One of the first things you will almost certainly be told, as the owner of a laminitic horse, is “no treats, no carrots, no apples..”. A grape or prune is sometimes suggested as a suitable treat for hiding pergolide tablets, but I’ve heard of owners being warned not to use a slice of carrot or apple for the same purpose. So what’s the science behind this?
I compared the analysis of carrots, apples, plums, grapes and prunes – all fruits/veg that might be given to a horse as a treat or to hide medication – on the SELF nutrition data website. So both on an as fed and a dry matter basis, the carrot wins hands down for having less sugar/starch – just 6.1 g in 100 g. It has the least calories/energy, it has the most fibre of all the above fresh fruits/veg, and it has a huge amount of vitamin A – a 500 kg horse’s minimum requirement for vitamin A is 15,000 IU/day, 100 g of fresh raw carrot provides more than this. Horses grazing will get plenty of vitamin A, but horses on an all hay diet, especially hay that isn’t green or is older than 6 months, may be short of vitamin A, so carrots provide an excellent source. Carrots also score well as being anti-inflammatory.
But how does the sugar/starch in carrots compare to other common feeds, such as hay?
A 500 kg horse eating 2% of its bodyweight would be having 10 kg dry weight, or approx. 11.2 kg as fed weight hay/day. Sticking to as fed figures, say the hay is 7.15% combined ESC (simple sugar) and starch (or 8% DM), that would be 800 g of sugar/starch eaten in a day. If eaten over say 16 hours (so 700 g hay as fed/hour), that would be 50 g of sugar/starch in each of those 16 hours.
So if 700 g of 7.15% sugar/starch hay as fed gives 50 g sugar/starch,
100 g hay as fed would give 7.1 g sugar/starch
and 100 g carrot as fed gives 6.1 g sugar/starch
– so a carrot doesn’t look quite so evil now!
To be fair, that 100 g of hay has also provided a lot of fibre, some protein, fat, minerals and vitamins, whereas the carrot has mostly provided water, but also that valuable vitamin A.
And compare a carrot to say Spiller’s High Fibre cubes which are approved by the Laminitis Trust – they contain 10% starch, sugar content not given, so 100 g of High Fibre cubes would give 10 g starch, plus possibly some sugar – more sugar/starch than the same weight of carrots.
Carrots may have a reasonably high glycaemic index (GI), but glycaemic load (GL) is now considered more important – this takes into account the effect on blood glucose from eating a typical portion. High water content foods like carrots usually have a low GL (less than 10 is considered low – carrots have a GL of 3). Glycaemic load is often recommended as a tool for diabetics to manage their diets.
In her book “The Truth About Feeding Your Horse”, equine nutritionist Clare Macleod busts the myth that carrots “should not be fed to .. those prone to laminitis” and agrees that although on a dry matter basis carrots are relatively high in sugar, on a fresh weight basis they are low in sugar (she suggests a fresh carrot contains around 7.5% sugar). She recommends feeding carrots for their betacarotene content (vitamin A precursor), particularly for older horses, to help provide antioxidants.
As always, common sense should prevail – if a horse’s insulin is too high and/or it currently has active laminitis then I’d hold back on the carrots and keep the diet as strict as possible, just analysed & soaked hay with appropriate levels of protein, minerals & vitamins, plus I like to feed linseed to provide Omega 3 if a horse doesn’t get grass. But once insulin levels and symptoms are under control, then a carrot or two a day, particularly if sliced and fed throughout the day rather than in one go, is unlikely to do any harm, and could do a fair bit of good. Andy Durham’s comments in his presentation at BEVA 2011 (Inter-relationships of hyperinsulinaemia and PPID) that our treatment of EMS horses could inadvertently be contributing to them developing PPID really sticks in my mind – and my current personal opinion is that we should try to treat laminitic horses as “normally” as possible as long as that treatment doesn’t increase their risk of further laminitis.
For more information – www.thelaminitissite.org
