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1.
JWA LARSEN N ANDERSON† AL VIZARD‡ GA ANDERSON‡ H HOSTE§ 《Australian veterinary journal》1994,71(11):365-372
SUMMARY A study on 3 farms, each having a preventive strategy for the control of nematode infections, determined the risk factors associated with diarrhoea among Merino ewes in winter. Comparisons were made among groups of mated and unmated ewes with and without treatment with controlled-release capsules containing albendazole. Diarrhoea was assessed from the accumulations of faeces around the breech (dag score) and related to worm egg counts, total worm counts and histopathological findings. The overall prevalence of severe dag in ewes not treated with a capsule was 26% (221/844). In comparison, only 2.7% of treated ewes had severe dag. The adjusted odds ratio on each farm indicated that untreated ewes were between 12 and 16 times more likely to be affected with severe dag than ewes treated with a capsule. The effect of lactation was significant on only one farm whereas initial body weight had no significant effect. There was no significant association between worm egg counts and the occurrence of severe dag. There were significantly more eosinophils in the small intestine of ewes affected with severe dag compared with unaffected ewes. There were no significant differences in mast cell and globule leucocyte numbers between affected and unaffected ewes. This study provides strong evidence that the main cause of diarrhoea among Merino ewes grazing winter and early spring pastures is the ingestion of trichostrongylid larvae even by sheep that have a well-developed protective immune response to these parasites. New strategies for the control of nematode infections are needed to prevent diarrhoea and dag formation in adult sheep. 相似文献
2.
Objective To compare the prevalence of breech flystrike (‘breech‐strike’) on 12–20‐month‐old Merino hoggets that were mulesed, had breech and tail clips applied (‘clipped’) or were left unmulesed but treated strategically with long‐acting insecticide. Design A cohort study on three farms in southern Victoria. Methods Three treatment groups were established at lamb marking on each farm. The unmulesed group was treated with dicyclanil when 12 months old in September or October (‘early‐season treatment’). The prevalence of breech‐strike and key risk factors, including soiling of the breech with faeces (‘dag’) and urine (‘stain’), and breech wrinkle, were compared between the groups. Results Over all the farms, breech‐strike occurred on 1.1% of mulesed sheep and 7.7% of clipped sheep. Clipped sheep had a relative risk of breech‐strike of 18.2‐, 16.8‐ and 3.0‐fold that of mulesed sheep on the three farms. Unmulesed sheep treated with dicyclanil had a similar prevalence of breech‐strike to that of mulesed sheep (overall 0.9%, range 0–2.5%), but had significantly more dag, stain and wrinkle. Conclusion Early‐season treatment of unmulesed sheep prevented most breech‐strikes during the spring and early summer, and offers a short‐ to medium‐term option for the control of breech‐strike in south‐eastern Australia. There were some benefits associated with using clips, namely less dag and stain, and a shorter time spent crutching. However, to control breech‐strike the clipped sheep should be treated the same as unmulesed sheep. Reducing the prevalence and severity of dag will be a major component of strategies to control breech‐strike of Merinos in this region. 相似文献
3.
Objective To compare infections of gastrointestinal nematodes in 2-year-old ('maiden') spring-lambing Merino ewes in the upper and lower 25% of body weights (BW) at joining.
Design An observational study over two consecutive years on two farms in western Victoria.
Methods On each farm, ewes were weighed at the end of mating. Ewes within the upper and lower quartile of BW formed two groups that grazed together for the remainder of the year. On each farm, 20 ewes from each group were also treated with controlled release capsules containing ivermectin to minimise the effects of parasitism. Measures of worm infections were worm egg counts, total worm counts and assessment of breech soiling ('dag score'). Measures of production were BW, numbers of deaths, pregnant ewes and weaned lambs in each group, and response to treatment with a capsule.
Results No consistent difference was found in mean worm egg counts between ewes in the high and low BW groups and total worm counts of ewes before lambing were not significantly different in either year. Breech soiling of low BW ewes was consistently higher on both farms in both years. Those ewes also reared 7% to 14% fewer lambs. The difference in BW between the low and high groups remained highly significant on both farms throughout both years.
Conclusion A strategic approach to worm control is appropriate for ewes in both high and low BW categories. Management options for low BW ewes include culling, supplementary feeding to increase BW before mating, or delaying mating for 12 months. 相似文献
Design An observational study over two consecutive years on two farms in western Victoria.
