Weanling and Yearling Diets Require Feed in Addition to Mare's Milk

Balance the diet of your weanling or yearling with the right feeds and healthy supplements.

It’s absolutely essential to provide foals with balanced, nutritious feed. After all, young horses can’t manufacture what they need out of thin air! Young Horse bones and tissues don’t just magically get bigger. They have to be built from the nutrients supplied in the foal’s diet.

Historically, young horses have gotten their nutrition from their dams’ milk and the plants they browse in the surrounding environment. That’s it.

Even today, horses living in the wild don’t have tubs of grain or supplements available to them. Those are modern-day dietary conveniences that we provide to our beloved domestic horses.

This isn’t to suggest we should go completely back to nature’s way. Modern horse breeds, especially, can have higher nutritional requirements than their sturdier wild cousins. And if truth be told, wild horses may be more stunted and scruffy than they would be if they were receiving better nutrition.

Modern Management
But far more often than not, young horses are fed in a way that bears little, if any, resemblance to nature’s way. Instead of a very gradual weaning process over 9 to 12 months, many foals are deprived of their mothers’ milk at a young age. Emphasis is put on rapid growth, even “fattening.” Future soundness can suffer as a result.

First, it is important to realize that young horses do not need grain per se. Overfeeding calories in the form of grain encourages very rapid growth. Between growth spurts, the calories are deposited as fat. Both rapid growth and excess weight have been identified as risk factors for a variety of developmental skeletal problems including osteochondritis dissecans (OCD), contracted tendons, and physitis (inflammation surrounding the growth plates).

If minerals are not available in the correct amounts and balance, bone quality can suffer as well. Splints used to be a problem with young horses when put into work at an early age. Now you can see them on a significant number of babies at yearling sales.

If you’re like most people, you’ve been conditioned to think that young horses have to have grain to get the nutrition they need. You may also think that as long as a foal seems to be growing okay, your feeding program must be doing a good job. You could be wrong.

Take a look at Table II, Key Nutritional Requirements, which appears on page 56. Two of these feeds have recommended feeding levels for weanlings. Two aren’t recommended by the manufacturer for weanlings. But even those two provide as many calories as the growth formula feed, and babies getting those two adult formulas instead would grow just as fast. The difference is, they wouldn’t be getting the extra protein and minerals they need to build strong tissues, bones, blood and a healthy immune system.

Now take a look at the two feeds on the chart that this manufacturer does recommend for weanlings. It looks like the mare formula provides more protein and minerals, but the fact is, the concentrations in both feeds are nearly identical, but they recommend feeding weanlings more of the mare formula than the youth feed for some reason. In any case, the point is that none of these feeds, fed at the recommended level, actually meet all the young horse’s needs for all the nutrients listed here. If you fed the mare formula according to label directions, you would be feeding a 450-pound weanling almost 7 pounds of grain a day. Over 60% of the calories he needs would be coming from grain, which is a fairly common practice on some farms. But there are two major problems with this.

Studies have shown that some horses on high grain diets develop exaggerated sugar and insulin responses to such meals, which puts them at higher risk of OCD. The other problem is that even with all this grain, you still haven’t met the foal’s complete calorie, protein and mineral requirements.

The feed bag suggests that you should also feed hay or pasture, but there’s a huge difference between fresh grasses and hay, depending on the time of year. Spring pastures are as high as 20% protein (computed on a dry matter basis, after you subtract the water), but key mineral levels are often lower than in mature grasses or hay.

Feeding Junior

• A youngster that is big, even fat, is not necessarily “well fed.”
• Calories control growth rates.
• A good weanling and yearling diet includes adequate-and balanced-
vitamins and minerals.
• Even top-of-the-line foal feeds do not completely meet the young horse’s needs. Hay and pasture still contribute.
• Smart supplementation starts with balancing nutrients to match your hay or pasture.
• Once hay or pasture imbalances are corrected, you can use balanced grains or mineral/protein supplements to meet the higher nutritional needs of growing horses.
• Feed grain only in the amount needed to support a moderate growth rate.
Meet any additional protein or mineral needs by using protein/mineral supplements, not more grain.

If you look at the average analysis figures for something like timothy hay, the 450-pound weanling would have to eat 7 pounds of hay on top of that 7 pounds of grain to meet calorie needs for a moderate rate of growth (the lower calorie, protein and mineral requirements on the chart). This is possible, but it’s really pushing the upper limit of how much a 450-pound foal will eat in one day. If the foal does eat all this, the hay would only have to be about 7.5% protein to meet protein needs for moderate growth. He’s already getting almost all his calcium and more phosphorus that he needs from the grain. He’ll probably be okay with those minerals if he’s getting something like timothy hay. However, he wouldn’t be all right if he’s getting a very high calcium hay like alfalfa, or a very high phosphorus hay like oat hay, in which case, the calcium/phosphorous balance would be out of whack.

