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Title: Disease in sheep flocks and its prevention
Author: Sime, Hazel A.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1988
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To establish the prevalence of diseases in sheep flocks in North-east Scotland responsive to the application of preventative measures which may be incorporated in flock management plans. A survey of a sample of commercial sheep flocks was carried out to ascertain management and marketing practices. A critical assessment was made of the 'Flock Diary' 'Detailed' and 'Daily' Lambing Diaries produced by the Meat and Livestock Commission and their use. A mastitis survey showed an overall incidence for acute severe and chronic mild mastitis of 1.5% and 4.2% respectively. Orf was a particularly important predisposing factor. Antibiotic therapy at weaning resulted in a reduction in the number of ewes culled for chronic mastitis but growth rate of subsequent lambs was unaffected. A survey of trace element status of flocks showed that deficiencies were not always recognised especially selenium. On-farm trials were set up to examine the implications of copper, cobalt and selenium deficiencies and possible methods of control and monitoring. Trials of these procedures in commercial flocks included measurements of blood composition, ewe body condition score, lambing data, lamb birth weight and early growth rate. In lamb based trials blood composition and growth rate were the only parameters measured. Trials over a 4 week period were carried out to test the effectiveness of selenium-cobalt supplemented anthelminthics. The cobalt content of such products was inadequate to maintain pre-existing cobalt/vitamin B12 status in weaned lambs, however, selenium content induced a sustained rise in selenium/GSH-Px. Treatment with oxytetracycline reduced the number of chlamydial abortions in vaccinated gimmers while selenium treatment reduced the stillbirth rate. There was a suggestion that a compliment fixation titre of 1/16 was indicative of infection. Factors limiting implementation of preventive measures in flocks were the absence of performance and health records, accurate diagnosis, effective communication between farmers and external agencies and sources of integrated advice.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available