Features
Tackling Sheep Lameness
by Dr Agnes Winter
Lameness in sheep flocks is one of the most common and persistent disease problems. As well as being a major welfare concern, persistent lameness in a significant proportion of the flock has direct economic consequences. These result from failure to gain weight (or actual weight loss), metabolic diseases in pregnant ewes, reduced birthweight of lambs and poor colostrum production by ewes leading to increased lamb mortality, and reduced growth weight.
It is unrealistic to expect that lame sheep can ever entirely be eliminated, for there are many types of lameness, with causes involving infectious agents, environmental and mechanical factors, variations in horn quality and other unknown factors. However it is possible to reduce the most common types – foot rot, scald and contagious ovine digital dermatitis (CODD) – and to keep other types under control by regular inspection and trimming where necessary.
The Moredun Foundation has produced an eight page newssheet which details the major causes of sheep lameness and their control and prevention. Details of how you can obtain a copy of this free newssheet are given at the bottom of the page. This article will therefore attempt to highlight what farmers can do in an effort to keep their sheep’s feet healthy, and make general suggestions to help aid the control of lameness in a flock.
Routine Foot Care
Routine foot care and dealing with flock problems are more likely to be successfully performed if good handling facilities and correct equipment are available. Several systems which incorporate devices to turn the sheep over are available, so that work can be carried out in the normal standing position reducing back strain; these are well worth investigating particularly for larger flocks. An adequate footbath should be available, preferably one large enough to stand a number of sheep in rather than the narrow 'run through' type. A special mat can be placed in the bath to reduce the volume of chemical necessary to ensure proper coverage of all feet. A dry area where the sheep can stand for a while after passing through the chemical will ensure that efforts are not wasted by turning sheep out immediately into wet grass.
Foot health, including shape, horn quality and susceptibility to infections such as footrot may be at least partially be inherited; thus more attention could be paid to selecting breeding stock with sound feet.
Foot Paring
This should be carried out with care, particularly avoiding over-paring which causes bleeding. This is unnecessarily painful and may cause permanent damage to the foot. Where loose horn is present, it should be carefully pared back, but if an animal is badly affected with foot rot, treatment with injectable antibiotic (after discussion with your vet) may be the most useful first line of attack. Paring can then be done a few days later when healing has commenced. Try and receive suitable training before attempting foot paring for the first time.
When paring - a good quality pair of precision foot shears and a sharp knife are required. These should be disinfected after paring infected feet, and at the end of each session. They should be cleaned and oiled, not left to rust!
Precautions on Introducing New Sheep into a Flock
Many important disease can be introduced to flocks by failing to take simple biosecurity procedures. Both Footrot and CODD can easily be inadvertently introduced into a flock with the purchase of new sheep (don't forget the rams as well as the ewes). These should never be added to the resident flock without a period of quarantine, during which time the feet should be examined and appropriate treatment carried out where necessary. Even if all appears well it is good practice to footbath as a precaution.
Diagnosiing Lameness
Although scald, footrot and CODD are the most common types of lameness, there are many other causes, including toe and foot abscesses, shelly hoof and granulomas. It is important to make sure that the diagnosis is correct before deciding upon treatment. This may sound simple, but confusion can arise and misdiagnosis can be the explanation if well recognized treatments for footrot do not seem to have the desired effect.
Treating Lameness
Lame animals should be dealt with as soon as practically possible, although the difficulty in dealing with the odd lame sheep in a large flock is acknowledged. Ewes which become lame during late pregnancy should be treated rather than being left until after lambing. Gentle handling should ensure that no extra stress is involved; if necessary the affected foot can be lifted and examined with the sheep standing restrained against a wall to save turning the animal over.
All infectious causes of lameness, (scald, footrot and CODD) must be dealt with on a flock basis. With footrot and CODD particularly, picking out and treating the obviously lame animals will never result in satisfactory lameness control in the whole flock.
In conclusion - there are many reasons why sheep become lame. These may involve the foot, joints, bones, nerves or muscles of the legs, or highly infectious diseases such as foot and mouth disease. If lame sheep are not responding to treatment or if many are lame, veterinary help should be sought.
Footnote: this article first appeared in the Sheep Farmer magazine and is reproduced with their permission