Methods On each farm, ewes were weighed at the end of mating. Ewes within the upper and lower quartile of BW formed two groups that grazed together for the remainder of the year. On each farm, 20 ewes from each group were also treated with controlled release capsules containing ivermectin to minimise the effects of parasitism. Measures of worm infections were worm egg counts, total worm counts and assessment of breech soiling ('dag score'). Measures of production were BW, numbers of deaths, pregnant ewes and weaned lambs in each group, and response to treatment with a capsule.
Results No consistent difference was found in mean worm egg counts between ewes in the high and low BW groups and total worm counts of ewes before lambing were not significantly different in either year. Breech soiling of low BW ewes was consistently higher on both farms in both years. Those ewes also reared 7% to 14% fewer lambs. The difference in BW between the low and high groups remained highly significant on both farms throughout both years.
Conclusion A strategic approach to worm control is appropriate for ewes in both high and low BW categories. Management options for low BW ewes include culling, supplementary feeding to increase BW before mating, or delaying mating for 12 months. 相似文献
4.
夏洛莱羊、白萨福克羊与中国美利奴羊(新疆型)杂交一代母羊生产性能观察 总被引：1，自引：0，他引：1
为了改善与提高中国美利奴羊(新疆型)的肉用性能,采用夏洛莱公羊、白萨福克公羊与中国美利奴羊(新疆型)母羊进行杂交试验,并对其F1的初生重、3月龄重、6月龄重、剪毛后体重、剪毛量、羊毛细度等性状进行了测定。结果表明,白萨福克公羊×中国美利奴母羊(新疆型)F(1白中F1)、夏洛莱公羊×中国美利奴母羊(新疆型)F(1夏中F1)2组之间的初生重、3月龄重和剪毛后重差异均不显著(P>0.05);而夏中F16月龄重,则比白中F1高4.5%(P<0.01);2组之间毛纤维直径差异不显著(P>0.05),毛长和剪毛量差异均极显著(P<0.01),夏中F1的剪毛量比白中F1高9.8%。说明在新疆伊犁地区,夏中组合较白中组合更适合用作肥羔生产,而且从毛用性能方面看,夏中组合也较白中组合更具优势。 相似文献
5.
CB Garland 《New Zealand veterinary journal》2013,61(4):220-226
AbstractAIM: To conduct a cost-benefit analysis of the administration of anthelmintics to adult ewes around lambing.METHODS: Production data from comparisons of different anthelmintic treatments with no treatment were used in a cost-benefit analysis. The data were from 14 trials (part of an experiment carried out on one farm in 1 year) conducted on sheep and beef farms (eight in 2011 and six in 2012) in the Wairarapa region of New Zealand. The cost structure involved the purchase price of products and the labour cost of administration. The four key benefits identified for the calculation of economic returns, relative to untreated ewes, were: increased value of ewes sold (culled) at weaning, additional lambs weaned related to ewe liveweight at mating, increased total weight of lamb weaned per ewe, and reduced number of ewes requiring removal of soiled wool at weaning due to a lower dag score. Commercial values for these variables as at December 2013 were used, with the measured production data, to calculate a net (NZ$) benefit for every treatment-trial combination.RESULTS: The economic return on treating ewes around lambing with anthelmintics was highly variable and across all trials treatment resulted in a financial loss in 18/38 (47%) groups of ewes. The mean net benefit from pre-lambing administration of a controlled release capsule (CRC) containing albendazole and abamectin was 5.36 (95% CI=?2.64 to 13.35) $/ewe, but overall was not different from zero (p=0.171). A breakdown of the overall gross benefit into its various components showed that weight of lamb weaned per ewe had the largest influence (a mean benefit of $5.68/ewe), followed by ewe liveweight pre-mating ($2.45/ewe), ewe liveweight at weaning ($0.66/ewe) and reduced dag score ($0.15/ewe). Other anthelmintic treatments all showed highly variable responses amongst trials, with some negative cost-benefits. There was no significant difference between any of the treatments except a short-acting oral treatment at tail-docking had a lower net benefit than a CRC containing albendazole administered pre-lambing (p<0.05).CONCLUSIONS: A positive financial return resulting from the anthelmintic treatment of adult ewes around lambing is neither consistent nor predictable, and is often not achieved. Given that the additional costs of accelerating the development of anthelmintic resistance were not included in these calculations, farmers need to consider carefully the merits of administering anthelmintics to ewes around lambing. 相似文献
6.
