Roughage plays an important part of the horse’s diet. But in many parts of the world, horses only have access to pasture at certain times of the year. To ensure a continuous supply of roughage throughout the year it is necessary to preserve the forage in some form.
Traditionally, hay was the main method of storing forage for horses. But if poorly conserved, it can be of variable nutritional value. It can also become contaminated with mould spores, which contribute to airway disease. Consequently other forms of preserved grass have become popular, such as silage and haylage.
Each type of preserved forage has its advantages. But do horses prefer hay, haylage or silage?
Studies that have looked at this in the past have compared the voluntary intake of forages from different sources. Recent research has examined whether horses preferred hay, silage or haylage produced from the same crop of grass.
The research was carried out in the Department of Animal Nutrition and Management at the Swedish University of Agricultural Science in Uppsala. Dr Cecilia Müller and Dr Peter Udén investigated the preference of horses for four different forages; hay, two haylages and silage.
The forages used in the study came from the same grass field and were cut at the same time. Silage was baled at 350 g dry matter (DM)/kg, haylage with low dry matter was baled at 550 g DM/kg and haylage with high dry matter was baled at 700 g DM/kg. Hay was put on a barn-drier when the dry matter level in the field had reached 700 g/kg. The hay was dried in the barn for nine days to 870 g DM/kg. Small bales (80cm x 48cm x 36cm) were used for all forages.
The researchers monitored the chemical composition and microbial content of the grass immediately before baling and from the bales as they were fed.
The horses were kept at pasture for 3 months before and during the study except for the 2-hour experimental sessions when they were offered the four different forages.
The study extended over 5 days a week for 4 weeks. Four horses were offered 1kg DM of each of the forages and the researchers observed them for 2 hours. They recorded which forage the horse s chose to eat first, the time spent eating each forage, and whether the horses finished all of a particular forage.
They found that the horses preferred the silage. It was the first choice forage on 85% of occasions. Horses also spent more time eating silage (about 28 minutes) and ate more of it (0.9kgDM /day) than any of the other forages.
Hay was the least favoured forage. On average, only 0.23 kg DM of the 1kg DM offered was eaten. Horses spent less time eating hay (about 7 minutes) and never completely finished eating the hay they had been offered. The two types of haylage gave intermediate results.
Although there have been previous studies on horses preference for different forages, this particular study was interesting because all of the forages tested were produced form the same grass at the same time. It suggests that the method of preservation of forage has an impact on the horse’s preference.
For more details see:
Preference of horses for grass conserved as hay, haylage or silage. CE Müller, P Udén Animal Feed Science and Technology (2007) 132, 66-78.