Types of Haylage

Professor Meriel Moore-Colyer, Dean of the School of Equine Management and Science at the Royal Agricultural College talks about the different types of haylage and their uses.

(Look out for the part 2 to this article where she discusses the challenges posed by the different types of haylage.)

Haylage is fermented forage that ranges in nutritional value, with early-cut leafy haylage being more acidic and more nutrient-dense than the later cut more fibrous type.

Early cut haylage is therefore more suited to horses with high energy demands. Once opened and exposed to air haylage has a limited shelf-life (aerobic spoilage) ranging from 5 days for early cut to only 3/2 for late cut haylage.

Haylage is a popular and suitable forage for stabled horses, with 45% of UK owners (King, 2012) choosing haylage in preference to hay. As with hay it is the grass species it contains and the quality of the conservation process that influences the nutritional and hygienic quality of the forage. With haylage this is also determined by the time of cutting and nutritionists generally categorize haylage into early or late cut.   

Early cut haylage. Often made from a single grass species such as Italian Rye Grass, this type of haylage has a low pH (high lactic acid content) and a low dry matter (DM) of 45-55%.  It has a high leaf to stem ratio and is very nutrient dense.

Once wrapped in plastic (6-8 layers ensures good anaerobic conditions) the sugars are fermented by bacteria into lactic acid which essentially pickles the grass so preserving it. A pleasant ‘acid-sweet’ smelling forage is produced in approximately 6 weeks.

Later haylage. Generally made from mixed lay or permanent pasture, so contains a variety of grass and legume species, this haylage has a high stem content so is more fibrous and drier at 55-70% DM.

Later-cut haylage is closer to hay in nutrient content with a relatively low energy content of 7-8 MJ DE/kg and a CP content of 6-8%. This haylage is preserved simply by the exclusion of air, so it is very important that when conserving it 6-8- layers of plastic are used to ensure good anaerobic conditions.  

Table 1. Significant difference between the nutrient and microbial content of early (June) and late cut (August) haylage and the effect on intake time and chews per minute when fed to stabled horses (adapted from Muller 2012)

Table 1 gives a clear indication of the characteristics of early and late cut haylage and the potential effects both have on diet nutrient status and horse health. Later cut haylage is much closer to hay in nutrient status so owners can feed more bulk encouraging foraging behaviour and more natural time budgets in stabled horses. The higher fibre content requires more chews / kg and as chewing promotes saliva production a fibrous forage such as late cut haylage or hay can help promote good gut health.

Early-cut nutrient dense haylage is more suitable for performance horses with high energy demands. With a higher leaf:stem ratio it is more digestible than late-cut haylage so there is less indigestible ballast held in the gut. Feeding this type of haylage allows racehorse trainers to feed more forage with all the benefits that brings without their horses developing a fibre-belly.

Horses find post-steamed haylage very palatable and with the lower dust and microbial levels you can feed it for longer than freshly opened haylage. Haylage can contain considerable levels of respirable dust, with pollen being particularly high in some types. Bacteria and mould content can also be high, so the best way to preserve nutrients, increase shelf-life and reduce microbial content is to steam it in a high-temperature Haygain steamer.

References

White S^1,2, Moore-Colyer M¹, Coüetil L³, Hannant D², Richard E⁵, Marti E⁶ and Alcocer M². (2017) Development of a Multiple Protein Extract Microarray for Profiling Allergen-Specific Immunoglobulin E in Horses with Severe Asthma. World Equine Airway Symposium. Openhagen, Denmark, July 2017.

King L (2012) A survey of forage feeding practices in UK. BSc thesis. Royal Agricultural College, Cirencester Glos. UK

Leggatt, P., and Moore-Colyer, M.J.S (2013) The effect of steam treatment on the bacteria, yeast and mould concentrations in haylage for horses. Proceedings of the British Society of Animal Science. Nottingham UK, April 2013

Seguin V, Lemauviel-Lavent S, Garon D, Bouchart V Gallard Y, et al (2010) Effect of agriculture and environmental factors on the hay characteristics involved in equine respiratory disease. Agric Ecosyst Environ 135: 206–215

Gere, I and Dixon, P.M. (2010) Post moretum survey of peripheral dental caries in 510 Swedish horses. Equine Veterinary Journal 42: 310-315

Vanderput, S., Istasse, L., Nicks, B. and Lekeux, P. (1997) Air borne dust and aeroallergen concentration in different sources of feed and bedding for horses. Vet Q 19: 154-158