The earliest positive reaction in an affected sheep was recorded 4 weeks post inoculation. In 23 known affected sheep tested at 35 weeks post inoculation, 10 were positive to the Zaki test. No false positive reactors were recorded. The localisation of focal lung lesions in the interstitial tissue suggests that pulmonary abscessation caused by C. pseudotuberculosis develops via the haematogenous route.  相似文献   

6.
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7.
The objectives of this study were to estimate the genetic variation in pasture intake and digestibility of the selected diet by young and by adult sheep, and to determine the genetic relationships between pasture intake and productivity traits. The pasture intakes of groups of young and adult sheep, each containing sheep from 11 bloodlines, were measured using the paired alkane technique. The wool grown, and its fibre diameter, over the intake measurement period were also estimated, as were liveweight and fat depth. Differences in pasture intake between bloodlines were largely related to liveweight in both groups of sheep, and were repeatable (t=0.8) between the groups. The repeatability of wool growth and wool growth efficiency was a little higher (t>0.9). Combining all the known estimates improved the precision of the genetic parameter estimates. The pooled estimates of heritability of DOMI, wool growth, wool growth efficiency and fibre diameter were 0.12±0.04, 0.37±0.05, 0.25±0.05 and 0.66±0.08, respectively. The genetic relationships of wool growth efficiency with wool growth and fibre diameter were 0.84±0.20 and −0.03±0.12, respectively, while those for feed intake (as DOMI) with wool growth and fibre diameter were −0.02±0.17 and 0.40±0.15.  相似文献   

8.
本研究旨在估计高山美利奴羊重要经济性状的遗传参数,为优化高山美利奴羊选育方案、建设品种完整结构、进行遗传评估及实施育种值选种提供理论技术支撑。采用甘肃省绵羊繁育技术推广站2003—2018年高山美利奴羊核心群数据资料,基于ASReml运用单性状个体动物模型和多性状个体动物模型估计高山美利奴羊体重、产羔数、产毛量、净毛量、净毛率、羊毛纤维直径、羊毛纤维直径变异系数、毛丛长度等重要经济性状的遗传参数。结果表明:高山美利奴羊产羔数为低等遗传力,其他所有性状均为中高等遗传力;大部分经济性状间呈正遗传相关,体重、产毛量、羊毛纤维直径与净毛率间呈负遗传相关,羊毛纤维直径变异系数与体重、产毛量、纤维直径呈负遗传相关。  相似文献   

9.
SUMMARY: A comparative study of various fleece properties known to influence fleece-rot susceptibility was made in a merino flock consisting of sheep which were found to be either resistant or susceptible to fleece-rot and body strike following heavy rains. The fleece properties measured were fibre diameter, fibre diameter variation, wax content, suint content, wax to suint ratio, suint pH, insoluble nitrogen content, wool colour and wettability. Fibre diameter variation, due mainly to the presence of coarse, secondary fibres in the staple, was the only fleece property which differed significantly (p < 0.001) between resistant and susceptible animals. The coefficient of variation of fibre diameter was lowered from a mean value of 22.7 ± 0.3% in susceptible sheep to 20.0 ± 0.3% in resistant sheep. A causal relationship between high fibre diameter variation and fleece-rot susceptibility is suggested. Sheep with irregular fibre size may retain free moisture in the fleece for longer, and thereby become more susceptible to fleece-rot than sheep with uniform fibre diameter, other predisposing factors being equal.  相似文献   

10.

