Practical relationships between the biology and control of cattle grubs

This paper deals with the toxic effects of treatment of cattle against warble infestations, including the incidence of symptoms and whether these are due to death of migrating larvae or insecticide poisoning, or both. It was concluded that the likelihood of deaths associated with treatment by systemic insecticides is much less than 1 in 5 000 and may be as rare as 1 in 100 000. The importance of a national scheme to eradicate cattle grubs in Britain was stressed in view of the successes in controlling cattle grubs in Northern Ireland and in Eire.     

Efficacy of a pour-on formulation of doramectin against lice, mites, and grubs of cattle

OBJECTIVE: To determine effectiveness of a pour-on formulation of doramectin against Damalinia bovis, Haematopinus eurysternus, Linognathus vituli, Solenopotes capillatus, Chorioptes bovis, Sarcoptes scabiei, Hypoderma bovis, and Hypoderma lineatum. ANIMALS: Cattle of various ages with naturally acquired or artificial infestations with 1 or more species of lice, mites, or grubs. PROCEDURE: In 10 louse and 6 mite studies, cattle were treated with doramectin (500 microg/kg, topically) on day 0, and parasite counts were performed approximately weekly from days 0 to 35. In 6 grub studies, cattle expected to harbor Hypoderma spp were treated before emergence of warbles. After warbles began to emerge, they were counted every 2 weeks, and grubs were collected and identified by species. RESULTS: Burdens of D bovis, H eurystemus, L vituli, and S capillatus on doramectin-treated cattle were 0 by 28 days after treatment. Burdens of C bovis and S scabiei decreased to 0 in naturally infested cattle and approximately 0 in artificially infested cattle by day 14 to 15. In grub studies, 107 of 136 control cattle had warbles, whereas 2 of 136 doramectin-treated cattle had 1 warble each, which represented a cure rate of 98.5%. CONCLUSION AND CLINICAL RELEVANCE: One topical application of doramectin was highly efficacious against common species of lice, mites, and grubs known to affect performance, health, and appearance of cattle.     

Toxicity of Sevin (1-Naphthyl-n-Methyl-Carbamate) To Cattle Grubs, Lice, and Cattle

Sevin, a cholinergic insecticide, was used for the control of cattle lice Haemotopinus eurysternus and Bovicolar bovis and cattle grubs Hypoderma lineatum and H. bovis. Partial or complete spraying of the animal body with 0.5 per cent Sevin was equally effective for louse control and one application killed the lice and prevented reinfestation in `carrier' cows for 17-20 weeks.

The dermal or parenteral administration of Sevin to the host animal had no larvicidal effect on cattle grubs migrating in its body. Similarly, the sprays of Sevin had no lethal effect on grubs encysted in the back of cattle.

     

Systemic control of cattle grubs (Hypoderma spp.) in steers treated with Warbex and weight gains associated with grub control.

When applied to yearling steers on November 30, pour-on applications of famphur at 40 or 50 mg/kg were unsatisfactory for systemic grub control as they only reduced the number of warble grubs by 52.2 and 68.4%, respectively. The treatments, which had no adverse effects on the health of steers or cellular constituents of their blood, reduced the whole-blood cholinesterase, with the maximum reduction occurring 15 days after treatment. Low ambient temperatures prevailing at the time of treatment and during the two following weeks might have impeded the absorption of famphur through the skin and reduced its effectiveness for grub control. With the grub damage kept to the minimum by weekly manual removal of warble grubs, the groups treated with famphur at 40 or 50 mg/kg outgained (P less than 0.05) the untreated group by 29.9 and 13.4 kg/steer, respectively, during the posttreatment period of 181 days. These results indicate the economic benefits of grub control.     

Persistence of cattle grubs (Diptera: Oestridae) on a Canadian ranch with long-term, continuous therapeutic control

Sero-prevalence of cattle grubs (Diptera: Oestridae) was monitored on two large western Canadian ranches from 1992 to 1999. One ranch has had a long-term programme for therapeutic control of cattle grubs as required by legislation in the province of Alberta. The other ranch, located in southeast Saskatchewan, has not used any treatment for grub control for an extended period of time. Serum from calves was tested each fall for the presence of antibodies to Hypoderma spp. using an ELISA. Percent positive sera on the Ranch 1 ranged from 8.0 to 73.3%. There was substantial variation among years and among two separate herds maintained on the ranch. Percent infested calves on the Ranch 2 ranged from 76.5 to 99.0%. Improved surveillance for cattle grubs using serological techniques is the only effective means to monitor the status of this important parasite.     

