I will look into a slowfeeder because she tends to scarf down her food rather quickly
Ditto the slow feeder but that "scarf down her food rather quickly", if that means hay, she may have a tendency toward insulin issues, even if she has lost weight. While the mental image of a metabolic horse is always that of a fat horse, one of my metabolic horses is now a hard keeper and would look like a refugee from a slaughter auction if I didn't fill him full of rice bran
Or, as has been mentioned, she may be scarfing her hay down because she's been too many hours with nothing to eat --- slow feeder nets solve that. The ones I buy will hold about 12 pounds of hay which is about half of an average sized horse's daily forage requirement.
Arabs are on that awful thing called "Predisposed List"
That being said, no corn oil, no vegetable oil. They don't have a balance of Omega -3's to -6's. They are very high in Omega-6 which is established to exacerbate any type of inflammation.
This link talks about the high amount of Omega-6 in cooking oils. Healthy Cooking Oils
Where it says in part:
Omega 6 oils are found abundantly in corn, soy, canola, sunflower, safflower and other commercially used cooking oils. The problem is that people are consuming too much of these oils, thus throwing off their omega 3 to omega 6 ratio. The proper balance is fats in a body is important, as if our fat balance is off, cell membranes and other cellular processes do not function quite as well. People today eat way too much omega 6 oils. The ideal ratio of omega 3 to omega 6 is about 1:4.
Even though humans are referenced the same principle applies to horses; although I THINK the "understood" ratio (I don't think there has been a formal study yet) is more like 1:3 for horses but I may need corrected on that.
Rice Bran OIL might be the safest if you don't want to add rice bran meal or pellets; although oil can get really sloppy and has to be used quickly, once the seal is broke.
This link may help http://gettyequinenutrition.biz/Library/FatisFat.htm
Where it says in part:
Balance your oils
To feed flaxseed meal or Chia seeds, it is best to limit the amount fed to no more than 1/2 cup per 400 lbs of body weight (120 ml per 180 kg of body weight). The dosage for flaxseed oil should be 1.5 tablespoons per 400 lbs of body weight (22.5 ml per 180 kg body weight).
When feeding oils that are high in omega 6s, such as soybean, corn, and wheat germ oils, they should not exceed the amount of omega 3 sources. Even though soybean oil has about 7% omega 3s, the vast majority of its content is from omega 6s. And, if your horse requires more fat than these can offer, you can safely add rice bran oil (high in omega 9s). Finally, it’s best to avoid coconut oil and animal fat. These contain too much saturated fat and horses are just not designed to handle these feed sources.
Not all equines are the same
Depending on the health status, exercise level, and condition of your horse, supplementation of fat may be beneficial. But other equines such as ponies, minis, donkeys, and mules cannot tolerate the high levels horses can. They require some fat, but generally 1/3 to 1/2 the amount given to horses.
More I hope this helps - lol lol