IE41765B1 - A method of preventing or controlling parasitic infestation of livestock - Google Patents

Abstract

1530161 Anthelmintics AN FORAS TALUNTALS 30 Oct 1975 [30 Oct 1974] 44950/75 Heading A5B Parasitic infestation of livestock e.g. sheep, cattle, goats, pigs and horses is prevented or controlled by putting the animals on pasture at the beginning of the grazing season when the pasture is relatively free of helminth parasitic infection, and administering an anthelmintic to the livestock through their drinking water on a continual daily basis throughout a substantial part or all of the grazing season so as to suppress helminth egg or larval output from the animals such that heavy helminth contamination of the pasture is prevented. The anthelmintic is preferably morantel tartrate, levamisole and/or diethylcarbamazine citrate.

Description

The invention relates to a method of preventing or controlling parasitic infestation of domesticated mammals. By the word controlling as used throughout the specification and claims is meant the keeping of parasitic infection in mammals below clinical levels. It is well known that it is both medically and economically desirable to prevent or control the infestation of livestock, and in particular calves, with gastro-intestinal parasites, as such infection depresses appetite and results in poor liveweight gain.

It has been established that, in these islands, young calves normally contaminate pasture with the eggs of gastrointestinal parasites (mainly Ostertagia osteragi and Cooperia oncophora) from April onwards, and that this leads generally to a heavy larval infection on the herbage, beginning in early July (Michel, J.F. (T967), Proc. 4th Meeting, Uld. Soc. Buriatrics, Zurich, 1966, Michel J.F. (1969), 2· Helminth, 43, 111, Michel, J.F. Lancaster, M.B. and Hong, C. (1970, Res. vet Sci. 11, 255, Downey, N.E. (1973), Vet. Rev, 93, 505).

The infection resulting from this pasture contamination is the main cause of parasitic disease in the calves, and is difficult to control as the pasture is continually being contaminated from April through to September. The conventional method of controlling parasitic gastro-enteritis in calves consists in administering a single dose of an anthelmintic to each calf in early July, the dose being in the region of 8 mg per Kg. liveweight of the calf. The calves are then moved to a clean pasture (i.e. a pasture which is substantially free of larval infection), e.g. silage aftermath, where they graze from July onwards. The calves may need to be dosed again before winter.

This method suffers from the disadvantage that it presents management problems and may not always suit the overall grassland production system of the farm. It also imposes heavy demands on labour.

It is an object'of the invention to overcome the aforesaid disadvantages and to provide a method of suppressing worm-egg or larval output from calves and other livestock such as pigs, sheep and horses during specific parts of the grazing season and thereby prevent the heavy infection of the pasture.

The word livestock as used throughout the specification and claims is intended to cover ruminants such as sheep, cattle and goats, and non-ruminants such as pigs and horses.

According to the invention a method of preventing or controlling parasitic infestation of livestock as hereinbefore defined comprises putting the animals on pasture at the beginning of the grazing season when the pasture is relatively free of helminth parasitic infection, and administering an anthelmintic to the livestock through their drinking water on a continual daily basis throughout a substantial part or all of the grazing season so as to suppress helminth egg or larval output from the animals such that heavy helminth contamination of the pasture is prevented. The anthelmintic is administered in amounts dependent upon the type of infection and.anthelmintic employed. As a general rule the amount administered to each animal per day is approximately 1/3 that of a conventional single dose for example about 3 mg per kg. liveweight of the animal, and the amount added to the drinking water is such that an average daily dose in the range 0.01 to 20.00 mg. of active ingredient per kg. liveweight of the animal is available to each animal. In the case of calves the anthelmintic is preferably administered continually from April to July. However, for economic reasons it may be preferred to administer the anthelmintic on a continual daily basis for intermittent periods of a week or several days at a time throughout the grazing season. In the case of some parasites, e.g. lungworms, anthelmintic administration may be needed beyond July, e.g. up to the end of September.

