Five steps to good equine nutrition

As an equine nutritionist, I am often called when the you-know-what has already well and truly hit the fan. Whether it be anxiety, excess/lack of energy, obesity, or lack of muscle and conditioning, most of these issues can be easily avoided by following the following five steps to good equine nutrition…

Water - This is a no-brainer. Horses must have plentiful access to clean, fresh water. Without it there’s almost no point in getting anything else right.

Roughage - Not the sexiest part of the equine diet, but what it lacks in excitement it makes up for in importance... Horses don’t really have a minimum calorie requirement, but they do have a minimum roughage requirement. Unless under advice from a vet or qualified nutritionist, no horse should have access to less than 1.5% of its body weight in roughage (pasture and/or hay) per day. Most horses should have access to 2% of their body weight in roughage per day. This means that a 500 kilo horse needs 10 kilos of roughage every single day of every single year.

Most healthy horses, offered pasture and/or plain hay will naturally self regulate to eat around 2% of their body weight per day. There are a few exceptions to this though. Horses/ponies that have feed withheld (i.e. those thrown a biscuit of hay each day in a Jenny Craig paddock) have a tendency to gorge when they have do have access to food as they’re unsure where their next meal is coming from. This is why allowing ponies out to graze for eight hours and locking them up for 16 won’t work. In most instances they’ll just eat 24 hours worth of feed (if it’s there) in six hours and will then probably develop ulcers and behavioural issues in the 16 hours that they’re locked up with no feed.

The other thing that will stop self-regulation is particularly tasty feed. Like us, horses like what tastes good! If you have a buffet of burgers, chips and fried chicken in front of you, would you eat more of those than if you had unlimited access to steamed vegetables, grilled chicken and brown rice? A client of mine (bless her!) once put out four bales of lucerne to last her horse a week and was most surprised when she visited him the following day to find there was not a single stalk of lucerne left! Horses will gorge when they have access to highly palatable food, so this is another exception to the rule.

The other thing that hinders self regulation is endocrine disorders. Cushing’s (PPID), or Equine Metabolic Syndrome (EMS) can increase appetite and hinder self-regulation. It has been found that certain breeds are more genetically disposed to have metabolic issues, these include Andalusians, Quarter Horses, Morgans, Warmbloods, Drafts and pony breeds (breeds that historically adapted to living on sparse food sources). Therefore your ‘easy keepers’ are those that are likely to be predisposed or already have endocrine related issues. Moral of the story is, putting your fat Andalusian or pony on lush pasture or offering them free-choice, non-netted access to ‘premium’ hay is a recipe for disaster.

So why is roughage so important? This comes down to the anatomy and physiology of the equine gastrointestinal system. Horses are designed to eat for around 20 hours each day, so in the wild, where they’re not ridden, they’re pretty much asleep or eating. They must have food in their gastrointestinal tract to keep it moving. A lack of gastrointestinal motility means you have a very sick horse. The microbes in the equine gastrointestinal system are located throughout the intestine and aid in digestion. They allow the horse to gain the most nutrition from a roughage-based diet. The indigestible fibre in roughage assists gastrointestinal motility and encourages an ideal environment for bacterial digestion. Bacterial digestion is how horses get nutrients and energy out of food. A lack of roughage can also cause issues such as ulcers which in turn lead to other health and behavioural problems and prevention is always better than cure.

Protein - Protein in the equine diet is such a hot topic at the moment and this is probably because there is also a lot of misunderstanding about what protein is, how much is needed and why protein ain’t protein!

Let’s start at the beginning; horses have a daily protein requirement of around 10% of their total intake. If they’re on lush pasture or getting a lot of ‘premium’ hay and not in much work, chances are you have your protein bases covered. If your grass is mediocre at best and your hay isn’t much better and/or your horse is in a lot of work, growing, breeding and/or aging then chances are it needs some added protein in its diet. But not all protein is created equal...

Crude protein is the total amount of protein in a feedstuff. Crude protein does not tell you the quality of the protein or how available it is to your horse. The quality of the protein is determined by the number of essential amino acids in the protein. The more essential amino acids, the better quality the protein. So why are essential amino acids so important? They are the building blocks of all proteins and are essential for a number of physiological functions within the equine body.

