Two Year Old Nutrition

Question
Hi-
We have a two year old holstiener filly who is not yet in work. She's about 1000 lbs right now. She's eating ALOT of grain and not as much hay as I feel is adequate, but I don't know a huge amount about nutrition.

She's Eating:
8.5 lbs of Purina Ultium Growth / Day (over 3 meals#
10 lbs of Grass Alfalfa Mix 2nd Cut Hay


I feed her as much hay as she will possibly eat, and this is all she'll eat. When in the paddock -8am to 9pm- #with grass, but low grass#, she'll eat very little hay #maybe 4 lbs). Then over the course of the evening in her stall she'll eat 4-6 more pounds.

I'm concerned that this is too high grain to roughage ratio. I'm not sure if there is a risk of colic from such high grain and low hay/roughage eating. And I'm also concerned that % of sugars in the Ultium Growth might be too high since there is molasses in the grain.

Thanks,
Erin

Answer
Hi Erin,

Thank you for your question.  Once your horse reaches 2 years of age you should expect her growth rate to slow down considerably and as a result her nutrient requirements will decrease.  This will make her a little easier to feed as she should not need as much grain as she is currently eating.

I've run a ration for you using my 'Ration-X' ration balancing software.  Now, without a precise forage analysis for your hay I have to guestimate your program a bit but it should be fairly accurate. With a conservatively estimated mixed hay analysis, your mare can meet all of her energy, protein and macro-mineral requirements from forages alone...and should not require any Ultium.  However, her ration would be too low in Zinc and Copper on an all forage diet, and these nutrients are absolutely essential in creating healthy joints and preventing developmental orthopedic disorders.  I would suggest that you put her on Purina's Enrich 32, a protein based mineral supplement designed for growing and performance horses.  This will bring valuable essential amino acids to the diet that may be lacking in the hay without extra dietary energy, help you maintain an ideal calcium to phosphorous ratio for ideal bone density, and an adequate supply and ratio of Zinc and Copper for joint development.  

A diet of hay free choice and 1.75lbs of Enrich 32 per day will fulfill all of her requirements and actually allows a little cushion of extra energy and protein for growth spurts as they come along.  You can expect your mare to eat considerably more hay once she is off the Ultium, so ensure that you compensate for that as soon as you switch rations.  You can anticipate that she will eat closer to 27 pounds of hay per day...the amount she is currently eating plus the extra dry matter that she was eating in grain.  I realize that this seems like a drastic change from what she is used to, but remember the change of growth rate that she is experiencing...it really makes a difference in how much she needs to eat.  The ration that she is on may have been appropriate at 18 months but some change is necessary.

I hope that helps.

Thanks, Corlena