The effect of a sodium hydroxide spray treatment on digestibility of barley straw in sheep and goats

Abstract

To investigate the possible potential of cheaper foodstuffs for small ruminants, an experiment was designed to compare the digestibility and acceptability of barley straw and barley straw sprayed with sodium hydroxide (NaOH). In feeding trials involving six sheep and six goats, chopped untreated barley straw (US) was compared with straw chopped and sprayed with 5 g NaOH in 60 ml solution for each 100 g straw. The treated straw (TS) was neither washed nor neutralised. Both US and TS were fed to appetite to sheep and goats, with protein, mineral and vitamin supplements and water ad libitum. Both diets were readily consumed and there were no metabolic problems. Dry Matter Intake (g kg −1 W 0.75) was significantly increased (P < 0.05) in sheep but not in goats following alkali-treatment of the straw. The Energy Digestibility and Organic Matter Digestibility (OMD) of the TS diet were significantly higher than the US diet (P < 0.05) in both species. The digestibility of Crude Fibre (CF) by sheep and goats was markedly improved (P < 0.01) following treatment and the improvement was significantly higher (P < 0.05) for the sheep fed on US than for the goats fed US. Values for the OMD and Metabolisable Energy (ME) of the US and TS were derived and both parameters were significantly increased (P < 0.05) following treatment of the straw with alkali. TS, if adequately supplemented with nitrogen, minerals and vitamins is apparently capable of supplying the ME requirements for maintenance and limited production in sheep and goats.