Performance of fattening cattle and lactating beef cows on diets high in chemically treated wheat straw and poultry litter

Abstract

Three experiments were carried out to study the effect of chemical treatment on the nutritive value of wheat straw (WS) and the effect of diets containing such treated straw and poultry litter (PL) on the performance of fattening cattle and lactating beef cows. The chemical treatment consisted of treating half of the wheat straw with 60 kg sodium hydroxide/t and the other with 60 kg sulphuric acid/t, and then mixing the two to give “Celephos”. The digestibility coefficient of organic matter was 68.0 and 41.7 for “Celephos” and untreated straw, respectively. For a long term feeding trial, two mixtures were formulated: (a) including 23% WS and 19% PL; (b) including 30% chemically treated WS and 16% PL. A conventional high grain fattening diet (c) served as control. The metabolizable energy concentrations in the above diets were 2.37, 2.38 and 2.78 Mcal/kg DM. Protein content of the diets was regulated by PL or soya bean meal. Liveweight gain was 1059, 1137 and 1180 g/day, metabolizable energy conversion ratio to liveweight was 22.8, 20.7 and 20.0 Mcal/kg, and carcass gain was 565, 606 and 656 g/day for treatment groups (a), (b) and (c), respectively. In a third trial, lactating beef cows were fed on long straw or Celephos, PL and 1.5 kg grain per head per day. Intake of Celephos was 28% higher than that of untreated straw and milk output was 3 kg/day higher. This was reflected in an increase of 67 g/day in gain of suckled calves.