Farmer's Weekly (South Africa)
HORSE TALK
By giving your horse vegetable oil, you will improve its coat and condition, without the side effects of high sugar rations, says Dr Mac.
Vegetable oils that are used in human diets include maize oil, sunflower oil, olive oil, soya bean oil and canola oil. These contain unsaturated fatty acids as well as the essential polyunsaturated omega-3 and 6 fatty acids, in different ratios.
One of the reasons that horse owners like to add vegetable oil to show horse rations is that it is an affordable way to rapidly achieve the improved condition and shiny coat required of a horse in the show ring.
Another advantage of mixing oil into a horse’s feed is that it is palatable and provides more calories by weight than oats or maize, without side effects such as colic, laminitis, gastric ulcers or hyperexcitability. For example, 100ml of oil supplies as much energy as 300g of oats or maize meal does. Cereal grains supply energy (albeit empty calories) without essential fatty acids, which are the ingredients in plant oils that improve a horse’s coat and all-round show condition. However, oil-based supplements need to be kept in climatecontrolled feed rooms, as experience over the years has taught horse owners about the dangers of rancidity when there are increases in humidity and temperature.
In South Africa, there are commercially available feeds that contain vegetable and/or fish oil high in omega-3 and omega-6, which promote shiny coats and muscle mass gain. While they are highly effective, they are fairly expensive, and many horse owners therefore prefer to use oils sold in supermarkets.
DECIDING ON OPTIONS
The difference between omega-3 and omega-6 is more than just chemistry; omega-3 is involved in anti-inflammatory reactions in the body, while omega-6 is involved in pro-inflammatory reactions, so the two should be in balance.
Maize oil, for instance, is about 80% higher in omega-6 than omega-3. Canola oil contains two parts omega-6 to one part omega-3, but has several disadvantages. It comes from genetically modified canola and is popular in the US as a substitute for olive oil. Recent studies in humans have shown that canola oil goes rancid easily due to its high sulphur content. This can reduce the vitamin E content in the ration through oxidative reactions. Vitamin E and selenium are known to play a role in preventing ‘tying-up’ of muscles in competition horses, so this is an important consideration.
Soya bean oil is high in omega-6 and is a popular constituent in breeding rations for horses. It is better to use registered and processed soya bean meal and oil, as the unprocessed versions can have toxic effects due to the presence of phyto-oestrogens, which affect the hormonal cycles of mares and negatively affect thyroid function. Raw soya beans also contain a trypsin inhibitor that prevents digestion of the essential amino acids lysine and arginine.
Linseed oil must be specially processed, and only commercial varieties registered for horses should be used. Sunflower oil is higher in omega-6 than omega-3, but is generally well tolerated; supermarket quality is affordable and works well as a feed additive.
Whatever oil you decide to add to your horse’s feed, it is important to do so gradually. Start with approximately 100ml (20 teaspoons) divided up over a week. The optimal dose of oil to build condition and improve the coat in a show horse is about 100ml per day, divided into two feeds, for a 500kg horse.
Dr Mac is an academic, a practising equine veterinarian and a stud owner. Email her at farmersweekly@caxton.co.za. Subject line: Horses.
VEGETABLE OIL IS PALATABLE AND PROVIDES MORE CALORIES BY WEIGHT THAN EITHER OATS OR MAIZE MEAL