GR ALLERTON RP GOGOLEWSKI D. RUGG RE PLUE RA BARRICK JS EAGLESON 《Australian veterinary journal》1998,76(1):39-43
Objective To confirm the efficacy of ivermectin released from a controlled-release capsule administered to young sheep and to breeding ewes under field conditions. Design Randomised field trials. Procedure In each of ten field trials 25 weaned lambs were treated with ivermectin controlled-release capsules and 25 remained untreated. Eight similar field trials were conducted using adult ewes. Efficacy against infections of gastrointestinal nematodes was assessed by faecal egg counts and faecal larval culture. Body weights were recorded and faecal soiling of the breech wool (dags) was assessed. Results Nematode faecal egg counts in the two groups were not different (P = 0.13) before treatment in the weaner trials or before treatment in the ewe trials (P = 0.49), but thereafter eggs in the untreated sheep persisted, whereas counts in sheep given capsules were negligible (P ≤ 0.01). In the weaner trials, dag scores for the two groups were not different at the start of the trials (P = 0.18) but at the end, untreated sheep had significantly more dags (P = 0.04) than treated sheep. In the ewe trials, dag scores remained low in both groups. Weaners treated with the capsule gained 1.4 kg (95% CL: 0.7, 3.1) more weight over the 16 week trial period compared to untreated weaners (P = 0.01). Both groups of ewes lost weight as a result of parturition but the mean loss by week 16 was greater for untreated (3.7 kg) (95% CL: -5.1,-2.2) than for treated ewes (1.8 kg) (95% CL: -3.3, -0.4). The mean change in ewe body weight for the two groups was however not significant (P = 0.07). Differentiation of nematode larvae recovered from cultures of faeces from untreated animals indicated that the capsules were effective against the common parasites of sheep. Conclusion The capsule was efficacious against gastrointestinal nematodes judging from faecal egg counts. It has the potential to significantly reduce contamination of pasture with nematode eggs. Treated weaners had less dags for 16 weeks and gained more weight than untreated weaners. 相似文献
7.
A trial was carried out to determine whether selenium responsive unthriftiness existed on a property in the Strathbogie ranges of Central Victoria where unthriftiness of young sheep has been a problem for 10 to 20 years. White muscle disease had been diagnosed on the property in the previous year and on other properties in the area. Eighty Merino ewes and lambs were allotted to one of 4 groups in a 2 x 2 factorial designed trial in which sodium selenite (0.1 mg/kg) was given orally to ewes and/or lambs at marking time and to treated lambs at 3 monthly intervals thereafter. Selenium treatment of the ewes had no significant effect on subsequent lamb performance. Selenium treatment of the lambs produced significant responses: mortality in treated groups was 0% compared with 17.5% in untreated groups; body weight gains were 1.9 kg higher at both weaning and one year of age in treated than in untreated lambs; mean fleece weight was 14.4% higher in treated lambs and they produced 39% more wool than the surviving untreated lambs. 相似文献
8.
AbstractAIMS: To measure the magnitude and variability in production responses to anthelmintic treatments administered to adult ewes around lambing.METHODS: Ewes carrying twin lambs, from sheep and beef farms (eight in Year 1 and six in Year 2) in the Wairarapa region of New Zealand, were enrolled in 14 trials (part of an experiment carried out on one farm in one year). Experiment 1 compared ewes treated 2–4?weeks pre-lambing with a controlled release capsule (CRC) containing abamectin, albendazole, Se and Co, to ewes injected pre-lambing with a long-acting Se plus vitamin B12 product, and to untreated ewes. Experiment 2 included these treatments, plus a CRC administered at pregnancy scanning. Experiment 3 included the same treatments as Experiment 1, plus administration of a CRC containing albendazole, Se and Co, injectable moxidectin or oral derquantel plus abamectin, all administered pre-lambing, or oral derquantel plus abamectin administered 4–6?weeks after lambing. Variables compared were ewe liveweight at weaning and pre-mating, lamb liveweight at weaning, total weight of lamb weaned per ewe and ewe dag score at weaning.RESULTS: Ewes treated with a CRC pre-lambing were heavier than untreated ewes (mean 3.2?kg) at weaning in 12/14 trials, and pre-mating (mean 2.8?kg) in 9/14 trials (p<0.001). Compared with mineral-treated ewes the mean difference was 2.8?kg pre-lambing (9/14 trials) and 1.7?kg pre-weaning (6/14 trials). Lambs reared by treated ewes were heavier (mean 1.55?kg) at weaning in 6/14 trials (p<0.001), but there was no effect of CRC treatment on total weight of lambs weaned per ewe (p=0.507). Variation in weight of lamb weaned per ewe was largely explained by differences in lamb survival from birth to weaning (p<0.001), with no effect of CRC treatment (p>0.65).Treatment of ewes with a CRC at pregnancy scanning was neither better nor worse than a pre-lambing treatment (p=0.065).There was no difference in the response from treatment with either of the two CRC or moxidectin. Treatment with short-acting oral anthelmintics resulted in no consistent benefit.CONCLUSIONS: Anthelmintic treatments administered to ewes around lambing resulted in variable responses between farms and years, which in some trials were negative for some variables, and some of the variability was due to the mineral component of the CRC. The widespread perception amongst farmers and veterinarians that anthelmintic treatment of ewes around lambing will always result in positive benefits is not supported. 相似文献
9.
