Efficacy of a topical formulation of ivermectin against naturally acquired gastro-intestinal nematodes in weaner cattle

The efficacy of a topical formulation of ivermectin against naturally acquired gastro-intestinal nematodes in weaner cattle was evaluated. At slaughter, 14-15 days after treatment, burdens of Ostertagia spp, Trichostrongylus axei and Oesophagostomum radiatum were significantly lower in the treated calves than in the untreated controls (p<0.01). Efficacies (based on geometric mean worm burdens of treated and control groups) were 99.6%, 95.1% and 100% respectively. The sizes of the Cooperia spp and Trichuris ovis burdens in the treated group did not differ significantly at the 5% level of confidence from those in the control group.     

Trichostrongyle worm infection in cattle: Ostertagiasis and concurrent infections in dairy calves: Seasonal patterns of occurrence,pathology and diagnosis

In the three years from October 1979 to September 1982 over 6.3 million lambs were processed in two meat works and of these 0.5% had lesions of contagious pustuiar dermatitis (CPD). The proportion of iambs affected was highest in the months of December and January when up to 2.2% of the Iambs slaughtered had lesions of CPD. On average 13.4% of a consignment (referred to as a line) of lambs showing evidence of CPD were affected. The total lambs in affected lines constituted 4.1% of the total slaughtered.

If it was decided to reject for slaughter lines with CPD, approximately 1¼ million lambs would be returned to farms each year. It was concluded that such a policy would be unlikely to substantially reduce the level of infection in meat workers.     

The spring-rise phenomenon: Seasonal changes in the worm burdens of breeding ewes and in the availability of pasture infection

Extract

A Mastitis control programme is essentially a biological regulatory system involving the three essential components of any control mechanism:

• A signal from a detector indicating departure from normality

• The interpretation of the signal (diagnosis)

• A feed-back signal to the origin of the detection signal indicating corrective action.

     

The distribution of Nematodirus spp. occurring in sheep in New Zealand

Extract

Most outbreaks of parasitic gastro-enteritis in sheep in New Zealand have been ascribed to the presence of nematodes of the family Trichostrongylidae, and in particular the genera, Haemonchus, Ostertagia, and Trichostrongylus. However, during the period 1956–58, a number of outbreaks of disease occurred in lambs and the condition was associated with heavy Neniatodirus infestation. Although Neinatodirus spp. are commonly foundin sheep in this country, only moderate numbers of worms are usually present in any individual and the worm has been regarded as non-pathogenic. Similar views were held in the British Isles until about 1951, when an acute disease condition of lambs, associated with heavy Neniatodirus burdens, caused serious losses.