Feeding Momma-To-Be

What About Minerals?
Minerals are where we really count on the mare feeds to get the job done. Any feed, whether labeled specifically for mares or not, will meet the trace mineral requirements if it contains at least 50 ppm of copper, 150 ppm zinc and 120 ppm manganese, when fed at 6 lbs./day with 25 lbs. of hay that has been appropriately balanced. It's much more difficult to say with certainty if they are adequate for calcium and phosphorus.

For calcium for example, grass hays may be as low as 0.3% calcium, or as high as 0.6%. Phosphorus also has a wide range. Six pounds of a 0.6% calcium feed provides 16 grams of calcium compared to a requirement during lactation of 56 grams, which could leave the mare a bit short in calcium during lactation. The mare in late pregnancy could also need more calcium than that provided by a small amount of a 0.6% calcium feed. We'd recommend making sure the calcium level in a feed being used for pregnant or lactating mares be at least 0.75% calcium, 0.5% phosphorus.

At 0.6 ppm selenium, 6 lbs. will provide 1.6 mg of selenium. This too may be a little light, so consider adding an addition 1 mg/day, or having the mare's selenium blood level checked and supplementing accordingly. Many of these feeds also contain vitamin E, but it may not be stable for long in a feed. Supplementing pregnant and lactating mares with a separate vitamin E supplement is advisable.

Bottom Line
If your hay has 8% or less protein, low end for calcium (i.e., around 0.3%), and you're going to be feeding the usually recommended low-end 6 lbs./day of feed (about 2 lbs./day in late pregnancy), you'll need a feed that contains the minimal upper ends of nutrients:

• 16% protein
• 0.75% lysine
• 0.75% calcium
• 0.5% phosphorus
• 50 ppm copper
• 150 ppm zinc
• 120 ppm manganese.

Nutrena Youth, Nutrena Develop, Buckeye GrassPlus Developer and TDI 16 meet those high-end requirements, and we especially like that the TDI 16 specified manganese content. When fed at the 6 lbs./day level, even these feeds could stand a bit of a protein and lysine boost from a pound or so of a 50:50 mixture of soybean meal and alfalfa.

For hay with 8% protein or higher, calcium at least 0.5%, you can get good results with either a 14% or 16% protein feed with a calcium minimum of 0.6%. Note that many of the feeds listed here that are normally thought of as performance horse feeds will work just as well as a mare feed. If you go with a 14% protein feed and have a 8% protein hay, you'll need another 54 grams of protein on top of the 80 already mentioned when feeding 6 lbs/day of this feed.

Warning: The recommendations used in this article refer to an 1,100-lb. mare, whose base diet (both hay and grain) when not pregnant was known to be balanced and to meet the minimum National Reseach Council (NRC) requirements for protein, vitamins and minerals. If the base diet is not balanced or adequate, that will change her requirements.