The ewe in the above picture has sore feet. Her kneeling stance is typical of either foot scald or foot rot. The ewe to the right of her, who is lying down, also has sore feet.
All foot problems in sheep should be investigated and treated as soon as possible. There are lots of different reasons for sore feet and foot rot isn’t always necessarily one of them.
But lameness in more than one sheep is a red flag. Two or more limping sheep is cause for an immediate evaluation of the entire flock. Don’t ignore it or waste any time investigating the cause.
Foot rot is an infectious and very contagious disease in sheep. Foot rot is caused by the interaction of two different anaerobic bacteria – Dichelobacter nodosus and Fusobacterium necrophorum.
Foot scald while not as serious as foot rot, can be just as painful and if not treated promptly can lead to foot rot. Foot scald is caused by the opportunistic interaction of Fusobacterium necrophorum and another bacteria Corynebacterium pyogenes during wet weather or damp conditions.
For the sake of better understanding, we’ll call the different bacteria, Bacteria #1, #2 & #3 for short, and make the words hoof and foot, toe and cleat interchangeable.
Fusobacterium necrophorum (#1) is a normal bacteria from the digestive tract of sheep and other ruminants.It can live up to 10 months in the soil. In wet weather Fusobacterium necrophorum (#1) has the opportunity to interact with Corynebacterium (#3) to produce foot scald.
Foot scald is an infection of the skin between the toes of the hoof and is the precursor to foot rot. Mud is the perfect vector for the above bacteria, and is easily packed in and squished up between the toes of the hoof when sheep are on wet ground. Keeping sheep on wet ground is a perfect recipe for foot scald even in sheep that are not genetically susceptible -more about genetic susceptibility later.
Once the hoof is compromised with foot scald, Dichelobacter nodosus (#2) can begin to invade the foot. Dichelobacter nodosus (#2) produces an enzyme that destroys the connective tissue between the horn (the hard part) and tissue of the foot and allows the migration of bacteria under the horn. Once the bacteria are under the horn of the hoof it reproduces rapidly in the anaerobic environment. The bacteria are protected from air under of the hard covering (horn) of the hoof.
This is one of the reasons foot rot can be difficult to treat. It’s hard to actually get to the bacteria.
In my experience the best way to treat foot rot or foot scald is with isolation, a foot bath, trimming and Liquamycin -LA 200. It’s an injectable oxytetracycline solution.
Here’s what works for me:
First isolate the sheep into 2 groups -the limpers and the non-limpers. The two groups will be treated differently. Set up a bath for the non-limpers and make them walk through it.
Hold the sheep in the foot bath by a gate or hurdle if possible for a couple of minutes or so. After the foot bath move the sheep immediately onto fresh clean, dry ground.
Watch the sheep very carefully over the next week to make sure that none of them are limping even slightly. If you find another limper, move them immediately to the other group.
There are all kinds of products for foot baths, but a mild Clorox solution is what I use and recommend. Chlorine bleach is cheap; I think works best and it is readily available.
The foot bath mix is 10 parts water to 1 part Clorox. If you don’t have a special trough for a foot bath or only have a few sheep, a plastic bucket with the bleach solution will work fine as individual or single hoof foot bath. Just stand each hoof in the Clorox solution for about a minute.
Don’t forget to wash your footwear too. Boots and shoes that have walked over contaminated ground will spread foot rot. That’s why it is so important to change your shoes before you go into the barn or pasture after you have returned from the sale barn, auction or from visiting another farm.
Now back to the limpers. Confine all limpers onto a heavy bedding of fresh clean straw and proceed with the treatments below depending on whether or not you have foot scald or foot rot.
Examine and trim all 4 hooves – not just the lame one. The hoof with foot scald usually looks moist between the cleats (toes) and is slightly reddened. Clean out any packed in debris and wash between the toes. Next apply between the toes, a light coating of LA 200 with a syringe that has had the needle removed.
To fill the syringe, draw the LA 200 up into the syringe with the needle attached and then remove the needle. LA 200 is runny and can be hard to control where it goes. Drip and drizzle the LA 200 over the entire interior wall and skin between the toes. Any place that looks moist or inflamed make sure that it gets well covered. After treatment, keep the sheep on clean dry straw for a week. A difference in limping will probably be noticed within 24 – 36 hours. LA 200 applied directly to the scald is an extremely effective treatment for foot scald.
The hoof with foot rot will have a foul smell. You can’t miss it. The hoof will sometimes look crumbly, soft or will peel away. Sometimes the bulb at the back of the heel will be over soft, white or spongy. Sometimes the hoof will be bloody.
Clean and well trim all 4 hooves. Try and trim the hoof so that a line of white or faint light pink can be seen around the fresh trimmed rim of the hoof. Try not to over trim or the hoof will bleed. Using the same treatment for foot scald, apply LA 200 directly to the foot with a syringe that has had the needle removed.
Next with a clean needle attached to the syringe, give a 10cc IM injection of LA 200, divided into two 5cc doses, into two different injection sites. Be aware that LA 200 is an extremely painful injection -it really burns. Expect bucking, rearing up and general carrying on from your sheep when you give it.
Keep treated foot rot sheep on dry clean bedding for at least 7 -10 days before they are turned out again. Do not let the sheep return to infected pastures or paddocks. Dichelobacter nodosus (#2) can live on pasture for up to 14 – 22 days.
Once the disease mechanisms involved are understood, both foot rot and foot scald can be prevented and eradicated with careful flock management.
Any breed sheep can end up lame given the right conditions, mismanagement and bacteria. As a rule sheep with black hooves are less prone to foot rot. Fine wool breeds or sheep with white, pink or striped hooves are much more prone to foot problems and don’t do well on wet ground. Polypay, Merino, Dorset, Finn, Rambouillet and Columbia breeds of sheep have given me problems in the past. I think if my farm was drier they would do better for me.
Some individual sheep seem to have a genetic susceptibility to foot rot. I have often wondered if it is not some type of innate immune system problem. I just don’t know. But what I do know is that sheep that show a susceptibility to foot rot or foot scald and don’t respond well to treatment should be culled from the flock and their offspring not kept for breeding.