NADIS Veterinary Report and Forecast – July 2006
CATTLE


ADULTS

Fertility
Interestingly, the number of fertility problems reported by NADIS vets
increased in June, with both missed heats and anoestrus cases
increasing. This suggests that fertility problems this summer may
remain high as they did last year, when 32% of all non-detected heats
were recorded between June and September (as opposed to an average
around 23%). It is unclear why there was an increase in summer
fertility problems last year, there is certainly no discernible trend
in previous years. Even in average years NADIS veterinarians report
over 3500 non-detected oestrous cases during the summer, so although
detecting bulling in cows at pasture can be very time consuming it is
essential. Indeed when heat detection is done effectively submission
rates at pasture can be much better than in housed cattle. Heat
detection aids such as beacons and tail paint are particularly useful
at this time of year as false negatives due to knocking against
architecture are much less common.



This device glows when pressure is applied


The dairy industry needs to focus on heat detection as it’s probably
the fertility variable which varies most between farms and thus has
the most potential for improvement even on average farms. The main
problem with improving heat detection rates is that, unlike pregnancy
(or conception) rate which can be calculated using PD and service data
which most farms will collect, not many farms collect data to show how
good they are detecting oestrus. Thus it can be difficult to show the
farmer that there is a problem or that additional measures have
improved the situation. However heat detection data can be easily
collected, provided the cows due for service can be identified, and
when collected representative data using either can be monitored on a
short three week basis so problems can be identified quickly and
solutions implemented as soon as possible.



Figure 1: Monthly patterns for non-detected oestrus, showing the
marked increase in cases seen in June and the very high figures
reported last summer


June also saw an increase in the already high levels of endometritis
reported by NADIS vets. The number of endometritis cases seen so far
this year has been the highest of any year since 1998, continuing a
trend of steady increase since 2001. Interestingly, like missed heats,
2005 saw a very high number of summer endometritis cases, with 34% of
all cases reported between June and August (in contrast to the average
of 28% in previous years). Again, 2005 appears to have been an unusual
year as there was no previous trend towards an increase in
endometritis cases during the summer

Figure 2: The NADIS reports show that, although last year the number
of summer cases of endometritis increased markedly the long term trend
is one of stability rather than change.


Another fertility problem which was much more common in June than
average was uterine torsion, with the figures in June being very
similar to the very high figures reported in May, confirming that the
figures for that month were not an aberration. The number of cases of
uterine torsion has increased greatly since 1997 and seems to be
following a linear trend upwards, with an average of ten cases more
per year. The cause of this trend is unclear but is probably
associated with changes in genetics resulting in larger cows (with
more abdominal space) and heavier calves (increasing potential torsion
forces).

Figure 3: Change in the number of yearly reports of uterine torsion
from 1997 to 2005 (with prediction for 2006), with linear trend line.
The linear trend is statistically significant and explains over 75% of
the variation between years


Metabolic disease
The relative lack of dietary control in cattle at pasture means that
the summer remains the peak period for metabolic disease. So far this
year, except for displaced abomasums the number of metabolic disease
cases has been below average. This remained the case for
hypomagnesaemia (grass staggers) during June, which meant that this
year has been a good year with the number of reports being less than
60% of the average. It is likely that the effect of the poor weather
in April on grass growth and turn-out significantly reduce the risk
this year. It will be interesting to see whether a similar effect
occurs during the autumn peak as this has been much more variable in
recent years than in the past. In contrast to hypomagnesaemia, reports
of both hypocalcaemia (milk fever) and acetonaemia (ketosis) cases
increased in June, though neither was at unusually high levels.
Displaced abomasum reports, however, were at their highest ever level
for June. This means that despite a lower peak in cases, overall
figures for 2006 are very similar to those of 2005 which were the
second highest ever (after 2004). Although the peak number of cases
is March to May, over 30% of DA cases occur in the next four months,
so we need to keep implementing preventative measures even though many
cows will be out at pasture.

