Effects of sodium hydroxide and of energy and protein supplements on the voluntary intake and digestibility of barley, oat and wheat straw by cattle

Abstract

SUMMARYThree change-over experiments with yearling cattle examined the effects on voluntary intake and digestibility of treating barley, oat and wheat straws with NaOH. Increases in intake due to the NaOH treatment were: with barley straw 31 %, oat straw 9% and with wheat straw 1 %, and the corresponding improvements in digestibility were 36, 13 and 24%. A further three experimentswith yearling heifers and steers measured the effects of supplements on the responsein feeding value to NaOH treatment of wheat straw. Increasing the daily supplement of rolled barley from 10 to 3·4 kg led to a decrease in voluntary intake of treated straw from 4·6 to 3·6 kg organic matter (OM), while including urea, to increase the concentrationof nitrogenin a beet pulp supplement from 19 to 24 gN/kg dry matter (DM), gave an increasein intakeof straw from 3·4 to 4·8 kg OM. Providing more than c. 15 gN/kg dietary DM did not lead to a significant increase in voluntary intake or digestibility. In a further experiment, isonitrogenous supplements of rolled barley and soyabean meal, or rolled barley and fishmeal, led to similar intakes and digestibilities of treatedstraw. The variation in response to NaOH treatment is discussed.

Palatability of the Feeds Developed from Senegalia Mellifera Encroacher Bush when Fed to Weaned Damara Sheep

“…All the diets were isonitrogenous with a CP of 10% which was in excess of the 8% required for rumen microbial activity (McDonald et al, 2010) and in addition contained molasses which provided readily fermentable sugars and also enhanced palatability. It has been reported that goats consumed 37% more wheat straw organic matter after it had been sprayed by molasses to improve taste and smell (Ng'ambi and Ngosa, 1995), which supports the ready consumption of the S. mellifera-based diets observed with the Damara sheep in our study…”

“…Despite the ready availability of encroached bush species such as Senegalia mellifera, the use of bush-based animal feeds is limited by poor voluntary intake and low crude protein concentration, which is associated with poor degradability (GIZ, 2016;MAWF, 2017a). Utilization of poor quality forages, for example, wheat straw for feeding livestock, may be constrained by palatability (Ng'ambi & Ngosa, 1995). Alkali treatment (e.g., NaOH and urea) of crop residues improved the feeding value of ruminants (Ali & Jabbar, 2014).…”