3 October 2008

5 minute read

Europe

Adult Cattle

Metabolic disease

Around this time last year we were predicting the start of a downward trend in DA cases .At the end of the year the predicted fall was smaller than expected because of a high number of cases in October to December. This year, except for January and March, reports of DAs have been higher than in 2007; even the August figures were higher than last year despite 2007 seeing a non-seasonal increase in cases. The NADIS data suggest that by year end there will have been between 700 and 740 cases of DA reported, around 10% higher than last year – no evidence of a downward trend!

Figure 1: Number of monthly reports of DA in 2008 and 2007 compared to mean of 1997-2006.

Compared to last month, acetonaemia reports rose dramatically resulting in only the second month above the long term average. It would be interesting to hear thoughts on why there was such a marked difference between the two summer months in acetonaemia cases.

The number of milk fever reports rose considerably in August, as they did in 2007. However the reports were still well below the long-term average. Indeed, so far this year no month’s reports have approached the long term average, and the year-end estimate is around 400 reports, which is only 80% of last year and <40% of the number of cases reported in 1997. It would be useful to know whether this fall is reflected in calcium sales!

Figure 2: Total yearly reports for milk fever from 1997 to 2006 with estimated results for 2007

Mastitis

July is usually the first month when significant numbers of summer mastitis problems are recorded. Usually a poor July, with high numbers of cases, is followed by an August with few reports. However this pattern has been significantly altered in the last two years, with very low reports in July being followed by small rises in August only.

Figure 3: Comparison of summer mastitis reports in July with those in August for the years 1997 to 2008 showing that low numbers of reports in July are closely linked to high numbers in August except for 2007 (yellow box) and 2008 (red box)!.

Interestingly despite the apparently strong link shown in Figure 3 for summer mastitis, there is no such link for the other major fly-associated summer disease, New Forest eye. The NADIS data also show no link between the July to September figures for New Forest eye and summer mastitis case numbers

Fertility

The number of reports of retained fetal membranes increased in August. However the ratio RFMs to endometritis cases remained at 8 to 1, similar to the average seen for the last two years. The total number of endometritis cases seen so far this year has been markedly above the reports with August’s figures being the highest for that month since 1997 and higher than any monthly figure since January 2004. However, using non-detected oestrus as a baseline suggests that this apparent increase is partly due to increased veterinary workload as the ratio of endometritis to NDOs is lower this year than last, although the ratio has been higher than the long-term average.

Figure 4: Trends in monthly reports of endometritis for 2007 and 2008 compared to the average of 1997 to 2006 using non-detected oestrus as a baseline

Lameness

White line disease, sole ulcer and digital dermatitis increased in August. Overall lameness reports are just above the levels seen last year; if this continues it will be the first year since 2004 to see an increase in lameness reports

Figure 5: Trends in monthly reports of lameness for 2007 and 2008 compared to the average of 1997 to 2006

Other diseases

The number of outbreaks of New Forest Eye increased dramatically in August; so that, for the first time this year, levels were significantly above those seen last year. September and October are often significant months for this disease so continued watchfulness is important.

Figure 6: Comparison of number of outbreaks of New Forest Eye recorded so far this year compared with 2007 and the average for 1997 to 2006

Lungworm is not commonly reported by NADIS veterinarians so individual month data can vary quite wildly. August’s data suggests that there were far more outbreaks in adult cattle than youngstock with levels that are usually seen towards the end of the grazing period rather than in mid-summer. Any reports on why this seems to be the case would be gratefully received.

A Powys vet diagnosed listeriosis in a heifer, which he put down to being fed from a trough which was getting dirty due to the continual showers, so would have been contaminated with potentially infective soil. With the very wet summer this scenario is likely to have been repeated on quite a few farms round the country.

We received a query from one reporting vet about the incidence of wooden tongue on organic farms. The main conclusion from the NADIS veterinarians was that they hadn’t seen more cases on organic farms but it was difficult to make a conclusion as they only saw wooden tongue rarely. One commented that many farmers treat wooden tongue themselves, so it was difficult to get a true estimate of disease incidence. A North Eastern vet reported that although he still sees wooden tongue it’s not common, whereas his father (also a vet now 80) saw a case every week – which was linked to baling hay with wire which caused wounds on the tongue. Another vet suggested that it may be related to organic pasture being more mixed and deeper rooted bringing “more things to the top’. Interestingly the incidence of wooden tongue in New Zealand seems to be higher than in the UK, which may be related to the greater use of grazing in New Zealand. Additionally lesions seen in that country are commonly not confined to the tongue but are also seen in the cheeks as well as in the skin of the neck. In New Zealand, the disease is most commonly seen in yearlings and two-year olds, with a link to tooth eruption and grazing poor quality pasture

Calves

The summer months are usually months where there are low levels of calf disease. For enzootic pneumonia and scour this has been the case so far this summer. However, joint ill reports increased again in August resulting, for the fifth month running in the figures being around the long term average. By comparison, last year only two months in the whole year were near that average. In contrast there were only two months last year when levels were near the average.

Further Reading

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