What does a forage nutritional analysis for horses tell you?
This figure measures the energy that is apparently digested and absorbed by the animal. It is determined by subtracting the energy contained in the faeces from the gross energy. In horses, the fecal energy loss is typically 35 – 40% of the gross energy. The DE is used to balance the energy portion of the equine diet. Energy requirements are expressed as megacalories (Mcal) in the nutrient requirement tables. In Europe we use megajoules but an easy conversion can be accomplished by multiplying the Mcal figure by 4.187. This calculation will then give you the MJ/kg figure.
Dry Matter (DM)
This measure equals and represents everything in the forage sample other than water including protein, fibre, fat, minerals, etc.
Horses consume the forage they are eating to meet their DM needs, because it is the dry matter that contains all of the nutrients. This means that a horse eating a 900 g/kg dry matter content hay will eat less than a haylage containing more water, and thus a lower dry matter content of say 700 g/kg. A wetter forage will cause the horse to consume more.
This vitally important figure is often not included on analysis reports but there is considerable variation in the water content of forages. Grass can vary from 15% right up to around 34%. Hay can vary from 85% to higher than 90%. Haylage can be anything between 55% and 85%, some haylages are even slightly higher than 85%.
Do not buy a report without the DM measure as the figures become useless without it for mineral balancing and a forage focused approach to horse nutrition. For an article which will help you further understand the importance of dry matter content click here.
This column is the nutrient results for a sample in its natural state including the water. Also known as as fed or as received. Livestock nutrient requirements may be expressed on either an as sampled or dry matter basis. It is important to use analytical results expressed on the same basis as the nutrient requirements. In general, most livestock requirements are expressed on a dry matter basis, therefore the forage results on a dry matter basis should be used to balance the ration. Again, the key point is to make sure that the requirements and results are expressed on the same basis.
Crude Protein (CP)
This is a measure of the total protein in the sample including true protein and non-protein nitrogen. Proteins are organic compounds composed of amino acids. They are a major component of vital organs, tissue, muscle, hair, skin, milk and enzymes. Protein is required on a daily basis for maintenance, lactation, growth and reproduction.
The number on the report is an estimation of total protein based on the amount of nitrogen in the hay. It does not tell you anything about the amino acid composition or the protein quality. Many forages particularily those which have been fertilised with an NPK fertiliser can have amino acids which are poorly formed. This leads to some of the essential amino acids being unavailable to horses.
If your horse has skin issues, poor hoof health, cracks and white line disease, and or lethargy problems and you have addressed minerals in the diet so that they are forage focussed you may be looking at a protein deficiency. This can be helped by feeding alfalfa or where calcium levels or concerns about weight gain prohibit this Whey Protein can be added to the daily feed. Another approach is to feed only Essential Amino Acids.
This is an indispensable amino acid required for growth in the young horse and the maintenance and support of muscles in the adult horse. The figure is estimated from the crude protein content. Lysine is the most limiting amino acid in forage and is often low in comparison to a horses daily needs. For this reason supplementation of around 10 grams per day or more for lactating, pregnant, young or hard working horses is very important.
Acid Detergent Fiber (ADF) and Neutral Detergent Fiber (NDF)
This figure measures fibers (there are 5 types). Since fibers are digested by the microbes living in the hindgut (cecum and large colon), a healthy microbial population is important to allow your horse to derive calories from fiber. However, there is one type of fiber that is indigestible—lignin; the lignin ends up as manure. Lignin content increases as the plant matures so the later cut your hay is, the stalkier it is, the higher the lignin content.
A hay that is harvested early in the season when there is more leaf will have a lower lignin content. The higher these two values (ADF and NDF), the more lignin the hay contains, so the more of this type of hay a horse will have to eat to maintain their weight. The ideal ADF is less than 35%; ideal NDF is less than 45%. However, most hays have values 10 points or more higher than these desired levels. 10 or more points higher is not a problem but to compensate more hay needs to be consumed. This can be easily solved by allowing your horse to have free access to hay 24 hours a day.
