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