An outbreak of polio-encephalomalacia in cobalt-deficient sheep

Extract

A great deal of evidence has now accumulated that immunity to helminth infection is acquired following natural exposure. Although this immunity is not absolute, animals that have been exposed to infection and survived are able to tolerate a much heavier intake of infective larvae than animals that have never been exposed.     

A vitamin e response in a young dog

Extract

This subject will be covered in three sections, first, a brief history of how the idea of using trained dogs to help the blind was conceived, then the present-day methods of training guide dogs, and, finally, how the blind person is trained with their guide dog to work together as a team.     

Potentiated trimethoprim for the therapy of calf scours

Abstract

Extract

Trimethoprim became generally available 3 years ago, following its original discovery as a unique antibacterial agent for combating diseases of both man and animals (Hitchings and Bushby, 1961 Hitchings, G. H. and Bushby, S. R. M. 5-Benzyl-2, 4-diaminopyrimidines a new class of systemic anti-bacterial agents. 5th Int. Congr. Biochem. Moscow. pp.165–165.  [Google Scholar]; Pugsley et al., 1969 Pugsley, D. G., Mwanje, L., Pearson, C and Blowers, R. 1969. Use of trimethoprim and sulphamethoxazole in tropical Africa: Typhoid fever; Salmonella typhi carriage and Staphylococcus aureus sepsis. Postgrad, med. J., 45: 95–99. Nov. 1969, Suppl. [Google Scholar]; McGuinness, 1969 McGuinness, B. W. 1969. A combination of trimethoprim and sulphamethoxazole in upper respiratory infection. Postgrad, med. J., 45: 99–101. Nov. 1969, Suppl. [Google Scholar]; McCaig, 1970 McCaig, J. 1970. A clinical trial using trimethoprim-sulphadiazine in dogs and cats. Vet. Rec., 87: 265–265.  [Google Scholar]; Barnett and Bushby, 1970 Barnett, Margaret and Bushby, S. R. M. 1970. Trimethoprim and the sulphonamides. Vet. Rec., 87: 43–51.  [Google Scholar]; Rehm and White, 1970 Rehm, W. F. and White, G. 1970. A field trial with trimethoprim and sulphadoxine in bacterial diseases of cattle and pigs. Vet. Rec., 87: 39–42.  [Google Scholar]; Craig 1972 Craig, G. R. 1972. The place of potentiated trimethoprim in the therapy of diseases of the skin in dogs and cats. J. small Anim. Pract., 13: 65–70.  [Google Scholar]).     

The field detection of “inter-unit milk flow” in pipeline milking equipment

Abstract

Extract

There are many ways in which a milking machine can transmit infection from cow to cow. The immediate transfer of infection by the, teat-cups is obvious and the reduction of the effectiveness of this vector has been shown to reduce the incidence of mastitis (Wilkinson, 1965 Fell, L. R. and Richards, R J. 1970. A farm survey of milking machine performance, milking management and California Mastitis Test results. Aust. J. Dairy Tech., 25: 39–45.  [Google Scholar]). The change from bucket to pipeline milkers has been associated with an increase in the incidence of mastitis arid this has been attributed to the vacuum instability of the latter system. Fell and Richards (1970 Whittlestone, W. G. and Fell, L. R. 1969. Machine milking and mastitis. Proc. N.Z. Soc. Anim. Prod., 29: 22–25.  [Google Scholar]) have studied the relation-ship between machine stability and the level of somatic cells in milk, and Whittlestone and Fell (1969) Whittlestone, W. G., Leonard, R. O. and Brookbanks, E. O. 1970. Breakthrough in mastitis research. N.Z. Jl Agric., 120: 66–67.  [Google Scholar] have suggested that milk line vacuum instability could be associated with flow conditions that could give rise to the movement of potentially infected milk from the pipeline back into the clusters. This potential vector has been overlooked in the past but its presence, would clearly negate the beneficial effects of “back flushing”. A field study was therefore undertaken to estimate the frequency of occurrence of the “inter-unit flow” effect in pipeline systems, and Whittlestone et at. (1970) Wilkinson, F. C. 1965. Bovine mastitis control in Western Australia. Aust. vet. J., 41: 93–97.  [Google Scholar] found a high incidence of milk movement back to the cluster in high pipeline systems though the effect was not found amongst the limited number of low-line installations examined. Two types of “inter-unit flow” were detected: whole liquid movement which appeared as liquid milk in the measuring trap inserted between the cluster and the milk pipe, and “aerosol” which could only be detected by the use of plugs of cotton wool inserted in the test teat-cups. Evidence for the presence of “aerosol” and its role in transmitting infection within the cluster has been collected by A. Tolle (pers. comm.). This establishes the possibility that once infected milk has reached the cluster it can be transferred to the, end of the teat during milking.     

Apparent zinc absorption and zinc status of weanling rats fed moderately zinc‐deficient diets enriched with beef tallow or sunflower oil

The aim of the study was to compare apparent Zn absorption and Zn status of weanling rats fed diets that differed in Zn level, fat level and fat source. Semi‐synthetic diets, which were about isoenergetic and contained 3% soyabean oil, were supplemented with 7 or 100 mg Zn/kg to create a mild Zn deficiency (LZ) or a high Zn supply (HZ) and with 0 (LF), 22% beef tallow (BT) or 22% sunflower oil (SF) according to a 2 × 3 factorial design of treatments. They were fed ad libitum to 6 × 8 rats for 28 days. Energy intake and growth rates were comparable among the HZ groups. Weight gains in the LZ‐LF, LZ‐BT and LZ‐SF groups averaged 5.54, 4.95 and 4.15 g/day, and apparent Zn absorption averaged 79.4, 60.3 and 48.0 μg Zn/day, respectively, whereas faecal Zn excretion was comparable among these groups. Apparent Zn absorption, and plasma and femur Zn concentrations were lower in the high‐fat groups than in the LF group, possibly due to the high cellulose content of the BT and SF diets. Plasma Zn concentrations were higher in the animals fed the BT‐based than in the SF‐based diets, whereas femur and soft tissue Zn concentrations were comparable among these groups. The differences between the LZ‐BT and LZ‐SF groups in growth rate, Zn absorption rate and Zn status were confirmed in a second experiment. The results indicate that moderately Zn‐deficient diets enriched with SF in relation to BT affect Zn metabolism of weanling rats by a yet unknown mechanism.     

Risk factors for Salmonella enterica subsp. enterica infection in senegalese broiler-chicken flocks

Our objective was to assess the association of managerial practices, general hygiene and Salmonella infection in Senegalese broiler flocks. Seventy broilers farms were studied from January 2000 to December 2001 around Dakar. A questionnaire was submitted to the farmers and samples of fresh broiler droppings were taken. A 28.6% of the flocks were infected by Salmonella (mainly Hadar and Brancaster serovars). Salmonella infection of the previous flock (OR=6.82) and of day-old chicks (OR=3.73), frequent poultry farmers’ visits (OR=5.38) and keeping sick birds inside the farm (OR=5.32) increased the risk of Salmonella infection. But, using antibiotics on day-old chicks (OR=0.17) and a detergent for cleaning (OR=0.16) decreased the risk.