Figure 4: Change in the number of reports of displaced abomasum
between January and June for 1997 to 2006, with linear trend line. The
linear trend is statistically significant and explains over 80% of the
variation between years. On average there has been an increase of 45
cases during this period per year over the last 8 years




Cattle lameness

The dry and warm weather in June was marked by low levels of lameness
overall, with decreases in sole ulcer and digital dermatitis.
Foul-in-the-foot cases increased despite the dry weather but still
remained below average, while white line disease cases increased to
average. Summer marks a significant change in the risk factors for
lameness on many herds. The risk factors change from those associated
with housing (concrete and slurry) to those associated with pasture
(tracks and gateways). In particular, increases in white line disease
can be linked to poor cow tracks and management of cattle entering the
collecting yard. Peak levels occur in September/October but the damage
that eventually results in clinical disease starts long before then,
so on farms with a history of white line disease paying attention to
tracks now can significantly reduce future problems.

Figure 5: Seasonality of cases of foul-in-the-foot reported by NADIS
veterinarians, showing that the number of reports per month has been
consistently low so far this year.


CALVES

The number of scour cases remained low in June continuing the trend
seen in the rest of the year. Indeed this year’s trend follows the
pattern seen since 1997 of a decrease in veterinary reports of scour
problems (and is similar to the trend seen in the data from the
VLA/SAC). On face value this seems like good news, diarrhoea and its
consequences, particularly dehydration, are the primary causes of calf
loss, so a reduction in incidence can only be a good thing. However
this simple evaluation misses the possibility that economic factors,
such as poor calf values, rather than reduced diarrhoea may be the
primary driver of the reduced veterinary reports. We urgently need a
better measure of actual incidence of calf diarrhoea on farm.



Figure 6: Change in time with number of scour outbreak reports showing
the almost continuous decline in the number of reports by NADIS
veterinarians since 1997 (2006 data estimated)


No lungworm cases have been reported by NADIS vets since January,
which is not unusual as July is usually the first month of the
lungworm season. Recent years have seen higher peaks of disease in
August/September so a focus on prevention now is still likely to
result in significant benefits.

__________________________________________________ __________

SHEEP
Go To…….Cattle Pigs

Parasitic disease
Problems with coccidiosis continued in June, it seems likely that
problems will persist until July and maybe longer.


Coccidial oocysts



Undoubtedly the poor grazing conditions during spring have been part
of the problem. If future years have similar weather, more farms may
need to feed coccidiostats to their sheep in order to prevent the
effects of coccidiosis. These effects do not only extend to clinically
affected animals; sub-clinical disease also leads to major losses with
poorer growth rates and decreased resistance to other parasites being
the major problems.

As predicted problems with Nematodiriasis continued into June in the
northern regions of the UK, however they are unlikely to remain a
problem in July.

Fluke problems continued to be reported in June. There is no evidence
from. NADIS vets of significant triclabendazole resistance problems,
but this is something that needs greater attention.

Other diseases
Copper toxicity was again reported by NADIS veterinarians in June.
This is by far the most common poisoning reported in sheep, with a
significant variation between breeds in their susceptibility. However
as the NADIS reports show, copper poisoning can occur even in breeds
which are not thought of as susceptible (e.g. Scottish Blackface)




Jaundice showing in the eye of ewe suffering

from chronic copper poisoning

Most problems are chronic in nature rather than acute and deaths
should thus be avoidable. The problem is that in too many cases
insufficient attention is paid to what the sheep are being fed.

__________________________________________________ ___________

PIGS
Go To…….Cattle Sheep
The increased surveillance under the NADIS clinical veterinary
monitoring programme is starting to bring useful data forward. The
chart below indicates the prevalence of each disease in the various
age groups:-


ADULTS
As is usual case reports of problems in the adult population can be
separated into production issues either as a result of stockmanship
errors or disease and other health issues unrelated to breeding
productivity.



Within this month’s stockmanship/production reports, fertility issues
are particularly prominent.

1) Timing of service relative to actually identifying a sow on heat
(ie delaying 30-60 min) was blamed for poor results.

