Low level feed administration of morantel tartrate in the prophylaxis of experimental nematode infections in lambs and calves

Efficacy of morantel tartrate on milk production of dairy cows: a field study

Eighty Holstein herds on Quebec Dairy Herd Analysis Service were paired into 40 blocks of two herds each to test the effects of systematic deworming with morantel tartrate. Cows in treated herds were given morantel tartrate in May, June, and July, and cows in control herds were given a placebo of ground corn, wheat bran, and barley; both products were administered at 1 kg/1000 kg body weight. Records were obtained from May 1983 to April 1984. Each farm was visited monthly from May to October 1983 to obtain herbage samples and fecal grab samples from a random 10% of lactating cows. Production records were obtained for the year prior to commencement of this trial for covariate analysis. Fecal worm egg counts and infective larvae counts in pasture were reduced by 83 and 93%, respectively, in treated herds. The pattern of worm egg excretion differed between groups due to repeated treatments with morantel. Treated herds produced 323 kg more milk per cow per yr and 1.2 kg per cow per d more fat-corrected milk than controls. Milk fat and protein percentages did not differ between groups for the 12 mo. Deworming lactating dairy cows at the beginning of and during the pasture season improved production performance.

Efficacy of morantel tartrate in a sustained release bolus on the control of subclinical gastrointestinal parasitism in first-year grazing dairy replacements

Thirty-four heifers (24 Holstein, 8 Ayrshire, 2 Jersey) and 12 Holstein steer calves were grouped into 23 blocks of 2 animals each according to breed, sex, and body weight. Animals in each block were randomly assigned to control or treated groups. The treated group received an anthelmintic bolus containing morantel tartrate before they were permitted access to pasture. A 2.6 ha pasture was divided in half with a double fence; the resulting two pastures had separate feed and water troughs. Steer calves were slaughtered upon termination of the trial to ascertain gastrointestinal parasite burdens. Two worm-free tracer calves were placed on each pasture every 2 mo and slaughtered after 4 wk of grazing to determine parasite infectivity of pastures. Herbage samples were obtained monthly and analyzed for infective larvae. The trial was conducted for 141 d during the grazing season. Treatment resulted in 90% reduction in infective larvae on pasture, 74% reduction in fecal worm-eggs, 91% reduction in adult worm burdens, and a trend toward reduced worm burdens in tracer calves by 52%. An overall average daily gain of .68 and .88 kg was obtained for control and treated animals. Reproductive data for the heifers remaining in the herd from the trial showed that treatment resulted in 44 less days to first breeding.

Low-dosage phenothiazine in the prophylaxis of trichostrongylid infection in calves

Phenothiazine (PTZ) given indoors to calves artificially infected with Ostertagia ostertagi and Cooperia oncophora showed ovicidal activities of 100, 93, 98 and 85% respectively at daily doses of 9, 8, 7 and 6 mg kg-1. In a grazing study, one group of calves was treated with PTZ via the drinking water, using a "Profel" liquid dispenser. The dispenser was calibrated to add PTZ to the water at a daily dose of 7 mg kg-1, but in practice the dose far exceeded this amount. A dose of 7 mg kg-1 day-1 was given manually to a second group and a third group acted as control, receiving no PTZ. PTZ-induced photosensitivity was widespread in the first group due to over-dosage of medicament by the dispenser and was suspected in one calf in the manually dosed group. PTZ in both treated groups showed marked ovicidal activity and, apparently as a result of this, caused striking reductions in trichostrongylid infection on the pasture and in the calves as evidenced by pasture larval counts, calves' egg counts, pepsinogen levels and live weight gains. Necropsy worm counts showed that the PTZ medication prevented heavy infection by arrested as well as by adult Ostertagia. The reduced infection on the treated calves' pasture was carried over for a second grazing season. Untreated calves grazing the pasture in that season showed lower infection and improved weight gains up to mid-September compared with calves on the control pasture. These effects did not persist for the whole of the second season.