深圳高尔夫球场草坪蛴螬发生及其生物防治效果研究

调查了深圳2个高尔夫球场春季草坪蛴螬发生情况,研究了昆虫病原真菌绿僵茵对球场不同龄期蛴螬的致病性。调查发现,不同草坪样地的虫口密度为0-16只／m^2,对草坪危害不严重,草坪质量为中等偏上;虫口密度与土壤含水量呈显著负相关,虫口密度与土壤温度显著正相关,草坪色泽、根系完整性都与虫口密度呈显著负相关;草坪密度随虫口密度的增加而减小,但二者间的相关性未达到显著水平。从球场采集到主要为害虫为红脚绿丽金龟成虫,经产卵和孵化饲养获得幼虫用于致病性试验,结果表明绿僵菌对各龄期幼虫均有较强致病力,其中对1龄幼虫作用最强。在土壤舍菌量66．7×10^8孢子／kg和33．3×10^8孢子条件下,1龄幼虫分别在6和9d内死亡率达到90％;在土壤含菌量16．7×10^8孢子／kg时,对1、2、3龄幼虫致死中时LT5。分别为7．3,14．3扣18．0d。增效剂能加速绿僵菌对蛴螬的作用。     

皮蝇幼虫在牦牛体内移行动态与伊维菌素最佳驱除时间

2004年经剖检60头幼年牦牛,对牛皮蝇幼虫在牦牛体内移行动态进行了观察。8月份,第一期幼虫在牦牛体内出现,10月中旬牦牛体内第一期幼虫呈高峰。从11月中旬到第二年2月中旬第二期幼虫出现,元月中旬二期幼虫出现高峰,三期幼虫从元月中旬到6月初出现,3月中旬出现高峰。用伊维菌素给45头幼年牦牛投药:9月中旬,10月中旬和11月中旬各15头。9月中旬和11月中旬的投药群,在12月中旬均出现瘤疱,而10月中旬的投药群未发现瘤疱,表明10月中旬对第一期幼虫为最佳驱除时间。     

Eradication of Hypoderma species in Northern Ireland

The field measures for the control and eradication of the warble fly in Northern Ireland are described. The level of infestation and the main economic losses before the introduction of these measures are indicated. The limitations of the control measures used before the introduction of systematic insecticides are discussed.A limited field trial with a systematic insecticide was conducted in 1964, but the main national programme for warble control was implemented in 1966 and 1967. Under the programme, the treatment of all cattle was compulsory.The nature and organization of the programme and its staffing and cost are described. The field monitoring, the extent and nature of adverse reactions in some of the treated animals, the effects on the rate of warble infestation, and the current status of “warbles” as a Notifiable Disease are discussed. Also described is the practicality of the eradication of cattle grubs from the Island of Ireland as a whole through synchronization of the warble control programmes in Northern Irelabnd and Eire.     

Detection of circulating hypodermin C: an antigen capture ELISA for diagnosis of cattle grub (Diptera: Oestridae) infestations

An antigen capture assay for the detection of circulating hypodermin C was developed for diagnosis of hypodermosis. A murine monoclonal antibody to recombinant hypodermin C was raised using rapid immunization and a one-step hybridization-cloning technique. A highly reactive, specific monoclonal antibody was tested using sera spiked with known quantities of purified, native hypodermin C or with recombinant hypodermin C. Sensitivity of 96.4% and specificity of 95.6% for the antigen capture assay was assessed using a panel of sera from animals unexposed to cattle grubs and from cattle with palpation proven cattle grub infestations. Data from this panel of sera was used to establish the cut-off OD for further testing. The kinetics of circulating hypodermin C was assessed using the assay in three groups of cattle artificially infested with 50, 100 or 200 first instar Hypoderma lineatum. Antigen was first detected approximately 6 weeks after infestation. The amount of antigen detected increased in each group of animals reaching peaks at different times in each group. Levels of antigen fell quickly following arrival of grubs at the back and completion of the molt to second instar.     

Application of an electrometric method for measurement of blood cholinesterase activities in sheep, goats and cattle treated with organophosphate insecticides

A modified electrometric cholinesterase method has been described for use in ruminants exposed to organophosphate insecticides. The method was used to measure cholinesterase activities in the plasma and erythrocytes of sheep, goats and cattle treated with organophosphate insecticides under field conditions. The animals were treated topically to control ectoparasites with malathion (0.05%) or diazinon (0.06%). The treated animals did not suffer from adverse effects related to cholinesterase inhibition. However, 2 h after treatments, plasma and erythrocyte cholinesterase activities significantly decreased in sheep by 20% and 39% and in goats by 18% and 30%, respectively, when compared with respective untreated control values. Diazinon did not significantly affect plasma and erythrocyte cholinesterase activities in the cattle. The results suggest that the described electrometric method could be efficiently used for detecting cholinesterase inhibition in ruminants exposed to organophosphate insecticides.     

