Nutrition Newsletters
Lucerne Hay - Friend or Foe?
Lucerne hay enjoys a varied reputation amongst horse people, with some using it as a highly valued component of their horse's diet and others avoiding it with an almost religious fervour. So, who is right? Is lucerne hay a suitable forage for horses? Or are there other more suitable forages? The answer is, both arguments are correct in a sense. Lucerne hay is a valuable forage for horses, but it must be fed to the right classes of horses' and in the correct quantities for its full benefit to be realised. The following newsletter will look at lucerne hays nutrient profile and its many and varied uses in the horse industry.
Lucerne Hay - What is it?
Lucerne hay is made from the lucerne plant (Medicago sativa), a temperate perennial plant which originated in the Middle East and was introduced into NSW, Australia in 1806. The lucerne plant is a leguminous plant species, meaning that it belongs to the family of plants that produce seed pods and have nodules on their roots that are capable of taking inert nitrogen gas from the atmosphere and converting it to organic nitrogenous compounds that are available to the plant.
The lucerne plant may be cut to make lucerne hay at various times during the plants life cycle, but is most commonly cut at the 10% flowering stage, when 10% of the buds on the plant have opened into flower. Lucerne hay, when it is produced and stored correctly is commonly green in colour and should, on closer inspection contain a high percentage of leaf material and fine stems. Lucerne hay that has been weather damaged or baled when too dry will be dull green to brownish in colour, and will commonly contain a high percentage of stems and a much lower leaf content.
The Nutrient Profile of Lucerne Hay
Lucerne hay is a high protein forage that contains more energy than grass or cereal hays and chaffs. Lucerne also contains high concentrations of calcium and magnesium, and when fresh, the vitamins A and E. Lucerne is typically low in phosphorous and depending on where it was geographically grown, contains varying concentrations of other macro and micro minerals. The table below shows an abbreviated nutrient profile of early bloom lucerne hay in comparison to grass hay and oaten chaff (lucerne hays energy content decreases as the plant progresses further into flowering).
Table 1: The digestible energy, crude protein, calcium, phosphorous and magnesium concentrations in early bloom lucerne hay, grass hay and oaten chaff.
The protein in lucerne hay is high quality protein and contains appreciable amounts of the amino acid lysine, which is thought to be the first limiting amino acid in a horse's diet.
Given these nutrient characteristics, which horses can lucerne hay be fed to?
Lucerne hay may be fed to safely to all classes of horses, however due to its high protein and energy characteristics, it must be fed to horses in controlled quantities to prevent problems that may be caused by excess energy and protein in the diet. The suitability of lucerne hay for different classes of horses is discussed in more detail below:
1. Growing Horses
Lucerne is a valuable forage in the diet of growing horses. Lucerne provides growing horses with a digestible source of energy as well as a source of high quality protein and the essential amino acid lysine. Lucerne's calcium rich characteristic is also beneficial for growing horses that typically have high calcium requirements.
However, when feeding lucerne to growing horses, the amount fed should not exceed the growing horse's energy requirements. Growing horses fed energy in excess of their requirements have a much higher chance of suffering with developmental orthopaedic diseases including osteochondritis dissecans (OCD).
Feeding protein in excess of the growing horse's protein requirements does not appear to be detrimental as the protein can be utilised as a source of energy. However, protein is an expensive source of energy and to quote Susan Garlinghouse "it is sort of like using bundles of dollar bills to start a barbeque. It'll get the job done, but there are much cheaper, easier and more efficient ways of doing it". Therefore, instead of using lucerne hay to meet 100% of a growing horse's energy requirements (which will far exceed their protein requirements) it would (depending on pasture conditions) be more economical to use some form of cereal grain to provide additional energy in the diet when needed.
Another point to be aware of when feeding lucerne hay to growing horses is their intake of phosphorous. While feeding lucerne hay to meet a growing horses protein requirements will also in most cases meet their calcium requirements, their phosphorous requirements will not be met. Feeding cereal grains will help to increase a growing horse's intake of phosphorous, however, in many cases, phosphorous supplementation may be required (remembering that the calcium to phosphorous ratio in the diet of a growing horse should be maintained within the range of 1: 1 to 3: 1).
It also must be kept in mind that lucerne hay is not a complete feed and will more often than not contain insufficient concentrations of trace minerals and in particular copper and zinc, to support sound musculoskeletal development. Thus diets utilising lucerne hay as a protein and energy source must be balanced using an appropriate trace mineral supplement for the best results.
2. Pregnant and Lactating Mares
Lucerne hay is an exceptional source of energy and good quality protein for pregnant and lactating mares. Lucerne hay will also help to support these mares' elevated requirements for calcium and the essential amino acid lysine.
When feeding the pregnant mare lucerne hay, care must be taken not to exceed her energy requirements which will then cause her to become overweight. Pregnant mares should remain within a body condition score of 5 to 7 (using the Henneke scale of condition scoring) to prevent reduced milk production during the lactation period.
In the reverse, lucerne hay alone will not be capable of meeting the early lactation mare's energy requirements and may, depending on pasture conditions, need to be fed in conjunction with cereal grains to maintain body condition throughout lactation. Likewise, the lactating mares phosphorous and trace mineral requirements will not be met by a diet based on lucerne hay, thus these components must also be supplemented accordingly.
