Your weanling needs attention to calories as well as actual nutrients.

There’s no time in a horse’s life when diet is more important than when they are growing. In nature, foals grow and mature normally on nothing but their dam’s milk and grass. However, the trend over the last several decades with domestic horses has been to rely heavily on grain and to wean too early. Because the hind gut is not well developed at this age, old recommendations were for feeding as much as three times more horse grain than horse hay for the first year of life.

Current feeding recommendations also focus on rapid growth, tending to produce large, and fat, yearlings that appeal to halter judges and sales-ring buyers. As an outgrowth of this heavy grain feeding, manufacturers developed horse feeds that would deliver high concentrations of minerals, supposedly to take the guesswork out of feeding the young horse.

No One Formula
There are several problems with this no-guesswork approach. The first is that the young horse’s mineral intake is tied to calories. If the young horse happens to be a perfect fit for the National Research Council (NRC) growth rates and requirements, fine. Otherwise, you’ll end up either feeding more calories than the weanling needs to meet mineral needs, or cutting feed to avoid the youngster becoming fat but also cutting critical minerals in the process.

Studies have also found that some young horses experience abnormally high blood sugar elevations after grain feeding, and this puts them at risk of developing OCD (osteochondrosis), possibly as a result of wide hormonal fluctuations caused by the blood sugar swings. The third issue is whether or not these feeds actually get the job done.

Our products table lists the nutritional requirements of a six-month-old weanling weighing 475 to 500 pounds, which will mature to a weight of 1,100 pounds, and nutrient intakes (from label information and feeding recommendations) when using some commercial feeds specifically labeled for use in weanlings. We selected these national brands as examples for the purposes of our story.

Triple Crown Growth, when fed in the middle of the recommended feeding range, meets or exceeds all requirements except crude protein, lysine and for possibly being a little light on the manganese for keeping all trace minerals in balance. It also has the most extensive list of guaranteed levels, so you can actually be sure all the bases are being covered.

To make up the protein deficit, all you’d have to feed would be a little over seven pounds per day of a 10% protein hay. The only problem with this strategy is that the hay intake is always going to be 50% or more of the young horse’s diet. Unless you know your hay has a reasonably good mineral balance, you could be introducing mineral imbalances into the diet.

Put It To Use
Most signs of possible nutritional deficiencies can have multiple causes (e.g. parasitism), which means some investigative work for you: • Poor immune function (runny eyes, runny nose, skin problems). • Slow shedding of the foal coat. • Dull coat. • Lethargy.   • Physitis. • OCD. • Splints.

Purina Junior, which is fed as a complete feed, also meets or exceeds the requirements for the nutrients they actually guarantee on the label. However, even with this abbreviated list, the levels of four key nutrients (manganese, potassium, magnesium and lysine) are unknown for that feed. There’s generous leeway with the copper, zinc and vitamin A, but to get enough protein (the most expensive ingredient to add to a feed) you have to feed the full recommended amount. If your weanling is getting too fat on this level of feeding, any drop will provide inadequate protein. A drop of more than 25% will result in inadequate calcium intake too.

The other two feeds are fed with hay and rely on hay to provide key nutrients much more than the Triple Crown Growth formula does. For example, if feeding Platform Mare and Foal in the middle of their recommended feeding rate, even a slow-growing 500 lb. weanling would still need:

• 510 grams of crude protein • 21.5 grams of lysine

• 17 grams of calcium • 8 grams of phosphorus

• 275 mg of zinc •50 mg of copper

To get that much protein, you would have to feed 9 lbs. of straight 14% alfalfa, which would give you more than twice as much calcium as needed and throw the calcium phosphorus ratio out of balance.

Life Design Junior at the middle feeding range leaves the youngster 450 grams short on protein, which would call for 10 lbs. of a 10% protein grass hay (that would probably also meet lysine needs). However, whether or not it would correct the mineral shortfalls in a balanced manner depends entirely on the type of hay and its mineral profile.

Only the Purina Junior, which is fed as a complete diet, adequate covers the nutritional needs for the nutrients they actually list on the label. However, you have to feed their recommended amounts. The diet is about 30% forage, 70% high NSC concentrates, and there is no information or guarantee for several key nutrients.

Triple Crown Growth, 6.6 lbs.,  with 7 lbs. of a 10% protein hay, is a little better but you’ll need to know you’ve got a good hay to make up differences, and it could still be too much concentrated sugar and starch for some.

What’s The Alternative?
Get back to raising, managing and feeding the young horse like a horse:

• Wean as late as possible. Mare’s milk is the perfect food for the developing horse, and the perfect supplement even late into the first year of life. Unless you have a rambunctious colt that is trying his dam’s patience to the point of risking serious injury, you can allow the weaning process to occur naturally.

• Maintain the mare and foal on as large a quality pasture as possible, minimizing reliance on grains.