Accidental poisoning of a group of yearling cattle by the organophosphate insecticide trichloronat

Eight yearling cattle were accidentally poisoned with the agricultural organophosphate insecticide trichloronat. One animal showed signs of acute organophosphate poisoning and died. The others showed signs of chronic organophosphate poisoning (organophosphate-induced delayed neuropathy) after 2–3 weeks and one animal died from renal failure at 12 weeks. High levels of trichloronat were measured in fat samples at 6 1/2 weeks. The remaining animals still showed signs of ataxia, possibly due to distal axonopathy, 1 year later but no trichloronat was detected in fat samples at this time.     

Accidental poisoning of a group of yearling cattle by the organophosphate insecticide trichloronat

Eight yearling cattle were accidentally poisoned with the agricultural organophosphate insecticide trichloronat. One animal showed signs of acute organophosphate poisoning and died. The others showed signs of chronic organophosphate poisoning (organophosphate-induced delayed neuropathy) after 2-3 weeks and one animal died from renal failure at 12 weeks. High levels of trichloronat were measured in fat samples at 6 1/2 weeks. The remaining animals still showed signs of ataxia, possibly due to distal axonopathy, 1 year later but no trichloronat was detected in fat samples at this time.     

Ivermectin as an antiparasitic agent in cattle

In experimental trials on cattle, ivermectin given SC at 200 micrograms/kg had 95% or better efficacy against adult and immature GI and pulmonary nematodes, including inhibited fourth-stage larvae of Ostertagia ostertagi. Studies of efficacy against ectoparasites revealed nearly 100% efficacy against sucking lice, psoroptic and sarcoptic mange mites and cattle grubs. Safety trials revealed no adverse effects with the recommended dosage, including bulls and pregnant cows. A few grub-infested cattle died from acute esophagitis associated with a host-parasite reaction after ivermectin injection.     

Terbufos poisoning in a dairy herd

This report describes the accidental poisoning of over 200 head of Holstein cattle by the organophosphate, terbufos. The ingestion of an acutely toxic dose (approximately 7.5 mg/kg) of terbufos by 84 heifers resulted in severe respiratory distress as the primary clinical sign and death within 12 hours. There was no response to treatment with atropine sulfate. One hundred and twenty milking cows received a portion of the contaminated feed diluted approximately ten times. These cattle had typical signs of organophosphate poisoning and responded to atropine sulfate. Severely affected cows received pralidoxime chloride and activated carbon 48 h after terbufos ingestion but did not respond to the drugs. Diagnosis of organophosphate poisoning was confirmed by tissue and feed analysis for terbufos and measurement of whole blood cholinesterase activity.     

The Effects of Age and Previous Infection on the Development of Gastrointestinal Parasitism in Cattle

An age resistance in cattle to establishment of infection with Cooperia oncophora was not demonstrated. Cattle exposed to a heavy infection for the first time at approximately 15 months of age were as susceptible to establishment of infection as 3 to 4 month old calves, but stunting of worms and inhibition of ovulation did occur in the older animals, possibly due to a rapid development of resistance as a result of sensitization by a previous extremely light infection.

An age resistance in cattle to infection with Nematordirus helvetianus was not clearly demonstrated. At necropsy, 8 of 9 calves and 2 of 6 yearlings exposed to pasture infections for the first time did harbour Nematodirus worm burdens, while yearlings which were heavily infected previously were completely free of this species.

Under the conditions of this investigation, age and acquired resistance to Ostertagia ostertagi were not demonstrated, since previously non-exposed calves and yearlings and previously infected yearlings had comparable worm burdens.

This study demonstrated the adverse effect that heavy parasitism has on the development of susceptible animals. Animals which had little or no exposure to parasitism were found to be much more susceptible to the effects of parasites than were resistant animals.

