Feeding Down to a Science Part 2

On the December 7th post, I began the process of evaluating JB’s feed in an effort to play scientist for a bit in determining if his ration’s were on track.

I began in the last post figuring out exactly what JB needed to begin with. The process I went through to calculate his rations out is to be used as averages and is not absolutes. I had to keep in mind a few things in this process like: his current condition, his weight, appearance, energy levels, and attitude.

Several times during the course of trying to work out some of these figures, Tom would ask me why I was going through all of this. It was a valid question, seeing as how difficult it was and how the variables can change so easily regardless of what numbers I came up with.

So what motivated me to do this in depth analysis? Other than the fact that once I start something, I see it through to the end, and by getting as close as possible to seeing where JB was at with the feed he was receiving was important given some of the conditioning rides this past summer . Many times he seemed sluggish. I was never really sure if it was his energy level or the fact that he really didn't want to leave the herd. I was hoping this might reveal something more. Was his lack of enthusiam to go due to his feed not supplying enough energy level or was it just the fact that he didn't get excited about leaving home.

Here is what I found:

The last post I left off knowing two main things; the first was how much % of his body weight was he receiving in forage and concentrate combined. JB who weight roughly 850 lbs or better, is receiving 1.87 % of his body weight in forage and .28 % of his body weight in concentrate for a total of 2.87% of combined feed of his body weight. He was a bit above the recommended percentage, (2-2.5% of body weight) for his body weight but I feed him enough hay so that he has it in front of him most of the time.

The second bit of knowledge was determining what JB actually needed in daily requirements. For ease of reference I have listed this again below: again for 850 lbs

Digestible energy:19.5 mcal/day
Crude Protein: 1.7 lbs/per day
Calcium: 24 gram per day
Phosphorus: 16 grams per day
Vitamin A: 17 IU’s per day

The next step was to take his grain ration (Running Horse Cut and Slide) and his hay ration , about 22 lbs of hay per day , and calculate those items above for each, giving me his totals.

At first glance I thought getting this information for his grain and hay would fairly straight forward but as it turned out, I had to do some additional research to find the right numbers for the type of hay I feed and I had to some additional calculation to manually figure out the requirements for the grain he receives. The rep at Running horses surely thinks I have gone a little crazy.

I will start with the Hay. On the websites I was using for reference
www.ces.purdue.edu/extmedia/AS/AS-429.html did not list the types of hay that I feed. I was able to locate another site that allowed me to key in a much closer version of the hay that I feed. That site is http://nrc88nas.edu/nrh/. There is a tool on the page that you can use and fill in the feed type and the appropriate maturity levels of the hay. The tool will then calculate for you and will even allow you to customize it to your horse. The problem with this tool is that it calculates in percentages and for my purposes I needed lbs per day or grams per day. So you will have to do some additional calculations as a result.

The hay that I feed is mostly grass. I know that it has quite a bit of crested wheatgrass and some Timothy. Other than that, I can’t really say exactly what it is. In some bales there is more alfalfa. So, I had to use my best quess based on what I see in the bales. Unless I wanted to pay to have samples taken from the core of every round bale I have sitting out there, it would have to get me close enough. While it would be nice to be that accurate by testing, it wasn’t economical.

On the tool , I chose the option of Grass Hay – cool season (mid- mature) and Wheat hay ( mid to mature). JB gets approx 22 lbs of hay per day . Since I don’t know how much of that 22 lbs is grass and how much is Crested Wheat, I split the difference in my calculations, 11 lbs of each. I had to do some initial converting from Kg to lbs, and percentages to grams. For simplicity, I will give you my calculations for the lbs and grams that I have already done the conversions on. I have also shown below that I took those numbers and multiplied by the 11 lbs of each for final totals.

Grass Hay Cool Season:

Digestible Energy : 99 Mcal/lbs x 11 lbs = 10.89 Mcal (this was in Kg and had to be converted to lbs; ff you know there are 2.2 lbs in every Kg, than you can take 2.18 mcal/kg in this case, divided by the 2.2 gives you the .99 mcal/lb
Crude Protein: .146 lbs x 11 lbs= 1.61 lbs
Calcium: 32,99 grams x 11 lbs = 32.9 grams
Phosphorus: 1.32 grams x 11 lbs =1. 32 grams
Vitamin A :not available

WheatGrass Hay

Digestible Energy : .97 mcal/lbs x 11 lbs= 10.67 Mcal
Crude Protein: .113 lbs x 11 lbs= 1.24 lbs
Calcium: 15.47 grams x 11 lbs =15.4 grams
Phosphorus: .09 grams x 11 lbs = 9.9 grams
Vitamin A : not available

Vitamin A % was not available but I know that Vitamin A is lost as hay is stored. The final piece to calculating hay requirements is to calculate the total amounts of nutrients fed for the two hays fed.

