NADIS Cattle Veterinary Report and Forecast – November 2007

UK - This is a monthly report from the National Animal Disease Information Service (NADIS), looking at the data collected from their UK farm inspections

15 November 2007

5 minute read

Europe

ADULT

Fertility

The number of fertility reports fell further in November with all the main reproductive problems, except for anoestrus cows, having fewer reports than average. The number of reports of non-detected oestrus (NDO) remained below average, with the normal October rise being absent. However, missed heat remains by far the most commonly reported reproductive problem, accounting so far this year for almost 15 times the number of reports of anoestrus. Indeed the NADIS data show that this ratio has changed significantly since 1998 when the ratio was around 12 (see Figure 1).

Figure 1: Graph showing the ratio of non-detected oestrus reports to anoestrus reports showing the rise since the start of NADIS, although this seems to have plateauxed since 2005.

Overall the number of NDO reports by NADIS vets has remained fairly consistent over the past nine years, with a moderate increase in reports occurring in the last few years. This year, as in 2001 the numbers have been significantly impacted by the FMD outbreak, so far this year there have been fewer reports of NDO than any year except for 2001. This is lost work that will never be recovered and lost money for clients who will have longer calving intervals and less efficient milk production.

The number of anoestrus reports in October increased in line with expectations. Last year, the October figure was far higher than expected but presaged a much lower than expected number of cases in the winter. Perhaps the early rise led to preventative programmes being put into place. It will be interesting to see whether this year’s more normal rise will be associated with higher winter problems.

Figure 2: Monthly figures for anoestrus reports by NADIS vets. Last year high October figures were followed by a much better than average winter.

Metabolic disease

Overall, metabolic disease cases were well over 40% below average in October, with hypomagnesaemia reports being < 25% of those seen last year. This year has seen fewer reports of grass staggers than any previous year. It was probably last year’s warm wet weather that was responsible for the much higher number of reports, so far this autumn has been similarly warm but much drier. Even if the weather turns wet it is unlikely that there will be any rise in the cases of hypomagnesaemia.

Figure 3: Seasonality of hypomagnesaemia showing the almost complete absence of an autumn rise in cases this year

DA cases increased in October after the low number seen in September. However overall, the NADIS data suggest that the downward trend from the peak reached in 2004 is continuing, with the estimate of around 650 cases being lower than any year since 2003.

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 so far this year has been lower than in any previous year, with the number of reports in October being lower than any month since January 1997 except for April this year. Of the four main causes of lameness, only foul-in-the-foot has been reported more often this year than last. As in 2001, there is undoubtedly an FMD effect but it has come on the back of a long-term trend downwards in the number of lameness cases treated by NADIS vets. Is it less veterinary involvement or less lameness (or both)? We just don’t know. This again highlights the problem that despite lameness being by far the most important welfare issue in the dairy cow there is no specific funding for recording what the levels are in the UK dairy herd. We have to rely on veterinary reports such as NADIS and on research projects which provide data which are not directly comparable

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

Mastitis

After five months of following the average quite closely, there was a marked reduction in reports in October, a month when there is usually an obvious rise in cases; the most likely reason is that the weather as this was relatively dry and warm. Overall this year there have been fewer reports of toxic mastitis than in any previous year at the same stage.

Figure 5: Toxic mastitis figures showing how reports have followed the long-term average except in April and October.

Other diseases

A Somerset vet reported that he has seen a number of digestive upsets in cattle being fed on stubble turnips, particularly bloat.

A North west England vet recorded an interesting problem on of his farms. He examined an adult cow with profuse scour on a farm where 6 others with similar symptoms had already died in the previous 12 months. The animal was therefore sacrificed and post-mortemed at the VLA. Previous deaths had been tested for worms, fluke and Johnes but all had had negative results. This current cases was shown to have chronic fluke, husk and Johnes!

CALVES

All of the major calf diseases continued their long-term trend of decreasing veterinary reports with neither pneumonia nor scour showing any evidence of a seasonal rise. As with lameness we need independent data to confirm whether this is reduced vet involvement or reduced disease. Certainly anecdotal data suggest that it is probably both better prevention and less use of the vet.

It is important to highlight that prevention doesn’t always work, particularly when the management system results in a very high risk of disease. For example, an outbreak of pneumonia due to Histophilus (Haemophilus) somni in calves was diagnosed which resulted from an automatic calf machine dispensing too little chlortetracycline.

Figure 6: Calf scour figures showing the low number of reports for this year compared with the long-term average

One disease which did increase significantly in October was lungworm, with levels 25% above last year and reaching the long-term average for the first time since 2002. Even at these levels, lungworm problems are still only rarely reported by NADIS vets. It would be interesting to hear from vets or farmers as to what turns a lungworm problem from one dealt with by the farmer to one that requires a vet. Obviously severe problems (either in numbers or in disease signs) are more likely to be seen by the vet. Indeed last month one vet reported that he had seen a dairy cow with a severe allergic reaction to lungworm, a presentation of the disease that he reported that he had seen quite frequently recently.