Detection, Prevention and Treatment of Lameness in Sows12 September 2013
An overview of the detection of lameness as well as its prevention and treatment from the Moorepark Research Dissemination Day 'Lameness in Pigs' in July 2013.
Awareness is the first step in addressing the problem of lameness. This has to start with an assessment of reasons for culling sows, and sow replacement and mortality rates. It can also help to note whether sows being culled for reproductive/poor performance are also lame and to start keeping track of the number of sows you see with missing dew claws and external abscesses on their limbs. The farrowing house is a good place for this.
Lameness is much easier to identify in group compared to individually (i.e. stall) housed sows. Provided that gilts/sows are not overstocked, clinical (i.e. severe) lameness is relatively easy to detect in any group system but especially those in which sows are fed simultaneously at specific times of the day. In such systems, sows are usually observed during feeding and animals that do not stand up or that have obvious difficulty moving to the trough at the point of feed delivery are clearly visible.
However, detecting sows in the earlier stages of lameness at which time they are more likely to respond to treatment requires a more specific lameness protocol or locomotion scoring system. Visual locomotion scoring systems take the speed of walking and indications of asymmetry such as step length, head and hindquarter movements, willingness to walk and contact between the feet and the floor into account. They do not give any information as to the cause of lameness.
The best time to do locomotion scoring is on transfer to the farrowing house when sows walk down a dry and level surface. A simple scoring system involves a three-point scale where no lameness = 0, mildly lame = 1 and clearly lame = 2. A mildly lame animal moves freely from one location to another but has an abnormal gait and a clearly lame sow needs encouragement to move.
It is important to remember that lame sows will tend to move better immediately after weaning when their body condition is lighter so this is not a good time to diagnose lameness in the sow herd.
Clearly, there are very good reasons why we should try to prevent lameness in sows. This is complicated by the fact that lameness is a multi-factorial problem with genetic, mechanical, chemical and biological processes involved.
The majority of sows are affected by claw lesions and the risk factors for these are well understood. For example, improvements can be made to the housing environment such as replacing damaged slats and to management by ensuring that gilts have good conformation at selection and mixing them in specialised pens to protect the feet.
Two less well known but essential factors in the prevention of claw lesions is a claw care/trimming programme and supplementing the diet with trace minerals.
Incorporating routine foot inspections into the management programme for breeding sows is the first step in addressing claw lesions. This will enable the producer to become familiar with different types of claw lesions and the anatomy of the foot.
Routine inspections will also mean that the lesions can be monitored such that intervention happens early rather than later to prevent lameness occurring. The best time to do this is when sows are lying down in the farrowing accommodation.
The ultimate goal should be to incorporate corrective claw-trimming into the management programme for breeding sows.
Feed trace minerals
Research in North America shows that sows in a highly prolific herd maintained mineral stores across seven parities. This is also likely to be the case in Europe where feeding regimes are even better matched to requirements.
Nevertheless nutrition is vital in developing the hoof structure and the importance of the trace minerals manganese, zinc and copper in the keratinisation process is well known. Hence, supplementing the diet with additional trace minerals could help to prevent lameness caused by claw lesions.
Research from the University of Minnesota showed that sows fed a diet iso-substituted with complex trace minerals (CTM) had lower total claw lesion scores and a lower proportion of lame sows than those fed inorganic trace minerals. Interestingly sows fed CTM also had more piglets born alive compared to sows fed inorganic trace minerals (11.07 versus 10.44 piglets per litter).
Biotin is another essential component of hoof health. However, if biotin levels are too high, the claws can become overgrown. It is best to check biotin levels in the sow diet with your nutritionist on a regular basis.
Incorporate a lime box in the ESF station
Dutch vets recommend putting a tray filled with dry lime (seek veterinary advice) into the electronic sow feeding (ESF) station for sows to stand in while eating. The lime dries out and disinfects the feet every time the sow enters the station and this could help to prevent lameness.
Treatment of Lame Sows
Prevention is clearly better than cure but where sows become lame, they can recover with appropriate care and treatment. Unfortunately, this is lacking on many units where often the only ‘treatment’ is to cull and too less often, to euthanise, the affected animal.
What is often forgotten is the tremendous investment of money, time and resources that are associated with bringing a replacement female into the herd. It may make better economical sense to try and keep a lame sow with good performance records in the herd by treating her rather than to introduce a young and unproven gilt in her place.
Lame sows and especially those with claw injuries (e.g. dew claw amputation) should be kept in a solid floored, bedded or rubber mat covered recovery pen where they do not have to compete for food and water.
Treat sows with anti-inflammatory drugs and broad-spectrum antibiotics to improve chances of recovery lame sows should also be given analgesics (pain killers); the pain relief they provide encourages sows to get up and walk around and to eat and drink, thereby speeding up their recovery. The surface of exposed, cleaned lesions may be sprayed with antibiotic, e.g. tetracycline or dusted with an antibiotic wound powder.
Culling should not be delayed for sows that do not recover following the treatment outlined above. Sows that have great difficulty walking or that are clearly in a lot of pain should not be sent for slaughter and instead euthanised as soon as possible.
Go to our previous article from the conference, Lameness in Pigs, by clicking here.