NADIS Veterinary Report and Forecast

December 2009

 

So far so good with bluetongue. A better vaccination strategy in Europe has reduced the risk of diseases spreading to the UK ; demonstrating again that our best defence against exotic diseases such as bluetongue and FMD is to control them better elsewhere.

Unfortunately the absence of disease may have bred complacency, with very few reports to Defra of potential bluetongue cases. To eradicate the disease we need to be vigilant, so be on the look-out for potential problems and get Defra involved if there’s any suspicion.

ADULT CATTLE

CATTLE

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Metabolic Disease

Overall metabolic disease cases declined in November, but at a lower rate than last year. Except for January and February reporting of metabolic disease has been around 50% of the long term average and, with much variation around the mean, at 80% of last year’s figures.

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Figure 1:  Comparison of reports of metabolic disease with those for 1997-2007 and 2008.

The number of reports of hypomagnesaemia was higher in November than October. This would seem surprising, as on average November reports are 70% of October’s, but this is the fourth year of the 13 that NADIS has been active when cases have increased in November.  The peak in November meant that autumn reports of hypomagnesaemia were 75% higher than in spring; so for six out of the 13 years, autumn figures for hypomagnesaemia have been higher.


 

Fertility

There was a moderate decline in the number of fertility reports in November as although the number of non-detected heats remained static, there were falls in all of the other main problems. The most marked change was in anoestrus reports which fell almost 50%, in complete contrast to last year when there was a marked rise in cases.

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Figure 2: Number of monthly reports of anoestrus in 2009 and 2008 compared to average of 1997 to 2007.

Endometritis reports decreased in November, to below the long term average. At the beginning of the year, endometritis reports were at an all-time peak, but since April, figures have only been 80% of last year. Nevertheless, 2009 is still second in the list of total cases to November – suggestions as to why endometritis cases have become more common welcome.

Lameness

Overall lameness reports were also declined moderately in November. Of the main four diseases only white line disease showed an increase, although levels still remained well below last year. So far this year, except for January, reports of white line disease have remained below the levels reported last year. The high January figure is likely to be due to hold-overs from the previous December which had a precipitous decline in cases.

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Figure 3: Number of monthly reports of white-line disease in 2009 and 2008 compared to average of 1997 to 2007.

 

CALVES

In contrast to last year when there was a decrease in cases in Novemeber, last month cases followed the usual seasonal trend with the largest number of reported outbreaks since 2004. Still well below the numbers seen in the late 1990s though

 

SHEEP

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Beef And Sheep Census Report

Liver fluke is commonly being reported by NADIS vets and, in fluke areas, it remains one of the main health constraints on the profitability of sheep farming. Indeed there is considerable that the area affected by fluke is increasing with areas where the parasite has been rare now frequently seeing outbreaks.

NADIS is now collecting targeted data from sheep and beef farms, and we now have results from 814 farms (over 450 000 ewes). Fifty-four % of all flocks have experienced liver fluke problems although only 3.2% have reported problems with acute fluke. The proportion routinely treating for fluke, at 70%, is considerably higher than the proportion reporting disease.

Data from 712 beef suckler farms shows that routine treatment for fluke is far less common (40 vs. 68%), clearly highlighting the relative importance of fluke to sheep rather than beef farms. This difference means that cattle are far more likely to be treated after a faecal egg count or after showing clinical signs than sheep. Fluke treatment in beef cattle has recently been given a boost by the introduction of a pour-on flukicide, perhaps this may mean that earlier treatment becomes more feasible. This is important as early treatment is the key to minimising the losses from fluke

 

PIGS

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NADIS BPEX Commentary – November 2009

Respiratory disease, presenting as coughing, laboured breathing and slowed growth is one of the most important and prevalent syndromes seen and reported by NADIS surveillance Veterinary Surgeons.  Whilst the causes are often complex, the trends in disease levels may reflect both environmental conditions and active control measures for specific components.  Over the last 18 months, PCV2 vaccines have become widely used in pig farms and it is likely to be no co-incidence that the decline in recorded prevalence in 2009 has occurred.  However, over the last two years disease levels, especially in growers has risen dramatically in the autumn and winter.  We are now entering that period, but if the same picture is repeated it is at least starting from a lower base (graph 1).

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Furthermore, in 2007, a jump of disease was also seen in the summer, especially in straw yard systems.  This pattern, however, has not now been seen in the last two years, possibly reflecting less extreme heat.

The abattoir derived SEP scores (graph 2) arising from BPHS, in NADIS recorded farms, has broadly reflected the clinical picture with a year on year decline and an autumnal rise in 2008 (though not in 2007).

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Regional variation over the last year is very marked, with disease levels in the two major pig-keeping regions quite different (graph 3).  East Anglia – with its preponderance of straw-based systems has reported more than double the level of disease seen in North East England – where slatted systems with controlled ventilation predominate.

The less pig-dense areas see even lower levels of disease.

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The picture, in terms of management systems, tends to reflect the regional picture.  (Graph 4.)  Disease in straw based systems is nearly double that of slatted systems – suggesting perhaps that active ventilation management is beneficial as part of disease control.  Perhaps, a little surprisingly, outdoor derived pigs show more disease than indoor produced piglets, but this may coincide with both the regional bias and the tendency for outdoor derived pigs to be kept on straw.

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As might be expected, continually occupied systems have higher levels of disease than batch systems, although the difference is small (1% v 1.2% prevalence).  It is, therefore, somewhat surprising to see much higher levels of respiratory disease in nursery/finisher sites, which tend to lend themselves to batch production.  (Graph 5.)

 

 

 

 

 

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Graph 6 reveals no particular pattern with respect to herd size of the feeding herd.

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The pig industry now has at its disposal a range of vaccines used to control growing pig respiratory disease.  (Enzootic pneumonia, PRRS, PCV2, Glässers Disease etc.)  Over time, the “population effect” of these vaccines would be expected to continue to improve the disease picture – all that is needed is the availability of effective, safe and economical combination vaccines.

 

 

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  Mark White BVSc DPM MRCVS

Copyright © NADIS 2009       www.nadis.org.uk

 

BPEX is a division of the Agriculture and Horticulture Development Board (AHDB). BPEX seek to ensure that the information contained within this document is accurate at the time of printing. However, subject to the operation of law BPEX accepts no liability for loss, damage or injury howsoever caused or suffered directly or indirectly in relation to information and opinions contained in or omitted from this document.