NADIS disease forecast – cattle (May)
| The NADIS disease forecast is based on detailed Met Office data, and regional veterinary reports from 37 farm animal practices and the large animal units at six UK veterinary colleges. NADIS data can highlight potential livestock disease and parasite incidences before they peak, providing a valuable early warning for the month ahead. |
May 2004
Richard Laven BVetMed MRCVS
NADIS Cattle Disease Forecast
Adult cattle
Fertility
The spring calving period is well underway and NADIS vets are seeing more calving problems than normal (50% above average).
The number of caesareans is also very high with oversized calves being the most commonly reported reason. This increase in problems is likely to continue into May and June, so get together with your vet to work out a plan to minimise the problems with difficult calvings.
Even with low milk prices, it makes economic sense to get vet assistance early in bad calvings rather than waiting until all including the cow are exhausted. This usually leads to, in addition to a dead calf, a cow that never produces properly.
This year has seen a higher level of abortions than average; the numbers are likely to increase as the spring calving season continues. The causes of these abortions have been very variable, but one of the commonest has been a bacteria called Bacillus licheniformis.
This bacteria is associated with mouldy feed, particularly silage. The rate of diagnosis of this condition is highest when samples of placenta are included with the aborted calf. If there are no membranes ask your vet to come and collect some samples from the cow.
Leptospirosis (lepto) is another important cause of abortion and infertility. This bacteria is present on many farms and infection causes a significant economic loss.
Many of the risk factors for lepto, such as natural water sources and contact with sheep (or areas where sheep are grazed), are encountered only after turnout. It is thus important to ensure that your lepto vaccination is up to date as soon as possible after turnout.
Lameness
Alongside the rise in calving problems and caesareans, there has also been a significant rise in downer cows and post calving paralysis. These problems accounted for over 13% of all lameness cases seen by NADIS vets.
Although April was dry, the start of May has been cold and wet in many parts of the country. This is likely to make lameness problems worse. So far this year lameness levels have been higher than average, although the three most important diseases (digital dermatitis, white line disease and solar ulcer) have been seen less than average.
However the number of cases of digital dermatitis increased significantly in April, so if the wet weather continues we could see significant problems in May, particularly in cows that are being buffer-fed indoors.
Check the areas around gateways, feed and water troughs, if possible make them freely draining and prevent the build-up of mud or puddles of water.
On those farms where cows have to travel significant distances for grazing, poor quality cow tracks are the major cause of lameness in the summer and early autumn need for cow tracks. Time spent now maintaining cow tracks will save significant time and money treating lame cows later in the year.
Mastitis
Mastitis cases increased by almost 15% last month. Environmental bacteria, particularly Strep. uberis, were the most commonly reported cause. This sort of mastitis begins either around calving or during the dry period, so if the dry period management hasn’t been high quality, environmental mastitis can occur in cows that have calved outside in clean dry conditions.
In many mastitis investigations, particularly if only a small number of samples are submitted, no cause of the mastitis is identified. The most common reason for this is contaminated samples.
Clean sampling is essential, dirty samples significantly reduce the chance of identifying the bacteria causing the mastitis. In a contaminated sample, it is impossible to tell whether an E. coli has come from the milk or the faeces. Some contamination is unavoidable, so to increase your chances of a diagnosis submit more samples.
Metabolic disease
The number of metabolic diseases reported by NADIS vets increased by over 100% in April. Grass staggers were 50% up on average and milk fevers by 60%, but the most dramatic rise was seen in displaced abomasums (DA’s), which were over 200% up on last year, and were seen more often than all other metabolic problems put together.
This is a startling increase and indicates that something has changed in the UK dairy industry so that a disease, which was an occasional problem on many farms, is now starting to become a major source of economic loss.
The cause of the rise is unclear but in some herds they are even occurring in late lactation, rather than normal early production period. The dairy industry needs to start investigating this rise now so that we don’t end up with continually increasing rises in DA’s (and increasing losses).
The most commonly seen initial sign of a DA is failure to meet expected yield. Look out for such cows as early treatment of a DA can restore the cow to virtually normal, and result in only a very small reduction in lactation yield.
The number of cases of hypomagnesaemia (grass staggers) began their seasonal increase last month.
Prevention is the aim for hypomagnesaemia, supplementation is essential (ask your vet for advice as to what is best in your situation), but also remember that fertiliser usage on grass, in particular the use of potash, depresses magnesium uptake and utilisation by both plant and animal. Don’t use these pastures in the early grazing season.
Other diseases
Problems with fluke have persisted this year. Action needs to be taken soon to try and reduce the number of infected snails on the pasture.
In infected areas all susceptible livestock should be given a dose of an adult flukicide to stop eggs being laid onto the pasture. Now is also a good time to plan your control strategy for the coming winter.
Growing cattle
Eye diseases were a common problem seen by NADIS vets last month. Silage eye remained the most common problem as a result of the continued feeding of poor quality silage, but outbreaks of New Forest eye were also seen. This disease is likely to get more common, particularly if the spring is warm.
Lameness was still high in this age group last month. Problems were caused by many different factors, but foul-in-the-foot was common and this is likely to continue if the late spring is wet and warm.
Lameness in youngstock is as important as that in adults, preventing lameness, and treating it quickly and effectively, in growing cattle can significantly reduce the development of lameness in adult cattle.
Metabolic problems have also been common in this age group with ketosis and displaced abomasums being more common than usual.
As in the dry cow, for the late pregnant heifer the emphasis has to be on getting ready for the massive changes that occur around calving.
Wormer resistance in sheep gutworms has been much in the news. However, cattle worms have been neglected, probably because, except for fluke, wormer resistance isn’t a significant problem.
But it inevitably will be, so plan your grazing / worming strategy to minimise the development of resistance
Calves
The number of calf problems seen by NADIS vets increased in April. Scours was the most commonly reported problem with coccidiosis being more common than usual.
These scour problems are likely to be the result of the build-up of infection over the winter, with calves affected at or soon after birth.
Control needs to be aimed at the calving areas as wells as the areas the calves are housed. If possible calve the cows in a different area. If this not possible, cleaning, disinfection and rebedding is essential.
For coccidiosis it is important to check that the disinfectant is effective against the coccidial oocyst which is very resistant to disinfectants.
While every effort is made to ensure that the content of this forecast is accurate at the time of publication, NADIS cannot accept responsibility for errors or omissions. All information is general and will need to be adapted in the light of individual farm circumstances in consultation with your veterinary surgeon
Copyright © NADIS 2002
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