Bloat has created stress on many UK dairy farms that are covered with thick lush clover dominant pastures this summer & continues to be a threat. Pastures high in potassium & low in Sodium are a real silent threat. The high potassium levels can come from fertilizer or slurry/muck spreading or even paddocks that have regularly been used for night grazings. High risk paddocks could be cut for silage & not grazed ....this will lower the potassium levels. However this silage should be fed to young stock not cows.
Sodium to Potassium ratios create a risky bloat scene when Sodium levels are low. These can be corrected to a certain extent by fertilizing with salt or by putting extra rock salt out for the cows or young stock. Make sure it is close to the water troughs say less than 20 meters from the water/drinking trough. This will need to be moved each grazing.
These are not guaranteed to be bloat preventative by themselves but over the long term do help. Bloat is also highly heritable....so at risk cows will breed at risk daughters. Chose NZ AI bulls that have low risk.
I have seen many clover dominant pastures that are very lush. Some of these appear to be risky yet so far have not created havoc.....yet others that appear to be low risk have caused deaths. It is very unpredictable so take all care & be prepared. This means dosing the water troughs with oil or anti foaming agents well before the problem occurs.
Mowing in front continues to help on many farms reducing the risk by drying out the clover before grazing.
Current Pasture Covers & Pasture Growth Rates
Cheshire organic 2200 kgsDM/ha & growth 40kgsDM/ha/day
Cumbria 2440 & 60
Staffordshire 2430 & 46
Dorset 2100 & 24
Somerset 2200 & 40
Devon 2284 & 32
Cornwall 2360 & 57
Pembrokeshire 2550kgsDM/ha average cover & 70kgsDM/ha/day