15 March 2007

5 minute read

Europe

ADULTS

Metabolic disease

In contrast to last year the number of cases of displaced abomasums (DAs) reported in February fell compared to January, resulting in the lowest number of reports since 2002. The pattern so far this winter has been almost identical to the average number of reports for 2002-2005 This is further evidence that the number of DA cases is no longer increasing dramatically but has stabilised at a level about almost four times that seen in the late 1990s. March to May is the peak period for DAs so the next few months will be the real test for whether we can start reducing the number of cases.

Two other metabolic diseases also had fewer reports in February than January. Acetonaemia reports fell by almost 50% to the lowest recorded level in February, indicating, perhaps that forage quality was generally good. It would be interesting to hear your views on why acetonaemia levels are so low. It was a similar story with milk fever, a 40% drop to the lowest reported numbers in February. Is this better feed management or just good luck?

Fertility

The number of reports of both non-detected oestrus and anoestrus were both low in February, a record low for anoestrus and an almost record for non-detected oestrus (beaten only by February 2004). Both these low February figures followed low January figures so, provided these figures match what’s happening on farm, fertility has been good since the turn of the year. Is this another indication of cows having good quality feed in front of them? The only major fertility problem to be significantly above average in February was ovarian cysts. This resulted in an average of just over 6 missed heats per case of ovarian cysts, much lower than the long term average of around 8.5. There doesn’t appear to be any long term consistent trend (see Figure 2) but the data clearly show that there are different risk factors for ovarian cysts and missed heats. We would be interested to hear what factors you think are keeping ovarian cysts rates relatively high.

Lameness

The OTMS scheme has been effectively dismantled for over one year. 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 2006 were lower than in any previous year

2007 looks likely to see a further continuation of the downward trend with the total number of reports in January and February being 40% below the long term average and almost 30% below the levels reported in 2006. The effect was much less marked for three of the four main diseases, with white line disease, foul-in-the-foot and solar ulcers all being reported at levels similar to those seen in 2006. Digital dermatitis reports were well over 50% below the long term average and 30% below last year.

Mastitis

Sand bedding is currently very popular in the US because of its impact on lameness and mastitis. One Lincolnshire dairy farm has seen a massive reduction in mastitis cases since changing cubicle bedding from straw to sand in 2004, with cases reducing from 104 in 110 cows in 2004 to 45 cases in 135 cows in 2006. We would like to hear of other reports of using sand, as except for the disposal problem, sand-bedded cubicles seem to offer significant benefits over conventionally bedded versions. The vet reported that he believes that some of the improvement was due to the use of internal teat sealants throughout the herd, with those that require antibiotics also getting teat sealants. This combined therapy has proved very popular with around 50% teat sealants being used in combination with antibiotics, despite the obvious increase in cost of the combined therapy. Reports of the use of teat sealants would be very welcome, particularly the process of how combined therapy is chosen. Interestingly on the same farm megasupplementation with vitamin E has been used to control retained fetal membranes (RFM) with 1500 IU of Vitamin E being given per cow per day via the dry cow minerals. Current UK recommendations are equivalent to less than one tenth of this figure! More recent American (NRC) recommendations suggest a higher figure of around 1000 IU for dry cows. The primary effects of vitamin E appear to be on mastitis and RFM, with the evidence for the latter being a lot stronger than the former. The vet intends to monitor the response of the herd further. Is anybody else using vitamin E megasupplementation?

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. Although there was a slight rise in February it was not significant. These low figures suggest that the quality of baleage is probably better this year than average.

Figure 3: Change in number of reports of bovine iritis during January and February

CALVES

In February both calf scour and enzootic pneumonia remained at levels well below the long term average, with the number of pneumonia outbreaks being the lowest ever recorded by NADIS except for 2005. So far this winter pneumonia outbreaks have been around 70% of the long term average with the lowest number of reports since the winter of 2001/2002. This is part of a long term trend but it is unclear whether it’s because we’re getting better pneumonia control or whether it’s simply that farmers are less likely to call out the vet to treat pneumonia. Comments on the relative importance of these two factors would be welcomed.

Figure 4: Change with time in the number of reports of calf pneumonia during the winter season. (The dip in 2001 is almost certainly due to the lower number of calves on farm that season)

Further Reading

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