• Don’t tie mineral intake to grain calories. Work with an independent equine nutritionist or your veterinarian for determining your young horse’s protein, mineral, vitamin and calorie needs and how best to meet these without having the horse become overweight or forcing rapid growth.

• Adjust calorie intake so that the ribs are always easily felt. Ribs may even be visible when the horse is on a rapid growth spurt but, as with a lanky teenager, this is normal.

• When supplemental calories are needed, include generous amounts of easily fermented fibrous foods to encourage development of the hindgut.

Insulin Resistance And OCD
Studies have found a higher blood glucose response to feeding is a risk factor for OCD. While this had initially been blamed on insulin resistance, the insulin response to the higher blood glucose was actually proportionately the same as the insulin response in young horses whose blood glucose did not rise as high, so it’s not likely to be related to insulin resistance.

Putting It In Practice
We know of several youngsters that have been raised completely grain free, while maintaining normal growth curves and even showing successfully in hand. Others have been raised with grain intakes considerably below what they’re supposed to require for normal growth. In addition to the health benefits from not overfeeding grain, the approach below has the advantage of allowing you to feed all ages and classes of horses the same base diet, adjusting easily to individual calorie, protein and mineral needs.

STEP 1. Start with a balanced base diet. Hay or pasture is the cornerstone. If relying on pasture and/or hay from the same fields all the time, speak with your agricultural extension agent about the proper way to sample your fields for analysis or what a solid range of nutrients is for hay grown in your area. Once you know what is and is not in your grass and hay, you can add a supplement to balance the diet. If you set the supplement goals for adult maintenance, you can boost this with mineral or mineral/protein supplements to suit other classes of horses as need be (pregnant, lactating, growing horses).

STEP 2. Concentrates. When more calories are needed than hay and/or grass alone can provide, use a concentrate that does not upset the balance you just achieved. Obviously a balanced grain mix will do this, but so will these higher fiber alternatives with acceptable calcium-phosphorus ratios:

• Beet pulp with 2 to 4 oz. of rice bran (no calcium added) or 4 to 6 oz. of wheat bran per pound of beet pulp

• 50:50 beet pulp and whole oats

• 1 part alfalfa cubes or pellets, 2 parts oats

• 2 parts alfalfa, 1 part wheat bran

STEP 3. Boosting minerals. Once you have the base diet balanced in minerals, it becomes easy to meet the higher needs of the growing horse by using a balanced commercial supplement. To maintain moderate growth, a six-month-old weanling requires about 10% fewer calories than a mature horse his eventual adult size at maintenance, but 70% higher mineral intakes for bone and soft-tissue development.

Exactly how much more you need to feed will depend entirely on how your base diet worked out. With most hays, by the time trace minerals are balanced you will likely be feeding close to the weanling's requirement anyway, and both commercially supplemented grains and the alternatives we've listed here provide generous amounts of calcium, phosphorus and magnesium.

In most cases, the addition requirement of the weanling will end up being no more than 7 to 10 grams of calcium (maximum) above what the balanced base diet is already giving him, plus the proportional amount of other minerals a correctly balanced supplement will provide.

If you like the convenience of a pellet, something like Triple Crown's (www.triplecrownnutrition.com, 800-451-9916) 12% supplement will do fed at as little as 8 oz/day, or as little as 2 to 3 oz/day of a more concentrated mix like one of Uckele’s economical Equi-Base supplements (www.uckele.com, 800-248-0330).

STEP 4. Protein. Our sample six-month-old weanling needs 750 grams of crude protein a day and a diet that provides about 0.6% lysine if he’s consuming 12 lbs. of hay/pasture and concentrate per day. When pasture quality is high, this isn’t a problem. If feeding 10% protein hay and one of the alternative feeds above, in equal amounts, the diet will provide from 11 to 13% protein depending on which feed you choose. In the worst-case scenario, he will need about 200 grams of additional protein, down to as low as 50 grams. There are many options for doing this, from high protein and relatively low mineral combination supplements like Buckeye’s Gro N Win (www.buckeyenutrition.com, 330-828-2251), to both high protein and high mineral such as Triple Crown 30% supplement. If your mineral bases are covered, your nutrition consultant can give you advice about a protein supplement or make adjustments to your concentrate formula to boost the protein a bit more.

Bottom Line
The hardest part about changing how you feed is changing how you think. That becomes a whole lot easier when you realize that your current feeding might not actually be doing all that you think it is, and the consequences this can have for a developing horse. We like a low-grain, low-fat, moderate-calorie approach to feeding young horses. Considering protein and vitamin/mineral needs separately from calories is the safest and healthiest way to go. Even if you choose to go with high-grain feedings, remember you can’t necessarily rely on the product to cover all the bases and a critical analysis of your entire diet, not just the grain, is necessary.