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Nutritional Analysis

Forages are a natural component of the horse's diet. It is critical that the quality of the forages fed to horses is optimized to ensure continued health and well-being. Harvesting forage in Ireland is complicated by poor drying conditions, heavy dew and the threat of rainfall. In an effort to avoid these conditions forage is often baled before reaching recommended levels of dry matter which can result in the development of mould and reduced nutritional quality.

Managing horses efficiently demands good quality forage. Good quality hay and haylage is nutritious, very palatable and also play a vital role in maintaining a healthy and functional gastrointestinal tract. The nutritional value of feedstuffs and forages is important for correctly formulating diets for equines. The quality of the forage that horses are being maintained on is largely unknown. The results of nutritional analysis are given in two forms. ‘As Sampled’ also known as ‘as fed’ gives the results of the sample in its natural state or how it is fed to the animal. When the results are expressed as ‘Dry Matter Basis’ (DM) this removes the moisture as a factor. This is used in diet formulation for the horse.

Dry matter represents everything in the sample except water. It includes protein, fibre, minerals etc. Moisture is the total amount of water in the forage. Animals consume feeds to meet their dry matter needs as the dry matter contains all the nutrients. Therefore animals need to consume more of a wetter feed than a drier feed in order to receive the same amount of dry matter. Protein is vital to all physiological stages in the horse. Protein is essential for maintenance and growth. Protein is made up of amino acids. Protein is required on a daily basis for maintenance, lactation, growth and reproduction.

Fibre is essential to every physiological stage in the horse. The fibre quality of the forage is determined using fibre fractions; neutral detergent fibre (NDF) and acid detergent fibre (ADF). Neutral Detergent Fibre is the best representation of the total fibre content of the forage as it represents the available and unavailable fibre fractions. NDF is closely related to feed intake. Therefore, it can be measured to determine and estimate the quantity of forage an animal will consume. Acid Detergent Fibre (ADF) is a quantitative measure of the indigestible fibre portion of the sample providing an estimate of the digestibility of the sample. Protein availability is affected by the levels of ADF, as high levels of ADF will decrease protein availability.

Ash is the amount of residue that remains after all of the organic matter in a sample is completely incinerated. The amount of ash is a measure of the total mineral content in a given sample.

For horses energy requirements are determined in order to account for maintenance, growth (average daily gain), lactation, reproduction and levels of activity. Failure to supply adequate energy will result in poor performance. Digestible energy is a predicted value based on the protein and ADF in the sample. It is important that the digestible energy content of the horse’s diet is appropriate for the amount of work the horse is doing.

Forage Sampling Procedures

The analytical result is only as good as the sample submitted for analysis. Collecting a representative sample is the first step of the analytical procedure. The following recommended sampling procedures will help ensure that your results reflect the true nutrient composition of your sample.

Hay & Haylage: Different types, cuttings or lots should be analysed separately. Using a forage sampler or a hay probe*, bore at least 10 bales selected at random. Combine all the core samples and submit for analysis. The sample should weigh at least 80 – 100g. The sample should be enough to fill a bag similar in size to a supermarket carrier bag.

Grass: Randomly select at least 15 – 20 sites where the animals have been grazing and clip at grazing height. Combine in a clean plastic bucket and mix. Take at least 500g and pack tightly in a plastic bag and freeze for 12 hours prior to submitting to the lab.

Grains and Mixed Feeds: Randomly collect between 10 and 20 samples as the grain is discharged and combine in a clean plastic bucket. Submit at least 500g for analysis.

*If a fodder/bedding sample probe/core is not available then simply take a handful of fodder/bedding from ten different bales and place in a sealed bag together as one sample. Make sure to wear and replace gloves between different types of samples.