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1.
The effects of anthelmintics treatments in controlling gastrointestinal nematodes in breeding ewes in a semi-arid area of Kenya were determined. The study carried out during two breeding seasons, between June 2000 and December 2001 where albendazole was administered to groups of ewes, 2 weeks before mating, 3 weeks to lambing and mid lactation indicated significantly lower nematode egg counts in treated than untreated groups of ewes. In the first breeding season, reduced rainfall resulted in pasture scarcity and weight loss in both groups of ewes through out the gestation period, but losses were higher for the untreated group. In the second season, both groups of ewes showed a steady increase in weight gain during the gestation period and post-partum, but weight gains were higher in the treated group. In lambs, weight gains at 6 weeks were higher for treated ewes than control groups, in both breeding seasons. The results of this trial indicate that anthelmintic treatments in breeding ewes in the study area are beneficial in reducing gastrointestinal nematode infections and improving performance of the ewes and their lambs. In addition to the treatments, breeding ewes should be given feed supplementation particularly during periods of pasture scarcity.  相似文献   

2.
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   

3.
Whole bloods from weaned lambs with severe selenium responsive unthriftiness usually contain <5 ng Se/ml. Mildly or moderately affected lambs have blood levels of 5-10 ng/ml. Selenium responsive infertility in ewes appears to be associated with whole blood selenium levels below 10 ng/ml.  相似文献   

4.
Control of nematode parasites with reduced reliance on the use of anthelmintics was studied in 16 ewes with suckling twin lambs on contaminated pasture in Denmark. Ewes and lambs were treated with albendazole at turn-out 3 May. Ewes were removed from the groups on 26 July, and lambs were slaughtered on 11 October. The animals were allocated to 4 groups of 8 lambs and their 4 ewes. Group TS was treated with albendazole at weeks 3, 6 and 8 after turnout and set-stocked; group TM was similarly treated but moved to clean pasture in conjunction with the last drenching; group US was untreated and set-stocked, and group UM was left untreated but moved to clean pasture week 8 after turn-out. Supplementary feed was offered in June and August due to scarcity of pasture. Strategic treatments of ewes and lambs weeks 3, 6 and 8 after turn-out, with or without a move to clean pasture, were highly effective in controlling nematode infections for most of the season. This was reflected in better weight gains and carcass characteristics in the treated compared to untreated lambs, resulting in an average increase in the value of the product by 36%. The effect of moving without treatment (UM) on faecal egg counts was limited but peak pasture infectivity was reduced to less than 10% compared to the set-stocked group and weight gains of lambs were significantly better despite poor feed availability in late season. The study showed that under set-stocked conditions repeated anthelmintic treatments of both ewes and lambs in early season may ensure sufficient nematode control whereas moving animals to clean pasture without dosing was less efficient. The latter may, however, still be a viable option in organic and other production systems where routine use of anthelmintics is banned, particularly if weaning and moving are combined or a second move is performed.  相似文献   

5.
Thirty ewes naturally infected with Sarcoptes scabiei var. ovis, were allocated into three groups of 10 animals each. Animals in groups B and C were treated on day 0 and on days 0 and +10, respectively, with moxidectin 1% injectable at a dose of 0.2mg moxidectin/kg body weight (BW). Group A remained untreated. Seven days before treatment, the geometric mean of Sarcoptes scabiei var. ovis per square centimeter of skin in groups A, B and C were not significantly different. From the day of treatment to the end of the trial, the average number of mites/cm(2) increased in untreated animals and decreased in groups B and C, but these values were higher for group C. Active lesions produced by S. scabiei var. ovis consistently increased during the trial in the untreated animals; in group B the minimum count occurred on day +56 this reduction being more evident in group C (no lesions on days +49 and +56). Also in this group, the number of cured animals was 100%, therefore, the application of two treatments with moxidectin (group C) showed higher efficacy than a single treatment (group B). Body condition score decreased in the three experimental groups along the trial. All animals were individually weighed on days -1, +28 and at the end of the trial. No adverse reactions were observed in the animals treated with 0.2mg moxidectin/kg BW.  相似文献   

