Assessment of hygienic quality of haylage fed to horses.
Hay wrapped in plastic, called haylage and silage is common food for horses. But we know little about the microbial composition. The technology (wrapping hay in plastic) is only possible for a few decades now. This assessment dives into the hygienic aspect of haylage. They investigated the risk of mould in the bales.
In this paper haylage is defined as a wrapped forage containing more than 500 g dry matter per kg. At this stage (2005) there is not a lot of knowledge about wrapped forage with this high amount of dry matter. A lot of earlier studies had a lower dry matter content. Dry matter is the major factor influencing the course, speed and type of fermentation. It has the most effect on the PH, lactic acid and microbial composition. Previous studies have reported that there could be in increased risk of mould grow in haylage because of the higher dry matter content. Certain moulds could cause respiratory diseases, mycotoxicosis, skin disorders and reproductive failure. Other bacteria may be present and could cause gastrointestinal disorders as well as toxicosi.
Samples were taken from 19 different horse farms. Sampling was in November 2007 and may/june from the same haylage harvest (from not punctured bales). They had 2 different sampling times because of the expectation that storage time would also effect the presence of mould. All forage samples were analysed for counts of mould, yeast, enterobacteria and clostridial spores.
In this case it looks like storage time did not have an effect on the chemical or microbial composition. This is different than earlier studies, where moulds where high in autumn, lower in winter and increased again in spring (note: this was forage with a lower dry matter). They also found out that the yeast count was higher then proposed limits for spoilage (suggested by Kamphues 2005). The forages have been fed to horses, and there were no reports of health problems.
Expert opinion by Jantine Steehouder
It is too bad they did not do the same research on hay. This way it is difficult to compare both common feeds. I am very curious about what the difference would be.
> From: C. E. Müller et al., The Journal of the British Grassland Society - The Official Journal of the European Grassland Federation 66 (2011) 453-463. All rights reserved to Blackwell Publishing Ltd.. Click here for the online summary.