Suitably the anthelmintic used is water-soluble, and may comprise, for example, morantel tartrate (the 3-methyl analogue of trans - 1 - methyl 1,4,5,6 - tetrahydro - 2 -(^2 - (thienyl) - vinyl]tartrate, levamisole (-2,3,5, 6-tetrahydro-6-phenylimidazo -[2,l-b]thiazole, and diethylcarbamazine citrate (1-methyl-4-diethylcarbamyl piperazine citrate), or a mixture or two or more of these compounds depending upon the type of infection involved. Where morentel tartrats is used alone it may be administered in an amount of from 1.5 to 7.00 mg., preferably about 3 mg., per kg. liveweight of the animal per day, for stomach worm control. In the case of levamisole the average daily therapeutic dose available to each animal is from 1.00 to 6.00 mg. per kg. liveweight, and in the case of diethylcarbamazine it is from 3.00 to 20.00 mg. per kg. liveweight of the animal.

The anthelmintic is dissolved in the drinking water avail£0 able to tho calves in amounts based on an estimated drinking water intake. It has been found that the intake of drinking water by calves varies somewhat with the age of the calf and with the amount of rainfall at the particular time. In a year of normal rainfall we have found that calves of a liveweight of 70 kg. have a daily consumption of water amounting to about 3% of their bodyweight. This increases to about 7.5¾ in June/July when the calves weigh about 100 kg. In an exceptionally dry summer, such as the summer of 1975, the water consumption of the calves could range from 4¾ to 10¾ of their body weight over the period May to mid2o July. The concentration Of anthelmintic xn the drinking water may be in the range of from 3 to 600 mg. of active ingredient per litre of water. In the case of morantel tartrate the concentration, preferably, is in the range 45 to 205 mg. of active ingredient per litre of water, in the case of levamisole, preferably it is in the range 30 to 178 mg. per litre of water, while in the case of di ethylcarbamazine. citrate nreferably it is in the range 65 to 440 mg. per litre of water. Preferably, the anthelmintic is added to the drinking water by means of an automated dosing unit. For example, the anthelmintic may be added to the drinking water using the method and apparatus described in Patent Specification No.

The following Examples give the results of experiments using the method of the invention: - 4 41765 EXAMPLE I The experiment was part of a large-scale grazing trial involving initially 84 calves divided into 6 groups and turned out to grass in early April. Each group was grazed ti rotationally on a separate area of pasture. Morantel tartrate was continually administered to the calves of one group (those in Area B) in accordance with the method of the invention, the dosage being about 3 mg. per Kg. liveweight per day. For the purpose of this experiment, calves and pasture assigned to the other 5 groups acted as controls for the calves and pasture in Area B.

Worm egg counts (Parfitt, J.W. (1958). Lab. Pract. 7, 353) were carried out on faeces samples collected from, each calf at weekly Intervals. Herbage from each plot was sampled 1», weekly (Taylor, E.L. (1939) Parasitology, 31 473) to determine the number of infective strongyloid larvae and Dictyocaulus viviparus larvae using the method of Parfitt (Parfitt, J.W. (1955). Lab. Pract. 4, 15).

Continuous anthelmintic medication for calves in Area B ceased in mid-July. At that time, the calves in all the other 5 Areas (but not those in Area B) were given full therapeutic doses of the anthelmintic levamisole (Nilverm, I.C.I). Two groups (those in Areas A and D) were then moved on to silage aftermath, but the remaining 4 groups (including 2b those in Area B) stayed in their original area. These areas were enlarged so as to provide sufficient herbage for the calves, taking into account their increase in body weight as the trial progressed.

The results of the experiments are summarized in the accom30 panying Tables. The data presented are taken only from groups of calves and. their respective areas which are comparable from the point of view of location, or grazing management, or both. - 5 41765 TABLE 1 - Average monthly egg counts (eggs/g faeces) of calves in the 5 experimental groups.

Area May June July* August September A 183 517 715 99 142 D 124 357 384 151 99 C 116 259 327 531 155** F 107 254 246 417 165** B 20 4 8 74 183 * These figures . are the average egg counts for the first 3 weeks of the month. ** The calves in Area G and F were dosed for the second time on August 30th • Note: Weekly egg counts for May, June and early July were examined statistically, the counts of the calves in Area B were significantly lower than those in the other groups.

