Forage
Throughout the year, especially during the winter, most horse owners rely on baled forage, such as teff, eragrostis and lucerne, to supplement grazing. But how do we know if the forage we are feeding is meeting our horses’ nutritional needs, or simply providing extra fibre in their diets?
A horse’s forage requirement is 1.5% of his ideal body weight per day (with an absolute minimum of 1%) and should make up the bulk of his diet, whether it’s in the form of fresh grass out in the paddock, or supplemented by baled forage, or a combination of both. Yet, we’ve all known a horse who gets piles and piles of baled forage and somehow manages to remain underweight. The reason for this is often simply that the horse is not getting enough calories from his forage, as the forage is of low quality and, thus, poor nutritional value.
Quality considerations
There are numerous factors that contribute to the overall quality and nutritional value of baled forage.
Firstly, during baling and storage, nutrient and protein values decrease, so the duration of the storage is critical.
Fat-soluble vitamins A and E deteriorate most quickly during storage – 75% of carotenes (precursors to vitamin A) are lost within 24 hours of cutting and a further 10% of vitamins A and E per month are lost after that.
Forage that is more than two years old is essentially devoid of these vitamins.
Minerals are inorganic and therefore remain quite stable over time.
Secondly, whilst fibre is the most important energy source for horses and is the major component of all grasses and lucerne, the true value of fibre is determined by whether this available fibre is digestible or not.
The fibre portion of a plant consists of the digestible fibres cellulose and hemicellulose, and the indigestible fibre called lignin.
Billions of microbes in the horse’s intestinal tract, break cellulose and hemicellulose (digestible fibre) down into volatile fatty acids.
These volatile fatty acids are passed into the bloodstream, where they are used as energy/calories, or stored for later use.
Lignin, on the other hand, cannot be used by the horse, as it is indigestible.
Therefore, the amount of digestible vs indigestible fibre is key in determining its nutritional value.
Thirdly, the maturity of the grass when it is cut plays a role in determining nutritional value.
Fresh grass or good-quality baled forage will be higher in sugar and digestible fibre and lower in indigestible fibre.
Mature hay has less sugars available (as they were used by the plant for growth) and more indigestible fibre as the grass becomes ‘stalkier’.
Therefore, the maturity of the forage when it was cut and baled, makes a big difference to the overall quality and digestibility of the bale.
Finally, the time of year that the forage was cut and baled will also make a difference.
Fresh green spring grass is much higher in digestible fibre and sugars than dry summer grass.
What are NSCs?
NSC stands for ‘non-structural carbohydrate’ and is the food (starch and often fructans) that the plant stores in its own cells. NSCs are dangerous in high levels as they end up in the hindgut, where they are fermented rapidly, creating an acidic environment. Structural carbohydrates, on the other hand, are the carbohydrates that, as the name suggests, provide structure to the cells and the plant. They tend to be fibrous, are much safer for the horse and can safely be digested in the hindgut.
Analysis
The best way to accurately know the nutritional value of baled forage is to have it analysed.
This is not always possible, particularly in South Africa. The best option here is to make an educated estimate by looking at the bale.
Hay should be green in colour, with a pleasant aroma.
A sickly smell can indicate overheating, while a ‘straw-like’ colour can indicate excessive sun exposure.
Brown hay can indicate rain damage.
Most important, however, is that the hay is clean and free of weeds and field contaminants, such as tin cans and twine.
Hay that is mouldy should not be fed to horses. Hay containing dust or mould can inflame the respiratory tract and impair breathing ability. If no other option is available, dusty hay can be soaked or steamed to improve quality.
Leaves have a higher level of digestible nutrients than stems and, thus, larger leaf content is desirable.
If the hay has a higher proportion of rough, thick stems and very low leaf content, it generally points towards a less nutritious batch, which may contain more indigestible fibre.
Hay that is green and leafy with fewer stems or seed heads will generally provide more energy and be more digestible.
Horses have evolved to constantly graze different types of grasses, leaves, flowers and plants and, therefore, we want to provide them with as much opportunity to graze as possible.
However, if your horse is a ‘good doer’ (gains weight easily) and there is a need to minimise his calories, rather than limiting food intake and preventing him from exhibiting his natural behaviours, it’s best to assess the situation and provide a type of forage suitable for his diet.
For example, mature hay can be provided to ensure ‘chew-time’ for the horse, which stimulates saliva (essential for a healthy gut) and keeps him feeling full, without adding large amounts of unnecessary calories to his diet.
When choosing the type of hay to purchase, it is always wise to not only choose the type your horse prefers, but also the one that matches his nutritional needs.
NOTE:
Local availability often influences the popularity of a particular variety of hay in a geographical area. If a regular supply of a particular hay in your area cannot be guaranteed, rather choose one that will be readily available on a consistent basis.
Best case scenario
Ultimately, it would be ideal if all horses could have unlimited access to high-quality grazing, from a nutritional, social and physical perspective. A 500kg horse living out in lush pasture may consume 6-10kg per day – far more than his 1% (5kg) minimum requirement. If paddocks are well managed and covered in thick pasture, the daily nutritional requirements of a horse in light to moderate exercise could be met. However, generally, this is not the case and additional forage will be needed. Also, should the workload of the horse increase, other sources of energy and nutrients will need to be added to his diet – surviving on forage alone in these cases is not possible.
Types of hay
Lucerne
Lucerne generally has a higher nutritional value than most hays and is thus more suitable for horses with higher needs, such as those in hard work, mares in foal, or those lactating.
Lucerne typically has a good ratio of stems to leaves, and provides a good level of calcium, quality fibre and other valuable nutrients.
However, due to its higher level of calcium and lower levels of phosphorus, lucerne should never be fed as the sole forage, in order to avoid an imbalance of calcium and phosphorus.
