Effect of ammoniation of wheat straw alone or in combination with wet corn gluten feed on fibre digestion kinetics

Abstract

Wet corn gluten feed (WCGF),a moist byproduct, was ammoniated with 4% urea, 50% moisture, 10 days incubation, 44.4°C alone or in combination with. wheat straw (WS) and in vitro and in situ fibre (NDF) digestion kinetics was compared with that of untreated WS (50% moisture, similarly incubated) and switch grass. In vitro fibre degradation of WS and switch grass was similar and improved by amrnoniatioll of WCGF and mixture of WS+WCGF. Shorter lag time for ammoniated mixture than ammoniated· WCGF showed the assoqiative effect of WS. Rate of fibre degradation of WCGF was highest while it was lOWest for untreated WS and switch grass, however, higher rate was. recorded in situ for untreated WS than that in vitro. PED of fibre was impTeved by 33% due to ammoniation of WS alone and 54% in mixed WS and WCGF. In a feeding trial, 3 Holstein heifers (11 months, 336 kg b.wt.) were fed on untreated WS., 4% urea ammoniated WS alone and 4% urea ammriloniated mixture of WS and WCGF 1: 1 alongwitn concentrate ingredients in similar quality and quantity. Total DM was offered @ 2% of b.wt. in a 3x3 latin-square design. Untreated WS was supplemented with 1 g urea daily. Fungal growth and abnoxious odour were absent in the ammoniated mixture and it was consumed readlly and completely. Rate of passage ofWCGF through the GI tract was improved following the ammoniation, however, it did not affect the rate of passage ofWS which influenced digestibility of fibre fractions. It was concluded that ammoniation of mixture of WS and WCOF for 21 days is an alternative technology to harvest the double advantage i.e. improvement of nutritive value of WS and preservation and utilization of WCGF for the feeding of livestock.