TABLE 2 - Monthly peak herbage larval levels (strongyloids) in each of the 5 areas of pasture Area April May June July August September A 23.4 37.4 91.7 647.9 503.1 - D 2.6 58.1 14.7 88.0 37.2 - n 11.5 29.3 52.6 276.0 186.8 106.5 F 13.9 20.1 10.8 238.6 297.4 137.8 B 7.2 16.9 18.0 2.6 12.5 7.9 - 6 41765 TABLE 3 - Average serum pepsinogen levels in calves in the experimental groups I.U. pepsinogen per ml serum Area September 10th September 24th A 2.3 D 2.1 G 2.7 F 2.6 B 1.6 2.2 2.1 3.0 2.3 1.4 It is apparent from Table 1 that worm egg output by the calves in Area B was drastically suppressed during the contamination phase of the season (i.e. May, June and early July). In August/September, the egg counts of Area B calves rose, but were la far lower in August than those of calves in Area C and F. The reduced egg counts (Table 1) of the groups in the latter 2 areas occurring In September resulted from a second full dose of anthelmintic which these calves required on account of their developing clinical parasites. Dosing and a change to clean pasture re20 duced infection levels of calves that originally occupied Areas A and D, as is evident from their lower egg counts in August and September (Table 1).

Data in Table 2 show that suppression of egg output in Area B prevented the rise in pasture infection levels that occurred in 3b the other areas during August/September.

Pepsinogen levels in the calves' peripheral blood, determined on two occasions in September, were consistently lower in the calves in Area B compared with those in other areas (Table 3). This is evidence that there was less abomasa! a damage due to O.ostertagi infection in the Area B calves.

The method of the invention obviates the need for both conventional dosing and for a permanent change to clean pasture. The method has the added advantage that it can be entirely automated. This would effect a considerable saving in labour costs and would eliminate the upset to animals that inevitably accompanies conventional dosing.

EXAMPLE II This experiment was intended to test the effectiveness of the invention to control lung worms using levamisole and diethylcarbamazine citrate. The calves were divided into three groups A, B and C of four calves each. The experiment was conducted indoors. The calves of all three groups were given 10 Dictyocaulus viviparous larvae per lb. body weight of the calf over a period of five days. Each of the groups was fed separately on meals plus hay. The levamisole was administered to the calves in group A through their drinking water using an average daily dose of 4.2 mg/kg. liveweight. Diethylcarbamazine citrate was administered to the calves in group B, again through their drinking water, at an average daily dose of 8.00 mg/kg. liveweight. No anthelmintic was administered to group C which acted as a control group.

The anthelmintic was administered on a continual daily basis to groups A and B for a period of some six weeks. It was found that with group A, to which levamisole had been administered, that there was complete, suppression of larval output and the results with group B showed that the diethylcarbamazine citrate was less effective although with this group the larval output was less than that of group C. The advantage of using levamisole was also reflected in respiratory rates, food intakes and weight gain data.

EXAMPLE III This experiment was intended to test and compare two dose levels of levamisole. The calves were again divided into three groups A, B and C of four calves each. The experiment was conducted indoors, all groups were penned separately and were fed on barley meals plus hay. The calves in all three groups were given 10 Dictyocaulus viviparus larvae per lb. bodyweight of the calf over a period of five days. Levamisole was administered to the calves in group A through the drinking water using an average daily dose of 2.68 mg/kg. liveweight, and to group B using an average daily dose of 1.9 mg/kg. liveweight. The anthelmintic was administered on a continual basis to groups A and B for a period of some weeks. No anthelmintic was administered to group C, which acted as a control group. It was found that with group A, to which the higher dose of levamisole had been administered, that three out of four calves showed no count. The count was rather low in group B but all the calves in control group C were positive. Respiratory rates and liveweight data confirm the response.

