ADULTS

Fertility

Neither non-detected oestrus nor anoestrus showed their expected rise in January. The number of missed heats reported in January fell compared to December and was over 30% down on the average, while anoestrus cases were almost 50% down. January to March is usually the peak season for missed heats and anoestrus cases, with January usually being the peak month so if these figures are truly representative of the current season they suggest that fertility is relatively good this year. So predictions that it would be a bad winter based on a very high number of anoestrus reports in October were incorrect. Any explanations for the change would be gratefully received. Is the food in front of the cows better than it was in October or is that vets are not being called out and we’re just storing up trouble for the future?

Figure 1: Reports of anoestrus cases showing that even with a steep rise the number of cases reported was half that of the average


Reports of ovarian cyst were about average in January although the level was still lower than in December which had had a very high number of reports. Overall in 2006 the number of reports of ovarian cysts was lower than in 2005, continuing a downward trend since 2004. The number of cases of ovarian cysts seems to be cyclical with no obvious long term trend, in contrast to anoestrus where the NADIS data suggest that there has been a real decrease in reports since the late 90s.

Figure 2: Reports of ovarian cysts and anoestrus showing that the number of reports of the former is cyclical whereas anoestrus reports seem to have stabilised at a lower level than the late 1990s

Metabolic disease

Overall metabolic disease reports were average in January. The most commonly reported metabolic problem was displaced abomasum, with a higher number of reports than 2006 but lower than the peak year of 2004. This is more evidence that the number of DA cases has plateauxed at a level about three time that seen in 1997. Certainly most NADIS vets are no longer reporting that DA cases are rising in their area. The NADIS data suggest that February is going to be another bad month for DAs.

Figure 3: Reports of displaced abomasum in January and February showing the increase in cases over the past 8 years.


Other metabolic diseases were around average. Unlike DA the number of NADIS reports has tended to fall since 1997, with milk fever cases being around 80% of the numbers seen in the late 1990s. However the numbers seen in the winter haven’t changed so dramatically, suggesting that the fall is a real effect due to better control of milk fever during the summer months.

Figure 3: Monthly reports of milk fever in January and February.

Lameness.

The January figures, like December’s, were again low, with none of the main causes being near average. These figures are consistent with a slow decline in the number of lame cows seen by NADIS.

Figure 4: Total monthly reports of lameness in January and February, showing the slow decline since 1997.


The number of reports of digital dermatitis in January was the lowest ever, consistent with reports from NADIS vets that digital dermatitis is now a problem that farmers live with and do not seek veterinary attention for. The peak months for digital dermatitis are January to March and it is in these months that have shown the greatest decline, whereas the summer figures have not reduced by anywhere near as much. This suggests that the January decline is real and that digital dermatitis is becoming less seasonal. It could be that our control measures are working or that digital dermatitis is becoming an endemic infection with reduced virulence (or both). However it is still a significant problem on many farms costing significant amounts for control and treatment. On some farms NADIS vets have reported that whole herd antibiotics are still needed to maintain the disease at manageable levels. We would be interested to hear your thoughts on how digital dermatitis is presenting on farms 20 years after first being recognised in the UK.

Figure 5: Change in monthly reports of digital dermatitis since 1997 showing the much greater change in January than July



An interesting lameness problem was reported by a Somerset vet. He reported that a 160-cow dairy farm had inadvertently over fed protein causing increased urea production and urination and that this had resulted in damage to the feet of 120 cows with foul in the foot, digital dermatitis and slurry heel all being seen. He also reported that affected cows showed signs of laminitis and cellulitis. We would be interested to hear of similar reports.

Other diseases

Reports of bovine iritis (silage eye) usually increase greatly in January and then continue to climb until March. However this year’s figures are much lower than normal and lower than 2006 which was already very low. The NADIS figures show no significant trend but the low figures suggest that the quality of baleage is probably better this year than average.

CALVES

In January both calf scour and enzootic pneumonia remained at levels well below the long term average, with the number of calf scour outbreaks being the lowest ever recorded by NADIS. Calf scour outbreaks have now been below average since July 2005. Is this just better management or reluctance to call out the vet to treat calf problems?

Figure 6: Calf scour figures showing the reduction in reports since 2002 for January and the greater variability in February

Further Reading

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