The Perfect Storm for Acidosis
There has been a lot of talk about forage this year, with the late spring and dry summer some farms, particularly in the South of England, may be short of forage for winter 18/19. If that applies to you this is the season to pay close attention to your forage analysis results when preparing diets to feed your cattle, sheep or goats.
Forage samples already analysed by Trouw Nutrition this year have shown that in general 2018 grass silages are giving typical results in terms of dry matter, energy and protein. They are also on average highly fermentable and relatively low in fibre. Maize silage samples are on average drier than last year, high in energy and low in fibre. So, most of our forage stocks are high in starch and sugar, rapidly fermentable and low in fibre. The acid load figures are also high, meaning that we have a high risk of acidosis this winter. In fact the average acid load figures for all forages analysed are over 50, which is the upper target for a whole diet, if forage is in short supply then balancing diets to prevent acidosis could be challenging this winter.
Signs of acidosis on farm
Acidosis occurs when the pH of the rumen drops below its optimum range of 5.8 – 6.2, this begins a downward spiral where the correct type of rumen bugs are killed off and then the rumen becomes even more acidic as a result. Acute acidosis can cause bloat, abomasal ulceration, bleeding within the gut and ultimately death as was unfortunately the outcome in the case pictured here.
We more commonly see SARA or Sub-acute Rumen Acidosis – signs of this normally include loose dung or scour containing undigested feed, poor cudding rates (we want to see over 60% of cows that are lying down chewing their cud) and cudballs. In dairy animals we often also see a drop in milk butterfat and yield.
Some diets are particularly high risk for acidosis, for example, if they are high in concentrates, low in fibre or if the acid load figure is very high.
Clinical cases will require veterinary treatment and diagnosis can be confirmed through sampling the rumen fluid. It is important to remember that SARA, the less acute form, is an iceberg condition, meaning that you may only see one or two animals affected but that a larger proportion of the group is also suffering and as result they are not performing as well as they could be.
If you are concerned about acidosis on your farm please give us a call, we are very happy to work with your nutritional advisors on this and take a team approach on farm. Short-term solutions may include adding more fibre to the diet, e.g. Straw or Soya Hulls before balancing the diet more thoroughly.
In terms of prevention monthly forage analysis is recommended, particularly this year. This will help you ensure your diets are balanced not only in terms of energy and protein but also in terms of acid load.