HAY TOTALS

Digestible Energy: 21.56 Mcal/lbs
Crude Protein: 2.85 lbs
Calcium: 48.46 grams
Phosphorus: 11.30 grams
Vitamin A : not available

Then I compared just the nutrients JB was receiving from Hay with the nutrient requirements that he needs . His numbers came out a bit in excess and initially I was a bit concerned, however there are quite a few variables. His weight is likely more than what I calculated at, the hay types I used from the charts are Hay types on the east coast and may have different nutrient values than what I am actually feeding, and then there is nutrient loss. I also am not certain if this truly is mid to mature level feed because given our spring last year, what would typically be mid to mature might have instead been cut a bit later.


The last part of my analysis is to include the requirements I was able to determine from the grain that JB receives. Last summer I started him on Running Horse Cut and Slide. According to the feed tag, for every pound of feed he receives the daily minimum requirements found on the feed tag. For instance, the feed tag indicated 15% protein for every pound fed. If I were to feed 4 # per day, it would calculate out to .6 lbs of protein, .36 lbs of fat, etc. JB received at the height of his conditioning 2.4 lbs of this grain per day... which really isn't much and quite a bit less than the recommended amounts.


The one thing I did not have for the grain was Digestible Energy. Many feeds will not list DE on the tag and therefore you will have to use the Crude Fiber and Crude Fat percentages to determine the DE (MCal/lb) of the grain mix. I was able to find a reference on the internet on how to calculate DE if it is not on the feed tag That link is www.infovets.com/healthyhorseinfo/A575.htm

For Running Horse Cut and Slide, 14 % crude Fiber and 9 % Crude Fat, DE works out to be 1.15 Mcal/lb. At 2.4 lbs of Running Horse per day, I came up with following nutrient values on his grain ration:

Digestible Energy: 1.15 Mcal/lb x 2.4 lbs = 2.76 Mcal per day
Crude Protein : . .36 lb/day
Calcium: 10.23 grams
Phosphorus: 7.6 grams
Vitamin A: 9000 IU’s

In addition to the Hay values outlines above, combined with the grain, I can see JB is in excess on most of these items.

Digestible Energy- JB needs 19.5 Mcal/day; he is receiving total 24.32 Mcal per day with hay and grain concentrate. He is in excess of 4.82 Mcal /day

Crude Protein: JB needs 1.7 lbs per day; he is receiving 3.21 lbs per day. He is in excess of 1.51 per day.

Calcium: JB needs 24.15 gram per day; he is receiving 58.69; he is in excess of 34.54 grams per day.

Phosphorus: JB needs 16.42 grams per day, he is receiving 18.9 grams per day. He is in excess 2.48 grams per day.

Vitamin A: JB needs 17.4 IU’s (1000 IU) per day or 17,400. This was an unknown on the hay but the grain indicated 3750 IU /LB. Based on the 2.4 lbs he was receiving per day, he was getting 9000 IU’s per day. I am fairly certain he is receiving at least close to the remaining 8400 IU’s /day in his hay.


To go one step further, I want to calculate the Calcium to Phosphorus ratio; Even though JB’s intake is in excess of the requirements I know that these two minerals should more importantly be in balance with each other. Too much Phosphorus to Calcium or not meeting the minimum requirements could lead to various diseases. If I divide the calcium by the Phosphorus I come up with 1.82:1 which is an acceptable range.

What does all of this analysis tell me?

Well, in an broad sense, it tells me JB is getting plenty of what he needs. His Digestible energy is a bit high but I know that his DE requirements can increase dramatically when carrying a rider so I may not be as high as the numbers actually look. Also, he may weight more than 850 lbs which would change a few #’s. I can also see that JB may be a bit high on the protein for an endurance horses needs. That might be part of his lower than expected energy levels that he seemed to be displaying. I might opt to go to the senior feed that Running Horse offers or look at other options that would get the protein levels down without cutting back on fat levels too much. It’s possible that I may consider giving JB straight beet pulp this summer with just a touch of grain for extra flavor. Grain concentrates, like what I feed JB should be in the 7-10% range for fat levels. Running Horse is 9% per pound so it’s right in there. Fat is one of the most important feed requirements for an endurance horse because it can be metabolized for energy during aerobic trotting and cantering speeds, and helps conserve muscle glycogen (high energy sugars) during prolonged exercise. Also, aerobic metabolism of fat produces metabolic water within muscle cells, which may be of benefit to maintain cell fluid levels during exercise.It appears this “fat” topic could launch me into further research of available feeds on the market that provides adequate fat for energy but without the added protein. I’ll save that for another day. If anyone has any recommendations or suggestions on feeding the endurance horse, feel free to share. In the meantime I might put a call into my vet for more accurate feed recommendations. Turns out, she is an endurance rider