6.
产羔期、补饲水平对考力代羊生产和繁殖性能影响的研究   总被引：2，自引：1，他引：1  
为了研究草地一绵羊系统中草畜供求间的动态平衡，寻求在人工草地放牧条件下适宜的产羔时期及在此时期给产羔母羊的合理补饲水平，１９９０～１９９３年，在贵州省威宁县灼甫联户示范牧场进行了两期产羔期及补饲水平对绵羊生产性能影响的试验。产羔期的改变，导致了母羊及羔羊体重的不同变化趋势。结果显示出母羊体重对其生产、繁殖性能的重要性。春羔母羊配种前体重较之冬羔母羊提高９．７５ｋｇ，两者产羔率分别为１３９．２％和１１６．１％。春羔母羊较高的双羔率导致了春羔母羊较之冬羔母羊更低的繁殖成活率（分别为９１．２％和１０４．７％）。断奶时，春羔较之冬羔体重高５．２５ｋｇ，但断奶以后这种优势即消失了。补饲水平的差异对母羊及羔羊体重有一定的影响，但在牧草丰富的条件下表现得并不很强烈。  相似文献   

7.
The effect of tilmicosin on the incidence of clinical mastitis and subsequent lamb performance was studied in 9 sheep flocks in Ontario. Ewes were treated randomly with either tilmicosin or placebo approximately one month prior to lambing. Outcome was assessed by comparing rates of clinical mastitis, palpable udder abnormalities, and preweaning (50-day) lamb weights between the 2 treatment groups, while controlling for other important variables. Lambs raised by multiparous ewes treated with tilmicosin were significantly heavier than lambs from placebo-treated multiparous ewes at 50 days. Lambs from tilmicosin-treated ewes were on average 0.52 kg heavier than lambs in the placebo group. There was no difference between treatment groups in the weight of lambs from first parity ewes. Tilmicosin treatment resulted in a 43% decrease in palpable udder abnormalities. Incidence of clinical mastitis did not differ between experimental groups. The administration of tilmicosin prelambing, at the time of routine clostridial disease vaccination, may be a beneficial and convenient way to reduce mastitis infection and improve the preweaning gain of lambs.  相似文献   

8.
The objective was to determine the influence of year, season and age of hair sheep ewes on their susceptibility to gastrointestinal nematodes during pregnancy and lactation and to record the number of treatments within a selective anthelmintic (AH) treatment programme. A trial was performed with 46 grazing ewes kept in hot humid tropical conditions. Data included: average daily weight gain (ADG, kg), packed cell volume (PCV, %) and nematode eggs per gram of faeces (EPG) obtained during 2 years (2009 and 2011–2012). Ewes reaching 1000 EPG were treated with AH. Irrespective of year, season and age, ewes were more susceptible to GIN during lactation (higher EPG, lower PCV and net weight loss) and less susceptible during gestation (lower EPG, higher PCV and net weight gain). As a result, 24.4% of the ewes were left untreated during lactation, while 63.0% of the ewes needed no AH treatment during pregnancy. Even under the hot humid tropical conditions of the farm, the individual EPG helped to maintain a considerable proportion of animals without an AH treatments within the flock.  相似文献   

