Could suboptimal cow performance be due to a damaged rumen wall? 88% of the VFAs from the diet are absorbed via the rumen papillae, which is why rumen wall integrity is so important. (Fig.2)The causes of rumen wall damageDisruptions to the rumen, such as changes in rumen pH, caused by sudden dietary shifts (even turn out to grass is a risk), environmental stressors and physical illness, can lead to rumen wall damage. All of this causes a ‘leaky’ rumen wall; the natural layers of the rumen wall are damaged, and it becomes thinner. Supporting rumen wall integrity for optimised performanceProducers need to be mindful of supporting rumen wall integrity from the weaning stage to ensure optimal performance in the mature animal.