Calming, Equine Vit&Min, Foundations of Good Nutrition, Horse Health, Nutrition, Weight Management

Can I blame the supplement? Part 2

Should I blame the feed?

How often do you hear someone say that a few days after changing to a new mineral supplement, or a new bagged feed, their horse has gone crazy? Usually, the change in feed gets the blame, and an owner will think, “I can’t feed that stuff to my horse…..” but this is not always correct.

Changes in horse behaviour can be due to excess energy in the diet but a new environment, stress, separation anxiety, mycotoxins, a new or inexperienced rider and a myriad of other factors can impact on how your horse conducts himself. Sometimes a horse only plays up when away from home, other horses will change in their normal environment. Horses experiencing an ulcer flare or other types of pain will also often exhibit unruly behaviour. Problem behaviours may be corrected by changing the diet, the workload, the method of riding/handling, checking saddle fit, ulcer treatments or treatments for pain, increasing exposure to new situations, desensitising to the stimulus or a combination of these things.

Diet is frequently blamed for naughty behaviour, and often it is at fault but not always for the most obvious reasons. Horses can become boisterous when they feel good, often due to consuming more energy than they use. We all know the phrase “overfed, underworked” but sometimes we can be unaware that we are overfeeding. It can be as simple as subtle changes in grass quality (and the not-so-subtle changes when the spring flush of grass comes through) or availability as is commonly seen in spring when grass changes are more obvious. A horse who has been very slowly gaining weight can cause suddenly reach the point where they tip over the edge into silly behaviour.

Whilst these large changes occur in the background, we often miss them as we focus more on the obvious changes such as the introduction of a new supplement (only a few grams per day) or a change from one hard feed to another (maybe a kilogram or two per day). Yet quite often, the background change is the largest change most likely to have an impact on the diet as it could be around 10 kilograms of dry matter per day.

When you change from one feed to another, check the digestible energy (DE) on the bag label. If both products provide the same amount of energy per kilogram, in most cases you would expect your horse’s behaviour to be the same on both feeds when fed by weight, not volume. If the new feed has a higher DE, you will need to feed less of it (by weight) than your older feed to provide the same level of energy intake in the diet. A new batch of hay or a new batch of grain or pellets can contain more energy per kilogram than your previous batch so even though you haven’t changed the amount you feed, your horse is consuming more energy. If you feed by the scoop rather than by weight you may be inadvertently feeding more kilograms of feed than you realise if changing to a more dense ingredient.

So if your new feed is providing the same amount of energy as your old feed, and your horse goes off its rocker, then you’ve either got a problem with your horse being super sensitive to the new feed, the new feed is exacerbating ulcer pain or there’s something different in the background (like your hay or pasture) that is adding in lots of extra energy.

Some horses tolerate extra energy in the form of fibre or oil without changes in behaviour, but get unruly when the same amount of energy is provided by starches.

Another explanation could be that you haven’t worked your horse as long or as hard this week, or the weather has warmed up, and so your horse hasn’t used as much energy as she does when it’s very cold, leading to an excess of energy. Remember that keeping warm uses a lot of energy, and unrugged horses need extra feed during winter to maintain weight.

Say you’ve added a new vitamin and mineral supplement and your horse goes bonkers, is it because of the supplement? If your horse was previously deficient, you would expect her to feel much better when her diet is delivering all the vitamins and minerals she needs to function optimally. Many horses begin to use the energy they consume more efficiently when no longer deficient due to having sufficient vitamins and minerals to build digestion enzymes and metabolise their feed correctly. In this case, owners should be cutting back the energy intake of the diet (usually by feeding less grain/pellets/super fibres) because adding the supplement has increased the horse’s ‘fuel efficiency’ (and this saving can often more than pay for the cost of the supplement). However, you should also consider whether a change in workload or the background of the diet (hay or pasture) has led to an increase in excess energy in which case a reduction in the hard feed is still warranted.

The best way to manage these bursts of extra energy is to develop an eye for changes in body condition score in your horse. You should always know whether your horse is gaining or losing weight, or staying the same (The internet has many illustrations of body condition scoring systems – there’s a nice one at If you increase the workload without increasing the energy content of the diet, you can expect your horse to lose weight. Likewise, if you reduce the workload but don’t change the feed, your horse should gain weight and possibly start to behave differently.

It is imperative that the dietary energy intake is adjusted in response to changes in pasture and body condition score. In other words, if your horse is gaining unwanted weight and feeling full of himself, cut down or remove the grain/pellets/oil from the diet as a first step. If you need to reduce weight further, limit hay intake to 1.5% of body weight and buy mature grass hay with a low sugar and starch content. If you can’t access low enough energy hay, your hay can also be soaked (half an hour in hot water or an hour in cold) and drained for 10 minutes to remove some sugars before feeding.

Likewise, if your horse loses weight, even with free choice grass or hay available, you will need to increase the energy component of the diet (pellets, grain, super fibres or oils).

Once you’ve ruled out pain, excess energy or a response to your riding/handling methods as being the cause of the problem behaviours, you can try eliminating and re-introducing one ingredient to identify if one feed source is to blame.

Ideally, you need to still balance the entire diet to contain the same energy level and provide all recommended daily intakes of vitamins and minerals in balanced mineral ratios both with and without the suspect ingredient. It will be a long process, but necessary if you are truly to know whether you can blame it all on the feed!

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