The Internet says- a “forage based diet”
If you spend much time in Facebook groups right now that are focused on horses in general or nutrition in particular, you may have noticed the go-to recommendation for any ailment or complaint is “feed that horse a forage based diet!”. And they’re not wrong! Every horse should be on a forage based diet- it’s how horses’ GI tracts work. The other thing to note is, almost every horse is ALREADY on a forage based diet. Let’s dig in to what a forage based diet is, what the internet thinks it is, and what are reasonable plans for your horse specifically
A forage based diet is one that starts with grass or hay as the base. All horses require a forage based diet, and most have a base or either hay, grass, or some combination of the two although beet pulp, hay cubes, hay pellets, soybean hulls and complete feeds count towards this total also. Horses require at very very minimum 1.25% of their ideal bodyweight daily. That works out to be 12.5 pounds of forage for your average 1000 lb horse, just to keep their gut functioning and acting like it should. Most horses need 1.5-2% of ideal bodyweight daily (15-20 lb if you don’t love math) to maintain condition, but some horses may need more. The amount of forage matters, and the quality matters as well. 15 lb of a high quality alfalfa hay may contribute 16,500 Kcal (calories) to the diet, but 15 lb of a low quality hay may contribute just 9.750 calories…and they’re hard to digest as well. The high calorie hay would suit a hard keeper well, but be too many calories for the easy keeper. A hard keeper may not be able to even eat enough of the lower quality hay to meet their calorie needs, and you may not be able to decrease the high quality hay down enough to meet their minimum forage needs.
The forage base of the diet is always going to need to be balanced with nutrients that are missing from the grass/hay. No forage is going to provide all the things an equine needs, in the correct amounts. This is where the concentrate portion of the diet comes in. It’s a smaller amount than the forage, and provides a concentrated source of the nutrients missing from the forage. This includes loose minerals, mineral/protein tubs, forage balancers, ration balancers, and formulated feed. Deciding which of these fills your nutrient needs based on the available forage, the horses’ age/workload/calorie requirements, and your management system can be a bit of art and science. This one of the places having a nutrition specialist on your care team can be super helpful. There are so many choices available, and it can be overwhelming to sort through what’s a good fit for your specific situation. A forage analysis can be helpful here- it will tell you what it being provided in the largest portion of the diet, and lets you save money and streamline your plan to provide only what’s needed- beneficial for both your pocketbook but also the horse and the environment. Over supplementing nutrients can throw off physiologic processes in the horse (see Ca:P ratio causing growth disorders, minerals blocking other minerals’ uptake, or things like selenium toxicity), is “costly” in terms of the horse’s body having to excrete the excess, and can be less than ideal for the environment. The environment is typically a concern rasied more in food animal production, but some of that goes for horses too. It makes sense to have a hay analysis pulled if you have 3 or more months worth of hay stored, if you have a metabolically sensitive horse or possibly a high performance horse or broodmares. If you’re buying a new load of hay every month or two, it may not make sense to have a hay analysis done, but solid assumptions can made for most hays- they’re almost always going to be deficient in lysine (an essential amino acid), copper, zinc, magnesium, selenium, sodium. Testing pasture grass has really limited application- the compostion of the grass changes almost hourly, and you’re going get limited information that you can make decisions on. Dr Siciliano at NCSU has done a lot of helpful research on pasture and gives us some good tools to make estimates on consumption based on hours on pasture and height/quality of grass.
On to the Internet portion of this- the Internet says a “forage based diet” and kind of ignores the fact most horses are already on the literal definition of this phrase. Often times, what people actually mean is 1) an entirely forage diet- just grass/hay and nothing else. I’d say this is a less common meaning of the phrase, but we’ll explore it a bit for clarity. There are a great many horses in the world who live on grass/pasture only with NO supplementation. Some of these horses are certainly within the parameters of “doing just fine”, and some are surviving as opposed to thriving, and some are doing very poorly. Some horses do appear the casual eye to do just fine on forage only. Most of them would do better with supplementation- better quality feet and haircoat, better toplines/muscling etc. And some are doing poorly and could do with extra calories as well as a host of other nutrients.