Mid-cut lucerne hay has a lower content of NSCs and sugar, making it suitable for horses suffering from conditions such as laminitis, insulin resistance and Cushing’s disease.
Lucerne also has what we call an ‘acid buffering’ capacity, due to its higher levels of calcium, which can be ideal for horses suffering from issues such as ulcers.
Lucerne can be high in energy and protein, which can be advantageous, but this could cause excesses, if the energy and protein amounts are not adjusted in the concentrate food of the average horse.
Ideally, no more than 50% of the daily roughage portion should be lucerne.
Oat hay
Cereal grain hays, such as oaten, barley, or rye hay, are all high in NSCs during their growth phase.
When cut at the optimum pre-bloom stage (before flowering), they can contain in excess of 30% NSCs and sugars.
This makes cereal hays less ideal for metabolically sensitive horses.
Once they seed (mature cut), however, the sugars are transferred to the seed head to form starch in the grain, leaving the stems with less sugar content.
Good-quality oaten hay is probably the most dangerous for metabolically sensitive horses, as it is often cut and cured before, or at, milk-seed stage.
Teff and Eragrostis curvula
Teff and eragrostis are the two most widely used hay varieties in South Africa.
They are palatable and provide a good amount of fibre, without providing too high an energy value. This makes them suitable for the majority of horses.
The major disadvantage of these hays is that the nutritional value can range hugely, from excellent to extremely poor quality.
Always select these types of hay carefully, looking for optimum harvesting stage, colour and leaf-to-stem ratio.
Studies have shown that teff hay can have a low NSC content, averaging around 10% or less.
This makes it a suitable grass for horses with ailments like laminitis, Cushing’s disease and insulin resistance.
Relative feed values (RFVs) have also proved to be higher in teff hay, meaning that, generally, there is better intake, higher digestibility, and less additional need to supplement the diet of the horse, compared with other grasses.
Paddock type
To evaluate your horse’s needs and forage requirements, you must first evaluate the quality and abundance of plants in his paddock. Paddocks can be classified into five categories, namely:
Drylot
A drylot is a paddock free of any plants, weeds or grasses. This type of paddock will not provide for any of the horse’s forage requirements and his diet will have to be supplemented with baled forage, chaff, forage cubes or pellets.
Poor
Poor-quality paddocks contain a mixture of grasses and legumes, and weeds or non-grazed species may account for the majority of the paddock. The pasture is likely to be over-grazed, with areas of short-grazed grasses, bare spots and rough, weedy areas. A poor-quality paddock will not meet the minimum forage intake per day and can only contribute about 25% of a horse’s fibre needs.
Fair
Fair-quality paddocks will also have a mix of grass and/or legume species, and weeds and other non-grazed species may be more densely interspersed. This type of paddock is unevenly grazed, with closer-grazed areas and bare spots. Plant height is inconsistent and ranges from 2-15cm.
Moderate
Similar to fair-quality paddocks, moderate-quality paddocks will be interspersed with grass and/or legumes, weeds and other non-grazed species, and will be unevenly grazed, but have minimal bare spots. Plant height is again inconsistent, ranging from 2-15cm, and this type of paddock will only contribute a maximum of 75% of the horse’s forage requirements.
Best
Best-quality paddocks contain a lush carpet of grass and/or legumes, and minimal weeds. Few or no bare areas are present and there is an even distribution of grazing across the paddock. Plant height ranges from 15-25cm and will support up to 100% of a horse’s forage requirements.
Only once you have analysed the quality of your horse’s paddock, can you begin to estimate the amount of baled forage or concentrates that are required in addition, according to his intake during paddock time as well as his workload.
It’s important to remember, however, that the nutritional quality of a paddock is constantly changing due to changes in season, weather and how it is managed. Remember to allow your paddocks time to rest and recover before they become over-grazed and overrun with weeds and bald spots. Changes in pasture quality and abundance should be carefully monitored, and your horse’s diet adjusted accordingly.
Should the quality of grazing be less than sufficient, you may consider supplementing your horse’s diet with fibre alternatives, such as sugar beet pulp (like Speedy-Beet), lucerne chaff, or lucerne pellets. This will be far more beneficial to his intestinal and overall health than adding too much high-protein food.
Choosing the best-quality forage
Tips for choosing the best-quality forage for your horse:
- Find out when the forage was cut and baled. The value of one-month-old baled forage will be far greater than six-month-old forage.
- If buying direct from the farmer, ask at what age the hay/lucerne was baled, and how it was stored.
- Choose leafy, green hay or lucerne with minimal stalks and seed heads.
- Open up and smell the bale. Does it have a pleasant grassy smell, or does it smell mouldy and dusty?
- Order your horse’s forage well in advance, in order to get the most freshly cut forage available.
- Calculate your horses forage requirements and plan accordingly. Don’t store the bales for longer than necessary.
- Should your horse be stabled for long periods of time, consider adding some lower-quality baled forage to his diet, enabling him to trickle feed as he would out in the paddock.
- If possible, plant your paddocks with a mixture of evergreen and seasonal grasses, and herbs.
- Control the number of weeds in the paddock by implementing a weekly weeding schedule.
- Rotate paddocks regularly to prevent areas of over-grazing and bald spots – which take longer and longer to recover each time.
In summary
Essentially, forage requirements are reasonably complex. Unfortunately, in South Africa, it is difficult to get an accurate forage analysis done timeously, so, to a large extent, we have to rely on more basic signs. This means that we need to evaluate both our pasture and our quality of forage, to assess what our horse is really receiving. As owners, it can be easy for us to assume that the only option in a horse requiring more condition is concentrate feed, when, in reality, a healthier intermediate step exists – one in which we increase the quality of the forage or grazing provided to our horse, to improve his nutritional intake in a more natural way.