Growing Horses Need Supplemented Minerals

If all we had to do to keep our foals and mares sound and healthy was to feed enough to keep them in good flesh we’d have it made. Calories are easy. But it’s often the big, strapping youngsters that run into trouble with epiphysitis, or bone cysts in their stifles, or bucked shins in early training.

Poor nutrition isn’t the only cause of developmental problems, of course, but it’s a big factor — and one that is completely within your control. It’s also not enough to get aggressive about ration balancing when it’s time for creep feeds and weanling rations. Problems like OCD get their start long before the foal is born. And minerals are the biggest problem, as it’s difficult to find a grain/hay combination that meets these levels adequately.

Two Birds With One Stone
In a perfect world, we could simply purchase a mare-and-foal fortified grain mix and feed it with high-quality hay, meeting the higher mineral needs of growing horses without forking out extra money for a supplement. But it’s not a perfect world.

To their credit, feed manufacturers do try to meet these higher required-nutrient levels, with at least one formula in most lines claiming to fit with virtually any hay. We decided to see how one of these special feeds stacked up in the real world.

We took Triple Crown 14 (TC14), a top-of-the-line feed that targets breeding and growing stock, and matched it to various hay types in the diet of a 1,100-lb. mare in her last trimester of pregnancy. The formula of this feed is: protein 14%, average calcium 1%, phosphorus 0.65%, magnesium 0.55%, lysine 0.75%, zinc 150 ppm, copper 60 ppm, selenium 0.55 ppm, manganese 120 ppm.

Timothy: You have to feed 9 lbs. per day of TC14, with 10 lbs. of average-composition timothy hay, to meet the calorie, protein, lysine and mineral requirements of this mare. The zinc and manganese levels are less than ideal but workable.

Alfalfa: You need 8.5 lbs. of TC14 and 9 lbs. of alfalfa to get enough copper, but you’re still a bit low on zinc and manganese. The protein and lysine levels are fine, but your calcium:phosphorus ratio is now over the recommended ceiling of 2:1.

Orchard Grass: You need 9 lbs. of TC14 and 10 lbs. of orchard grass to get the copper, zinc and calories where you want them. Manganese is way too high. Protein and lysine are low, and the calcium:phosphorus ratio is also low.

While you might be discouraged by our findings, we were pretty impressed. We got a heck of a lot closer to meeting this mare’s needs with this blend than you could ever hope to get with plain grains.

Oats And Timothy: At 10 lbs. of oats and 10 lbs. of timothy a day, our mare gets half or less of her requirements for lysine, calcium, phosphorus and trace minerals. If you fed less grain and more hay, you’d have difficulty maintaining her weight.

Straight Timothy: Our example mare would have to eat 26.5 lbs. of timothy a day — if she’ll eat that much! — to get up to speed on calcium. Still, lysine and other minerals are low.

With young horses, these specially fortified mixes work similarly well, provided you feed according to National Research Council recommendations for feeding hay and grain: at age 4 to 6 months, 70% of grain, 30% hay; at 12 months, 60:40; at 18 months, 45:55.

Of course, your timothy hay must match NRC published values for nutrient content or you could get into ratios that aren’t ideal on the major- or trace-mineral front — or both.

Unsupplemented Products
Our charts include supplements that specifically target mares and foals. However, all the products in our article on minerals for adult performance horses (September 2001) also claim to be suitable for pregnant and growing animals. Rather than include all these products as well, we only included those that we believed show promise for mares and foals.

We used the highest mineral-demand periods — the mare in peak lactation and the four-month-old weanling — to establish our needs.

For simplicity, we chose oats and timothy as our base diet, since only timothy is correctly balanced to begin with.

Because feeding more than six ounces of a straight mineral supplement is expensive and likely to be less palatable, we put an upper limit on the amount we had to feed per day at 6 oz. To stay under this volume, the supplements also had to have at least a 6.5% calcium content in them. (A mineral-protein supplement was allowed to go higher in volume.)

When feeding oats and timothy in the proportions recommended by the National Research Council (50:50 grain:hay for the mare and 70:30 for the foal), the heavily lactating 1,100-lb. mare needs about 13 lbs. of oats and 13 lbs. of hay.

She will still have an 11-gram deficit in calcium and a 4.5-gram deficit for phosphorus. She’ll also only receive one-third of her trace-mineral requirements. Protein intake on is also inadequate.

Our comments on how the supplements fill the gaps in this mare’s oats/timothy diet are listed in the chart.

Growing Horses
The weanling is at a critical stage in his development. Calorie and mineral requirements stay almost the same because even though the weanling gets larger, his rate of growth slows from when he was born.

