Hay quality - sampling - testing protocols - importance of hay quality - for racehorse trainers
/
By Alan Creighton, Head of Environment and Nutrition Department, The Irish Equine Centre
Late last year, the Environmental and Nutrition Department at the Irish Equine Centre completed a study of hay which was being fed by many of the leading racehorse trainers in Ireland and the UK. The results have answered a lot of the theories we have held over the years in relation to hay quality. The results of this study also have been used to aid hay producers and trainers in making the right choices when it comes to making and feeding hay. The study also highlights the reasons why testing hay is very important.
Good forage is key but the balance needs to be right too.
At this time of year, we are inevitably asked questions in relation to the quality of hay versus haylage. When is the best time to test this year’s forage? How is it stored properly? The obvious difference is that you can get a good idea about hay quality prior to purchase, whereas with haylage you often have to wait until you open that plastic to know your faith. When we look at the top-level trainers in Ireland, the UK and France, the breakdown of who feeds hay versus who feeds haylage is approximately 75% hay versus 25% haylage. The decision to feed a particular forage is often based on availability, cost and storage facilities. Some trainers prefer to feed haylage because they believe this product is a better source of digestible energy and protein. The nutritional content of large batches of haylage can be very variable and without analysing each batch of forage, it is impossible to know exactly what the nutrient profile is. The Irish Equine Centre analyses thousands of samples of hay and haylage every year for both hygiene (mould and bacteria levels) and nutritional content. The reality is that we get both hay and haylage with extremely good nutritional and hygiene values; we also get hay and haylage with very poor nutritional and hygiene values. It is really important for trainers to realise that constantly changing forage types is extremely detrimental to horse health and is often responsible for gastric problems and colic. Ideally you should produce or purchase enough of the same batch of good quality forage for the whole season. It is our experience from testing forage that getting haylage with consistent nutritional values can be very difficult. This is mainly due to the variants in moisture content. Hay that is well made and stored well does tend to be much more consistent and therefore better for overall horse health.
Haylage has a much higher moisture content than hay which therefore means that more haylage is required to be fed as compared to hay to meet the daily recommended guidelines for dry matter intake. Haylage can contain higher crude protein, fat and digestible energy. If a trainer feeds that amount of haylage as suggested in guidelines, the animals tend to get too heavy. When feeding haylage, the spoilage process can begin quickly if the bale is exposed to air; this may be due to damaged wrapping or not using the bale quick enough once opened. Fungal spores will develop, and this should be carefully assessed before feeding. This is a major problem we encounter on a regular basis. Often trainers are feeding big bales of haylage to a small number of horses, which means the bales are exposed to air for a prolonged period of time. Pathogenic fungi will develop very quickly and often lead to both respiratory and gastric problems. For that reason, the Irish Equine Centre recommends that opened bales of haylage are used inside of four days in the winter and three days in the summer. This recommendation will often determine the choice between hay and haylage as you would therefore need to be feeding a larger number of horses to feed large bale haylage.
The digestive system of the horse is designed to graze constantly. Digestive disorders such as stomach ulcers increase when we move too far away from constant grazing. Horses are designed to have a regular intake of forage. Since the horse's stomach continually secretes acid, gastric ulcers can result when the horse is not eating regularly. Saliva in the mouth contains bicarbonate which buffers (neutralises) acidity in the gut. More chewing produces more saliva, and the chew time with hay is a lot longer than with haylage. The horse therefore produces a lot more saliva when fed hay as compared to haylage. Horses also tend to eat haylage quicker which often leads to longer periods with no forage in the stomach.
Both hay and haylage are prone to fungal contamination in different ways. With haylage, the fungal contamination occurs as a result of inadequate fermentation or when air pockets or punctures occur in the plastic. Fungal problems in hay occur because of high moisture levels during the baling process and because of inadequate storage during winter months. We have now shown that those fungal problems are compounded and elevated since farmers have moved away from the traditional small bale and moved to large round or rectangular bales.
Racehorses are athletes, and they need a fully functioning respiratory system to maximise performance. IAD, COPD, RAO (all forms of equine asthma) and EIPH (bleeding) are respiratory conditions that are major causes of poor performance in racehorses. Fungi and mycotoxins are now recognised as a major cause of these conditions, and in particular the pathogenic fungus Aspergillus is the main culprit. Fungi that penetrate the airways can cause unwanted inflammation and can be infectious, toxic, allergenic or all three combined. The further the distance a racehorse is asked to race, the more detrimental this inflammation will be to performance. The main sources of this fungus are hay, haylage, straw and oats. This fungus is a storage fungus and so it propagates in stored foodstuffs overtime where the moisture level is above 14%. When the fungus contaminates a foodstuff or bedding, the horse has no choice but to breathe in the harmful spores in their stable environment. The fungus also causes a level of immunosuppression, which often can be the precursor to secondary bacterial and viral diseases.
An Irish Equine Centre study in 2006 showed that Aspergillus contamination levels in hay produced in Europe for racehorses that year was approximately 50% as compared to 37% in haylage and 13% in the North American hay used in Europe at that time. This was a very worrying statistic as forage can often make up to 60% of the racehorse’s diet. The cost of North American hay in Europe was significantly higher than barn-dried European hay. The temperate climate in Ireland, the UK and northwestern France can make it difficult to make and store hygienic hay as compared to North America. Scientific information available for farmers to aid in the production of hygienic hay is now limited as government research facilities have concentrated on silage and haylage production for cows. It has long been the contention of the Environment and Nutrition Department that apart from the difficulties with making good hay, it is actually how we store hay in our damp climates that predisposes the hay to fungal contamination. We have always felt that hay which is uncovered in storage will act like a sponge and absorb moisture from the air during our damp winters. When the temperature is mild, this moisture encourages fungal growth on the outside of bales.
In order to help hay producers and consequently help trainers, the Irish Equine Centre felt we needed to establish the following:
1. The links between the effects the different hay preservation methods and storage methods have on the moisture levels of the hay and the resulting fungal and mycotoxin presence.
2. To determine the prevalence of pathogenic fungi and mycotoxins (secondary metabolites) in hay produced by five of the biggest producers of hay for racehorses in Ireland and the UK over a two-year period.
3. Determine the most suitable time during storage for trainers to test their hay. Prior to this study, the IEC recommended the month of September.
The study looked at hay produced and stored over a two-year period. Five hundred twenty-five samples were taken post-harvest, post-storage and at three intervals during storage in hay barns. The moisture levels were taken at each sampling interval. All the samples were tested for pathogenic fungi and a panel of six mycotoxins. …