J. R. EDWARDS J. J. GARDNER † R. T. NORRIS‡ R. A. LOVE P. SPICER R. BRYANT‡ R. V. R. GWYNN C. D. HAWKINS¶ R. A. SWAN¶ 《Australian veterinary journal》1985,62(11):361-365
A random sample of 200 Merino sheep owners was interviewed by telephone during April 1983 and asked questions relating to the prevalence of ovine dermatophilosis in their flocks, methods used for prevention and treatment of dermatophilosis, management strategies employed and the location and annual rainfall of each farm. The response rate was 99.5%. During the previous 12 months 62.3% of farmers had observed dermatophilosis in their flocks. The prevalence within flocks was highest in hoggets (mean 2.2%, range 0 to 75%) followed by lambs (mean 0.8%, range 0 to 25%), ewes (mean 0.6%, range 0 to 20%) and wethers (0.2%, range 0 to 20%). The mean weight of wool identified as affected by dermatophilosis was 58 kg (range 0 to 882 kg). Preventive measures were used on 57% of farms and the most common methods were changes in dipping practice (23.6%) and culling of affected sheep (21%). An average of 13.7 sheep per farm were culled for dermatophilosis and of these, 82% were sold and the remainder (18%) were killed on the farm. Antibiotics, of which most were combinations of penicillin and streptomycin were used to treat dermatophilosis on 8.5% of farms and treatments other than antibiotics were used on 10% of farms. The prevalence of dermatophilosis and its relationship to various environmental and management factors varied with the age and sex of sheep. Discriminant analysis indicated that of the factors studied, average annual rainfall, month of lambing, average fibre diameter and the month ewes were shorn were related to the prevalence of dermatophilosis in lambs.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
10.
A series of 10 farm trials was conducted in which the lambing performance of ewes immunised against polyandroalbumin was compared with that of untreated ewes in the same flock. The trials show that polyandroalbumin treatment is a reliable method of increasing lambing and tailing percentages in New Zealand flocks. An average of 39 extra lambs born per 100 ewes tupped was achieved on farms where ewes were given two treatments about four weeks apart and rams were introduced 18-26 days after the second dose. On farms where rams were introduced less than 12 days after this booster injection an average of 19 extra lambs born per 100 ewes tupped resulted. On farms where rams were introduced at 18-26 days post booster injection an average of 35 extra lambs were tailed for every 100 ewes tupped. The response for immunization increased in direct relation to the liveweight of the ewes at tupping. 相似文献
11.
