Sub-clinical and clinical acidosis occurs as rumen pH falls. The greater the fall and the longer low pH conditions remain, the more severe the consequences are on rumen health and performance.
The concept of trying to add fibre to cows diets at grazing is one that isn’t new, many will switch to a hdf type cake at grazing to try and mitigate low fats.
One of the main issues is not percentage of fibre/effective fibre in the diet it is total fibre intake, the main driver behind falling milk fats is overall forage intakes. We tend to overestimate the availability or the ability of the cow to consume the amount of dry matter needed from grazing. This in turn causes a subtle but important switch in the concentrate to forage ratio. There have been several studies that support this with low rumen pH being seen at grazing even with very low supplementation.
As Karen has talked about in her article about heat stress with cattle, there is another another layer added to this problem with animals intakes dropping when they become uncomfortable, and it tends to be the forage dry matter component that decreases making this fat issue worse.
One option is to give the cow a bit of a helping hand by using a rumen buffer, these can be added to your buffer feed and are a useful tool in helping rumen function at grass.
Equalizer and Equalizer Cool Cow
Equaliser is a combination of several different buffering agents that has been shown to outperform the buffering capacity of its competitors. Available as a powder or incorporated into mineral packs, compound feed or blends. Equaliser is included at a rate of 100-150g/day for dairy cows or 80-100g/ head/day for beef cattle.
Biotal SC acidease.
A unique rumen specific live yeast and high quality dead yeast farm pack designed for targeting acidosis. Available as a farm pack to be fed at 25g/head/day for dairy cows and 20g/head/day for beef animals.