Disease Warning

At this time of the year the main threat to growing lambs is the strongyl parasite Nematodirus battus. Most worm eggs hatch and develop to the first of several larval stages as soon as they are passed onto pastures and will have several cycles during the year. Nematodirus is different as all of the eggs passed last year wait on the pasture and are all stimulated to develop to infect young lambs as soon as they start to take in grass in any quantity. This effect tends to be exaggerated after a cold winter. Already there have been reports from the Veterinary Laboratories Agency of this infection from north Staffordshire. The chances are there is more nematodirus about this year but it is difficult to find out just how many farms are affected.

Preventing Dehydration

Remember this is a disease that  lambs have to deal with each year. If possible used different fields for the young lambs, or make use of reseeded pastures that will be free of the disease. It always surprises me that as this seems to be a sophisticated parasite it has not been able to become resistant to the original three classes of anthelminctics. All of the wormers will work against nematodirus, as long as you give them an adequate dose as it can be difficult to estimate the weight of growing lambs. Losses can be severe with this parasite on severely contaminated fields it may be necessary to repeat the worm dose every two and a half weeks so you do need to be vigilant. Young lambs can become severely dehydrated when they have internal parasites, at first their kidneys are poorly adapted to produce concentrated urine and many die from nephrosis, sometimes some days after anthelminctic treatments when all of the worms have gone.

Prolapsing Ewes

We are coming towards the end of the lambing season and the thing that has been most evident this year is that in most flocks there have been few if any ewes with a vaginal prolapse. Vaginal prolapses tend to occur in ewes that are carrying more than one lamb, ewes of any age can be affected. They can occur any time in the last four weeks of pregnancy, most occur close to lambing. Over the years there have been several theories as to why they occur, bulky feed, grazing on steep slopes when heavily pregnant, lack of exercise and being overweight have all been put forward as a cause. Affected ewes will always prolapse again at the next lambing so most are culled.

National Situation

Working in just a small area of the country sometimes we can get a distorted view of what is happening nationally. I am the Vet in Shropshire who reports cases to the National Animal Information Service which publishes disease trends every month in a magazine. I have asked the other forty vets throughout the country who contribute to NADIS if they have seen many vaginal prolapses this year. Of the ones who replied most have not had to deal with any cases at all and two had seem cases, but only on one particular farm. I know that this is not a scientific survey. We have had cold winters before, but it still does not explain the pleasant news that there will be few ewes that will have to be culled in the autumn because they had a vaginal prolapse this year.

Prolapsing Cow

As if to even things out it is several years since I have treated a cow with a vaginal prolapse. Hereford cows are particularly prone to this condition, it happens only occasionally to other breeds and sadly there are few Herefords about now. Yesterday I went to see a cross bred cow who had prolapsed her vagina one week after calving. If the sheep are not having problems the cows will instead.

Cows at Grass

This has been a late spring and it has taken ages for the grass to get growing. After the cold spell, then the dry conditions the grass will grow quickly now, particularly if you have used much nitrogenous fertiliser on the ground. When grass grows quickly it does not get the chance to take up much magnesium from the soil. Cows need a small daily dose of magnesium as they cannot store the mineral and will develop severe fits if their intake is inadequate. Dairy cows should be getting sufficient supplies as the mineral levels are boosted in the dairy ration at this time of the year. Suckler cows are more vulnerable especially if they are feeding calves. It is a good idea to let them have access to mineral buckets with extra magnesium for the next two months to ensure they maintain adequate levels in their blood stream.

Horses at Grass

Horses also suffer from grass related problems when the grass grows. It is proteins in the young grass that triggers a reaction to cause inflammation in their feet. Laminitis is a painful condition, but it does respond to treatment in the early stages. Sometimes as well as anti inflammatory drugs we administer other treatments to lower the blood pressure and stop permanent changes developing in the feet. Every time a horse has laminitis the pedal bone will rotate slightly and you can end up with permanent distortion of the hooves. There is a high risk of laminitis at the moment so keep horses on bare pastures and feed hay to satisfy their appetite.

Confusing Letters

Most of the letters that DEFRA send out are generated by computer. Recently it has changed the format of the ones relating to TB and blood testing and has made them difficult to understand. Often if they are asking for extra tests to be carried out at a different time to your normal testing pattern it will be a tracing test for individual animals or a small group of animals and not involve the whole herd. We are slowly getting used to the new forms and can usually translate them for you. If not we will be pleased to ring the Animal Health Office  and find out what they are concerned about.

Could History Repeat Itself ?

Foot and Mouth Disease is endemic in South East Asia and parts of the People’s Republic of China. It is known that several different serotypes are active in the region, some of them might cause only mild symptoms. In 1999 the disease was seen to be spreading in China and the Republic of Korea before it was detected in Japan and Hong Kong. This was the disease that eventually found its way to South Africa and to us in Europe in 2001. Animal diseases tend to come in cycles. It is known that FMD of unknown serotype has occurred recently in several regions of China and Korea. On April 20^th FMD sero type O was confirmed in Japan for the first time since 2000. The Institute of Animal Health is urgently calling for coordination and sharing of information between all of the countries affected as the way this virus spreads around the world is still poorly understood and we need to do more to ensure it stays where it is.

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