FROSTY FEAST I can recall reading somewhere that it’s bad for horses to eat frosty grass – but I can’t recall why and can’t find the article! It was an English article, and it recommended waiting until the frost has melted before turning your horses out i
Vet Dave replies:
The concerns with horses eating frosty grass are that there is an increased risk of laminitis and an increased risk for medical colic.
It’s believed there is an increased concentration of sugars in the grass following a frost, thus horses who have equine metabolic syndrome and are insulin-resistant are at risk of a higher than normal sugar intake by eating frosty grass, and thus laminitis.
In a practical sense this would require the grass which is frosty being springtype grass, and having an already reasonable level of sugar present. From the perspective of the ordinary horse, the risk of laminitis is nil from eating frosty grass.
For our fatter four-legged friends who suffer from laminitis, there is the possibility of eating frosty grass causing a repeated bout. However, it would be hoped that the owners of said curvy ponies would already be on guard for the ingestion of too much grass.
With regards to frosty grass causing colic, there are two suggested methods. The first is upsetting of the digestive system through a change in diet, the second is temperature shock from cold grass hitting the stomach. The more likely method in my opinion would be the former, especially for a horse who had been stabled and then turned out. However, the risk here is also very minimal and unlikely to be of real concern.
My opinion is that there is minimal risk for horses grazing on frosty pasture and I would not alter my management strategy
Nutritionist Lucy replies:
Hi Amy, animals will typically not eat frozen grass – unless they are very hungry. In winter, eating anything cold can cause problems as it can reduce core body temperature – hence why mountaineers are always told never eat snow no matter how desperate they may be.
Also, when the weather is frosty, the grass will continue to photosynthesise, producing sugars, but when temperatures are low, the grass will not grow and lay down fibre, as it will in other seasons. Hence frosted grass can be very high in sugar, which is a problem for laminitic and sugar-sensitive horses.
In general, grass will be higher in sugar on bright sunny days – so it’s a good idea to try to dilute out any negative effects by providing them with a high fibre forage source – such as hay or baleage from fibrous pastures.
the suggestion in human medicine that high levels of omega 3s, such as those found in fish oils, may have some health benefits. How well this research crosses over from human biology to equine and to what extent horses are affected by differing omega 3 and 6 ratios is not well known.
For me, the jury is still out as to whether the increased cost of feeding flax seed oil justifies the potential benefits and I would not fault you for feeding the cheaper vegetable oil – especially if that freed up some money that could be spent elsewhere of more benefit to a senior horse such as regular dentistry and farriery. Hi Sue, it depends on what you’re trying to achieve. Research is still undecided about the balance of omega oils in horse diets, although typically they need more omega 3s than anything else, as horses cannot manufacture these in their cells.
However, take heart as there is a good middle ground for you! Canola oil is high in omega 3s but is still available via supermarket shelves. Indeed, research has shown that canola oil is good for joints and for reducing inflammation in horses, as well as being a source of ‘cool’ energy and omega 3s.
All the omega oils of varying lengths are needed in animals for various functions, but the 3s are often the most lacking in the diet, especially where a horse is fed cerealbased feed. Typically, recommendations for mammals vary from 3:1 and 5:1 for omega 3 to 6 ratios, which gives you an indication of balance required. However, your primary goal is to feed extra cool energy to your horses, so using canola oil should help achieve this without increasing the omega 6 levels and still getting the energy into them.
The oil for human consumption should be stabilised with vitamin E to prevent rancidity. As always, when introducing oil into the feed, do so slowly to ensure the gut can adapt accordingly. Up to 15% of the total dietary intake of feed as oil has been proposed as the maximum safe level of delivery of oil for horse feeds. Other research suggests limiting oil to 80-100 ml/ day for a 500kg horse in moderate work.