This study investigated variation in the keratin-associated proteins gene, KRTAP6-3, in 5 Pakistani sheep breeds/crosses using polymerase chain reaction-single strand confirmation polymorphism (PCR-SSCP) analysis. Different banding patterns were revealed, including previously described patterns and a novel pattern (named variant H). The amplified PCR product of the novel banding pattern was directly sequenced, and a synonymous nucleotide variation c.51T>C was revealed. Among the wool traits assessed, a strong correlation (r = 0.929; P < 0.001) was observed between fibre diameter standard deviation (FDSD) and coefficient of variation of fibre diameter (CVFD), between FDSD and medullation (r = 0.720; P < 0.001), between FDSD and medullation standard deviation (MeSD) (r = 0.734; P < 0.001), between MeSD and coefficient of variance of medullation (CVMed), (r = 0.903, P < 0.001), and between CVFD and medullation (r = 0.660), CVFD and MeSD (r = 0.786; P < 0.001), CVFD and CVMed (r = 0.701; P < 0.001) and medullation and MeSD (r = 0.771; P < 0.001). Variant B was found to be associated (P = 0.018) with CVFD; the presence of B being associated with a higher CVFD, than in its absence (41.08 ± 3.98 versus 36.34 ± 3.08). Variant C was associated with CVMed (P = 0.040), where sheep with C had a lower CVMed than sheep where it was absent. Variation in KRTAP6-3 was found to affect fibre diameter related traits of wool.

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11.
Merino wether lambs were individually confined and fed a basal diet of oaten chaff containing essential minerals which was untreated or contained 3% urea. Within each dietary group animals were orally infected with either 200 H. contortus (H), 1000 T. colubriformis (T) or both species (H + T) thrice weekly or remained uninfected (C). Weight gain, wool production, and parasite burden were measured over a 19-week period. Sheep on the diet containing urea gained more weight, consumed more feed and grew more wool of higher fibre diameter than their counterparts given no urea. On both diets uninfected sheep consumed more feed than infected sheep and the sheep given no urea and infected with both H and T worm species consumed the least feed. Parasitised sheep gained less weight than uninfected control sheep. Sheep with urea in their diet had lower faecal egg counts when infected with H alone or with H and T but there was no effect of urea on egg count of sheep infected with T alone. In contrast, T numbers after slaughter were reduced in sheep fed diets containing urea whereas H numbers were not affected by diet. It was concluded that supplementation with urea can increase resilience to parasitism thereby improving production and also enhance resistance mechanisms against worms in young sheep on low quality roughage diets. These responses can be partly attributed to stimulation of feed intake, presumably due to enhanced ruminal digestion, but also to elevated rumen NH3-N levels which would be expected to have increased rumen microbial protein synthesis and availability to the intestines.  相似文献   

12.
Pseudotuberculosis, an infection caused by the ubiquitous enteropathogenic bacterium Yersinia pseudotuberculosis, is a recurrent veterinary problem in livestock and zoo animals. The only vaccine currently available in zoos is Pseudovac (a mixture of killed strains of various serotypes), but its efficacy is not well established. We show here that Pseudovac does not protect guinea pigs against a severe Y. pseudotuberculosis infection. We thus evaluated the possibility of using a live attenuated Y. pseudotuberculosis strain (IP32680) as an oral vaccine against animal pseudotuberculosis. We report that IP32680 is avirulent for guinea pigs and induces a strong IgG response against various serotypes of Y. pseudotuberculosis. One and two oral inoculations of IP32680 provided 50% and 83% protection, respectively against a severe infection with a highly pathogenic strain. The avirulent Y. pseudotuberculosis IP32680 is therefore much more protective than Pseudovac and may represent a valuable oral vaccine against pseudotuberculosis in zoo animals.  相似文献   

13.
微卫星座位与超细型细毛羊羊毛性状的关联性分析   总被引：3，自引：1，他引：2  
本研究选取了绵羊基因组1号和3号染色体上的8个微卫星座位,对超细型细毛羊的232个个体的遗传多样性进行了检测。计算了各微卫星座位的等位基因频率（p）、杂合度（H）、多态信息含量（PIC）和有效等位基因数（N）。同时检测了研究样本的羊毛纤维直径（WFD）,毛纤维直径离散度（FD-D）,单纤维绝对强力（WAS）,单纤维相对强力（WRS）,强力离散（WSD）,单纤维自然长度（WNL）,单纤维伸直长度（WEL）和单纤维弯曲度（FW）等羊毛性状的8个表型数据。微卫星座位与羊毛性状表型数据的关联性分析结果表明,微卫星 BL-4和KRT2-13两个座位与WEL之间极显著相关（P<0.01）。微卫星Oarcp43座位与WSD之间、微卫星座位Bms1248与羊毛单纤维直径之间极显著相关（P<0.01）。座位Fcb5和OarDB6分别与FW和WAS表现出显著性关系（P<0.05）。  相似文献   

