Barry Mccarthy, of Dunedin, asks :-

I have some young fallow deer which I have been feeding on crushed oats and lucerne. A couple died. Could their diet or the cold have been a problem?

Alastair Nicol, a deer specialist at Lincoln University, responded.

Both crushed oats and lucerne (hay or chaff) are suitable feeds for young fallow deer but as usual ‘the devil is in the detail’. Grains like oats, especially when crushed are broken down very rapidly in the rumen and if too much, greater than 150 g, is eaten at one time, (I’m guessing your young fallow deer weigh around 25-30kg) they can suffer from ‘grain-overload.’ The rumen can’t handle the massive quantity of volatile fatty acids produced from the fermentation of the grain, the rumen malfunctions; animals stop eating and can die.

It also takes the rumen days to adjust to a novel feed, so they should be offered new feeds in small amounts, say 50 g/day and slowly (over a week or so) built up to the full amount. Lucerne, because of its higher fibre content is less of a risk in this regard.

Don’t wait until it is cold to start offering supplementary feeds, get them used to them in good weather, so you can increase the amount feed when it gets cold.

Young, small animals are more sensitive to the cold than larger, older ones, particularly if they do not have plenty to eat.

Without a post-mortem it is impossible to be confident about what might have been the cause of death of your two young deer.