Scholtz AJ Cloete SW du Toit E van Wyk JB van der Linde TC 《Journal of the South African Veterinary Association》2011,82(2):107-115
Blowfly strike and the methods used to combat blowfly strike were recorded on 33 properties in the R?ens area of South Africa during 2003/2004. Data were recorded on Merino and Dohne Merino hoggets (n = 4951) with at least 3 months' wool growth. The following data were captured: presence or absence of strike, site of the strike (body or breech), presence or absence of dermatophilosis as well as subjective scores for wool quality and wool colour. Control measures recorded include: chemical treatment (preventative and spot treatment), crutching, mulesing and the use of the Lucitrap system. Blowfly strike was not significantly influenced by gender or breed. Hoggets suffering from dermatophilosis were more likely to be struck, compared with contemporaries not suffering from the skin disorder (0.057 vs 0.027; P < 0.05). Merino hoggets generally had higher scores than their Dohne Merino contemporaries for wool quality (32.6 vs 27.4; P < 0.05) and wool colour (29.0 vs 27.2; P < 0.05). There was an indication that the Lucitrap system may have reduced flystrike, but the effect was not statistically significant (P = 0.19 for overall strikes and P = 0.12 for body strike). The Mules operation benefited overall flystrike (0.013 vs 0.110; P < 0.05); mainly through an effect on breech strike (0.010 vs 0.109; P < 0.05). The proportion of fly strikes increased with wool length, and declined with an increase in farm size in wool colour score. None of the ethically acceptable control measures assessed could substantially reduce blowfly strike on their own, and an integrated pest management programme was proposed. 相似文献
12.
Gogolewski RP Rugg D Allerton GR Kawhia D Barrick RA Eagleson JS 《New Zealand veterinary journal》1997,45(4):163-166
Ten field trials were conducted in the North and South Islands of New Zealand to evaluate the anthelmintic efficacy of an intraruminal controlled-release capsule formulation of ivermectin. A total of 810 Coopworth, Perendale, Romney or Coopworth ' Romney ewes, weighing on average 42-70 kg, were used. Ewes were either untreated or treated shortly before lambing in late winter-early spring (eight trials) or in late spring (two trials) with an ivermectin controlled-release capsule which delivers ivermectin at 1.6 mg per day for 100 days (minimum dose rate 20microg/kg/day). Bodyweights, faecal nematode egg counts and dag scores were determined before treatment and at about 2 and/or 4, 6 or 8, 10 or 12, 14 and 16 weeks after treatment. Ewes treated with the ivermectin controlled-release capsule gained on average 1.1kg more than untreated sheep over the 16 weeks of the trials, but this difference was not significant (p > 0.10). Before treatment, faecal strongylid egg counts were equivalent (p > 0.10), but at each time point thereafter, egg counts in ivermectin controlled-release capsule treated sheep were significantly lower (p < 0.01; p < 0.05 at Week 2). Dag scores were not different at the start of the trial (p > 0.10), but at the end of the trial ivermectin controlled-release capsule treated ewes had significantly lower scores (p < 0.01) than untreated ewes. These findings indicated that treated animals shed significantly fewer nematode eggs and therefore pasture contamination with nematode eggs should be significantly reduced for at least 112 days. The control of dags should result in reduced direct losses due to the decreased value of dag wool, and indirect losses due to the cost of dagging sheep and the cost associated with the treatment and control of flystrike initiated by dags in the breech area. 相似文献
13.
D.R. Ris B.Sc. Dip.Agric. 《New Zealand veterinary journal》2013,61(1-2):2-7
A series of 10 farm trials was conducted in which the lambing performance of ewes immunised against polyandroalbumin was compared with that of untreated ewes in the same flock. The trials show that polyandroalbumin treatment is a reliable method of increasing lambing and tailing percentages in New Zealand flocks. An average of 39 extra lambs born per 100 ewes tupped was achieved on farms where ewes were given two treatments about four weeks apart and rams were introduced 18–26 days after the second dose. On farms where rams were introduced less than 12 days after this booster injection an average of 19 extra lambs born per 100 ewes tupped resulted. On farms where rams were introduced at 18–26 days post booster injection an average of 35 extra lambs were tailed for every 100 ewes tupped. The response for immunization increased in direct relation to the liveweight of the ewes at tupping. 相似文献
14.
EFFECT OF SELENIUM ON WOOL PRODUCTION, BODY WEIGHT AND MORTALITY OF YOUNG SHEEP IN WESTERN AUSTRALIA 总被引：1，自引：0，他引：1
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.
C. D. HAWKINS S. Z. SKIRROW R. S. WYBURN J. Mc. HOWELL 《Australian veterinary journal》1983,60(1):22-24
Hemimelia at a prevalence of 11% of lambs marked, and low marking percentage (51%) was observed in a flock of mixed age Merino ewes and their lambs. Hemimelia occurred in one or 2 limbs of affected lambs. Lambs from other flocks on the farm were unaffected, and the condition was not reported from other farms. The condition had not occurred in the past, and has not recurred. No infectious or hereditary factors were implicated in the aetiology of the condition. Grazing Western Australian Blue Lupin stubble by the affected flock during and after joining was the only known difference between this flock and others on the farm. 相似文献
16.