There are many different amino acids that your horse needs. Your horse can manufacture a lot of these inside its gastrointestinal system. There are 10 however, that must come from the diet. This is absolutely not to say that we need to ensure we’re supplementally feeding our horse 10 different amino acids each day, but just that we need to be aware that different feed sources contain differing amount of amino acids.

To further complicate the situation, essential amino acids can be broken down further into limiting essential amino acids. A limiting amino acid is called limiting because if a horse doesn’t have enough of a limiting essential amino acid it can’t use any of the remaining amino acids to synthesize protein. The amino acid which runs out first so to speak, “limits” any further protein synthesis from proceeding. There are three limiting essential amino acids in the equine diet and these are lysine, methionine, and threonine. Of these three, lysine is the most limiting amino acid.

Some feeds contain very high crude protein and a very low amount of essential amino acids. Feeds/protein sources such as cereal grains, beet pulp and cereal hays have very low levels of essential amino acids. Feeds like lucerne hay, and copra contain moderate amounts and soybean meal, canola meal and and lupins (to a slightly lesser extent) contain the most besides whey protein concentrate which contains a huge amount of these limiting essential amino acids (but is quite cost prohibitive to the majority of us!). So if your horse is in work it’s important you ensure it’s getting enough of these essential amino acids so it can build and repair muscle.

If you’re concerned, then there are amino acid supplements you can purchase, or you can add a small amount of soybean meal (note this is different to Maxisoy) or, depending on the rest of the diet, a big biscuit of lucerne hay to your horse’s diet. If your horse isn’t an easy keeper and needs supplemental feeding then consider lupins and lucerne as an energy source along with beet pulp and/or ad-lib hay for its high fibre content.

Calories - Calories are incredibly important, but also vary incredibly between individual horses. Horses with metabolic issues have trouble eating their 1.5%-2% of their body weight in roughage per day without becoming obese, and therefore regular exercise and/or grazing muzzles or restricted grazing and hay is slow feeder nets are crucial to ensure they stay at a healthy weight. Obesity can not be underestimated as a big health risk and obesity-related issues are on the rise.

Many owners do not know or refuse to admit their horses are overweight, a small number can even be a little defensive about it. Just remember that horse’s can’t be fat-shamed, and a few too many extra pounds does more harm than you think. Research has shown that fatty tissue is not just fatty tissue; fatty tissue/fat deposits/adipose is a highly active metabolic organ that secretes hormones that play a major role in energy balance and satiety.

Fatty tissue produces inflammatory proteins and these may play a role in causing oxidative stress, damaging tissues, and affecting metabolism and may result in conditions such as laminitis, equine metabolic syndrome, insulin resistance, disturbances to the oestrous cycle (mares), lipomas (fatty tumours), and a negative effect on heat tolerance. In my next article I will be going into more depth about obesity and obesity related issues and what can be done about it.

Easy/regular-keepers tend to be perfectly fine on 2% of their body weight per day in relatively plain roughage, with the possible addition of some high quality protein, and hard-keepers need to be fed high calorie feeds daily to stay at a healthy weight. The best person to judge what your horse needs in terms of calories is YOU! So get informed about what a healthy weight looks like, start taking some progress photos and consult an independent nutritionist if you’re in doubt.

Minerals & Vitamins - Unless your horses are living on a very unusual property (previously an orchard which sprayed pesticides or similar) the pasture or hay that forms the majority of your horse’s diet will be deficient in at least four and probably more, essential minerals.

There are seven macro-minerals and seven micro-minerals essential to a horse's diet. These minerals in excess or deficiency can affect the biological function and therefore, the overall health of you horse. Deficiencies or excesses can occur even with an adequate diet and it is important to consider that as well as these minerals being present, they must also be balanced.

If you're lucky enough to have plentiful pasture full of native, low starch grasses with few high oxalate plants and weeds and your horse is in light to moderate work then it probably only needs a very basic supplement which contains the four minerals almost all Australian pasture/hay is lacking.

