Reports from studies and field observations have highlighted the following associations:

• Diarrhoea.
• Dermatitis
• Excessive hair loss
• Extended weaning to mating intervals.
• Haemorrhages on the solar surfaces of the feet.
• Lameness and laminitis.
• Poor litter size
• Reduce growth rates.
• Transverse cracks in hooves.

Clinical signs

Widespread lameness will be a constant feature particularly in sows. Detailed examinations should be carried out on at least 15-20 affected animals and the nature of the changes in the hooves documented. Examinations are best made when sows and gilts are at rest. The hooves will be soft over the walls and the soles will show slight evidence of haemorrhage. Dark transverse cracks will be seen on the hoof walls. If pigs have access to faeces biotin deficiency is unlikely. Assess trauma from poor floor surfaces as a cause.

Diagnosis

This is based on the clinical picture and the fact that the herd or a group of animals will be affected. The onset is usually gradual and this will distinguish the lameness from foot-and-mouth disease. Chronic lesions of swine vesicular disease could be confused with biotin deficiency.

Levels in the ration can be determined but firm recommendations are not available. 100-200µg(mcg)kg would appear adequate.

Treatment

• Where a herd shows widespread lesions add up to 0.5-1mg/kg to the diet. Any response will be slow, up to nine months but prevention gives more positive results.