The selection of good quality hay is the foundation of a sound, economical feeding program. It is EXTREMELY important to realize that MOST of the nutrients supplied to the horse comes from the FORAGE (hay and/or pasture) the horse is eating. The concentrate (grain) portion of the diet should be designed to supply the nutrients lacking or not in BALANCE in the forage.

Knowledge of the horse's requirements and the nutritional profile of the feeds to be used can result in a diet that meets ALL of the horse's requirements. One can then avoid expensive supplements chosen without regard to diet balance. In fact, random supplementation of vitamins and/or minerals can actually be detrimental to the horse, especially young, fast growing horses.

The tables below demonstrate how forage (hay) selection can affect the eventual balance of the diet for a weanling. Tables 1 and 2 address the requirements and nutrient excesses/deficiencies for young horses. Calculations are based on the assumption the horse will eat 2% of its body weight each day of the forage. Nutrient composition of the hay is based on NRC 1989 recommendations. These tables reflect only what nutrients are supplied by the hay - no grain is included in this example to demonstrate the impact of the forage on meeting the horse's requirements.

REMEMBER - these requirements are for the "average" horse. There is quite a bit of individual variation among horses above and below these recommended levels. Once diet balance is achieved, the horses which can be maintained on less feed have correspondingly lower requirements for the critical nutrients. Horses that need more than average feed intake to maintain their body weight have correspondingly higher requirements. Horse's feed intake is primarily controlled by their caloric requirement. The relation of the other nutrients to the caloric intake defines "diet balance". Many commercial diets have excess calories compared to theother nutrients supplied.

The absolute nutrient amounts required by the weanling are similar to the adult horse, but are being supplied to a horse nearly five times smaller!!! It is impossible to adequately supply the nutrients required by a weanling with the feeds designed for adult horses.

Tables 1 and 2 compare the nutrients supplied by alfalfa or bromegrass alone for weanlings. Results show a weanling consuming 2% of its body weight as alfalfa (Table 1) will NOT meet its requirements for digestible energy (DE), crude protein (CP), phoshorous (P) or zinc (Zn).

It is important in young horses to consider more than just crude protein, which is merely based on the amount of nitrogen in a feed. Protein quality is critical to the proper development of the young horse. Protein quality is determined by the amount and balance of essential amino acids in the entire diet (hay and concentrate combined).

A low level of lysine for instance, could retard a weanling's growth, even when crude protein appears to be sufficient. Soybean meal as a supplement compliments most grains in amino acid composition as it is relatively high in lysine, the first limiting amino acid for growth. Overfeeding protein or random protein supplementation can alter the amino acid pattern of a diet and result in negative instead of positive results.

Another important problem exists here - the Ca:P (calcium: phosphorous) ratio in this diet is nearly 6:1 (see "Nutrients Supplied" portion of table 1). It is recommended that this ratio be 1:1 to 2:1, at most. This severe imbalance in Ca:P results in an inability to properly utilize Ca, which can lead to abnormalities commonly believed to be due to Ca deficiency, such as epiphysitis, contracted tendons or other bone/cartilage maladies. But, in fact, Ca is sufficient in the diet - the true problem is the Ca:P ratio which can only be remedied by the addition of P to the diet (possibly from monosodium phosphate). The correction of the IMBALANCE is the proper action here, not supplementing more Ca (and sometimes concomitantly P), as would occur by supplementing with dicalcium phosphate, steamed bone meal or similar additives. This problem is likely to exist anytime straight alfalfa is used in a young horse's diet.

In addition, though the existing NRC, 1989 recommendations for Copper (Cu) and Zn are 10 and 40 mg/kg, respectively, more recent research supports Cu levels of 35-50 mg/kg and Zn levels of 100 mg/kg to prevent developmental orthopedic diseases (DOD) in young, growing horses. Neither of the higher requirements are met by alfalfa hay alone.

Table 2 shows the nutrients supplied and the resultant deficiencies when the weanling eats 2% of its body weight as bromegrass hay. This diet is low in DE, CP, lysine, Ca, P and Zn. Here the Ca:P ratio IS 1:1, but both are TOO LOW in amount. Supplementation of both is required to correct the deficiency - the balance is fine. The Cu level barely meets the existing NRC requirement, whereas the Zn level is below even the existing requirement - they obviously do not come close to meeting the updated requirements.

A well designed concentrate is needed when feeding either hay source, but, again, the concentrate should be different depending upon the nutrients supplied by the forage.

For example, Tables 3 and 4 show the effect of balancing the hay portion of the diet with oats and a well-designed ration balancer, such as Buckeye's Gro 'N Win® (fed with grass forage (hay and/or pasture) or Alfa Gro 'N Win® (fed with alfalfa hay and/or pasture).

As you can see, all the requirements addressed are met with the correct combination of hay, oats and the well-designed ration balancer. The Ca:P ratios are now optimal due to the well-designed ration balancer. This combination of feeds actually meets the more recent suggested levels of 35-50 mg/kg of Cu and 100 mg/kg of Zn (see amount of nutrients supplied).