NADIS Veterinary Report and Forecast – November 2006

UK - NADIS is a network of 40 veterinary practices and 6 veterinary colleges monitoring diseases of cattle, sheep and pigs in the UK. NADIS data can highlight potential livestock disease and parasite incidences before they peak, providing a valuable early warning for the month ahead.
calendar icon 20 November 2006
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Adults

Fertility
The number of fertility reports fell in October as summer came to its end. The number of reports of non-detected oestrous was below average for the first time since May. This fall was consistent with reports from NADIS vets that fertility was retuning to normal levels, although several reported that some herds still had major fertility problems. Andrew Biggs in Devon reported that one of his herds had started using the Genus Reproductive Management and had seen significant improvements. This service provides a technician who regularly visits the herd to take responsibility for the heat detection and insemination. Clearly on bigger herds this is likely to be of significant benefit if labour is tight, as it frees staff to concentrate on other management tasks. The claims made by Genus certainly suggest that there are significant economic benefits to be made, it will be interesting to see if heat detectors become as common as foot trimmers currently are. Nine years ago when NADIS started foot trimmers were not a common sight, yet most large farms use a foot trimmer regularly. It is highly likely that the trend for employing outside staff to undertake routine work on farm will accelerate, and there will definitely be money in it for the firm which spots the next opportunity.

The two fertility problems to show rises in October were ovarian cysts and anoestrus. The rise in the former was expected as there is normally a 30% in October and the cyst figures have been at or around average since July. In contrast the increase in anoestrus cases of almost 100% meant that October 2006 had the highest number of anoestrus reports of any October since NADIS began. As cases usually rise by over 130% between October and December it would pay to act now to try and reduce anoestrus problems now, otherwise it could be a bad winter. As the recent paper in the Vet Record showed energy problems remain by far the most common nutritional problem and it is energy deficiency that is likely to be the underlying cause of most anoestrus problems. We would be interested to hear the outcomes of any anoestrus investigations.

Figure 1:Monthly figures for anoestrus reports by NADIS vets. The usual winter rise seems to have begun one month early this year.


The number of endometritis reports fell slightly in October, which was the first month in 2006 that had a below average number of reports. Nevertheless the total number of reports this year is 20% above the long term average. The cause remains unclear as yet. We need more data.

There were several reports of misalliance problems reported this month with one vet even reporting a problem in sheep!

Metabolic disease
The moderate increase in cases in October meant that for the first time since February metabolic cases were above average. The usual autumnal rise in cases of milk fever did occur but to a much lower level than most years. So far this year 2006 looks like continuing the trend in falling numbers of cases since 2004, with only 2001 having fewer cases.

Figure 2: Number of yearly reports of milk fever showing return of downward trend seen in the early noughties.


Last month we predicted that there would be a rise in hypomagnesaemia cases in October. As predicted there was. However the rise was far larger than expected (almost 300%), with the warm wet conditions being responsible for the increase. There was thus a very pronounced autumn peak this year, which was 50% higher than the spring version.

Figure 3: Seasonality of hypomagnesaemia showing the very pronounced autumn peak seen this year.


The number of displaced abomasum reports fell in October but far less than in the past two years. With two months left in the year there have already been more DA reports than any year except 2004 and 2005. The high level of DA cases looks set to continue.

Lameness
With most cows now housed, November is a good time to look back at lameness during the summer and assess how it’s been relative to previous years. Overall there have been fewer cases of lameness reported by NADIS vets this summer than in all other years, except for 2001 and 2002. The data certainly suggest that the long term trend in veterinary treatment of lameness is once again heading downwards. Of the four main disease both sole ulcer and foul-in-the-foot have had fewer reports this year than last, with the warm wet conditions in October having no impact on foul-in-the-foot cases. Digital dermatitis and white line disease cases have been slightly above last years, but both were still less common than the long term average. The NADIS figures show that there is reduced veterinary involvement in lameness, but cannot confirm whether this is because there’s less lameness or whether vets are less likely to get called out to treat lame cows. The increased use of foot trimmers discussed above may be an important factor as although most of their work may be prophylactic trimming they undoubtedly do do some treatment of lame cows. This will have two effects, reducing the proportion of lame cows treated by a vet and, if trimming works as its proponents suggest, reduce the actual number of lame cows. Lameness is the most important welfare issue in the dairy cow, and its frustrating that there is no specific funding for recording what the levels are in the UK dairy herd.

Figure 4: Number of lameness cases reported in the summer (May to October) by NADIS vets. The long term downwards trend appears to have returned after the large rise in 2004.


Mastitis
As the July figures predicted, 2006 was a good year for summer mastitis with the peak number of cases being one third of the long term average. However this was not the case over the whole country. Ross Muir in Dumfriesshire reported that it was the worst summer for summer mastitis that he had seen in over 20 years, with the warm wet weather being associated with large numbers of flies and consequently spread of infection.

Toxic mastitis cases increased again in October. It would be interesting to hear whether the outbreaks were in housed cows or cows that had been outside during the warm wet weather.

Other diseases
Respiratory disease was the focus of several NADIS vet reports last month. Roger Blowey in Gloucestershire reported an outbreak of puffing and pyrexia in cattle which he suspected may have had influenza A, while Jereme Darke in Somerset report pyrexia of unknown cause in a group of cattle some of which had positive lungworm ELISA. Speaking of lungworm the prediction was that if there was warm wet weather then cases would start to rise. This has indeed been the case. Usually October figures are lower than September but this year the number of reported outbreaks almost doubled. If the warm wet spell continues then a high level of problems in November is anticipated.

Calves

Levels of both enzootic pneumonia and calf scours failed to show their normal October increase, with both remaining at levels similar to last year’s low figures. Calf scour outbreaks have now been below average since July 2005. Is this just better management or reluctance to call out the vet to treat calf problems? The calf pneumonia data suggest that it’s at least partly the former as the number of pneumonia outbreaks reported has been around average for the same period. Comments are welcomed.

Despite low reports of calf disease, several interesting reports were received from NADIS vets this month. In particular combined outbreaks of protozoal scour and enzootic pneumonia were reported from two practices in the West Country. Are these one-offs or an increasing trend?

Copyright © NADIS 2006

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