Oats for horses : selection and processing

Abstract

This study was conducted to investigate the effect that different levels of lignin in oats (Avena sativa L.) and the method that oat presentation to horses has on digestion. A survey was used to define the common oat cultivars grown and sold. Two of the identified cultivars (Yarran and Mortlock) were tested for lignin content and used in digestibility trials. A pilot study was used to establish that horses would tolerate faecal collection bags for extended periods of time. The horses were fed at maintenance levels with a 60:40 ratio of lucerne chaff to oats. By way of cross-over design both cultivars of oats were fed whole (Trial 1) and then both varieties were rolled and fed to the horses (Trial 2). The apparent digestibilities were 40.0% and 34.7% for diets containing rolled oats and whole oats respectively. The volatile fatty acid (VFA) concentration and pH were 12.4 mM/L and 7.0 respectively in the Mortlock cultivar diet, and 19 mM/L and 6.8 in the case of the Yarran cultivar diet. The associated effects of rolling oats were studied and by means of break­even analysis the cost of processing was compared with the increased advantage (15%) due to the improvement in digestibility. If oats are purchased in bulk then rolled on-site the cost of labour is an inhibitory factor. The buyer should instead purchase a low lignin variety and feed the oats whole. If oats are to be purchased bagged then they should also be purchased rolled as there is a cost advantage ($0.02/kg) compared with whole oats. The results suggested from this study provide practical feeding guidelines that will assist people to improve their horse feeding strategies and associated feeding budget and the horses' wellbeing. The horse will benefit from the increased digestibility of rolled oats. The total volume of feed for horses on high grain diets {where grain contributes 50% or greater to the diet (Kohnke, 1992)) can be reduced. This creates management efficiencies in the performance horse {horses in intense work i.e. racing, polo and three day eventing (Kohnke, 1992)) on high levels of grain and will have a financial impact for owners over time.