9.
Forty-eight Blackbelly X Dorset, 27 Finnish, 26 Finnish X Dorset, 28 Rambouillet and 8 Dorset Suffolk-sired lambs were used in this experiment. Three weeks before lambing, one-half of the ewes received a selenium emulsion (Se-E) containing .05 mg selenium and 3.7 IU of vitamin E/kg body weight (BW). A 2 X 3 X 2 factorial arrangement was used; lambs from either treated or nontreated ewes were randomly assigned irrespective of breed to one of six treatment combinations consisting of 0 or .025 mg/kg BW selenium (Se) injected at birth or two .025 mg/kg BW Se injections, one at birth and one 2 to 3 wk later, and two levels of injectable Vitamin E (E; 0 and 100 IU) given at birth. Both lambs and ewes were provided access to 75% concentrate diets supplemented with Se and E at recommended NRC levels. Plasma activity of creatine phosphokinase (CPK) was highest at 1 d of age and exhibited decreases (P less than .001) over time. In lambs, the E injection tended to decrease plasma activity of CPK. Plasma glutathione peroxidase activity was lowest at 1 d of age and increased over the course of the experiment but was unaffected by treatments (P less than .05). Plasma tocopherol concentration decreased (P less than .01) with time, with E therapy tending to increase tocopherol concentration. Differences in mean plasma tocopherol concentrations among breeds were also observed (P less than .01). Selenium concentration increased over time and with the E injection (P less than .01). An interaction between ewe and lamb Se-E treatments also was observed (P less than .10), with nontreated lambs from nontreated ewes exhibiting lower Se concentrations than treated lambs from injected ewes. An increase in lamb plasma Se concentration was noted in response to Se-E treatments (P less than .001). In the ewes, plasma tocopherol concentration was lower while Se concentration was higher at 18 d than at 1 d postpartum (P less than .01 and P less than .001, respectively). Milk Se concentration was lower at 18 d than at 1 d (P less than .001) and was higher (P less than .10) in Se-E-treated ewes.  相似文献   

10.
Ewes treated by intramammary infusion of cephapirin benzathine at the end of lactation were less likely to develop new intramammary infections by early in the next lactation. A controlled clinical trial involving 135 treated ewes and 145 untreated control ewes evaluated the prophylactic and treatment efficacy of intramammary antibiotic treatment of ewes at the time of weaning lambs. Milk samples for bacteriologic examination and identification of intramammary infections were collected at weaning of lambs and 1 to 3 weeks into the subsequent lactation. Untreated ewes were 2.6 times more likely than treated ewes to develop new intramammary infections between sampling times. Existence of an intramammary infection in one mammary gland significantly increased the risk of the other mammary gland becoming infected. Treatment also appeared to be associated with a higher cure rate of existing infections.  相似文献   

11.
枯草期选甘肃高山细毛羊成年母羊180只,后备母羊38只,羔羊40只,进行为期171 d的放牧与舍饲对比试验。结果表明:试验组(暖棚舍饲)平均每只成年母羊、后备母羊和羔羊体质量分别增加5.1、9.8和6.9 kg,增幅为:11.72%、30.81%和32.86%;对照组(放牧)每只成年母羊、后备母羊和羔羊体质量分别平均下降7.3、5.0和1.0 kg;试验末,试验组成年母羊和后备母羊体质量极显著高于对照组(P0.01),试验组羔羊体质量显著高于对照组(P0.05)。羊毛长度试验组成年母羊、后备母羊和羔羊羊毛每只分别平均增长3.9、3.8和2.7 cm,试验组成年母羊和后备母羊比对照组提高10.4%和16.0%,羔羊比对照组降低11.2%,试验组和对照组差异不显著(P0.05)。试验组各年龄段产羊毛量分别达5.24、4.56和3.79 kg,比对照组分别提高60.24%、73.38%和49.80%,差异极显著(P0.01)。试验组纯收入分别为成年母羊5.35元/只,后备母羊45.65元/只,羔羊59.57元/只,对照组由于掉膘损失严重,成年母羊和后备母羊分别损失28.32和13.05元/只,羔羊收益29.3元/只。  相似文献   

12.
AIMS: To investigate the production responses and cost-benefit of administering a controlled-release anthelmintic capsule (CRC) to pregnant yearling ewes prior to lambing.

