Finding Feed Formulation

Things are constantly changing in the world of horses. I think sometimes I'm doing well because I'm a planner, always a step ahead of everything.

For Moon and I, we will be moving on in the Spring. And that means it's time to start thinking about feed formulation. He's currently put on some unnecessary pounds (the vet was out yesterday and made a comment to W about all the fat ponies), and hopefully extra work will help correct that. But we also need to keep him healthy and fit over the summer time.

I have a ridiculous love for feed formulation. I aced the class in University (I have a degree in animal science) but haven't worked with livestock in years. This is my opportunity to have a real-life model to manipulate feed on and see the effects. So whether you're interested or not, here's your first lesson in feed formulation.

Now, most of us sort of toy around with feeds, aiming for a healthy, happy horse with the right amount of energy and an acceptable weight balance. But do we ever think about actually calculating our horse's needs?
The National Research Council (NRC) publishes nutrient tables for most livestock as well as a number of pets. They last published the horse guidelines in 2007 but I can't seem to track them down. Instead, based on the late 1990's tables, a 1100 lb horse in light work (this is in excess of Moon's desirable weight) should consume:

DMI or Dry Matter Intake (lb) - 18.5 <-- This is the weight of the feed they consumer, from forage to concentrate. It's typically a % of the animal's body weight, which allows you to judge if you're trying to force your horse to eat way more then he possibly could (or could lead to haybelly).
DMI % BW - 1.67 <-- this is a perfectly reasonable percentage. Typical horses, I'd expect anywhere from 1.5 to 2.5% of body weight consumed per day. Remember, you don't want this number too low or else your horse isn't getting enough forage and will have decreased gut motility and loss of ph balance.
DE, MCal - 20.5
CP, g or Crude Protein - 820
Lysine, g - 29
Calcium, g - 25
Phosphorus, g - 17.8
Magnesium, g - 9.4
Potassium, g - 31
Sodium, g - 25.1
Sulphur, g - 12.6
Iron, mg - 335
Zinc, mg - 335
Copper, mg - 84
Manganese, mg - 335
Iodine, mg - 0.8
Cobalt, mg - 0.8
Selenium, mg - 0.8
Vitamin A, IU (international units) - 22500
Vitamin D, IU - 2510
Vitamin E, IU - 669

I did some research at local extension offices and learned that in my area, native pasture has approximately:
May CP = 15.9% DE = 1.17 (MCal/lb) Calcium = 0.7% Phosphorus = 0.21%
June CP = 8.7% DE = 1.0 (MCal/lb) Calcium = 0.4% Phosphorus = 0.20%
Nov CP = 5.4% DE = 1.06 (MCal/lb) Calcium = 0.33% Phosphorus = 0.19%

My lightly working horse needs: anywhere from 1.35 to 2.25 DMI % or an average of 1.8%. Even at moderate work, this value would be close to the same.
Light Work Proportion of Dry Matter: 65% Forage, 35% Concentrate
Moderate Work Proportion of Dry Matter: 50% Forage, 50% Concentrate

Ideal Weight of Moon'er = 1000 lbs (let's just say).
Lbs of dry matter intake = 1000 x (1.8/100) = 18 lbs.

Assume a light work load:
Lbs Forage = 18 x 75% = 13.5 lbs.
Lbs Concentrate = 18 x 25% = 4.5 lbs.

Keep in mind you're wanting between 1 and 1.2% of body weight as forage. Which is 12 lbs for Moon (so 13.5 lbs is fine).
An average horse will consume about 70 lbs of pasture grass per day if left on to graze all day.
Pasture grass has a low %DM and I suspect where we're looking is at 20% at best.

Average daily pasture grass consumption of a horse is 70 lbs x 20% DM (tons of water in pasture grass) = 14 lbs. of forage/day.

Which means he needs 4 lbs of concentrate.

Now let's open up a neat little feed calculator, which is developed for the NRC tables. This saves us a lot of manual math...
Link to it here: nrc88.nas.edu/nrh

I enter his animal specs into the page (454 kgs) and an intake level of 1.75% (closest to the NRC predicted DMI for him at a light workload).

I fill in the details for our native pastures from the Extension table I found online, taking a mid-season estimate of 8.7% CP. I haven't a clue the %DM of this pasture, but native pastures tend to be between 10 and 30%. I'll go with 20% and be optimistic.

Do the math and the table tells me:

We're not getting our needs met on purely pasture (see the numbers under "Balance")

Now let's look at Buckeye Grow N Win at the recommended level of 0.68 kgs...

Insufficient. We're meeting our CP levels, but falling short on our DE as well as our intake levels.

Let's consider instead Buckeye "Show" at the recommended level...

And we're in excess!
Reducing to our necessary levels...

And we learn that Moon would do well on approximately 1.7 kgs of Buckeye show. That's 3.75 lbs almost the estimated 4 lbs we calculated earlier.

Alternatively, FrontRunner Pleasure would provide:

At only 1.6 kgs of feed.

I'm waiting on a pricing of the Buckeye, but the Front Runner is $14/bag for 20 kgs. That's 12 feedings per bag, or $1.20/day.

Phew. It's nice to get all that math done and out of the way!
So for Moon, we're looking at a daily supply of Native Pasture Grass grazing plus 3.75 lbs of Pelleted Feed.

The plan is to let him go on the barn feeding program for a couple of months after the Springtime move to see how he adjusts. Chances are (hopefully) he'll start losing the weight which means I can swap him over to "Show" and maintain him on that over the summertime. Healthy and happy.

Now you're probably wondering about "the move". We were never planning on staying at W's past the springtime and have been giving long and arduous thought to where we're headed next. And it seemed like right as I decided what was happening, a great opportunity came along. One that seems better and better every time I think about it. : ) We have a looming move-in date likely May 1st or so (lots of flexibility). Details to come, as I'm still sorting them out myself! Let's just say it offers variety, access, adventure and fun. And I'm already wishing the snow would melt so we could have at it!