Partial quote from OP’s article:
A study published last year by Waltham, which provides the science underpinning the Spillers feed brand, in collaboration with Michigan State University, discovered that feeding a hay-only diet resulted in reduced digestibility of calcium, magnesium, copper and zinc.
…the hay diet was lower than the other two diets for fat intake, amount digested and percent of apparent digestibility. However, perhaps most importantly the apparent digestibility for various macro and micro minerals (including key trace elements) was consistently lower when fed the hay diet compared with the other two diets.
“It seems that many micro and macro minerals are less available to the horse from a hay only diet than when the hay is fed together with a fortified feed,” said Spillers research and development manager Clare Barfoot.
Look, we all know that some horses, older horses, horses with heavy work loads, pregnant mares, may need other feeds, fats, or supplements to stay healthy. I’m not disputing that. But I have a few comments about this study and the scientific value of it. There are several glaring problems which pop out at me and I am not a scientist by any measure, so it would be interesting to hear from some of you who are.
First of all, the study was done by company employed by the feed manufacturer, and that makes me skeptical. Saying that it was done “in collaboration” with a respected university doesn’t mean anything because the collaboration could mean something as simple as Waltham getting data from the school; who knows what that means?
Second, a result saying that something is “lower than” is meaningless scientifically. Sugar is lower in fat that butter – that doesn’t mean I should eat a bunch of sugar. Of course a low-quality forage is going to have less fat and minerals than a feed concentrate; are we really surprised to read that hay, which is very fibrous, is “lower in fat intake, amount digested and percent of apparent digestibility”? Isn’t that the whole point of feeding hay? If the horse is getting what it needs from the hay that is all that matters, and although this study pointed out “less than,” it didn’t address sufficient at all.
There have been so many studies done, respectable studies, which show the benefits of a high forage diet, and which clearly demonstrate all sorts of different benefits ranging from heat production in the gut which occurs during digestion of hay and is a benefit in cold weather, to good dental health from the even wearing of teeth in horses which eat a high forage diet, to reduced ulcers and colic incidents, and on and on. How many posters have problems with their easy-keepers who need a low-quality hay to maintain their weight while being able to have something to eat more than twice a day?
Bluey pointed out another problem with this study, which was the lack of information on the type of hay. I cannot keep my Thoroughbreds in good weight with grass hay, but alfalfa works well. This gets back to the whole concept of sufficient, and that makes me wonder about excessive, which is a whole 'nother subject.
I think this study is little more than a cleverly-worded advertisement.
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