Abstract
Six kg whole wheat straw (Claire variety) samples were taken randomly from a small bale and either kept dry (Soaking 0:1) or soaked (Soaking 2:1) in tap water (2 units’ water: 1 of straw) and left for 16hs. Urea solutions were prepared according to the concentration of urea in straw by thoroughly mixing with 150 ml tap water in a garden hand sprayer. These solutions were mixed with the straw in plastic bags which were compressed to eliminate air, labelled, securely tied and stored in a room at 18˚C - 24˚C for 28 days. In-sacco studies were performed on two permanently fistulated sheep fed on a basal diet of 410 g concentrates and 820 g chopped hay/head/day over two time periods according to a 2 × 2 cross over design. Approximately 4 g of untreated and treated air-dried samples were weighed into nylon bags, which were placed in the rumen of these sheep for 0, 6, 18, 72, 48, 24, and 96 h. At the end of each incubation time, the bags were removed from the rumen and washed under running cold water until the rinsing water was colourless. Then the bags were oven-dried at 60˚C for 24 h and the un-degraded residues were weighed to estimate the dry matter degradability and the dried residues were ashed at 600˚C for 6 h to estimate the organic matter degradability of whole wheat straw. Only the OMD data were statistically analysed for this paper to compare the effect of soaking and urea treatments and their interaction on OMD at each incubation time at P < 0.05. Soaking showed a negative effect on the OMD of whole straw at most incubation hours, the urea treatment improved the OMD of straw at almost all incubation times. The OMD was significantly increased when urea was increased from 0 to either 2.5 or 5%. The final conclusion of the current study showed that treating straw with urea at different levels 2.5 and 5% increased OMD at various incubation times. On the other hand, soaking with water significantly reduced the OMD at most incubation hours. Subject Areas Agricultural Science