Claims (24)

1. A method of preventing or controlling parasitic infestation of livestock as hereinbefore defined, which comprises putting the animals on pasture at the beginning

2. A method as claimed in Claim 1, wherein the anthelmintic is administered on a continual daily basis throughout all or part of the period April to September inclusive. 15

3. A method as claimed in Claim 2, wherein the anthelmintic is administered on a continual basis throughout the period April to July inclusive.

4. A method as claimed in any of the preceding claims » I wherein the anthelmintic is administered on a continual

5. A method as claimed in any of the preceding claims wherein the average daily dose of anthelmintic administered to each animal is about 3 mg. per kg. liveweight of the animal25 ti.

6. A method as claimed in any of claims 1 to 4, wherein the anthelmintic is added to the drinking water in such amounts that an average daily dose in the range 0.01 to 20.00 mg. of active ingredient per kg. liveweight of the animal is available to each animal. 5 of the grazing season when the pasture is relatively free of helminth parasitic infection, and administering an anthelmintic to the livestock through their drinking water on a continual daily basis throughout a substantial part or all of the grazing season so as to suppress helminth egg

7. A method as claimed in any of the preceding claims, wherein the anthelmintic administered is morantel tartrate, levamisole, or diethylcarbamazine citrate, or a mixture of two or more of these compounds.

8. A method as claimed in Claim 7, wherein if morantel tartrate is used the amount added to the drinking water is such that the average daily dose available to each animal is from 1.5 to 7.00 mg. per kg. of liveweight of the animal.

9. A method as claimed in Claim 7, wherein if levamisole is used the amount added to the drinking water is such that the average daily dose available to each animal is from 1.00 to 6.00 mg. per kg. liveweight of the animal.

10. A method as claimed in Claim 7, wherein if diethylcarbamazine citrate is used the amount added to the drinking water is such that the average daily dose available to each animal is from 3.00 to 20.00 mg., per kg. liveweight of the animal. 10 or larval output from the animals such that heavy helminth contamination of the pasture is prevented.

11. A method as claimed in any of Claims 1 to 4, wherein the concentration of anthelmintic in the drinking water is from 3 to 600 mg. of active ingredient per litre of water.

12. A method as claimed in Claim 7 wherein the anthelmintic is morantel tartrate and the concentration thereof in the drinking water is from 45 to 205 mg. of active ingredient per 1itre of water.

13. A method as claimed in Claim 7, wherein the anthelmintic is levamisole and the concentration thereof in the drinking water is from 30 to 178 mg. of active ingredient per litre of water.

14. A method as claimed in Claim 7, wherein the anthelmintic is diethylcarbamazine citrate and the concentration thereof in the drinking water is from 65 to 440 mg. of active ingredient per litre of water.

15. A method as claimed in any of the preceding claims, wherein the animals are calves.

16. A method of preventing contamination of pasture by worm-egg or larval output from animals grazing the pasture comprises treating the animals by the method claimed in any one of the preceding claims.

17. An anthelmintic in aqueous solution when used in the method claimed in any one of Claims 1 to 14.

18. An anthelmintic as claimed in Claim 17, which has a concentration of from 3 to 600 mg. of active ingredient per 1itre of water.

19. An anthelmintic as claimed in Claim 18, comprising morantel tartrate present in the solution in a concentration of 45 to 205 mg. of active ingredient per litre of water.

20. An anthelmintic as claimed in Claim 18, comprising levamisole present in the solution in a concentration of 30 to 178 mg. of active ingredient per litre of water. 20 daily basis for intermittent periods of at least several days at a time throughout the grazing season.

21. An anthelmintic as claimed in Claim 18, comprising diethylcarbamazine present in the solution in a concentration of 65 to 440 mg. of active ingredient per litre of water.

22. A method of preventing or controlling parasitic infestation of livestock as claimed in Claim 1 substantially as hereinbefore described with reference to any of the Examples.

23. Livestock when treated by the method claimed in any of Claims 1 to 14.

24. Calves when treated by the method claimed in any of Claims 1 to 14.