A chronic infection was established in a group of twenty 18-month-old non-reproductive Merino ewes by oral administration of 3000 infective H. contortus larvae twice weekly for 12 weeks. Their live-weights and wool production were compared with those of 20 uninfected ewes grazing the same pasture. In the infected sheep, faecal egg counts increased over a period of 9 weeks to reach a mean of 5000 eggs per gram, accompanied by small, but significant effects on packed-cell volume and live-weight. The effects of infection on wool growth were also small, and not statistically significant, although there was evidence of a faster seasonal decline in wool growth in infected sheep. It was concluded that mortality induced by acute infection is the most important economic effect of this parasite. 相似文献
17.
18.
Lawrence KE Rhodes AP Jackson R Leathwick DM Heuer C Pomroy WE West DM Waghorn TS Moffat JR 《New Zealand veterinary journal》2006,54(6):283-288
AIM: To identify farm practices associated with the presence of resistance to a macrocyclic lactone (ML) anthelmintic on sheep farms in New Zealand. METHODS: A cross-sectional study was conducted to test for associations between the presence of resistance to an ML anthelmintic (ivermectin) and management practices on sheep farms in New Zealand. Selection of farms was both random (n=80) and purposive (n=32; being farms with a history of suspected ML resistance). Resistance was inferred from faecal nematode egg count (FEC) reduction (FECR) tests (FECRTs) when there was <95% reduction in FEC 7-10 days after treatment with a half dose of ivermectin (0.1 mg/kg). A logistic regression model was built to identify farm-level factors that were associated with the presence or absence of ML resistance. RESULTS: Of the 112 flock managers that were approached for interview, 103 (92%) returned useable questionnaires. The odds of ML resistance were increased: on farms that had used long-acting ML products in ewes as a pre-lambing treatment for > or =3 of the previous 5 years (odds ratio (OR) = 7.2; 95% confidence interval (CI) = 1.7-30.3); on farms where <70% of the total stock units mid-winter were from sheep (OR=6.5; 95% CI=1.6-25.6); on farms which over the year purchased >10% of the number of sheep present mid-winter (OR=7.1; 95% CI=1.5-34.7); and on farms where the average wool diameter of the main flock was <37 (OR=4.1; 95% CI=1.1-14.7) microns. The model provided a good fit to the data (pseudo R2=0.64; Hosmer-Lemeshow statistic = 0.38). CONCLUSIONS: Explanatory factors identified as associated with the presence of ML (ivermectin) resistance on farms included the use of long-acting anthelmintic formulations in ewes pre-lambing, sources of refugia of unselected parasites on the farm, breed of sheep and their requirements for anthelmintic treatments, and the importing of resistant parasites with purchased stock. The study provides support for controls that aim to provide refugia of susceptible worms and that minimise the risk of introduction of resistance through effective quarantine drenching. 相似文献
19.
Protecting sheep against early season myiasis (strike) is a significant problem in northern temperate farming systems, where fully-fleeced ewes and early-season lambs approaching market weight, are at high initial risk. Here, the prevention of early-season blowfly strike in ewes was examined on matched commercial sheep farms in south west England, using a new formulation of dicyclanil (CLiKZiN(?) pour on) with a short withdrawal period of 7 days. The ewes on seven farms received a prophylactic treatment with dicyclanil (CLiKZiN 1.25% pour-on suspension) in April 2011; ewes on three control farms received no treatment. The lambs at all farms remained untreated. No adverse reactions to treatment were recorded. On the treatment farms no ewe strikes were recorded between April and June (10 weeks). On control farms, there were 16 strike cases in ewes over the same period, giving a cumulative incidence of 31 cases per 1000 ewes. On the treatment farms only one lamb was struck whereas at the control farms 10 lamb strikes were recorded. The data demonstrate that CLiKZiN was highly effective at protecting ewes against early season strike-challenge. 相似文献
20.
Three farms with a high prevalence of periodontal disease (PD) were selected using data from a December 1983/January 1984 survey. On each of these farms in August 1984, the incisor condition and body condition score of about 50 ewes were noted. Two of the farms and an additional farm with a high prevalence of PD were visited again in August 1985, and on each, incisor condition and body weights of about 150 ewes were recorded. On one farm only was there a significant association between PD and body condition or weight, and it occurred in both years. 相似文献