It was found that over 50% of the hay batches were harvested too late. Late-harvested hay had crude fiber contents exceeding 340 g/kg DM and was therefore very low in energy. The microbiological and hygienic quality of hay is of great importance for horses due to the particular sensitivity of their digestive and respiratory tracts to deficiencies in hygiene. When feed containing germs or mold is administered, the gastric juices are insufficient to kill all germs. Only about a quarter of the 512 horse hay samples were completely free of any hygienic contamination. Exceedances of the VDLUFA guideline values (OW) for spoilage-indicating, spore-forming molds of the species Penicillium, Wallemia, etc., as well as yeasts, were observed in about a third of the hay samples.
These batches are unsuitable for horse feeding due to microbiological spoilage! Even a slight exceedance of the guideline value (for body weight 5: less than 100,000 colony-forming units per gram of feed; body weight 7: less than 150,000 CFU/g of feed) for spoilage-indicating molds or yeasts can lead to health problems in sensitive horses.
Hay drying systems, when operated effectively, can practically prevent mold growth in storage through rapid moisture removal within two to three days. This reduces dust levels caused by fungal spores to an acceptable minimum. Unfortunately, under-roof drying facilities are rare on horse farms. This hay preservation technique certainly has potential for further development to significantly improve feed hygiene for horses.
The results of the first Austrian horse hay project were presented on March 7, 2020, at the 9th Austrian Equine Symposium. A total of 62 horse owners participated in the questionnaire and analysis campaign on horse hay quality. The project participants submitted significantly better quality hay than the average from practical experience. This was evident because three-quarters of these samples were hygienically sound. Based on chemical and microbiological criteria, the 10 best hay samples were pre-selected and evaluated by a five-member expert jury using the ÖAG sensory evaluation method. The three best samples from the 2018 and 2019 project years were awarded prizes in the presence of 450 symposium participants. These award-winning hays are considered the "gold standard" for horse hay in Austria. More information on horse hay quality is available at www.pferdefachtagung.at and www.gruenland-viehwirtschaft.at
