READING THE HAY QUALITY REPORT

 

The results are determined in two different manners which are listed in separate columns. The As Is column is the determination of the content of the hay in its current form. The Dry Matter column is the determination of the content of the hay in its entirely dried out form. This is as dry as the hay will become, and gives a very good indication of the quality you will be feeding when it is six to 12 months old.

 

The crude protein is reported as a percentage overall that exists in the hay. However this protein is not necessarily available to the horse. The digestibility of the protein is determined by the source as well as the type of protein. The digestibility of source is partially determined by the fibre quality.

 

Fibre content for grass hay can reach up to 60%. Three types of fibres limit digestibility. They are hemicellulose, cellulose and lignin. Cellulose is less digestible than hemicellulose at only 40%. Lignin is entirely indigestible and impedes digestion of both hemicellulose and cellulose.

 

The ADF is the acid detergent fibre content, which consists mainly of cellulose and lignin. Ideal horse hay would have an ADF below 31%. At 45% or higher there is little nutritional value.

 

The NDF is the neutral detergent fibre content which consists of hemicellulose, cellulose and lignin as well as a small fraction of the non-structural carbohydrates. It should be below 40% to be excellent for horses. Above 65% most horses will refuse to eat it.

 

The lignin value is important as it acts as a model for other non-digestible fibres. As it’s content rises, so does that of the rest. It rises exponentially, with a dramatic increase at a value of 8. At 7 the digestibility is already seriously compromised.

 

The overall raw fibre digestibility of the hay is determined by the lignin/NDF  ratio. An ideal ratio would be approximately 4/40 or 1:10.  Other factors in digestibility include the amount of hay fed, the particle size of the fibre, the amount of starch (grain) fed in conjunction with the hay, the source and processing of the starch and finally the level of exercise.

 

When reading the hay quality report there is given for each parameter a typical range that is considered safe for horses. The range accounts for both grass and mixed grass/legume hay. When comparing your own hay to the typical range, please be aware that only the dry matter (DM basis) value is used.

 

The Digestible Energy (DE) value has relatively little meaning for horses as there is such a wide range of metabolic types ranging from the easy keeper pony to the highly fit eventer or race horse. It’s primary usefulness lies with breeding stock, particularly in late gestation and lactating mares as we know how many Mcal a mare needs to promote healthy growth in her foal. It is also useful in that it brings to our attention any hay that is too rich for the majority of horses.

 

The calcium to phosphorous ratio (Ca/P) is of great interest to those of us with performance horses, breeding stock and young, developing horses. Not only is the calcium necessary for the formation of good bone and joints, the phosphorous is required to ensure adequate absorption of the calcium. The Kingston area is known to be high in limestone and thus calcium. Our concern lies more with ensuring that our horses get an adequate amount of phosphorous to absorb the available calcium, but not so much that they actually end up with too much calcium and develop joint problems.

 

Magnesium is required for growth and potassium for proper development and fluid balance.

 

Kasia Miedzinska, PhD

Certified Equine Nutritionist