14.
The effect of regular selenium supplementation on the body weight, wool production and mortality of young Merino sheep was investigated. Groups of Se-treated and control sheep involving from 260–500 on each of 15 farms were observed from six weeks to 19 months of age. Ten mg Se as sodium hydrogen selenite was administered orally to the treated sheep at two-monthly intervals. Treated and control sheep grazed together throughout the trial period. Statistically significant responses to selenium were recorded in body weight gains on four farms, in decreased mortality on five farms and as an increase in fleece weight on eight farms. The response in fleece weight varied from 2.9-7.6% and could not be explained as a result of increased body weight. The increase in fleece weight was not due to an increase of grease in the wool but appeared to be due to an increase in fibre diameter and to a lesser extent an increase in staple length. A statistically significant decrease in the incidence of tender fleeces as a result of selenium supplementation was also recorded. All farms on which responses to selenium were obtained were in areas with average annual rainfall more than 20 inches. On two farms selenium caused statistically significant depressions in the parameters measured. Both farms were in areas with less than 20 inches average annual rainfall.  相似文献   

15.
Molecular genetics provides an increasing capacity to modulate the function of individual genes, but the practical implications of these technologies are still poorly understood. This study examined adult Merino or Merino-cross sheep that had an additional copy of the ovine GH gene with a modified metal-lothionine promoter, which resulted in a doubling of the plasma concentration of GH. Previous work showed that up to the age of 18 mo, GH sheep grew faster and had less s.c. fat, with only minor effects on fleece production. The present paper describes characteristics of reproduction, wool production, and animal health of these sheep during the following 2 yr of adult life. Ewes with the GH gene had a greater ovulation rate (1.78 vs. 1.35; P <0.05), but bore fewer lambs, apparently due to greater fetal loss after mating. Grease fleece weight was increased (P <0.05) due mainly to a greater content of suint (9.1 vs. 7.7 +/- 0.4%, P <0.01), which was associated with a deeper color of the raw wool. Effects on clean fleece weight and fiber diameter were not consistent between years. The GH sheep had swollen metatarsal and metacarpal joints, which was associated with a need for more frequent hoof-trimming, and more GH than control sheep died during the experiment (P <0.001). All of these changes are consistent with previously reported effects of increased plasma GH. Results of this study show that increased activity of a single gene (GH) affected several production characteristics and predisposed the animals to a number of distinct health problems, some of which developed after the normal age of genetic selection.  相似文献   

16.
Two isolates from the cervical canal of clinically normal sows were indistinguishable from Corynebacterium pseudotuberculosis in their biochemical properties and genetic homology by dna-dna hybridisation. Furthermore, three sheep inoculated with one of the isolates developed typical lesions of caseous lymphadenitis and gave antibody responses specifically to C pseudotuberculosis.  相似文献   

17.
The persistence of foot-and-mouth disease virus on wool   总被引：1，自引：0，他引：1  
SUMMARY Five Suffolk sheep, held in a high-security isolation room, were exposed for 2 hours to the aerosol of 3 mature pigs that had been infected with foot-and-mouth disease virus (FMDV), strain O1-BFS. The fleeces of 3 of the sheep were contaminated with FMDV at 2 days post exposure (dpe), while at 5 dpe the fleeces of all 5 sheep were more extensively, and more heavily, contaminated. The persistence of FMDV on contaminated wool was examined in vitro using multiple 0.5 g samples of Merino wool that were each contaminated with one of 3 strains of FMDV in tissue-culture medium: O1-BFS, O-Morocco (O-MOR 9/91) or an Asia 1 strain (TAI 1/90). Wool samples were held at either 4°C, 18°C or 37°C, and decay curves were established for each virus at each temperature. These curves predicted that O1-BFS, O-MOR 9/91 and TAI 1/90 would fall below detect-able levels at 72, 70 and 48 days post contamination (pc), respectively, for wool stored at 4°C; at 11, 12 and 12 days pc, respectively, for wool stored at 18°C; and at 57, 68 and 33 hours pc, respectively, for wool stored at 37°C. For wool contaminated with O1-BFS-infected sheep faeces, urine or blood, or with O1-BFS-infected cattle saliva, decay curves predicted virus to persist for 5 to 11 days pc at 18°C. We demonstrated that the simulated scouring of FMDV-contaminated wool at 60° to 70°C would usually reduce virus to below detectable levels. The detergent component of the scouring process had little, if any, antiviral activity, and scouring at 20°C or 50°C had limited impact on FMDV titres . We recommend that either (1) simple storage of FMDV-contaminated wool for 4 weeks at temperatures of 18°C or higher, or (2) scouring of contaminated wool at 60° to 70°C would be sufficient to remove the threat of FMDV-contaminated wool being infectious to other animals .  相似文献   

