Dieldrin toxicity in housed Merino sheep

An outbreak of nervous disease with deaths and reproductive failure was investigated in a fully housed flock of 640 super fine wool (Sharlea) Merino sheep. During the 4 months after the flock was dipped in dieldrin, 70 adult sheep died and no live lambs were produced by the ewes. The diagnosis of poisoning with dieldrin was based upon the presence of characteristic clinical signs, pathological findings and the detection of residues of dieldrin in tissues. Deficiency of vitamin A was confirmed in 2 sheep and may have contributed to the reproductive failure.     

Dieldrin poisoning of dogs

Extract

One of the obvious points of life today is the rapid pace of technological change. The veterinary profession worldwide, and in New Zealand, is not immune from such change. Most of the changes that professionals are now learning to live with are changes that they themselves helped to bring about. Over the last twenty years, and especially over the last ten years in New Zealand, the demand for veterinary skills and advice has increased dramatically. Prior to 1937, veterinary science in New Zealand was an infant profession. Since then the first stage was “selling” farmers an awareness of what veterinary science could do for them. The second stage saw the formation of the Veterinary Services Council, in which efforts were made to ensure equitable distribution of veterinarians, especially in rural areas. The third stage was trying to cope with demand. Today, numbers are reaching the stage at which we can afford the luxury of more detailed planning. The aim is to ensure that all facets of the potential of veterinary science for increasing live-stock production, furthering animal welfare, and in quality control of human food-stuffs, are adequately and efficiently exploited. This is the stage at which multi- disciplinary co-operation will have to be seriously considered.     

Within-flock transmission of sheep scab in naive sheep housed with single infested sheep.

The within flock transmission of sheep scab was studied in two trials, which lasted 14 and 12 weeks, respectively. A total of 40 non-infested, scab-naive sheep were divided into six groups of between 6 and 20 individuals. Each group was subsequently housed with a single infested index case, carrying scab lesions of different ages. The groups of sheep in both trials were video recorded continuously and all the sheep were individually examined on a weekly basis. The occurrence of transmission was measured in two ways: first, by the detection of early scab lesions during clinical examination and, second, by an increase in the rubbing of individual sheep as noted from the analysis of the video recordings. These two methods complemented each other in predicting the week on which transmission occurred. Overall, transmission was detected in 34 of the 40 scab-naive sheep. Transmission was shown to occur at about the time when the population of adult mites in lesions on index cases reached their peak numbers. The highest number of mites at this time, however, differed markedly between index sheep. There was no obvious relationship between the incidence of transmission and the time index sheep spent rubbing each day or other index sheep variables, including the age of the lesion or the time since the introduction to the scab free sheep.     

Pasteurellosis in sheep

Pasteurellosis is an important cause of economic loss to the sheep industry. There are two distinct syndromes. The pneumonic form of the disease caused by P haemolytica biotype A occurs as pneumonia in flocks and sporadically in individual sheep. The septicaemic form, caused by P haemolytica biotype T is associated with hyper-acute disease and occurs most commonly in the autumn coinciding with the folding of hoggs on rape, turnips and improved pastures. The factors which predispose sheep to the different forms of the disease are poorly understood but recently it has been possible to reproduce pasteurella pneumonia experimentally.