High winter mortality (28 per cent) in female Jersey calves (80 IU/l in healthy females aged 3-24 weeks, and correlated with serum aspartate transaminase (AST). Copper supplementation of total mixed rations during lactation was excessive (40-60 mg added Cu/kg DM) and reduced to 16-28 mg Cu/kg, but supplementation of milk replacer and creep feed (10 and 35 mg added Cu/kg DM, respectively) continued. The syndrome recurred two years later, and liver Cu remained high in casualties (13.6 ± 2.6) and culled cows (6.38 ± 2.38 mmol/kg DM) prompting withdrawal of all Cu supplements. Mortality remained low (6-9 per cent) thereafter. Three years after removal of all Cu supplements, six culled newborn were examined postmortem; five had normal liver Cu (4.5 ± 1.73), but a sixth had 11.65 mmol/kg DM. In live, healthy calves (1-6 months old) sampled at the same time, GLDH and AST increased with age to levels found five years earlier, indicating possible subclinical hepatopathy. Causative links between Cu supplementation, high calf mortality and hepatopathy are plausible, and reductions in Cu supplementation may prove beneficial in other dairy herds.
Recent outbreaks of bovine babesiosis caused by Babesia bovis in Swaziland had indicated the presence of the vector tick Boophilus microplus in the country although it had never before been directly identified. Engorged female Boophilus ticks were collected from cattle at diptanks in the course of a tick resistance survey and used to map the distribution of the two different species of Boophilus. B. decoloratus was found to be widespread throughout the country. B. microplus was identified for the first time in Swaziland and was found to have a patchy distribution. The implications of these findings are discussed.
A survey of ticks on cattle, camels, sheep, goats and donkeys in four different geographical locations of the Yemen Arab Republic (YAR) was carried out to provide more information on the possible risk of tick-borne diseases to imported exotic cattle included in the YAR's plans for livestock development. The most abundant ticks were Hyalomma spp. particularly on camels. Ticks found on cattle included Hyalomma spp., Amblyomma variegatum, Boophilus annulatus and Rhipicephalus spp. In general with the exception of camels tick burdens on all species of domestic livestock were very low. Two hundred and ninety eight serum samples from miscellaneous adult cattle throughout the country were negative to a test for Anaplasma marginale antibodies. It is speculated that tick burdens in the YAR are too low for significant disease transmission and the implications of the findings are discussed.
In a two-year study of the incidence of subclinical mastitis in two beef suckler herds over 2400 quarter milk samples from 180 cows were examined. Somatic cell counts and total bacterial counts were carried out and infecting organisms were isolated on sheep blood agar. Results of these tests indicated that: (a) in spite of extremely dirty udders, fewer contaminants were found in the suckler cow milk samples than in a group of over 1700 samples from typical dairy herds; (b) 18 per cent of all quarter milk samples were infected; (c) 67 per cent of all infections were due to staphylococci and 20 per cent to streptococci; (d) 56 per cent of staphylococcal infections were associated with cell counts less than 500,000 per ml compared with 39 per cent of other infections; (e) 70 per cent of samples had somatic cell counts less than 500,000 per ml. (f) 20 per cent of samples had somatic cell counts over 1 million per ml; (g) only 36 per cent of samples with cell counts over 1 million per ml were associated with udder infections; (h) high cell counts and udder infections were more frequent in early than in mid-lactation. Due to a shortage of animals in the late lactation little evidence was available to support the contention that cell counts rise and the numbers of infected quarters increase towards the end of lactation.
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