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NADIS Cattle Veterinary Report and Forecast – December 2008

02 January 2009

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

CATTLE

Fertility

The number of fertility reports was relatively static in November; however both non-detected oestrus and anoestrus cases remained above the long-term average. Endometritis cases fell by around 10% in November, but because October’s levels were so high (the highest since January 1998), November’s figures were the highest for that month since November 1997 and were the eighth month in a row that levels have been above the long-term average. Suggestions as to why this increase is so apparent would be greatly appreciated. Vet 29 ( Gloucester ) commented that an increase in the incidence of twins, particularly in the higher producing dairy herds, is leading to a lot of endometritis. He also thinks that post-calving metritis is becoming a much more significant problem than it used to be.

Figure 1: Monthly figures for endometritis reports by NADIS vets. Figures have been consistently above average since April.


The pattern for anoestrus this year has been similar to that for NDO, with both diseases being above the long-term average since April. This indicates that the underlying risk factors for anoestrus are similar to those for NDO. However a closer look at the monthly figures shows that this is not a complete correspondence with anoestrus being relatively more common in spring and NDO in autumn.

Figure 2: Graph showing the number of anoestrus reports as a percentage of missed heats showing the monthly variability around the mean figure (dashed line)


Similar figures for cystic ovaries and missed heats also show a significant monthly trend with a higher proportion of cystic cows being seen between September and December (see Figure 3).

Figure 3: Effect of month of year on ratio of ovarian cysts to missed heats (dashed line shows expected line if no monthly effect)


Clearly there are risk factors for ovarian cysts in late autumn / early winter which do not proportionately increase the risk of missed heats in cattle with apparently normal ovaries.

Vet 39 ( North Yorkshire ) described further investigations in a herd with a high embryo loss rate. He undertook a bulk milk sample for BVD antigen – this was negative. This result is consistent with the bulk milk antibody level which is very low even though the herd is vaccinated. This is an important point; vaccination does not necessarily produce detectable antibodies because the antibodies detected by the ELISA and the antibodies produced by the vaccine are not necessarily the same, it depends on which vaccine is being used and which test. So if a vaccinated herd has high bulk milk antibody levels it is likely that this indicates that wild type virus is circulating in herd.

Metabolic disease

Overall metabolic disease cases remained static in November at around 70% of average. None of the major diseases showed a marked change in numbers, which meant that grass staggers cases continued at relatively high levels, resulting in autumn figures that, even without December data, were almost twice spring levels. On average, since 1997 the total number of grass staggers in spring has been similar to the number in autumn, but this simple figure hides a lot of yearly variation, particularly in the number of autumn cases.

Figure 3: Comparison of reports in spring and autumn for grass staggers, showing the greater variability in autumn numbers.


Lameness

Overall lameness reports were also static in November. Of the main four diseases foul-in-the-foot and digital dermatitis reports decreased, while sole ulcer and white line disease reports remained flat. For white line disease, this meant that for the first time this year cases were above average for the month. This is because although white line disease occurs commonly throughout the year, cases peak in September / October at the end of the grazing season when there the impact of tracks and collecting yards is at its peak, so the lack of the usual November decrease meant average levels were beaten. It would be very interesting to know whether the autumnal peak in white line disease cases is in late summer / early autumn calving cows or whether it’s spread across the lactation.

Figure 4: monthly reports of white line disease showing above average numbers in November 2008


Other diseases

Vet 39 ( N Yorkshire ) described a classic example of a problem on too many farms – the lack of a quarantine plan for brought-in stock. In July a bought-in bull had died due to pneumonia and lungworm. Because of the history of the farm it was highly likely that the lungworm had come in with the bull. The client was advised to treat anything bought-in for lungworm. However the farmer got a replacement bull in September on loan and didn’t treat. The bull now has a serious pneumonia and has lungworm larvae in its faeces!

Vet 30 (Wiltshire) reported an unusual case in a Holstein heifer which was due to calve for the first time in around a fortnight. The heifer was distressed, had a prominent submandibular swelling and a tongue which was swollen and hanging out. Her temperature was 39.5 0C. She was given non steroidal drugs and penicillin / streptomycin, and the next day her temperature was normal and as the swelling was much reduced, he was able to examine the mouth more closely. He found an area of purple bruising on the lateral inside of the anterior mandible, but not over the incisor teeth. In the same group there was another animal with a fist-sized area of hardness at the root of the tongue in the submandibular area. This cow was drooling, had a runny nose and a temperature of 39.5 0C. Further investigations are ongoing.

We have had a couple of tumours reported in beef cows this month; one thyroid tumour and a melanoma the size of a cricket ball on a tail.

The wet summer has been good for the transmission of fluke. Vet 78 (Yorkshire) commented that there is an increased awareness of fluke problems following the wet summer and most dung samples are coming back positive as are bulk milk serologies.

CALVES

For the last three months, pneumonia cases in all age groups have been close to the average, however last month rather than following the usual upwards seasonal trend there was a 25% reduction in cases. For calves the picture is even better, November was the second month to show no seasonal rise. Is this evidence of better focus on management and vaccination?

Figure 5: Calf pneumonia figures showing the lack of the expected increase in numbers in November.

Further Reading

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


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