Articles and literature introducing the basics of sheep husbandry are often associated with a picture of a sheep having its feet trimmed. Why is the association between the sheep and trimming so strong?
The clinical signs of footrot are caused by the Dichelobacter bacteria. The bacteria themselves are covered with microscopic hair like structures which enable them to move through the hoof and cause the damage associated with the disease. The bacteria is also known as anaerobic meaning it does not require air to grow and survive. This is the fundamental reason why trimming has been used in the past to deal with footrot – the assumption is that exposing the diseased tissue to the air will kill the bacteria and cure the disease.
Before the availability of antibiotics this might have been the best solution, but over the last 20+ years we have had access to treatment options, so the trimming of feet is now unnecessary. On-farm practical research has even shown that trimming the feet of sheep affected with footrot makes it worse. Most of the bacteria in a footrot affected animal is deep within the tissue so removing the surrounding hoof wall does nothing to combat the disease. Worse than this is the subsequent damage that trimming can cause particularly to the inflamed tissue.
So, we know that antibiotics are the most appropriate treatment for footrot in sheep and vet advice should be sought on the correct product to use. Longer-term strategies are also important to avoid the over-reliance on antibiotics. Vaccination can help in reducing the disease and other tools such as isolation or the culling of repeat offenders is also important. The reason culling works is two-fold. Animals which are repeatedly lame are acting as a constant source of infection to other animals in the flock. We also know that susceptibility to footrot is in part under genetic control, so it is possible to breed for improved resistance to footrot.
Over the last few years the requirements of commercial ram buyers have changed and animals are being sought which have been bred for improved production traits and reduced disease problems. Improved resistance to footrot is one of these areas. The heritability of resistance is typically between 0.2 and 0.3. This means that on average 25% of the differences between animals will be down to inherited genetics.
Genetic improvements can, therefore, be made, but this is an ongoing process and good management techniques will also be required to combat the disease. Trimming, however, is not one of them. This is good news – the difficult and time-consuming job can now be avoided knowing that avoiding trimming feet will actually be helping reduce the lameness level for the flock. How can this be a bad thing?
Royal Vet College student Zara Heaven is investigating recognition of foot disease in sheep and the preferred treatment protocols used by UK farmers. She would be grateful if Texel breeders and other sheep keepers could complete her online questionnaire to facilitate this research.
The responses will be used as part of Zara's final year project for her degree in vet medicine. Zara has a strong interest in sheep, particularly in lameness and welfare, and hopes to develop these interests upon qualification. The survey can be found here: https://www.surveymonkey.com/s/DRQFDTV