What if you have a rapidly growing foal? Your baby’s calorie, protein and mineral needs then jump by 15%. You won’t know you need to increase your rate of feeding until after you can see the foal has grown. During that growth spurt, he was short on protein and minerals. He probably has less fat on him too, but that’s not a bad thing and is much easier to fix! Taking the tactic of overfeeding to provide a buffer against rapid growth isn’t the way to go either. This actually encourages rapid growth and/or excessive weight gain, not to mention the risk of glucose and insulin abnormalities.

The Solution
The solution here is actually quite simple. Don’t tie your weanling’s protein and mineral requirements to high calorie grains. Even the most highly fortified mare and foal grain mixes only meet minimum requirements-and then only if the foal will eat 3% of his body weight per day in both hay and grain combined. This is also assuming that the hay or pasture has a mineral profile that is as well balanced as the grain mix is-a big assumption.

• Wean the foal as late as possible. You can’t find a better feed or supplement anywhere than his dam’s milk.
• Try to keep the mare and foal on pasture. Grass is supposed to be his first “solid” food. If this isn’t possible, feed as many different types of hay as you can to get a better variety of mineral profiles. Check with your state university agriculture department for advice on what minerals are likely to be lacking in your pasture or hay types, and how much supplementation you should be doing to correct that. In other words, start by building your diet around details of the pasture or hay, not a grain.
• After your basic supplement program is set up (above) use a protein and mineral supplement to meet the increased needs of lactating mares and weanlings before you reach for grain. These pelleted supple ments are very palatable but lower calorie than grain mixes and pack three to four times the mineral levels and as much as twice the protein as grain mixes. In other words, 1 pound of these supplements, also commonly called “ration balancers,” replaces 3 to 4 pounds of even a highly supplemented grain at only one-third to one-quarter the calories. Most are fed at a rate of 1.5 to 2 pounds per day.
• When your supplement and pasture or hay alone won’t support good (not fat) weight and normal growth, use a 14% to 16% protein feed with the highest mineral concentrations you can find. Lactating mares and weanlings have very similar dietary requirements-downscaled for the babies of course, but the protein and mineral percentage concentrations are very similar. Truth is, most milking mares do need a grain mix to hold their weight and support milk production, but they may not need as much as the label suggests to feed them. Feed only as much grain on top of unlimited pasture and hay as you need to hold weight on the mare. The foal will inevitably begin sampling mom’s meals before he is weaned. Unless the mare aggressively protects her meals, there is usually no need to provide creep feed beyond this. A feed that is appropriate for the mare will be ideal for the weanling, too, and he will already be accustomed to it from sharing with his dam.
• When feeding grain, cut back on the protein/mineral supplement at a rate of a third to one-half pound less of the supplement for every pound of grain fed.

By the time they are a year old, rate of growth has slowed to only about 60% to 75% of what it was as a weanling. As a result, even though weight has almost doubled from the weaning weight, calorie requirements go up only about 30%. Don’t make the mistake of thinking the yearling needs twice as much grain because he’s now twice as big. That as sumption is where all the fat yearlings come from! The yearling’s hindgut is also fully developed at this point, which means he can very efficiently ferment hay and pasture. He still needs a diet that is higher in protein and minerals than an adult horse much bigger than he is, but not quite as concentrated as the weanling.

The simplest way to make the transition from weanling diet to yearling diet is simply to keep your level of grain or mineral/protein supplement feeding exactly the same from the age of 6 months through the yearling year, and meet the growing horse’s calorie requirements otherwise from increased hay. It’s really that simple.

Making It Work for You
Let’s see how you would actually go about all this in real life! The first step is to find out what you need to supplement (if anything) to bring your hay or pasture into balance. Your state university can help you with this, or you might want to hire a professional. What you will end up with is a supplement that is designed to meet adult horse needs, which you will feed depending on the amount of hay fed or in a set amount per adult size horse on pasture.

Once you have that critical hay/pasture portion of the diet balanced, it’s very easy to take advantage of a wide variety of products on the market for horses. Table III is a comparison of three different products-an adult type horse feed, a growth formula horse feed, and a concentrated protein/mineral supplement. The high protein and mineral supplements are usually pelleted and fed just like a feed, but in smaller amounts so there’s less chance of forcing rapid growth or excessive weight gain.

If you choose to go with a growth formula, weigh your youngster at 6 months of age, feed grain according to the body weight recommendations at that time, and continue this rate of feeding after he becomes a yearling. Meet increased calorie needs by feeding more hay, with the minerals to match it. If the horse gets too heavy on that amount of grain, you can substitute the protein/mineral supplement (these are pelleted) instead and cut back on calories without sacrificing protein and minerals. If you have adult horses as well, you can actually turn your regular adult horse feed into a growth formula by adding as little as 3¼ ounces of the protein and mineral supplement to each pound of your regular grain, then feed this combination at the same feeding level as recommended for the growth feed.

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