We eat to appetite and not to requirement so that in most cases, quantity dictates overall dietary satisfaction. This is well illustrated by the world-wide consumption of junk food in Western Society where bulk (chips?) seems to provide the right signals to the brain. Horses are no different. Although they practice selection this is not based on need as many horse owners would like to think. Horses are not nutritionally wise (like most of us!) and they cannot differentiate quality from quantity. It is a pleasant thought to imagine that a horse licking soil or chewing a tree is seeking out some essential nutrients but it is not. Furthermore, their failure to discriminate against poisonous plants means that they will consume yew, ragwort, etc if available. It is interesting to note that wild herbivores in the UK such as red deer or roe deer do not eat these poisonous materials; they studiously avoid them instead clearly lacking the will to die.
Horses kept extensively eat to appetite and spend their time actively foraging to meet this need. The seasons of the year dictate the availability of food and also its quality; young growing material in the spring and summer is always of higher nutritional quality than old senescent forage that is found over winter irrespective of whether it is grass, heather or browse. This means that, during the forage growing season, horses in the wild will over consume energy relative to need and thus deposit fat in their body mass. This energy reserve should see them over the winter period when forage is usually in short supply. There is a natural ebb and flow in terms of body condition that occurs amongst animals existing in the wild which reflects times of plenty and those of scarcity. Of course, natural bio-rhythms ensure that the young of equids are born when forage is most plentiful and at its highest quality so that the needs of the pregnant/ lactating animal can be met. It is coincident that quantity and quality of forage are both highest at this time.
Horses that have restricted grazing areas on managed pastures can be confronted with either very poor quality forage or high quality material or, all types in between! We are all familiar with the skinny horses/welfare cases grazing poor wastelands in peri-urban areas but we do not seem to be too worried about the obese horses or ponies, essentially welfare cases, grazing lush grassland. Because equids have this drive to eat for up to 16 hours in every 24 they can grossly over consume energy relative to need when grass is growing rapidly in the spring. They can eat a great quantity of grass (between 10 and 20% of body weight as fresh grass!!) irrespective of its quality; they do not differentiate between quality and quantity and thus do not eat any less because they have access to high quality grass. Contrast this with Zebra grazing on the savannah where food is scarce and is often of poor quality, these equids have to cover great distances to gain enough food to survive-a very different situation from that of a horse kept in a grass paddock. Essentially the animal in the wild has to really actively forage to get enough to stay alive whereas the captive horse in contrast, has its forage virtually “served up on a plate”. There is a quantum difference between having to forage and being fed.
We regard the quality of horse food as having two important components that are represented by its hygienic and nutritional characteristics. No matter what the nutritional quality, hygienic quality should always be maximised and never compromised. This means that although nutritional quality is not always the most important characteristic it is vital to support health and high productivity in terms of milk production, growth, etc. Quantity is important for occupation and normality of behaviour but can be extremely bad for animals prone to obesity or laminitis. An excessive quantity of food obviously causes fatness. In contrast, limiting the food supply to stabled horses can result in the development of stereotyped behaviours including some that are not very obvious (licking surfaces) unlike the well-recognised abnormal behaviours such as cribbing, wind-sucking etc.
Horses are generally regarded as requiring a minimum quantity of long forage to maintain adequate gut function. The figure used is 1% of body weight but often less may be fed in parts of the World where forage is in short supply. For example racehorses kept in full work in places like the West Indies, Cyprus, Saudi Arabia, Hong Kong etc may well get less. The least quantity I have come across was 2kg/day fed to 450kg horses in work. Inadequate tooth wear occurs in these situations and, as a result, more dental care is required. Also, these horses are more prone to large intestinal dysfunction such as acidosis and of course, gastric ulcers are more common. Thus, limiting forage supplies can result in abnormal behaviours as noted above but more importantly, there are serious health issues associated with this practice.
Quantity has been used as a sales tool in order to sell product and to allow sales people to claim that their product X contains more of an ingredient than someone else’s product Y. Remember that more is not necessarily better! Vitamin A levels have been used from time to time in this context because it has been a relatively cheap nutrient and thus an easy way to enhance a product’s specification. However, I would like to remind you of a quote by Albert Einstein that goes “Not everything that counts can be counted and not everything that can be counted counts”. To illustrate this quotation, one cannot count palatability but it is very important and whilst one can count vitamin A levels, at high inclusions they are irrelevant. Thus, in certain cases quantity can be meaningless. Furthermore, the quantity of an ingredient per se can be dangerous since it is the balance of ingredients that is important to the horse’s wellbeing. One of the simplest and best examples of balance in a horse diet is that of the quantities of the major minerals, calcium and phosphorus. The absolute amounts present in a diet could satisfy the animal’s requirements for these individual nutrients but if the ratio of calcium to phosphorus was 1:2 rather than the desired ratio of 2:1 then the imbalance could negatively impact calcium absorption and thus bone health.
In conclusion, I have considered the hygienic and nutrient aspects of quality and noted that high nutrient quality is not always the most important characteristic of a diet for a horse. The animal has basic requirements for nutrients but usually more is fed in order to meet recommended daily allowances. However, it is critical that appropriate nutrient balances are achieved within the diet to maintain health. It is worth remembering a couple of quotes by John Ruskin that are germane to these issues. Firstly, “Quality is never an accident; it is always the result of intelligent effort” and that is what goes into the production of quality horse feeds. Secondly,
“There is scarcely anything in the world that some man cannot make a little worse, and sell a little more cheaply. The person who buys on price alone is this man’s lawful prey.” This is worth bearing in mind when purchasing horse feed or any other commodity come to that, since quality always comes at a price-something to ponder when buying Christmas presents? Cost savings rarely confer benefits other than to the wallet…
First Published December 2013 Equi-Ads