As with growing horses, excess protein in the diet of pregnant and lactating mares does not appear to be harmful, however it is an unnecessary waste of this relatively expensive feed component and should be avoided if possible.
3. Performance Horses in Work or Training
Lucerne hay can be used to contribute energy, good quality protein and a source of fibre to the diet of a performance horse, however, as with the growing horses and pregnant mares, it must be fed in moderation. Unlike the above classes of animals, excess protein in the diet of working horses and particularly those that are stabled can be detrimental to their health and performance.
Excess protein intake will increase urinary ammonia production, which may inturn cause respiratory problems for horses confined to the stable and can contribute to dehydration due to water loss through increased urine production and excretion. Excess protein also increases the amount of heat produced during the digestion and utilisation of feedstuffs. Therefore a diet containing protein in excess of the horse's requirement can increase the horse's water and electrolyte loss through sweating and can contribute to hyperthermia, and decreased performance or endurance capacity.
It is important to understand that these effects are not as a direct result of feeding lucerne, but can result from feeding too much lucerne. They can be avoided by ensuring that a horse's protein requirement is supplied and not unnecessarily exceeded. This may involve using a grass or cereal hay to supply some of a horse's roughage/fibre requirement.
4. Spelling or Idle Horses
Lucerne hay can play a role in the spelling or idle horse's diet, and will help to supply these horses with good quality protein and calcium in their diet. However, due to its high energy content in comparison to other forages, lucerne hay is generally not suitable for this class of horse as it can encourage excess weight gain.
5. Ponies
Ponies may be safely fed lucerne hay, but again it must be fed in moderation. Lucerne hay, because of its highly digestible nature is capable of allowing significant weight gain in ponies, particularly those that are easy keepers. Feeding too much lucerne hay may therefore predispose ponies to laminitis, which can occur when ponies become overweight.
Lucerne hay is particularly useful in the diet of aged ponies. As horses and ponies age, they lose some of their ability to digest fibre and protein. Thus feeding them an easily digested fibre and high quality protein source in the form of lucerne hay will allow them to maintain bodyweight, particularly during winter.
Special Considerations for HYPP and Laminitic Horses
Lucerne hay may not be suitable for horses suffering with hyperkalemic periodic paralysis (HYPP) as its concentration of potassium is often quite high (in the range of 14 - 23 g/kg). In the reverse, and contrary to popular opinion, lucerne hay is a suitable feedstuff for horses that have suffered a bout of laminitis. The high quality protein in lucerne hay will help the horse to repair its damaged laminae while the energy derived from the lucerne will prevent these horses from entering a negative energy balance, which can then slow or prevent the hoofs healing process taking place. Again, lucerne hay must be fed in moderation to laminitic horses to prevent excess weight gain.
How is Lucerne Hay Digested by the Horse?
The fibre (structural carbohydrate) in lucerne hay is fermented by the cellulolytic bacteria in the horse's hindgut and provides the horse with energy in the form of volatile fatty acids. The protein in lucerne hay is digested by protease enzymes in the horse's small intestine.
Is Lucerne Hay or Lucerne Chaff Better?
Lucerne hay and lucerne chaff are exactly the same thing with the only differences being the feeds particle size and price (chaff being more expensive). Lucerne hay is chopped into pieces approximately 1 cm long to form lucerne chaff. Studies have indicated that the ‘chaffing' of lucerne hay does not improve the digestion of lucerne. So unless you have a reason to feed chaff, such as to slow the consumption of cereal grains by a horse or to aid a horse with bad teeth , lucerne hay is a cheaper feed for horses. Hay also provides the added benefit of increasing the time it takes for the horse to consume its allocated portion of lucerne, helping to reduce boredom and reducing the stabled or yarded horse's risk of developing behavioural problems.
Quality Considerations
The lucerne plants stage of maturity when cut, its weathering and handling during harvest/drying and the length of time it is stored prior to being fed will all affect lucerne hays energy, protein, vitamin and mineral content. Thus, when including lucerne hay in a horse's diet, it is important that you assess the feedstuffs stage of maturity and its quality, prior to feeding it to your horse. Care should be taken to ensure that the hay does not contain mould or dust. Mouldy and/or dusty hay is unpalatable and may contain fungal spores that are capable of causing heaves, coughing and bleeders and also may contain mycotoxins capable of causing abortion and death.
In Conclusion
Lucerne is a valuable feedstuff for horses and is capable of providing them with energy, high quality protein and often much needed lysine and calcium. However, lucerne hay must be used correctly in the diets of all horses to realise its full benefits. Problems with the feeding of excess energy and protein are possible when feeding lucerne hay. However you must understand that these problems are not as a direct result of feeding lucerne hay, but rather as a result of feeding too much energy and protein in the form of lucerne hay. Using grass hays in conjunction with lucerne hay to fulfil a horse's roughage requirement will help to avoid some of the problems associated with feeding excess lucerne hay.
A diet formulation program such as Equilize will allow you to accurately determine how much lucerne hay may be safely fed in the diet of your horse.