Grazing study in Ireland using the morantel sustained release bolus for controlling nematodiasis in calves

The morantel sustained release bolus was administered at turnout to first-season grazing calves in order to assess its efficacy in the seasonal control of infection by nematode parasites in Ireland. The pastures grazed by control calves showed a marked increase in gastrointestinal trichostrongylid infective larvae by September, while numbers of infective larvae on pasture grazed by bolus-treated calves remained at a low level throughout the grazing season. In consequence, the controls showed significantly higher worm egg counts in late season and significantly higher worm burdens (mainly Ostertagia spp) at necropsy carried out in November on representative number of principal animals selected from each group. These reduced worm burdens were attributed to the suppression of egg output during the early part of the season as a result of treatment with the morantel sustained release bolus at turnout in the spring. Pasture contamination with Dictyocaulus viviparus larvae was present on all treatment pastures. The bolus-treated calves however were subjected to an increase in D. viviparus infection which occurred on their pasture in late season after the active life of the bolus had expired. It was concluded that bolus treatment delayed (rather than prevented) the buildup of D. viviparus infection on the pasture by 60-90 days.

Morantel sustained release bolus: a new approach for the control of trichostrongylosis in Austrian cattle

The efficacy of a morantel sustained release bolus to control gastrointestinal parasitism during two consecutive grazing seasons was assessed in replacement dairy heifers raised under field conditions in Austria. Thirty calves were randomly allotted into two equal groups and maintained throughout the 1979 summer pasturing season on adjacent pastures of equal size with identical grazing history. Twenty-four of the thirty calves used in 1979 were monitored throughout 1980, each animal remained in the same treatment group as the previous year and grazed the same pastures as the previous year. In both 1979 and 1980 the bolus was administered to each animal in the treated group one week before turnout onto spring pastures, while the control animals received no anthelmintic treatment during either year. The efficacy of the bolus was assessed by comparison of faecal worm egg counts, herbage larval counts, worm counts from tracer and principal trial animals, weight gains and by the incidence of clinical disease found in both tracer and trial animals throughout the grazing season. Milk production was also monitored for all animals in both treatment groups during the first lactation. The system of treatment used in the present study with the morantel sustained release bolus was highly effective in preventing a significant buildup of infective larvae on pasture to the end of the grazing season in both years. In 1979 worm counts of tracer calves grazed on the treated pastures in mid-August were similar to those recorded at the beginning of the season, while worm counts in the control tracers were five times the total found at the beginning of the season. In 1979 the bolus-treated calves outperformed the control group by 34.8 kg (P less than 0.001) over the 168-day grazing period. These results demonstrated that administration of the bolus to calves at the time of turnout onto spring pastures was most effective both in controlling parasites within the cattle themselves and in reducing the level of parasite contamination. During the second grazing season (1980) no beneficial effect in weight gain was observed due to the second bolus treatment. Weight gains realized during the first year, however, largely remained through the second year and the bolus-treated heifers reached breeding weight on average 19 days earlier. No difference in milk yield was observed between the treated and control animals during thier first year of lactation.

Therapeutic and prophylactic efficacy of morantel when administered directly into the rumen of cattle on a continuous basis

The efficacy of morantel tartrate when administered on a continuous basis directly into the rumen/reticulum of cattle, either by a cannula or from a specially designed device, was evaluated against gastrointestinal parasites under laboratory conditions. In two experiments the continuous infusion of morantel at rates between 0.26 and 1.04 mg/kg body weight per day using a peristaltic pump was highly efficacious in both preventing the establishment of infections and removing established infections of the following species: Ostertagia ostertagi, Haemonchus contortus, Cooperia oncophora and Trichostrongylus colubriformis. The same dose rates also prevented establishment of Dictyocaulus viviparus infection but were ineffective against established infections of this parasite. In another two experiments the continuous release of morantel tartrate for at least 60 days (at rates between 0.65 and 1.11 mg/kg body weight per day) from a specially designed intraruminal sustained release bolus (secured at each end by a polyethylene impregnated semi-permeable membrane) was highly efficacious in both preventing the establishment of infections and removing established infections of the following species: O. ostertagi, T. axei, T. colubriformis and C. oncophora.