METHODS: Yearling ewes from two commercial sheep flocks (A, n=489; B, n=248) in the North Island of New Zealand were enrolled in the study. Prior to lambing, CRC containing albendazole and abamectin were administered to half the ewes while the other half remained untreated. Ewe liveweights and body condition scores were measured prior to lambing, at weaning and, for Flock B, prior to subsequent mating. Lambs were matched to dams shortly after birth and the weight and number of lamb weaned per ewe were determined. A cost-benefit analysis was undertaken for Flock B considering the increased weight of lamb weaned per ewe, and the weight of ewes at the next mating and the benefit in terms of lambs born.

RESULTS: The mean weight at weaning of treated ewes was greater for treated than untreated ewes by 2.76 (95% CI 0.64–4.88)?kg in Flock A (p<0.001) and 2.35 (95% CI ?0.41–5.12)?kg in Flock B (p=0.003); the weight of lamb weaned per ewe was greater for treated than untreated ewes by 1.43 (95% CI ?0.71 to –3.49)?kg in Flock A (p=0.041) and 3.97 (95% CI 1.59–6.37)?kg in Flock B (p<0.001), and ewe liveweight prior to subsequent mating was greater for treated than untreated ewes in Flock B by 4.60 (95% CI 3.6–5.6)?kg (p<0.001). There was no difference in the percentage of lambs reared to weaning between treated and untreated ewes in either flock (p>0.8). The overall cost-benefit of treatment for Flock B was NZ$9.44 per treated ewe.

CONCLUSIONS AND CLINICAL RELEVANCE: Pre-lambing CRC administration to yearling ewes resulted in increased ewe weaning weights and weight of lamb weaned in both the flocks studied. There was an economic benefit in the one flock where this was assessed.  相似文献   


13.
The aim of this work was to investigate whether Cu, alone or in combination with Mo, reduces the Se status of sheep. Thirty-six Hampshire ewes were separated prior to mating into four treatment groups of nine sheep each. The four groups consisted of 1) basal (alfalfa hay or legume-grass low-moisture silage, corn, oats), 2) basal plus 10 mg Cu/kg diet, 3) basal plus 10 mg Mo/kg and 4) basal plus Cu and Mo (each 10 mg/kg). Copper and Mo were added to both ewe and lamb diets. Treatments continued until lambs were weaned at 10 wk postpartum. The basal ewe diet contained, in mg/kg, 5.6 Cu, .05 Se and 1.0 Mo. The basal lamb diet contained, in mg/kg, 6.1 Cu, .07 Se and less than 1.0 Mo. Sulfur concentrations in the ewe and lamb diets were .24% and .20%, respectively. Copper supplements increased, and Mo supplements decreased, the concentration of Cu in the livers of ewes and lambs (P less than .05). Despite this, there were no effects of treatment on Se concentration or glutathione peroxidase activity in blood or tissues. Selenium levels in plasma of all ewes declined throughout pregnancy and lactation, indicating that .05 mg/kg Se was insufficient for the maintenance of Se status during pregnancy in Hampshire ewes. Copper and Se levels (mg/kg fresh weight) in the liver of lambs at weaning for Treatments 1 through 4 were 48 and .13, 158 and .10, 11 and .11, and 136 and .13, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
Fifty cyclic fat-tailed Syrian Awassi ewes aged 2–4 years, with a mean weight of 51.4 kg, were used for 4 years to assess the accelerated lambing system (three lambings in 2 years). Ewes were divided into two groups: treated (T) and untreated (C). Ewes in the T group were treated with flugestone acetate for 14 days and injected intramuscularly at sponge withdrawal with 500 IU of equine chorionic gonadotropin (eCG). Results indicated that ewes in the T group exhibited oestrus and were mated within 5 days post sponge removal compared to 11 days for ewes in the C group, and the difference in oestrus response between the two groups was significant (P < 0.001). Repeated hormonal treatments had no significant (P > 0.05) effect on the lamb birth weight. However, significant (P < 0.001) differences in the lamb birth weight were observed between singles and multiple births. In the treated ewes, the total number of lambs born was 211–157 parturitions, and the multiple birth rate reached 27.4%, whereas the rate in the untreated group was 6.3% with the difference being significant (P < 0.05). In the untreated ewes, the total number of lambs born was 14–13 parturitions (12 singles and 1 twin). Fecundity rates were 135.1% and 106.3% in the treated and untreated ewes, respectively, and the difference was significant (P < 0.05). Repeated administration of eCG had no negative effect on fertility of Syrian Awassi ewes. However, anti-eCG antibodies were produced following eCG injections with extremely high individual differences in the immune response among ewes.  相似文献   