At a diet of 70% oats and 30% timothy, Triple Crown 30 works at 1.5 lbs./day, and so does 1 lb./day of Milk & Grow. Nothing else came close because of the need for a high calcium:phosphorus ratio.

If the weanling gets alfalfa, there are more choices, since the calcium:phosphorus ratio is pretty ideal on its own. Select II, at 6 oz., does the job but with a bit of overkill on the trace-mineral end. Triple Crown 12 at 0.75 lb. works well, as does 0.5 lb. of Milk & Grow. Mare/Foal II-P fits well for major minerals but is too high in the trace, although balance is good.

Supplementation at the same rates as weanlings works for yearlings getting timothy and oats, but the yearling needs to eat more. The recommended ratio of grain:hay is a little different at 60% oats and 40% hay, but this doesn’t change the mineral requirements enough to make any special adjustments.

In fact, as long as you keep changing hay and grain proportions as recommended by the NRC and feeding the correct amounts to meet caloric needs, you can ease the youngster through the first 18 months using the same level of supplementation as when he was a weanling.

The situation changes if you’re feeding alfalfa and oats, however. Because alfalfa’s mineral profile is more unbalanced to begin with, changes in the amount you feed relative to oats makes more of a difference. At 12-18 months, the same supplementation works for Triple Crown 12 and Milk & Grow, but the others are too high in calcium and/or major minerals. You’re better off using Select I at 4 oz./day or Race-VM at 3 oz./day.

Bottom Line
The convenience of using specialized grain mixes for mares and foals to balance minerals makes it worth trying. If the mix works well with your hay — which will have to be close to average compositions for timothy — you won’t need additional supplementation.

However, there’s little margin for error, so have someone knowledgeable in nutrition check the numbers if you’re not sure. Remember, too, that a heavily pregnant or lactating mare or a rapidly growing young horse needs a diet that contains at least 50% grain.

With unsupplemented/non-fortified grains, you must calculate mineral intake from both the grain and hay and then search for an appropriate supplement to fill the gaps. Don’t assume that simply because a supplement says “mares” or “foals” on the label, it’s going to work.

Overall, with timothy and oats in various ratios depending on age and pregnancy/lactation status, we got a good fit on the mineral end with a combo of Select II and Select Mare And Foal Supplement II at $1.45/day. However, you still have a protein deficit.

Triple Crown 30 1.5 lbs./day at 75??/day or Uckele Milk & Grow, 1 lb./day at 74??/day fulfills both protein and mineral needs. Both products also work at these same feeding levels for all age groups and different ratios of oats and timothy in diets of growing horses.

Triple Crown 30 wins in palatability, as it’s a pellet, but we’ve learned it can be difficult to locate in some areas. Milk & Grow is a powder, but it’s sold by direct order from the manufacturer.

If expense is a consideration in choosing between a fortified grain mix and a plain grain and mineral/protein supplement, you may want to do some math.

Compared to the specially supplemented grains, which cost about $3.50/day for a 10-lb. feeding, plain oats will run about $2/day and the Triple Crown or Milk & Grow supplement another 75?? a day, so you can save $22.50/month over using a fortified grain mix.

With alfalfa and oats, it’s more problematic because the imbalances inherent to alfalfa cause big shifts in the mineral profile as you change the proportions of hay and grain. For pregnant or lactating mares, Race VM at 3 oz./day is the choice, costing 18??/day. It can also be used at the same rate for your yearlings and 18-month-olds.

However, for weanlings on oats and alfalfa, at a 70:30 ratio, the best fit in a single product was either 0.75 lb. of Triple Crown 12 or .50 lb. of Milk & Grow. The costs are similar, and the ratios/amounts good for both, so it’s your choice of powder vs. pellet, and regional availability.

A nursing mare on a 50:50 alfalfa-and-oats diet, needs 5 to 15 grams of phosphorus, no calcium and trace minerals in a 1:3:3 ratio of copper:zinc:manganese, starting with 200 mg. of copper.

When fed 6 oz. of Select I, major minerals are excellent. The zinc and manganese are just a little low but pretty close. Uckele’s Race-VM also works at 3 oz./day with this diet, hitting the trace-mineral profile and staying just within the upper limit for Ca:P.

Diets with other grass hay types and oats, details will vary a bit by hay type, the product most likely to work for most hays is Triple Crown 30 if you need protein assurance as well — and you usually will. The 2 lbs./day you need to use would cost about a $1.

Also With This Article
Click here to view “Target Growing-Horse Diets.”
Click here to view “Mineral Supplements For Oats-And-Timothy Diets.”
Click here to view “Products For Balancing Alfalfa-Oats Diets.”
Click here to view “Busting Feeding Myths.”

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