2) Delayed insemination following heat detection (8-12 hours) is
commonly reported to improve fertility but is highly dependant on
accurate and early heat detection.

3) Overfat sows at service was blamed for one outbreak of returns
to service.

4) The hot weather through the middle of the month is believed to
have accounted for extended weaning to service intervals, poor
appetite, and litter desertion outdoors .

5) Sows coming on heat during lactation – not uncommonly seen
outdoors in spring - was also reported.



A wide range of diseases affecting reproduction were reported. These
included Parvovirus, PRRS, leptospirosis, uncharacterised abortions,
post farrowing discharge, Arcobacter associated abortions and possibly
Clamydial infection.



Mange continues to be evident in sows – particularly in East Anglia
whilst other issues affecting sows included mastitis of unknown origin
and unusual front leg lameness/paralysis believed to be associated
with trauma as sows knock themselves getting through restricted
entrances to lying areas.


Hypersensitive (allergic) Mange in a sow





Swine flu was occasionally seen in the sow herd.



WEANERS
Two specific conditions dominate the health picture in weaners in
June.

1) Meningitis was widely reported and this continues the trend seen
since the spring. This disease does not seem to be afforded the
attention that its incidence would seem to justify.

2) PMWS – inevitably this continues to be widely reported although
there are an increasing number of success stories or at least signs of
improvement. Poor housing , overcrowding and concurrent disease –
especially Glasser Disease – are frequently highlighted as major
factors precipitating PMWS but increasingly, reporters are
highlighting the benefits of novel breed type boars in the fight
against this disease. Such breeding changes do not solve all the
problems but appear to give greater resistance to the weaners to cope
with the challenges they face.

Post weaning scour and colitis were not particularly prevalent
although removal of Zinc Oxide from weaning diets has been associated
with a number of problems, tending to confirm its need in the control
of enteric disease post weaning.



GROWERS/FINISHERS
As usual these dominate the disease picture and in addition to the
common problem of specific and complex respiratory disease, Glassers
disease and enteric problems (colitis/ileitis) grower scour, a wide
range of other conditions were reported.


Mild colitis with perineal staining and

loose faeces but no loss of condition

With respect to colitis a number of reporters commented on
improvements that have occurred following improvement to hygiene, feed
management and several commented upon the switch to meal feeding which
historically has proved effective at reducing maldigestion but is
often resisted because of handling problems, dust and reduced
appetite.



Skin conditions were raised. In addition to injuries resulting from
sharp metalwork, Sarcoptic mange was evident, unusually greasy pig
disease was seen in older growing pigs (with no reason found) in the
first reports of fly bite lesions this summer were received Worm
infestation including milk spot liver was a problem on one farm and
rectal prolapses were seen as a major issue in another.



PDNS was widespread in farms variably affected with PMWS.



Finally water supply featured in several reports. Salt poisoning was
seen following blockage to water although in one case the farmer’s
diagnosis of salt poisoning was actually an outbreak of infectious
arthritis causing pigs to go “off their legs”. One farm reported
increased water intakes for no obvious reasons.



PIGLETS
Investigations of problems in piglets were relatively sparse. As well
as the usual scour issues associated with E.Coli, rotavirus,
coccidiosis and clostridia, piglet respiratory disease usually
associated with Glassers disease was evident. Meningitis continues to
be common particularly in East Anglia.



Umbilical hernia detected early in life (before weaning) were seen as
a major concern and were believed to be associated with navel
infection at birth.



Through the warm summer weather expect problems with:-
1) Sunstroke and sunburn.

2) Summer infertility.

3) Litter desertions and rebreeding problems outdoors.

4) Farrowing house scour as sows wet solid floor pen to aid
cooling.

5) Erysipelas












"As I was walkin' - I saw a sign there
And that sign said - no tress passin'
But on the other side .... it didn't say nothin!
Now that side was made for you and me!"
Woody Guthrie

A prophet is only despised in his own country....
..........among his own relations...
............and in his own house