15.
Trials were carried out to compare the efficacy of copper heptonate with other available therapeutic products. On nine farms with a copper deficiency problem, over 2000 ewes were treated in mid-pregnancy. All the treatments increased whole blood copper levels and plasma caeruloplasmin (ferroxidase) activity in ewes, and protected their lambs from swayback. The lambs from ewes treated with copper heptonate and copper oxide needles had significantly higher blood copper levels than lambs from untreated control ewes. Treatment with copper heptonate was shown to have a therapeutic index of at least 5 in Swaledale ewes of normal copper status. In two groups of Welsh mountain sheep from different backgrounds, both with normal blood copper levels before treatment, the therapeutic indices were 3 to 5.  相似文献   

16.
Pregnant ewes (large frame [LF] and small frame [SF]) were nutritionally stressed in early gestation (EGS), late gestation (LGS) or fed 100% of NRC requirements (unstressed, US) throughout gestation. Lambs (128) from these ewes were slaughtered at birth, weaning (18 kg), 41 kg or 55 kg. Sixty-four lambs received a 13% protein diet from weaning to either 41 or 55 kg. Lambs from SF ewes were fatter at 55 kg, had a higher numerical yield grade and a lower percentage of carcass protein. Lambs from US ewes were youngest at slaughter and had the most carcass weight and protein per day of age at 55 kg. The LGS lambs had the lowest percentage of lean and carcass protein at 41 and 55 kg. However, at birth these lambs had the highest concentration of RNA and DNA in muscle. The EGS lambs had the lowest quality grade, carcass weight per day of age and fat percentage. Muscle DNA and RNA at birth was lowest in EGS lambs. However, EGS lambs produced the highest lean percentage and highest percentage carcass protein at 41 and 55 kg. Shortest metacarpals and metatarsals were also found in these lambs at weaning and 41 kg. Although frame size had little effect on carcass characteristics, the effects of nutritional stress in the first 80 d of gestation were apparent in lambs slaughtered at 31 kg. Stress in the last 50 d of gestation had more effect on lambs slaughtered at 55 kg.  相似文献   

17.
Twin lambs at pasture with their ewes, were divided into seven groups of 10 lambs. One group of 10 lambs served as a non-infected, untreated control. Five groups of 10 lambs were infected with 10,000 oocysts of Eimeria crandallis and 10,000 oocysts of Eimeria ovinoidalis when they were 3 weeks old (day 21 of the study). This produced a good level of infection with high oocysts production and diarrhoea in the lambs. Fourteen days after the primary, artificial challenge (day 35) four of these groups were treated with oral diclazuril at 0.25, 1.0, 2.0 or 4.0mg/kg. Diclazuril treatment was highly effective, dramatically reducing symptoms of diarrhoea and reducing faecal oocyst output by 79.7%, 97.3%, 99.4% and 99.5% respectively in the treated groups within four days. Two weeks post-treatment, and 28 days after the primary coccidial challenge (day 49 of the study), five groups of lambs were re-challenged with 100,000 oocysts of E. crandallis and 100,000 oocysts of E. ovinoidalis (secondary challenge). A group of lambs which had received neither the primary coccidia infection, nor drug treatment (susceptible controls) were also given the secondary challenge. All lambs given the secondary challenge produced high numbers of coccidia and exhibited varying degrees of diarrhoeic faeces. The lambs, which had previously received the higher doses of diclazuril at 2.0 and 4.0mg/kg, developed clinical signs of coccidiosis. These lambs were completely susceptible despite having received the early primary immunising infection of coccidia on day 21. The effects of the secondary challenge were more severe in the groups dosed with the two highest levels of diclazuril than in the susceptible control lambs, which had presumably been exposed to continued low levels of pasture contamination and had acquired a limited degree of immunity from this exposure. It would appear that treatment at the higher dose levels not only eliminated most of the oocysts from the primary challenge but also adventitious infection derived from the grazing paddocks. In contrast, lambs which had received the two lower drug levels of diclazuril (0.25 and 1.0mg/kg) whilst producing large numbers of oocysts, had only transient diarrhoea following secondary challenge. It was concluded that when used as a metaphylactic treatment, diclazuril works rapidly and is effective within four days of administration. Overall, a single dose of diclazuril at either 0.25-1.0mg/kg appears to be highly effective in the control of coccidiosis in young lambs at pasture whilst allowing the development of protective immunity against subsequent heavy coccidia challenge.  相似文献   