These four minerals are copper, zinc, selenium and iodine. These minerals are required for myriad functions including growth and metabolism, bone development, skin integrity, connective tissue, wound healing, thyroid function and so on.

Selenium needs to be provided at approximately 1mg - 2mg daily and iodine between 2mg and 4mg daily. Copper and zinc must be provided in the correct ratio to iron. Vet and leading equine nutritionist, Dr. Eleanor Kellon, recommends an iron: copper: zinc ratio somewhere between 10:1:3 to 4:1:3, with the latter ratio being recommended for insulin resistant / EMS horses. Excess iron can prevent the absorption of copper and zinc, so if you know how much iron your horse is ingesting you can know how much copper and zinc to provide. If you don't know how much iron your horse is ingesting then providing somewhere around 300mg of copper and 900mg of zinc to a large horse in work is about right.

Horses in light to moderate work who have 24/7 access to good quality hays, but don't have access to grass will need the above, but will also need a vitamin E supplement (around 1,000IU per day) and an omega 3 supplement as they will be lacking the omega 3 naturally supplied in grass. Omega 3 should be supplied by providing flaxseed/flaxseed oil or chia seed/chia seed oil to your horse’s diet. Provision of vitamin E is especially important if your horse is prone to laminitis.

If you can afford a pasture/soil/hay analysis then I would absolutely recommend it. It doesn't cost much (especially in comparison to regular shoeing, saddle-fitting, bodywork, lessons etc) and gives you a far clearer picture of what your horse needs. Australian soil is typically high in iron so I would immediately discount any supplement containing iron; horses can't easily excrete excess iron.

As mentioned above, our soil is low in minerals such as copper, zinc and selenium. If however, paddocks have been over fertilised or had a fungicide applied at some stage, the soil may not be deficient in these minerals and may in fact contain an excess of minerals such as copper and zinc. Therefore, if you suspect your soil may be unusual I would most certainly recommend getting a pasture analysis. A nutritionist can arrange it or feel free to contact me to find out how you can easily and affordably organise it yourself.

Keep in mind that minerals such as selenium can be toxic if over supplemented. There is a fine line between your horse not having enough, and having too much selenium in their diet, so knowing what your horse needs and what else it's ingesting is important. You cannot simply just provide any old supplement and be confident that your horse is getting all it requires.

If your horse is in work it probably also needs to have salt added to its diet. Sodium and chloride are required for things such as nerve function, intestinal movement and adequate hydration. Depending on its level of work, whether it's dehydrated and what the environmental conditions are like, your horse may need up to 70 or 80 grams of added salt each day! A safe level of supplementation would be 30-40 grams per day for a large horse. If your horse isn't in work then a salt lick MAY be enough, but providing a very small amount of salt in a handful of chaff is a better alternative as excess sodium and chloride (within reason) can easily be excreted.

If you're feeding a good quality, pelleted 'complete' feed at the recommended daily amount then, there is a chance your horse does not need a supplement. They keywords here are 'good quality' and 'at the recommended dose'. If you're feeding pellets that cost you $20 a bag with vague ingredients then I can almost guarantee your horse is not getting what it needs.

Additionally, if you have a 500kg horse in moderate work being fed only 1kg per day, and the bag recommends you feed 4kg then your horse is also not getting all the minerals and vitamins it needs.

If you can feed that 4kgs of pelleted feed over two or more feeds a day (your horse's stomach is not big enough to cope with 4kgs all at once), and 4kgs of that feed doesn't make your horse fat or fizzy then it probably doesn't need a supplement.

There are as many vitamin and mineral supplements on the market than there are sparkly saddle blankets and diamante browbands, but I’m sure it’s no surprise to you that they’re not all created equal. I only recommend a handful and these are all supplements that have been created by qualified nutritionists and not those put together by large feed companies in fancy packaging. The key to choosing a good supplement is one that contains adequate levels of copper and zinc and no added iron. Other additions such as magnesium, calcium, phosphorus, B vitamins and biotin really depend on what else your horse is eating.

I hope the above has gone some way to explaining what your horse needs each day to keep it happy, healthy and performing its best. In my next article I’ll discuss obesity, issues related to obesity such as laminitis and endocrine issues and what you can do to help a horse with these issues.