The owners of pampered and domesticated ponies are often encouraged to use natural seasonal variations in metabolism and food availability to control their animals’ bodyweight.
But how do those horses and ponies wintering out on the UK’s moors and uplands fare?
Some free-living moorland and hill ponies become very thin in the harsh winters on their home ranges, when food becomes scarce and shelter limited.
To see whether Shetland ponies suffered any ill effects from winter feed restrictions, German scientists compared the body weights and blood samples from out-wintered Shetlands given adequate food with those deprived of food in the way that would occur if they were foraging for themselves in the wild. The 2 groups were otherwise treated identically.
In the deprived group, food was reduced in quantity and quality over the winter until they were receiving only 70% of their maintenance requirement by the end of February.
Compared with those fed just enough, the deprived ponies did suffer some ill effects. Their body mass and body condition scores declined gradually before Christmas, when the loss accelerated. By the end of February, they had lost nearly 20% of their starting weight.
Their blood samples showed that the fatty acids in their blood rose initially, as they burned fat reserves. Total blood proteins then fell, ending up at or below critical levels. Interestingly, their metabolism differed from that reported for horses in similar situations.
So we should be concerned about free-living ponies in harsh winters. While blood samples may be useful in assessing starvation welfare cases in ponies, however, this is not necessarily the case with horses.