18.
为了深入了解东北地区细毛羊的羊毛品质状况,更好地开展细毛羊品种选育与推广工作,试验进行了东北部分地区细毛羊毛样的长度、长度离散度、细度、细度离散度、净毛率、油脂含量、色度以及部分毛样的毛尖、毛中、毛根细度检测及羊毛品质分级。结果表明:所测毛样组成为细羊毛(71.97%)、半细羊毛(2.28%)、等外级(7.19%)和超细型(18.56%)4类。说明东北地区拥有符合细羊毛纺织标准的当地细毛羊品种和符合高档毛纺原料需求的超细型细毛羊种群,同时广泛分布着以毛肉兼用为主的细毛羊生产群。  相似文献   

19.
Corynebacterium pseudotuberculosis, a Gram-positive bacterium is the causative agent of caseous lymphadenitis (CLA), a chronic disease of sheep, goats and other warm blooded animals. In the present study, a total of 1,080 sheep reared under semi-intensive system on organized farms situated in the semi arid tropical region of Rajasthan, India, was clinically examined. Pus samples from superficial lymph nodes of 25 (2.31 %) adult sheep showing clinical lesions similar to CLA were collected for laboratory analyses. On the basis of morphological, cultural and biochemical characteristics 12 (48 %) bacterial isolates from pus identified it as C. pseudotuberculosis. A polymerase chain reaction (PCR) assay targeting Putative oligopeptide/dipeptide ABC transporter, nicotinamide adenine dinucleotide phosphate (NADP) oxidoreductase coenzyme F420-dependent and proline iminopeptidase (PIP) genes of C. pseudotuberculosis was developed that showed 14 pus samples as positive. All C. pseudotuberculosis isolates were also found positive for these genes in the PCR. The specificity of the PCR products was confirmed by sequencing of the amplified products that showed 98–100 % homology with published sequences available in the NCBI database. The present study shows the incidence of CLA as 2.31 %, 1.1 % and 1.29 % based on clinical, bacterial culture and direct pus PCR assay, respectively. The PCR assay was rapid, specific and as significant as bacterial culture in detecting bacteria directly in the clinical pus samples. The PCR assay developed in the study can be applied for the diagnosis and control of CLA. Furthermore, the assay can also be applied to detect C. pseudotuberculosis in various clinical samples.  相似文献   

20.
The juvenile live weights, yearling fleece weight and wool characteristics of 2987 Romney progeny of 114 sires born over 9 breeding seasons in a fleece-weight-selected and a random control line were analysed. The high fleece weight-selected flock performance was higher (P < 0.001) for weaning weight and spring weight (6.9 and 8.4%), higher (P < 0.001) for greasy and clean fleece weight (23.8 and 24.3%), and also higher (P < 0.001) for FD by 1 μm, staple length by 6 mm, and wool yellowness by 0.3 unit than random control yearling sheep. Heritability estimates for weaning and spring live weight, greasy fleece weight, clean fleece weight, yield, fibre diameter, staple length, staple strength, loose wool bulk, brightness and yellowness were 0.15, 0.51, 0.35, 0.36, 0.40, 0.57, 0.41, 0.24, 0.46, 0.12 and 0.14 respectively. The heritability estimates are within the range of the long wool sheep breeds studied previously. The high selection differential achieved in the initial screening commercial flocks however facilitated to approach a selection response peak in a shorter selection duration and thus resulted in a non-significant genetic gain in greasy fleece weight when averaged over the 9 years of selection.  相似文献   

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