Water-soluble Carbohydrates (WSC)
This is a measure of the simple sugar and fructan levels in the hay which includes monosaccharies, disaccharides and some polysaccharides (mainly fructan). Simple sugars are digested in the foregut and raise insulin levels. Too much can lead to laminitis because of elevated blood insulin.
It has been thought in the past that fructan can contribute to laminitis, however the amount of fructan contained in pasture has not been shown to be a problem so it is now thought that the levels of simple sugar and starch are the figures to be aware of when trying to control laminitis in horses.
This is a subset of WSC without the fructan fraction and includes primarily monosaccharides and disaccharides. The ESC measure gives you a much better idea of the simple sugar level. This combined with the starch level is the figure that you should be interested in when controlling laminitis in horses.
The ideal level Dr Kellon and the ECIR Cushings Group have found for managing laminitic horses is an ESC and Starch combination of below 10%. Rinsing hay will reduce the sugar but you need to rinse in a specific way that is like washing detergent out of clothes.
This compound is normally digested in the foregut down to individual glucose (blood sugar) molecules; therefore, it has a strong elevating effect on blood insulin levels. For this reason it is important that this measure is contained on a nutritional analysis for a horse which is either actively laminitic or insulin resistant. You cannot lower starch levels by soaking or rinsing hay or haylage. It is therefore wise to feed hay or haylage which is low in starch. As stated above it is wise to feed hay to IR/laminitic horses which has a combined ESC and Starch amount of under 10%. Some horses will do better on an even lower % so experimenting with rinsing hay below 10% is sometimes also necessary.
Non Fiber Carbohydrates (NFC)
This is a mathematical estimate of non-cell wall (non-fiber) carbohydrates consisting of starch, sugar, pectin and fermentation acids that can serve as energy sources for the animal. NFC is calculated as 100% – (CP% + NDF% + Fat% +Ash%).
What does a full mineral analysis for horses tell you?
The easiest way to understand this is to imagine the minerals are balls in a lottery machine; too many of one colour ball will result in that ball having an unfair advantage in dropping down the shoot. So if you have a hundred blue balls and only 10 red balls the chances of a red ball dropping down the shoot (being absorbed) will be 10:1. If the correct ratio should be 2:1 then you will have a deficiency occurring where exposure cumulatively, over time, will result in greater and greater deficiency.
Calcium to Phosphorus ratio:
There should be more calcium than phosphorus in hay/haylage. Our hundreds of analysis of forages show that the typical profile in the UK is just this, with calcium often reporting as much higher than phosphorous.
Phosphorous is typically low in both UK and European cured forages. Most hay in this part of the world will have this balance. The ideal ratio is 2:1. The level of calcium can be higher and a greater ratio tolerated but it is better to ensure a 2:1 ratio for optimum health. For horses in heavy work or growing this ratio needs to be lower.
Where calcium is constantly at a high ratio it will lead to the lottery machine allowing too many calcium balls into the system and not enough phosphorous. In the UK many of our concentrate feeds are fortified with calcium and have raw ingredients such as alfalfa and beet pulp with are high in calcium. This is not a bad thing where mineral amounts in forage show a low calcium content but where calcium is sky high and phosphorous rock bottom low then this can lead to mineral imbalances which affect the horse.
Phosphorus concentration must never be higher than calcium levels but this is something we have NEVER seen in any of our forage analysis here in the UK.
The Calcium to Magnesium Ratio:
Ideally, calcium content should not be more than twice that of magnesium. Most hays have a magnesium level that is lower than what horses ideally require. The common ratio which we see in the forage reports here in the UK and Europe commonly puts the ratio between calcium and magnesium as high as 7:1 and an average of 4:1. It is very rare to see a report with results which show magnesium to be at the 2:1 ratio.
Where a horse is lamintic the ECIR Group and Dr Kellon have found that lowering the ratio further to 1.5:1 can have very positive effects on metabolism. Supplementing magnesium at a high level to target levels to a Forage Focussed level is extremely important.
