NADIS Veterinary Report and Forecast - May 2008

UK - This is a monthly report from the National Animal Disease Information Service (NADIS), looking at the data collected from their UK farm inspections.
calendar icon 2 June 2008
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Adult Cattle

Metabolic disease

The low number of displaced abomasum cases in March was followed by an increase last month, so for the first time since 2005 there were more cases in April than March. Overall so far this year there have been fewer cases reported than any year since 2002, although the total is still twice the average number seen in the same period in 1997 to 2001

Figure 1: Change in number of reports of DA in January to April

The number of reports of acetonaemia remained low in April, well below the long term average. For the last two years the number of reports of acetonaemia received during January to April has been much lower than any previous year (Figure 2). This means that the number of acetonaemia cases as a proportion of DA cases has fallen considerably since 1997 (Figure 2).

Figure 2: Number of reports of acetonaemia during January to April, and this number as a proportion of DA cases during the same period

Hypomagnesaemia and milk fever both increased slightly in April, but both remained well below the long term average. The low figures for hypomagnesaemia suggest that like last year it will be a good spring for staggers with around 60% of the long term average number of cases. Despite the apparent decrease in cases, preventable problems still occur. A Lincolnshire vet reported a staggers problem on a dairy farm which had thin cows but were only feeding hay with no mineral supplement.

So far this year the number of milk fever reports has been lower than any previous year, even 2001. The clear consensus among NADIS veterinarians is that farmers are increasingly treating milk fever cases themselves and not calling the vet in. It might thus be thought that the NADIS figures would show a decline in cases. However the picture is more complex than that. Between 1997 and 2000 there was a decrease in total cases seen of over 10% per year, however this was reversed between 2001 and 2004. Since then the decline has returned, again averaging at about 10% per year. Interestingly the decline in reports in January to April was much less marked until 2007.. However figures for milk fever for the whole year and for the first four months are now at <50% of the figures reported in 1997.

Figure 3: Changes since 1997 in the number of reports of milk fever over the whole year and in the first four months


The number of reports of anoestrus fell in April from a very low level in March, resulting in fewer reports than any other April except for 2001. In contrast, non-detected oestrus reports increased from very low March figures to almost the long term average. Reports of ovarian cysts, despite a decline in numbers for the second month in a row, were well over 50% above the long-term average. We would be interested to hear what factors you think are keeping ovarian cysts rates relatively high this year.

Figure 4: Monthly reports of ovarian cysts

Uterine torsion reports increased steadily between 2000 and 2006, except for an upwards blip in 2004. However in 2007, reports fell significantly to a level just above that seen in 1997 (figure 5). So far this year, the NADIS data suggest that there will be around 10% more cases in 2008 than in 2007. If the number of cases of veterinary dystocia are included in the figures a different pattern emerges. In 2000, uterine torsions as a percentage of dystocia cases accounted for over 8% of veterinary dystocia (50% up on the proportion seen in 1997). They have remained between 8 and 11% of cases since then. The decrease in torsion reports in 2007 was thus due to a decrease in dystocia reports by veterinarians, rather than decrease in the proportion of dystocias due to uterine torsion.

Figure 5: Changes in total number of reports of uterine torsion and in number of cases per dystocia case (Total figure for 2008 is an estimate)

There has been a significant change in the seasonality of uterine torsions since 2002; the summer dip in June has now been replaced by a peak and proportion of cases reported in November and December has reduced (Figure 6).

Figure 6: Seasonality of uterine torsion reports showing the change in seasonality between the first six years of NADIS and the last five years.

In comparison the dystocia figures are less seasonal and the changes in seasonality in the last five years have been less marked, with the only significant difference being a decrease in the proportion of reports in October from 10 to 8% (Figure 7)

Figure 7: Seasonality of dystocia reports showing the change in seasonality between the first six years of NADIS and the last five years.

