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SUMMARY Disease levels in calves were examined using a system which recorded the signs observed from treatment and its cost. The result in cost per sick calf and cost per calf place gave some indication of disease severity i. e. the number and degree of signs observed and their duration. The trials were used to indicate the use of the recording system. The size of the study was not sufficient for a positive assessment of the value of the different feeding and management systems. In trial 2 diarrhoea was much more common (40%) using a machine (M2) which dispensed reconstituted milk powder as fast as it was drunk than with once-a-day (OD) bucket feeding (8%) and calves on a machine (M1) which mixed feed on a two- minute cycle (13%). A high level of respiratory disease was seen in OD calves of trial 3, and this was the main difference seen in trial 4:12 and 13% in once-a-day fed calves (OD and ODC) and 50% in machine-fed (M2) calves. Combining the information from these three trials with that from a previous study showed that OD and twice-a-day bucket feeding produced less diarrhoea than machine feeding (M1, M2). More respiratory disease occurred between entry and five weeks in animals used in a controlled environment house than in a naturally-ventilated monopitch building. More disease occurred in each trial pre-weaning than post weaning (weaning at five weeks). Overall mortality was 1·1 % and the most common diseases experienced up to 12 weeks were respiratory disease (31·2%), diarrhoea (20·1%), eye infections (11·2%) and navel and joint problems (2·2%).

SUMMARY The degree of calf disease in three groups of calves was studied under different feedings systems. The animals were bucket-fed once (OD) or twice (TD) a day, or ad-libitum machine fed (M1). Various methods of examining the data were considered and it was suggested that the recording system should include some element of disease ‘severity’, i. e. the degree to which signs were present and the duration of the illness. A simple recording system to produce results for on-farm comparison was suggested based on treatments and their costs. This was affected by how long therapy was continued and, in general, more expensive and larger numbers of different drugs tended to be used at the same time in animals which were clinically considered to be more seriously ill. Cost was calculated on the basis of cost per sick calf and cost per calf place. Comparison between the use of OD and TD feeding revealed little difference in level of disease; in the M1-fed animals there was more diarrhoea and respiratory disease. Slightly more disease occurred pre-weaning than post weaning (weaning at five weeks). There was no mortality during the trial.