The second internet-people definition of this, which is more commonly what people mean, is the “forage based diet” where the horse gets hay/grass, and it’s concentrate “meals” are a forage balancer, some hay pellets and/or beet pulp, a bit of flax and some salt. This diet does work very well for easy keepers (providing they will eat it), and can work for some horses that need a little more calorie support if the correct hay for their situation is readily available and fed at the correct amount. The main thing that makes or breaks this diet is the forage- which makes sense as it’s such a bug portion of the horse’s diet. In an ideal world, the owner can source and afford the hay that meets the horse’s needs: low calorie hay for the easy keeper, high calorie hay for the hard keeper, low sugar hay for the metabolic horse etc. They would feed the right amount of it: maybe 1.5% of ideal body weight for the easy keeper, 2.5% of bodyweight for the hard keeper. The horse would get to eat all of “its” hay, and not have it stolen by a pasture mate. The horse would also willingly consume its meal- a whole concern of itself as minerals don’t taste particularly good, and this way of feeding has minimal ingredients to cover up their taste. The most perfect diet on paper is of no value if it doesn’t make it into the horse’s GI tract.
So what makes sense for your horse in particular? I like to take two main things into consideration: what are the horse’s calorie requirements like? And what forage is readily available and also within their budget? I want to choose a base forage diet that as closely matches what the horse needs as possible, so the concentrate portion of the diet isn’t doing any heavy lifting. In some cases, this isn’t possible. For a horse at a boarding barn who only has access to one type of hay and it isn’t suitable to meet the majority of the horse’s needs, or maybe the hay is suitable but the boarding facility isn’t able to feed enough of it to meet the horse’s needs. In these cases, the concentrate portion of the diet has to swoop in and make up the difference. In another example, the type of hay needed to match the horse’s needs much closer isn’t available locally or is too expensive to be able to feed at the required amount. Some areas are super lucky and have a great selection of hays regularly available, and others are limited to what’s locally grown or maybe a prohibitively expensive hay trucked in from another region. In those cases, the concentrate portion of the diet needs to balance out what’s lacking in the available forage. Sometimes that can be done with a higher quality hay substitute like hay cubes or pellets, but sometimes it’s just not possible to get the amount of those needed into the horse. In those cases, a high quality commercial feed may be the answer. Providing protein, calories, vitamins and minerals beyond what’s possible in a 5 lb meal of hay replacer, a commercial feed may be a good solution. I tend to choose ones that are low in carbs/starches, have a forage base to them like beet pulp and/or alfalfa meal, have a nutrient dense formula/low feeding rate and have good palatability. The good thing is, there’s quite a lot of these available on the market now as companies realize these formulations are popular with owners and work well for horses.
In the situations where a suitable forage- hay or grass- is readily available in the correct amounts for the horse in front of us, there are quite a few options for balancing that forage with a low feeding rate supplement. Almost every feed company has a ration balancer available now. These are designed to be fed at 1-2 lb daily and provide a good complement to nutrients that are in average hays. Amounts vary between companies, but most are going to do a decent job and a couple will do a very good job. Less available in-store, but readily available online, are the forage balancer type products- and even lower feeding rate than the ration balancers, these powdered or pelleted products are typically fed at 4-8 oz per day, and provide a small amount of amino acids, and a high amount of minerals. If your hay is lacking in protein and/or some of the macrominerals, these may not be as good a match as a ration balancer, but for decent quality hays, they can work well. The only downside I really run into with them is the palatability- minerals do not taste good, and most of these products are mineral-dense with very little added to cover the flavor. Some horses don’t mind at all, which is great for them. For the pickier horses, introducing the forage balancer super slowly might work, or combining it with a tastier feed like a small amount of senior feed or co-product like beet pulp may help. I find with a lot of horses it is a trial-and-error thing to find out what works. Which is one of the reasons commercial feed and balancers are a thing- they have done the palatability trials and have masked the minerals with ingredients that make sure most horses want to eat them.
To summarize:
a forage based diet means different things to different people, and it’s helpful to clarify exactly what’s being suggested
there are different ways to approach a forage based diet, and you should take your specific horse into account when planning one
there are nutrition professionals who can help you navigate this
the most important part of the diet is the forage, and everything else we do is balancing that forage to the horse’s needs