Ask the Nutritionist: Dr. Getty's Forum for Equine Nutrition
Welcome to my forum.
Here you will find more than 6 years of questions and my answers. It is searchable and offers a great deal of information.
Currently, I am discontinuing new questions. This may change in the future, but in the meantime, please know that It has been a true pleasure serving you.
Take a look at my Nutrition Library and Tips of the Month for a variety of answers on selected topics. Be sure to sign up for my monthly e-newsletter, Forage for Thought.
I also have a growing number of recordings on "Teleseminars on Nutrition Topics that Concern You" as well as the new, Spotlight on Equine Nutrition Series -- printed versions of favorite teleseminars.
And finally, look for my articles in a variety of local publications and online newsletters, as well as the Horse Journal, where I am the Contributing Nutrition Editor.
All the best,
Dr. Getty
Hello Shirley,
Congratulations on your upcoming foals!
Calf Manna is for cows, not horses and you are correct in your concern about feeding it. It is very high in starch and should be avoided.
Instead, give your mares all the grass hay they want, add 30% alfalfa to the mixture, and offer a safe feed such as beet pulp or a low starch commercial feed to their diet to meet additional calorie needs. A sweet feed is too high in starch and sugar to be appropriate and can lead to osteopathic disorders in the growing foal.
A good vitamin/mineral supplement that is designed for a pregnant mare is important. Platinum Performance can be used, but it contains molasses, so it is not my first choice. Mare/Foal IIP is worth considering, along with added flaxseed meal that is stabilized and does not have added grain. Nutra Flax fits this description.
Make sure your mares are getting plenty of salt -- at least 1 ounce (two level tablespoons) per day. And, always have a plain white salt lick available. Avoid the mineralized blocks -- they do not need the additional minerals and the blocks are often too bitter, so consumption is not adequate.
I hope this is helpful. If I can be of further assistance in customizing a feeding plan for your mares, I offer personal phone consultations.
All the best,
Dr. Getty 
Where are you from? Bayfield, CO