Digestibility by ponies of oat straw treated with anhydrous ammonia

Abstract

The digestibility of oat straw treated with anhydrous ammonia was studied in four Shetland-type ponies in a 4x4 Latin square experiment. The experimental diets which contained soya bean oil meal, corn, sugarcane molasses, and 65 % straw were: (1) straw treated with anhydrous ammonia, (2) untreated straw, (3) untreated straw plus urea, (4) untreated straw plus soya bean oil meal. Digestibility of the dry matter was 15% greater (P<0-01) and digestibility of cellulose 28% greater (P<0-01) in diets containing ammonia-treated straw than in those containing untreated straw. Ammonia treatment increased the nitrogen content of the straw by 50%, and nitrogen intake was 18 % greater when the ponies were fed diet 1 than when fed diet 2. The nitrogen of the treated straw was utilized as efficiently as the nitrogen of the diet containing untreated straw supplemented with soya bean oil meal. However, the amount of nitrogen provided by the diet of ammonia-treated straw was not sufficient for nitrogen balance in the ponies. Ammonia treatment of oat straw did not affect the utilization of Ca, P, or Mg.

Straw as an Alternative to Grass Forage in Horses—Effects on Post-Prandial Metabolic Profile, Energy Intake, Behaviour and Gastric Ulceration

“…The paper concluded that in contrast to most other feeds used, straw generally contained little digestible protein, had a comparatively high fibre content, low organic matter digestibility and accordingly, a low digestible energy content. The use of straw treated with ammonia to improve organic matter and protein digestibility has been studied [ 2 ] and untreated, as well as ammoniated wheat straw has been reported acceptable to horses at a level of 50% of a forage diet [ 3 ].…”

The need for in depth studies on diet

“…Estimates have been made on theoretical grounds employing approximations from zero change in body weight (Hintz 1%8, Stillons and Nelson 1972; Barth, Williams and Brown 1977). However, the digestible energy content of traditional and exotic feeds has been measured, eg, grape pulp (Wolter, Durix, Letourneau and Carcelen 1979), citrus pulp (Ott, Feaster and Sandi Lieb 1979), rape seed meal (Sutton and Stredwick 1979), dried maize forage and pelleted whole maize plant (Schurg, Frei, Cheeke and Holtan 1977) and ammonia-treated straw (Slagsvold, Hintz and Schryver 1979). Although the traditional crimping of oats, apparently, has little effect on its energy value (Morrison 1959), the rate of passage through the gastrointestinal tract and, therefore, of energy digestibility are affected by the mechanical treatment of many fibrous feeds (Wolter, Durix and Letourneau 1974; Haenlein, Holdren and Yoon 1966).…”