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Biomedical subjects

M T Fox

Publications and source records attributed to M T Fox.

70 records · Page 4Linked to original sources
PubMed1987

Early season parasitic gastroenteritis in calves and its prevention with ivermectin.

In a two-year trial involving successive batches of 36 autumn-born steers on two adjacent sites in Hertfordshire, calves treated with ivermectin at three and eight weeks after turn out contaminated pastures much less than untreated control animals. Each year dry summers prevented the larval challenge on the control pastures from building up to high levels until about the time of autumn housing. Atypical outbreaks of parasitic gastroenteritis were recorded in May and June of the second year in both groups of control calves. Clinical and parasitological aspects of these outbreaks are discussed in the context of the epidemiology of the disease. It is concluded that the application of measures to control gastroenteritis can bring benefits in the early part of the grazing season as well as later in the year.

Animals↗
PubMed1987

Field evaluation of the oxfendazole pulse release bolus for the chemoprophylaxis of bovine parasitic gastroenteritis: a comparison with three other control strategies.

Three trials were conducted in southern England involving 120 autumn-born calves to evaluate the ability of an oxfendazole pulse-release intraruminal device (OPRB) to control parasitic gastroenteritis (PGE). Matched groups were set-stocked on adjacent paddocks. One group received an OPRB at turn-out; one was treated with an alternative chemoprophylactic programme; while the third acted as an untreated control. In each trial clinical PGE occurred in the latter group but not in OPRB or alternative strategy groups. The OPRB, the morantel sustained release bolus (MSRB) and fenbendazole administered at 3 and 6 weeks after turn-out gave similar weight-gain benefits when compared with untreated controls (P less than 0.01), but the growth rate of animals given regular levamisole treatments from July to housing was significantly poorer than the matching OPRB group (P less than 0.05) although better than controls. Faecal egg-output of OPRB calves was reduced by 97.0-99.9% compared with 95.5 and 58.9% for MSRB and fenbendazole treatments. Consequently, the late summer/autumn peaks in pasture larval counts were considerably reduced in all treatment groups other than the late-season levamisole strategy which reduced overall egg-output by only 37.6%. Serum pepsinogen and gastrin values confirmed a greater degree of abomasal disturbance in calves grazing on the more highly contaminated pastures. Incidental lungworm infections became clinically apparent in the control groups of two trials but not in any OPRB or alternative treatment group.

Animals↗
PubMed1987

Interactions between chemoprophylaxis and immunity to bovine parasitic gastroenteritis and bronchitis: pilot studies using an oxfendazole pulse release bolus.

In separate experiments, the immune status of six matched pairs of yearling heifers from a field trial in which both parasitic gastroenteritis and husk had occurred in control animals, was tested with a single massive challenge of either Dictyocaulus viviparus or Ostertagia ostertagi. The clinical responses of untreated controls and animals that had carried an oxfendazole pulse release intraruminal device (OPRB) were in all cases similar (with the exception of one lung-worm-challenged control that succumbed to a fulminating pulmonary hypersensitivity reaction), indicating that both groups possessed comparable degrees of protection. Faecal larval/egg-output data and serum gastrin levels, however, suggested that larger worm populations had established in the OPRB cattle.

Animals↗
PubMed1986

Patterns of infection with Buxtonella sulcata in British cattle.

Buxtonella sulcata cysts were recovered from the faeces of adult cows on nine commercial dairy farms. Overall, 44.6 per cent of 496 animals sampled exhibited patent infections during the course of the study. Seasonal fluctuations in the prevalence of infection and cyst excretion rate were related to changes in diet and opportunities for transmission. An increase in prevalence of infection with lactation number was also demonstrated.

Animals↗
PubMed1985

Field evaluation of a method for the chemoprophylaxis of parasitic bronchitis in calves.

Studies on the epidemiology of Dictyocaulus viviparus infections in Denmark have suggested that the adult lungworms present in calves around the sixth week after turnout play an important role in determining the subsequent pattern of disease. This trial was designed to test whether prophylactic treatment at this time would control disease in calves kept under British conditions. Thirty autumn-born Friesian or Friesian-cross bull calves were allowed to graze the whole of a 5 hectare field for six weeks after turnout. The field was then divided into two and the calves split into matching groups, one group being put into each of the paddocks. One group was treated with levamisole at this time and again two weeks later while the other was kept as an untreated control. Anthelmintic treatment resulted in a marked reduction in larval excretion and considerably delayed the build-up of infection on pasture. This in turn delayed the onset and reduced the severity of clinical signs in the treated group. However, as disease was not eliminated completely this prophylactic programme cannot be recommended to the British farmer in its present form. These findings are discussed in the context of the yet incomplete knowledge of the epidemiology of parasitic bronchitis.

Animal Feed↗
PubMed1985

Effect of thiabendazole treatment on feed intake, digestibility and selected blood values in lactating dairy cows.

Observations of feed intake, digestibility, production and selected blood values were made during the winter housing period on 10 lactating dairy cows, naturally infected with gastrointestinal roundworms, which were either left untreated or dosed on two occasions with thiabendazole in-feed. While treatment had no significant effect on appetite or production, there was a 9.8 per cent improvement in cellulose digestibility (P less than 0.05). An increase in circulating cholesterol in treated cows was associated with the improved utilisation of cellulose. It is considered unlikely that thiabendazole's primary anthelmintic activity was responsible for this effect. Treated cattle also exhibited a significant improvement in thyroid function during the course of the study compared with control animals. This might account for the increase in milk production reported in several trials following anthelmintic treatment of dairy cows.

Animals↗
PubMed1982

Control of bovine parasitic gastroenteritis and parasitic bronchitis in a rotational grazing system using the morantel sustained release bolus.

Sixty cattle (12 first season and 48 second season grazing animals) were allocated to three groups according to age and bodyweight. Each group was divided into "control" and "treated" subgroups. Before turnout, a morantel sustained release bolus (MSRB) was administered to each animal in the "treated" category. The groups were moved from field to field according to the farmer's normal rotational grazing policy. Each field was, however, divided into two equal halves, one of which was reserved for the MSRB treated cattle, while the other was used exclusively for the controls. Severe parasitic gastroenteritis occurred in the first season controls during early September, while milder disease affected the untreated animals in the smaller of the second season groups. No gastrointestinal disease was apparent in the corresponding MSRB treated cattle. A mild outbreak of parasitic bronchitis occurred in the first year controls during October; there was evidence of less sever lungworm infection in the matching MSRB treated animals. The larger second season group showed no signs of parasitic disease.

Animal Husbandry↗
PubMed1980

Factors influencing uptake of nematode larvae in adult dairy cattle during the grazing season and sources of pasture contamination.

Investigations on nine well managed English dairy farms showed that 85.2 per cent of 460 adult cows harboured patent nematode infections, although the worm burdens, as judged by faecal egg counts, were small. Infection took place primarily by the ingestion of grass previously contaminated either directly with bovine faeces or indirectly with slurry. Calves did not appear to contribute to the infectivity of land grazed by adults on these farms. The parasitic challenge to which cows were exposed was dependent upon the feeding regime, grassland management and the season of the year. Generally the intake of infective larvae ranged from 0 to 1500 per day but daily intakes of up to 4520 were recorded.

Animal Feed↗