I understand your concern about the protein intake of your youngster because adequate protein and the proper amino acids are essential for healthy growth. Protein is not the only essential nutrient, however; there are many minerals and vitamins that work together to provide the substrates for optimal growth and development. All of these nutrients combine to produce a sound individual.

In looking at your yearling's diet, it might be deficient in certain nutrients. First, the feed is obviously designed for adult horses and does not supply adequate protein (amino acids), minerals, or vitamins necessary for growing horses. Second, the horse is receiving an amount of feed well below the recommended feeding rate, so the feed fails to deliver the nutrients in the quantities promised on its tag.

I have used KER's innovative ration evaluation software program, MicroSteed, to evaluate how all of the different components of the diet combine to meet the requirements of the horse. The results are given in different forms: one graph shows the amount of each nutrient relative to the requirement at 100%; another graph shows whether each nutrient is being supplied in optimal amounts; a pie chart shows relative contributions to energy from fat, fiber, and carbohydrate; a ratios graph for key minerals; two tables show the amounts of each nutrient supplied and the percentage of the nutrients; and a nutrient-by-nutrient evaluation.

The first report is your horse's current diet. This report is an approximation because I do not have an analysis of the forages or of the concentrate, but I used average amounts of nutrients for the types of forages you described in your question. In the reports, the concentrate feed is a generic 11% with 6% fat, not necessarily the one the horse is consuming, but I feel confident that the values for this feed are most likely very similar to the values of the one your colt is actually receiving. Looking at the intake bar graph, the part of each bar in green represents the portion your horse is receiving from the forage and the yellow represents the portion from the feed. As you will see, the feed offered at 1.5 lb/day does not supply a whole lot of any single nutrient. The protein is actually pretty good because of the quality of forage the horse is eating. You can see that 85% of the requirement for protein is supplied by the forage alone.

The major problem with this diet lies in the mineral nutrition. Bones are made of minerals, and without adequate supplies in the diet, the horse might not develop bone properly. Sodium (Na) and chloride (Cl) make salt, so if the horse has access to free-choice salt, that requirement may be filled. The iodine, selenium, copper, and zinc are particularly problematic. The following reports are included to show three options to balance your colt's diet.

Recommended Diet 1 is the simplest solution, but it might not be feasible if changing the feed is not an option. There are products on the market for the easy-keeper that not only reduce starch and sugar in the diet but also supply the other nutrients needed in a concentrated amount. The product I chose is called Pennfield All-Phase Balancer, and if you look at the report, you will see that with just 2 lb per day, all the nutrients are being supplied at the recommended amount or above. Looking at the pie graph, you can see that a switch in feed does not radically change the energy sources. Also added in this diet is plain white salt. I included this report primarily to show you what a difference it makes in the balance of the diet when the right type of feed for the needs of the individual is fed.

Recommended Diet 2 shows how to balance the current diet with soybean meal and a vitamin-mineral supplement. The horse would need 1/3 lb of soybean meal per day to meet the protein requirement not supplied from the 11% feed. To balance out the minerals, I used a KERx product called I.R. Pellet fed at 90 g per day (90 g = 0.18 lb = 3 oz). Compared to Recommended Diet 1, this diet is weak in calcium and phosphorus content. Of course, whether this is a problem will depend a lot on the forage you are feeding, both the hay and grass.

Recommended Diet 3 uses the Pennfield All-Phase as a protein supplement to top off the protein deficit of the 11% feed, fed at 1/2 lb per day. Using the All-Phase helped the calcium and phosphorus situation a bit over Recommended Diet 2. The vitamins and minerals were still a little low, so I added some of the I.R. Pellet here also, but only 60 g per day (60 g = 0.125 lb = 2 oz) because the All-Phase added to the minerals.

I hope this is of some help to you in understanding your horse's diet.

• Current Diet.pdf
• Recommended Diet 1.pdf
• Recommended Diet 2.pdf
• Recommended Diet 3.pdf