This lack of change in the seasonality of dystocia reports means that the seasonality change in uterine torsion is even more marked than Figure 6 suggests. Plotting the proportion of cases of dystocia which were due to uterine torsion (Figure 8) shows that prior to 2003 this proportion was relatively constant during the year with only a small peak in summer. However since 2003 the summer peak has become far more prominent

Figure 8: Seasonality of proportion of dystocia reports which were due to uterine torsion, showing the much larger summer peak which has occurred in the last five years.

The change in individual years is shown in Figure 9. This time series graph shows that the increase in the summer peak began in 2000, and that, even though the number of reports of torsion is now back near to the 1997 figures, the summer peak in proportion of dystocia due to uterine torsion still persists.

Figure 9: Time series graph of proportion of dystocia reports which were due to uterine torsion, showing that although the summer peak has decreased since 2003 it is still much larger than in 1997.

It is only with long term data, such as that collected by NADIS veterinarians, that we can identify such changes and highlight them. Ideas as to why dystocia in the summer is more likely to be associated with uterine torsion than winter calving problems would be gratefully received.

A N. Yorkshire vet’s farm client has been trialling sexed semen. Two groups of 100 heifers under identical management were used. Those given sexed semen had a conception rate of 25% whereas the conventional semen group achieved 61%. We would be very interested to hear more reports of the use of sexed semen


The OTMS scheme has been effectively dismantled for over two years. Lame cattle that are not fit for transport are thus worthless unless they fit the criteria for the OCDS. It might have been thought that this would mean that there would be more veterinary treatment of lame cows however this has clearly not been the case with the overall number of lameness cases continuing to decline. Overall lameness reports in 2007 were lower than in any previous year and 2008 has continued this trend with overall figures so far this year being just over 90% of the already low 2007 figures to the same date. We need to know whether this reduction reflects the situation on the ground or whether it reflects reduced veterinary involvement. The first is good news, the second is not! Lameness is the most important welfare problem in dairy cattle and the NADIS data are the most current and widest ranging data we have on its prevalence. With a bit more support from government the data could identify clearly whether the reduction in lameness is real.

Figure 10: Number of reports of lameness in January to April from 1997 to 2008.


The main change in mastitis control over the past 10 years has been the greatly increased use of internal teat sealants. They now account for around 25% of the dry cow therapy market, and that number is increasing year-on-year. Combined therapy is by far the most common use with over 90% of tubes being used after an antibiotic, despite the obvious increase in cost of the combined therapy. Anecdotal evidence suggests that in most cases teat sealants are used in addition to the standard dry cow antibiotic on the farm. Very few farms are using selective dry cow therapy, i.e identifying low cell count cows and giving those a teat sealant only and treating the rest with combination therapy, and even fewer are changing the antibiotic they use to take advantage of the protection against infection at the end of the dry period provided by the teat sealant. Reports of the use of teat sealants would be very welcome, particularly the process of how combined therapy is chosen.

There is no evidence so far that this increased use of teat sealants has had an effect on the rates of acute toxic mastitis reported by NADIS veterinarians, with the figures for previous years showing no continued downward trend. However the number of outbreaks reported so far this year is very low. On average, the January to April period accounts for 38% of yearly reports (range 35 to 45% in previous years). If this is the case this year then the NADIS data suggest that the number of reports in 2008 will be half that of previous years (Figure 11)

Figure 11: Yearly reports of acute toxic mastitis since 2002 showing no evidence of any significant trend before the current year. However the estimates suggest that 2008 will have the lowest number of reports of any year.

An interesting case of mastitis was reported by a N Yorkshire vet. Micrococcus roseus was isolated in pure culture from the milk of a cow with recurring mastitis; the lab commented that this was the first time they had isolated this bacteria from a milk sample. Further investigation is ongoing. Micrococcus roseus is an environmental organism being found in soil and fresh water. It has also been isolated from human and animal skin and been cultured from dairy products and beer. In the UK Micrococcus roseus has been linked to mastitis in ewes but apparently not in cows.

