Smältbarhet på ensilage och hö hos hästar i träning

Abstract: Horses are made to eat mainly roughage and it is essential for optimal health to offer them an appropriate amount of roughage with good hygienic and nutritional qualities. To produce good hay at the right time and be able to keep the hygienic quality until next summer is a problem. This has the effect that horse owners today choose haylage and silage to a larger extent. Science in this area is scarce, i.e. if the change from hay to silage has any effect on the horse. The aim of this study was to compare hay and silage from the same crop and measure digestibility, eating behaviour and plasma glucose levels in athletic horses and the effect of an abrupt feed change between hay and silage. Five standardbred trotters in training were used and fed two roughage-only diets (hay and silage) supplemented with minerals and salt. The study started with an adaptation period of nine days when two of the horses were fed one of the roughages and the rest of the horses were fed the other. At the morning meal the first day after the adaptation period there was an abrupt feed change that was the start of the first experimental period. All urine and feaces were collected the first 48 hours after the feed change. Also at the end of the experimental period, day 18-20, all urine and feaces were collected. Another abrupt feed change started the second experimental period that was designed exactly as the first. To calculate digestibility and fluid balance (results not shown in this paper) the samples of urine and feaces were weighed and analyzed. The digestibility for DM, OM, CP, ADF and lignin were higher on silage compared to hay already within 48 h after the feed change. There were no differences in the digestibility of NDF. There were no differences between plasma glucose or insulin levels in horses fed hay or silage. One hour after the feed change the plasma lactate were higher in horses fed silage compared to horses fed hay. Half a kg DM of silage was eaten during a longer period of time than half a kg DM of hay. Chewing frequency were however the same which means that in order to eat half a kg DM of silage a horse has to chew more times than to eat half a kg DM of hay. If the horses were allowed to choose freely between the two feeds they chose silage seven times out of ten.