Most of us have been conditioned to think about our horse’s protein needs as a percentage, like a 10% protein bagged feed. Nothing could be further from the truth.
For one thing, the bagged feed is only a fraction of your horse’s intake. Protein is also in hay and grass. A 10% protein feed provides about 45 grams of protein per pound. A horse getting 10 pounds of that grain consumes 450 grams of protein. that’s quite a difference.
The correct way to look at a horse’s protein requirement is by body weight and level of activity. An 1100-pound (500 kg) horse needs an average of 630 grams/day of protein when not working, and 768 grams/day if He’s in light work. Going back to that 10% protein feed, you would have to feed 14 pounds a day of that 10% grain to fully meet the protein need even when not in work. If you’re feeding a reasonable 4 to 5 pounds of grain per day, the horse is getting 180 to 225 grams of protein, 28.5 to 35.7% of his resting protein needs.
Hay to the rescue.
Hay is actually the major source of protein in the horse’s diet. If the horse is eating 15 pounds of hay a day and that hay is 7.5% protein, he will be getting 511 grams of protein from the hay. If He’s eating 20 pounds of hay, this jumps to 681 grams, more than his resting requirement just from the hay, despite it having ?only? 7.5% protein. Remember, the percentage only tells you how many grams of protein there are per pound. What you need to consider is how much He’s consuming.
You also need to consider the lysine intake, as this is the major limiting amino acid, at least for growth. Hay-analysis laboratories commonly use an estimate of 3.5% of the protein in hay as lysine. The National Research Council (NRC) recommends that lysine should be 4.3% of the total protein requirement. However, since most hays provide more than enough protein when fed in generous amounts, the lysine need will usually also be met, especially if He’s fed any other type of feed.
Are You Feeding Enough’
The most accurate way to check dietary protein is to know the horse’s requirements and calculate how much is coming from the diet. Our chart on page 11 lists some symptoms of protein deficiency, as well as other things that could cause those signs. If you rule out the other causes as the problem, it’s time to take a look at protein intake.
When having problems with young horses that are likely linked to protein, it’s important to get it right and analyze the dietary intake. it’s even more complicated to get correct with hoof or skin/coat problems.
The two most commonly encountered problems associated with protein intake are muscle loss in older horses and poor muscling in working horses, with or without muscle soreness.
Muscle loss is a normal part of aging, called sarcopenia of aging. it’s caused by a combination of hormonal changes (drop in sex hormones, rise in cortisol) and inactivity. The higher cortisol levels in horses with Cushing?s disease only worsens this problem. Treating underlying disease and encouraging exercise are important. However, at least one study suggests that the NRC recommended lysine intake may not be optimal. Supplementation with 10 to 20 grams of lysine may help.
When horses in work don’t develop muscle as expected, or start to lose it, inadequate intake of the branched chain amino acids (BCAAs), leucine, isoleucine and valine may be involved.
Leucine is in higher concentration in muscle than lysine and is the most metabolically active. The combined levels of the three BCAAs is much higher than lysine. Supplementation with mixed BCAAs or leucine alone, 10 to 20 grams after exercise, is often helpful.
A metabolite of leucine called HMB, beta-hydroxy-beta-methylbutyrate, has been identified as a potent muscle-promoting substance. Feeding 5 to 10 grams of HMB, preferably after exercise, is also effective for horses in work with muscle bulk issues.
When the working horse has muscle soreness, a different approach may be needed. Carnitine is a compound that is manufactured in the body from amino acids. It assists with the efficient utilization of fats and is an antioxidant. Carnitine at 1 gram/100 lbs. of body weight is effective in improving metabolism of muscle in horses in early training. Glutathione is one of the body?s most important antioxidants and is especially active in muscle. Exercise inevitably increases the production of oxygen-free radicals and antioxidants are important. Supplementing with 30 grams/day of glutamine, a precursor for glutathione, is effective when combined with adequate selenium and vitamin E dietary intake.
Our product chart describes some available protein/amino-acid supplements and how they can be best used. If you need to boost the protein level of a protein deficient diet, soybean meal is the least expensive way to go, but we like the added protein quality of the blend of soybean and milk/whey in Uckele?s Amino Fac.
If you’re only falling short on lysine, Vita-Flex Pure Lysine or bulk powder from a supplier like Pure Bulk will only cost you about 2??/gram. A dose of 10 grams/day is a reasonable starting point unless you know you need more from a diet analysis. This is also the place to start when supplementing older horses with muscle loss. If there are hoof-quality issues, go with Uckele?s Tri-Amino, which also has a generous dose of methionine.
Horses in work having trouble holding muscle need a more specific approach. Branched chain amino acids can be broken down at high rates during exercise.
We have had good results supporting these horses with branched chain amino acid products like Peak Performance BCAA Complex. For an added punch, combine with HMB as in Smart Pak?s BCAA Complex plus HMB. However, good results can also be obtained using only L-leucine, the major BCAA in muscle. Using Pure Bulk?s L-Leucine considerably cuts costs and we would start with this. If needed, combine it with Su-Per HMB.
For horses plagued with muscle soreness despite L-leucine, add L-glutamine for support of muscle glutathione. Remember that you also need adequate vitamin E and selenium for the glutathione system to function properly.