18.
The efficacy of leucocyte extract (LE) and sulphadimidine in preventing coccidiosis in naturally infected lambs on pasture was evaluated in 3 separate experiments, whereas the prophylactic effect of levamisole was studied in 1 of the experiments. LE prepared from ewes immune to coccidia (Eimeria spp.) was administered either intravenously or intraperitoneally to young lambs 7, 5, or 2 days before they were turned out on pastures contaminated with coccidia. In all experiments, LE failed to transfer protective immunity to the lambs against the first coccidial infection on pasture. The LE preparations used apparently had an immunosuppressive effect, which resulted in more severe clinical signs of coccidiosis in the recipients. The lambs given LE showed a higher incidence of diarrhoea, a poorer weight gain, a higher mortality, and a higher oocyst output than the untreated control lambs. In lambs treated with sulphadimidine at 200 mg/kg on days 12, 13, and 14 after turnout there was a reduced severity of the coccidial infections in all experiments. The sulphadimidine-treated lambs had better weight gains and passed fewer oocysts than the controls during the third and fourth week after turnout, but some of them developed diarrhoea. Lambs treated with levamisole at 2 mg/kg 2 days before turnout, at turnout, and 2 days after turnout were more severely affected by the first coccidial infection on pasture than the controls.To study the lambs’ immunity against a heavy challenge infection with coccidia as compared with their immunity against the natural reinfection on pasture, some of the lambs from the original groups (untreated, sulphadimidine-treated, LE-treated) were each inoculated with 2 mill. Eimeria spp. oocysts about 6 weeks after turnout. The oocyst counts of the challenged lambs, except the LE-treated lambs, increased to a new peak 19–20 days after challenge. The challenge infection caused a softening of the faeces and a marked depression in weight gain in all challenged groups of lambs, mainly between days 10 and 17 after challenge. The lambs were thus only partially immune to coccidia after the first coccidial infection on pasture. The lambs treated with either LE or sulphadimidine in connection with the first coccidial infection on pasture were not appreciably more susceptible to the challenge infection than the untreated lambs.  相似文献   

19.
藏系绵羊在产羔后分为4组,进行为期90天的补饲试验,结果:试验1组只均日补饲优质青干草0.5 kg,母羊和羔羊的增重分别为1.57kg和5.29kg;试验2组只均日补饲精料0.25kg,母羊和羔羊的增重分别为2.36 kg和7.9kg;试验3组只均日补饲精料0.5kg,母羊和羔羊的增重分别为4.25 kg和10.02kg;试验4组只均日补饲营养添砖0.15kg,母羊和羔羊的增重分别为1.7kg和6.51kg。4个试验组均达到了母羊保膘和羔羊成活的目的。其中,第3组母羊和羔羊的增重最高,饲料成本也最高;第1组母羊和羔羊的增重最少,但补饲成本最低。  相似文献   

20.
Abstract

AIMS: 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   

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