Whenever we think of feeding horses correctly, what we are considering or what we should be considering is achieving nutrient balance or maintaining it if that is not already the case. If we decide to add a complimentary feed to the diet at anytime we are doing it in the interest of balance. The reason for feeding some extra Magnesium for instance is to achieve balance if that is not the intention but fed as a drug to try to achieve a result in its own right such as calming a horse down then that is wrong, minerals are all connected and are nutrients not medicines.
A most important balance in horse nutrition that impinges of a whole host of bodily functions is the ration between calcium, phosphorus and magnesium. Very roughly the ration for the horse should be 3:2:1 in the total daily diet. Ratio is very important because calcium, phosphorus and magnesium all compete for absorption at the same receptor sites and it is easy for an over amount of one to take precedence over another and also the excretion of one requires the presence of another so excesses requiring to be got rid of are not just eliminated but are accompanied by a companion mineral whether in short supply or not.
Knowledge of this nutrient ratio can send the novice horse owner interested in feeding into a spin having forage analysed, referring to declared figures of known foods, weighing daily dry matter intake of each feed and then comparing with published results. As nutritionists we applaud such zealousness but in reality such exercises are less than common so how do most horse owners get it right so often? Well it is not coincidence that average hay and grazing is approximately 3:2:1 therefore we start more or less in balance if we feed good quality roughage to appetite.
As good quality forage provides nearly all the nutrients needed for maintenance and sometimes maintenance and a bit more getting good forage first must be the right thing to do and as long as we do not stray too far from this all will be well. Better to spend your money on good forage and nothing else than poor forage and an array of supplemental feeds. The ideal of course is to purchase good forage plus other feeds when needed as long as you stick to roughly 3:2:1 especially if you have an active, growing or suckling horse that happens to require more energy than maintenance and is more likely to require M+25% or M+50%, the energy density of forage can only meet a certain level of activity.
The calcium, phosphorus, magnesium ratio in Hay and Haylage can be out of kilter most commonly calcium can be higher but that is not too much of a problem as the higher the calcium content the less the body absorbs so there is a slight default system in place. Luckily the ratio of phosphorus being too high in forage is rare and again there is a default in as much as not all the phosphorus in forage competes with calcium absorption in the same place as does the phosphorus in other feeds. The most common incidences of the 3:2:1 rule being out is low magnesium in relation to calcium and phosphorus and this is why a little extra magnesium from Maglyte or Magfluid seems to just put things right. A little extra magnesium even fed with an already existing 3:2:1 forage is not harmful especially if horses are very sensitive and easily stressed but that to a certain extent should be the limit of feeding a single element without prior analysis.
A most important consideration to be kept in mind before panicking about the ratio getting out of balance is proportion. You can wrongly get worried about a kg or so of oats or maize being fed to meet required energy density of the total diet the Ca:P:Mg ratio of oats and maize are after all quite different at roughly 0.5:2.5:1 quite unsatisfactory to be fed in entirety but when a little is fed together with a good level of forage the ratio for the total diet does not move out of balance that much.
The same for bran that is likely to have a 0.3:2:1 ratio, obviously fed in large quantities without balance as the Romans did, feeding flour to the legionaries and bran to their horses causes calcium to be extracted from bone to meet the many requirements for calcium in the body and to accompany the excretion of excess phosphorus and in the case of bran competition where all the phosphorus is in competition at the same reception areas to calcium, but again when only a lb or so is fed with adequate levels of good forage it is not a problem, inexperienced advisors and salespeople with hidden agendas fall into this trap by giving dire warnings about feeding bran our advise to them is simply do the maths, nature is more tolerant to bigger variations than what a little bran imposes. Indeed if forage is grown on chalk or particularly well limed and cared for land a little bran would probably result in getting back to 3:2:1.
Other common feeds are not so dramatically different and are a relevant source of calcium dried beet pulp 2.38:0.34:1 and dried lucerne (alfalfa) 4.75:0.7:1 again small additions of these to the diet present no problem and for other nutritional and practical reasons can be an advantage but phosphorus and other nutritional parameters exclude large quantities without some attempt to balance them. Linseed, recently popular due to EU subsidies is roughly 0.6:1.35:1 and ground cereal straw often encountered with recycled fats as a ‘slow release’ feed is 1.5:0.36:1 but as limestone flour can be added very profitably under the guise of ‘Added Calcium’ the ratio can be quite different but on the whole no great problem if not overdone because the minerals will be very poorly absorbed AND pass out harmlessly albeit with little benefit.
Conversely some feeds if contained within a total diet ratio of 3:2:1 positively increase absorption EQUINOURISH which has a neutral 3:2:1 ratio of its own does not pretend to a add a great deal more Calcium, Phosphorus and Magnesium in such a small amount fed but what it does contribute is very usable indeed and it radically improves mineral transfer efficiency of all the feeds in the diet by various co-factors including the presence of natural boron that decreases magnesium and calcium in the urine. Maize has a higher magnesium absorption than other cereals and the availability of phosphorus in Soybeans is peculiarly beneficial.
The fact that many horseowners’s conserved forage varies from one small batch to another precludes any meaningful analysis being feasible for more than a limited period of time so getting a mineral analysis done is not an option however under such circumstances the law of averages comes the rescue. Not so if you have large parcel of one type of forage often to last the year then there is an augment to do mineral check this being particularly relevant to studs where grass analysis every few years should also be a consideration.
If you do have mineral analysis of current forage and would like some advise on balance let us know or if it is feasible to get one done and you would like our help let us know. Lab costs are about £30 for a complete mineral check and we add 10% to that for our services.