Other diseases

Bovine iritis (silage eye) cases usually peak in March as the final silage of winter is fed out. However this year’s figures have been much lower than normal and lower than 2007 which was already very low. These low figures are likely to be partly due to better farmer appreciation of the problem with feeding pure quality baleage. However it is likely that better recognition of the problem by farmers has reduced the likelihood of the vet being called to see a problem in the herd. Combined with additional data from focus farms, the NADIS data could be used to answer which of these causes are the more important, providing valuable information on an important and painful disease, which is the most commonly reported disease caused by Listeria in cattle.

Figure 12: Reports of bovine iritis by month showing that the peak of cases has been much lower in 2007/8 than average.

A Northern Ireland vet has seen 4 cows on different farms which were collapsed and sunken eyed. On rectal examination they all had firm dung in the rectum, which when removed was followed by diarrhoea. All the cows had been turned out to grass in the last few days, and had a low temperature. He is not sure what the cause of the problem is but suspects cold cow syndrome.


Reports of scour, pneumonia and joint ill all increased in April compared to March. For joint ill and scour this was not too surprising as April is the peak month for these diseases, but the rises meant that reports of both conditions were at a level more than twice that of last year, with joint ill reports even being over the long-term average.

The rise in joint ill reports looks likely to be a short-term blip in a downward trend since 2003. There were slightly more reports of joint ill in January to April 2006 than in the same period the following year, but this was followed by a large drop in 2007. The NADIS data show that the drop in January to April has fairly closely followed the drop in reports for the overall year, except that the rise after FMD in 2002 to 2004 was less pronounced and delayed for total yearly reports compared to just those in the first four months of the year

Figure 13: Reports of joint ill in January to April and for the whole year compared to reports in 1997

A report from Powys, highlighted a hopefully unusual problem. Scour samples from beef calves were submitted to the local VLA laboratory, with rotavirus and cryptosporidia being the most likely cause. However the VLA also cultured an E. coli that was resistant to enrofloxacin. Our current understanding of the aetiology of diarrhoea in calves would suggest that this was unlikely to be the cause of the scour, but the presence of resistance suggests a potential zoonotic risk.

The small rise in enzootic pneumonia cases was less expected as April is usually lower than March; last year, for example, there was a drop of over 60%. With the peak period of pneumonia now passed, May is a good time to assess how the pneumonia season has gone whether on the individual farm level, at practice level or at a regional/national level.

The NADIS figures are clearly dependent on the importance of veterinary involvement in treating pneumonia. However as Figure 14 shows veterinary reports of pneumonia this winter were below those seen in 2001/2, when calf numbers were low because of FMD. Interestingly the NADIS figures show that it was the yearly figures that increased most significantly after 2001, rather than the figures during the peak winter period (November to April), but both are now below 2001 figures.

Figure 14: Change in number of reports of enzootic pneumonia by year and for winter period (November to April of following year).

Despite an apparently declining incidence, pneumonia remains a major problem on many farms. For example a significant outbreak of pneumonia in beef calves despite introducing an early intranasal vaccination regime was reported in N Scotland. Many farms are in the same situation. Another problem was detailed by a N. Yorkshire vet. One of his suckler cow clients had a significant pneumonia problem in weaned calves, with several deaths despite vaccination on housing. He reported that there was continued IBR involvement despite vaccination, and that this was probably due to concurrent BVD and mycoplasma activity reducing the immune response. He is going to review the problem with the client and is looking at and instituting a different vaccine regime in the future.

An unusual problem associated with vaccination was described by a Shropshire vet. Five Belgian Blue calves were treated with 2 doses of vaccine 3 weeks apart. Two days after the second dose, one calf appeared to be delirious and was found wandering aimlessly. It had pyrexia, and convulsed and died before treatment could be given. The other 4 vaccinated calves all had high temperatures and tracheal coughs. A post-mortem examination of the dead calf showed a septicaemia type condition with excess fluid around the brain and no sign of tracheitis or lung infection. The vet wonders whether the act of vaccination could have affected the immune systems making the calves more susceptible to other pathogens? Cross-bred calves of the same age in the same building were not vaccinated and have no signs of illness.

Further Reading

More information - You can view the full report by clicking here.

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