Epidemiological and genetical studies in Norwegian pig herds. IV. Breed effects, recurrence of disease, and relationship between disease and some performance traits

Individual health records collected from 1984 to 1986 in 70 swine-herds in the south-eastern part of Norway were analysed by epidemiological methods. The incidence rate for most of the reported diseases was less than 1% per farrowing, and a majority of disease recordings concerned 6 frequently-occurring conditions. The incidence of several diseases was lower in crossbred sows compared to purebred Norwegian landrace sows. The risk of most diseases increased in sows that had been ill previously, and also in litters from sows that had previously had diseased litters. Disease risk in piglets also increased if the sow became ill during the first few days after farrowing. The reduced performance associated with most of the common diseases impacts adversely on economic returns.     

Epidemiological and genetical studies in Norwegian pig herds. II. Overall disease incidence and seasonal variation

The present epidemiological study is based on individual health records from 1984 to 1986 in 70 pig herds in the south-eastern part of Norway. For most of the recorded diseases, the incidence rate was less than 1% per farrowing. The majority of disease recordings concerned 6 frequently-occurring conditions; the MMA-syndrome, mastitis, metritis, neonatal diarhoea, arthritis and scrotal hernia. A seasonal effect on the incidence rate was shown for several diseases. The incidence rate for the MMA-syndrome of about 17.5% seems to be of the highest recorded for this disease in a population study.     

Epidemiological studies of pig diseases: 1. Use of French protocols for risk factor assessment to predict the health status of Australian herds

Objective To determine in Australian pig herds the accuracy of French protocols for risk factor assessment.
Procedure Data on health indicators and risk factors were collected for three syndromes, 'pre-weaning diarrhoea', 'post-weaning diarrhoea' and 'respiratory problems', using the French protocols. The protocols were used on 118 occasions in 32 Western Australian pig herds during 3 years (1988 to 1991).
Results There was a wide variation in pre-weaning performance, for example growth rate was 107 to 273 g/day (< 200 g/day in 33% of herds). Respiratory lesions at weaning were associated with poor pre-weaning performance. Post-weaning (21 days after weaning) growth rate was 114 to 408 g/day (< 250 g/day in 54% of herds). In the grower herds, 91% of herds had pneumonia, and growth rate was 439 to 625 g/day (< 550 g/day in 54% of herds). Pleurisy as well as pneumonia was associated with reduced growth rate. The risk factor most closely associated with respiratory health status was air volume per pig.
Conclusion Risk factors were most accurate at predicting the health status in post-weaning problems. A weaning weight of at least 7.9 kg and weaning age of 30 days optimised weaner performance. Stocking densities and shed designs providing at least 3 m³ air volume and 0.6 m² floor space per pig throughout the growing phase should be considered for an improved respiratory health status. Australian pig sheds often do not provide a satisfactory environment for optimum health. The technique of risk factor assessment as an aid to the maintenance of health in pig herds is applicable in Australia, but further research is necessary to determine the most important Australian risk factors.     

Epidemiological studies of pig diseases: 2. Post-weaning diarrhoea and performance in Western Australian pigs

Objective To determine in Australian pig herds the accuracy of French protocols for risk factor assessment of post-weaning diarrhoea and illthrift.
Procedure French protocols for the collection of data on health indicators and risk factors for post-weaning diarrhoea were conducted on 54 batches of weaner pigs from 28 Western Australian pig herds during three years.
Results Large variations in post-weaning performance were found. About one-third of the batches were growing at <200 g/day during the 3 weeks after weaning, and 54% had growth rates of <250 g/day. Weaning age and weight of at least 30 days and 7.9 kg, respectively, optimised weaner performance. Other risk factors associated with little post-weaning diarrhoea and good weaner performance were high creep feed intakes, relatively little diarrhoea as suckers, and, contrary to expectations, large temperature fluctuations.
Conclusion Overall, the 'predictability' of post-weaning problems as assessed by measurement of risk status, was good. However, the model was less accurate at predicting the performance of a single batch of pigs.