     

Stage specific mortality and humoral immune responses during pulse and trickle infestations of the common cattle grub, Hypoderma lineatum (Diptera: Oestridae)

Stage specific survival of larvae and pupae of the common cattle grub, Hypoderma lineatum de Villers, was compared in cattle artificially infested with larvae delivered by subcutaneous injection as a single infestation of 100 larvae, in trickle infestations of either two doses of 50 larvae, separated by 15 days, or in four doses of 25 larvae, separated by 9, 6, and 6 days, respectively. The duration of the migratory and 'warble' phases were also compared between treatments. The kinetics of the antibody response was monitored throughout the larval development by ELISA. No difference was noted in the level of antibodies among the three treatments. Mortality of first-instars differed among the infestation groups with mortality in the single pulse infestation group相似文献   

武威某奶牛场犊牛及职工球虫病感染情况调查

为摸清该奶牛场的球虫感染情况,在甘肃省武威市某集约化牛场随机抽10头犊牛粪便及与犊牛直接接触的一线职工10人的粪便为样本,采用麦克马斯特计数方法,检测球虫病的感染情况。结果显示：该牛场球虫总感染率为80%,但OPG均小于5000,属于亚临床型球虫感染,该奶牛场职工没有球虫病感染情况。通过对球虫病感染的检查,诣在为该场犊牛球虫病的防控治疗提供依据。     

Enhanced resistance to cattle grub infestation (Hypoderma lineatum de Vill.) in calves immunized with purified hypodermin A, B and C plus monophosphoryl lipid A (MPL).

The influence of an antigen-specific cellular and humoral immune response, stimulated by immunization, on survival of a challenge infestation of Hypoderma lineatum was investigated. Calves immunized with a purified combination of hypodermin A, B and C plus monophosphoryl lipid A (MPL) developed a strong antigen-specific cellular immune response by completion of the immunization schedule which persisted to 12 weeks post-infestation. Responsiveness of peripheral blood lymphocytes to the mitogens concanavalin A and pokeweed was also elevated at 4 and 12 weeks post-infestation. Western blot analysis at the time of maximum grub counts demonstrated that immunized calves responded to hypodermin A, B and C while those receiving only MPL or infested controls responded only to hypodermin B and C. The antigen-specific antibody response as measured by ELISA at maximum grub count was significantly higher in vaccinated calves than in infested controls while the response in calves receiving only immunostimulator was also significantly elevated. Immunized (antigen plus MPL) calves produced 5.0 +/- 6.9 grubs per animal which successfully pupated while those receiving MPL alone produced 16.4 +/- 6.1 and infested controls produced 32.2 +/- 10.9 grubs per animal.     

Effect of treatment on the dynamics of circulating hypodermin C in cattle naturally infested with Hypoderma lineatum (Diptera: Oestridae)

An antigen capture ELISA, using a murine monoclonal antibody recognising recombinant hypodermin C (rHyC), was used to evaluate the influence of early treatment with eprinomectin (Eprinex) or fenthion (Spotton) on the kinetics of circulating hypodermin C in calves naturally infested with Hypoderma lineatum. No viable larvae were collected from treated animals, whereas a variable number of warbles were found in control animals. Treatment provoked a decrease in circulating HyC levels that was significant 9 days post-treatment (p.t.). Circulating antigen levels in the treated cattle remained detectable for approximately 99 days p.t. In contrast, control animals had no detectable antigen at 64 days p.t., 42 days earlier than in the treated animals. These results suggest that larvae were either gradually killed, resulting in slow release of antigen or they were encapsulated, leading to the slow liberation of antigen. Kinetics of circulating HyC did not differ among the two insecticide treatments. Antibodies persisted, in all groups, throughout the 120-day study. These results suggest that the antigen capture ELISA will be useful as a technique for detecting successful treatment of cattle grub infestations and for the detection of new infestations in previously infested cattle.     

The role of European starlings in the spread of coccidia within concentrated animal feeding operations

To investigate the relationship between European starlings and bovine coccidiosis we collected samples from European starlings, cattle feed bunks, cattle water troughs, and cattle feces within concentrated animal feeding operations (CAFOs). These samples were screened for coccidia spp. to investigate (i) the prevalence of coccidia in starlings using CAFOs; (ii) if there is a relationship between bovine coccidiosis and starling numbers; (iii) if coccidia contamination of cattle feed and water is related to the number of starlings observed on CAFOs. Coccidia belonging to the genus Eimeria were detected in cattle feces and one water sample but no Eimeria spp. were detected in European starlings or cattle feed. However, many European starling samples were positive for Isospora. Starling use of CAFOs did not appear to be associated with coccidia spp. shedding by cattle and there was no correlation between starling numbers and contamination of cattle feed and water, suggesting that starling do not contribute to the amplification and spread of Eimeria in CAFOs.