Lysine, lactobacillus acidophilus, selenium, crude fiber, crude protein.  What is it?  What does it all mean?  This crash course on feed labels should help shed some light on that long list of ingredients and hopefully make decisions at the feed store a little easier.

Crude Protein.  This one can be a little misleading because it is not a true measurement of protein.  It is an estimate calculated by the amount of nitrogen found in the ingredients.  The trick here is that protein may not be the only source of nitrogen in your bag of feed.  Therefore, this percentage may not be entirely accurate.  This is when you want to pay close attention to the ingredients to determine the source of protein.   There are 2 essential amino acids to look for: lysine and methionine.  Sources of good quality protein include:  alfalfa meal, soybean meal, flax, beet pulp, and bran.   8-12% protein is considered appropriate for most horses, but can vary depending upon life stages and the horse's condition.

Crude Fat.  Another estimate.  The thing to look for is what kind of fat is inside the bag.  Check the ingredients.  Stay away from saturated fats i.e. animal fats and coconut oil.  Go for monounsaturated fats:  omega 9,6, and 3 found in rice bran, rice bran oil, canola oil, flaxseed oil and flaxseed meal.  A word of caution about omega 6.  Too much omega 6 can actually increase inflammation.  If your horse is experiencing arthritis or any other type of inflammation, stay away from corn oil, wheat germ oil, and soybean oil as they are very high in omega 6. 

Crude Fiber.  Yet another estimate.  However, the amount of fiber found in grain is minimal compared to your horse's total diet.  Forage should be the main source of fiber.  Grass and hay provide plenty of fiber to meet your horse's daily requirements.  Remember, horses spend 20-22 hours a day grazing.  Therefore, forage should be made available to them 24 hours a day.   

Vitamins.  Fresh pasture normally contains an adequate amount of vitamins including A and E.  Horses naturally produce vitamin C (ascorbic acid), B, and K.  Vitamin D is provided by the sun.  Hay looses vitamins A and E during prolonged storage.  When good quality pasture is not available, look for feeds that include vitamins A and E.   Horses that are stressed, heavily worked, or ill can benefit from supplementing all or some of these vitamins.  

Some common sources of vitamin B are:  thiamin (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), cobalamin (B12), biotin, folic acid, and pantothenic acid.

Minerals. The key minerals are calcium, chloride, magnesium, phosphorus, sodium and sulfur.  Good additional  minerals to look for are cobalt, chromium, copper, manganese, selenium, zinc, and silicon.  Sodium and chloride are electrolytes as well as potassium, calcium, magnesium, phosphorus,  zinc, copper, and manganese.

Forage is high in iron.  It not recommended to  supplement iron unless directed by your veterinarian.  Be careful with selenium.  Selenium toxicity can occur if overfed.  Make sure your feed and any supplements you are using do not add up to more than 5mg of selenium a day.

Probiotics.  Lactobacillus, Bifidobacterium , and Saccharomyces boulardii (yeast) are several common probiotics found in horse feed.  These are good bacteria that could aid in digestive tract health.

Feeding Tips:

It is important to know how many pounds of feed you are serving your horse.  Weigh your feed in the scoop.  That is the only way to know exactly how much food you are feeding.   Feed scoops measure  quarts, not pounds.  A scoop of sweet feed does not weigh the same as a scoop of oats.  Check your feed bag for the recommended number of pounds per day.

It is recommended to limit feed to no more than 4lbs per meal to avoid digestive issues.  Horses that require more than 4lbs of feed a day should receive multiple meals broken up into equal portions.  Check your feed bag for feeding instructions.

There are 3 non-structural carbohydrates (NSC) that are not normally found on the bag:  WSC (water soluble carbs: sugar and fructan), ESC (ethanol soluble carbs: sugar), and starch.  These 3 percentages are of greater concern for overweight horses, horses with cushings, insulin resistant horses, and horses prone to founder (laminitis) and colic.  You can typically find WSC %, ESC % and starch % on the manufacturer's website or by calling them directly and asking.  Dr. Juliet Getty of Getty Equine Nutrition, recommends a good rule of thumb is to pick a feed with an NSC value of less than 12% for horses with the above mentioned conditions. 

Provide a plain white salt block instead of a mineral block.  Mineral blocks often contain molasses.  The sweet taste can lead to cover consumption.  Between forage and fortified feeds, your hose should be receiving it's daily mineral requirements.

For additional information we recommend reading:
Nutrient Requirements of Horses
Feed Your Horse Like a Horse
Advances in Equine Nutrition IV