reduce the proportion of variable products used in a diet, increase the number of dietary components (this has the effect of ‘averaging’ feeds that may be higher or lower than their expected mean value, an example is provided), consider adjusting a feedstuff by a proportion of the SD to allow for the probability of the feed being above a specified nutri. Another way to look at variability is that there is uncertainty associated with the compositional value of a particular sample.ent level.