The Electrolytes Sodium, Chloride and Pottasium
The major electrolyte minerals are sodium, followed by chloride and in smaller amounts potassium. Very small amounts of calcium and magnesium are also needed. Some reports do not include chloride levels, do not buy a report like this as knowing chloride levels in forage is very important.
The National Research Council (NRC), in the current 6th revised edition of Nutrient Requirements of Horses (2007) gives the following calculations to determine maintenance requirements based on body weight (BW). For sodium it is 0.02 x BW and chloride, 0.08 x BW. A 450 kg horse requires 9 grams of sodium and 36 grams chloride per day. Note that these are minimum levels and do not take into account sweat losses on a hot day or through exercise.
Forageplus statistical analysis of forage has shown that on average horses often obtain far less than 9 grams of sodium per day through the forage they eat. Usually chloride is sufficient for maintenance and low levels of work. Pottassium is always provided in vast levels in forage and very rarely, if ever, needs supplementation even for horses doing up to 5 hours of sweating, as long as those horses are receiving ad-lib forage. Where horses are on a high cereal diet they made need supplemental potassium but such high cereal diets have a negative effect on gut ph so are to be avoided if possible.
The forage analysis above shows good levels of potassium and chloride in the forage. Levels of sodium however are low and although they will cover a 450 kg horse’s maintenance needs at 10.4 grams of sodium per day, once this horse begins to sweat then a shortfall will occur which needs to be supplemented to maintain optimum health and performance.
The Ratios between Iron, Zinc, Copper, and Manganese
Ideal ratios as reported by the NRC are: Iron:Copper — 4:1; Copper:Zinc:Manganese — 1:4:4 although Dr Kellon likes to supplement at 1:3:3.
We see ratios between iron and copper above 20:1 as the most common in the forage we analyse at Forageplus. This means that iron (which is a mineral the body finds very difficult to excrete) is being absorbed at much higher levels than is healthy. Cumulatively over time it appears that this high iron absorption predisposes horses to certain health issues. At the same time, copper is unable to get down the lottery shoot in the quantity needed for the body to be truly healthy. It makes no sense to routinely feed horses extra iron in the form of fortified supplementation in feeds or other nutritional supplements especially when many of the raw foods used in commercial feeds such as alfalfa and beet pulp are already high in natural iron.
It makes no sense to routinely feed horses extra iron in the form of fortified supplementation in feeds or other nutritional supplements especially when many of the raw foods used in commercial feeds such as alfalfa and beet pulp are already high in natural iron.
Manganese is another mineral which reports as being high in most of the forage reports we carry out for customers. You will see from above that the ratio between zinc and manganese should be 1:1 but we can tell you right now that we have NEVER seen this ratio in a forage report. Commonly the ratio is above 15:1, with the highest we have ever seen being 52:1. Zinc is extremely important for skin and keratin health but commonly it is at such low levels in forage that deficiency is probably the norm even on commercial fortified feeds because the levels of zinc added to these feeds are to low to counteract the antagonist effect of the high levels of manganese.
As most commercial feeds also include added iron and manganese you can see that an antagonist element makes the zinc and copper added to these feeds pretty worthless.
This is worth analysing as some areas of the UK are extremely low, yet some reports do not include it. Interestingly there are tiny pockets of high selenium in the UK, a bluff above Frodsham is one such area. Since selenium has a narrow range of safety (1 to 5 mg per day) it is important not to over supplement but 1 mg seems to be a safe average. Too little, however, can be just as damaging as too much, so it is vitally important to know your hay’s selenium level before you supplement. Horses in hard work are particularly vulnerable to the average low content of selenium in the forage in the UK and Europe as much more selenium is needed when a horse is in heavy work.
Iodine levels are generally low in the UK but there are pockets where very high amounts are shown. For this reason this mineral should be analysed yet some reports do not include it. It is particularly important to determine the amount of iodine in the diet of a pregnant mare as damage to the foetus can occur if amounts are too high.