Work with sheep indicated that fractionation of whole crop barley (WCB) further than material other than grain (MOG) and grain was of no benefit. Feeding WCB to sheep demonstrated the effectiveness of NaOH (53g/kg DM), aqueous NH<sub>3</sub> and anhydrous NH<sub>3</sub> (both 42g/kg DM) as treatment chemicals for mature (800g DM /kg) WCB, OMD being increased by around 5 percentage units for all three treatments. A laboratory scale trial indicated that aerobic stability of WCB was improved by NH<sub>3</sub> treatment, the optimum level being 30 to 40g /kg DM. In the work which followed WCB of between 350 and 800g DM /kg was treated with anhydrous ammonia at a level of 35g /kg DM and fed to steers of 350 kg liveweight. In cattle of this weight faecal grain loss was significantly correlated with dry matter intake (g /kg<sup>0.75</sup> LW). Ammonia treatment increased intake by 25% while grain loss increased from a mean of 0.177 of ingested grain for diets of 670 and 770g DM /kg to 0.284 after NH<sub>3</sub> treatment. Rate and extent of DM loss from whole grains incubated in the rumen were increased by NH<sub>3</sub> treatment of the WCB. Distribution of anhydrous NH<sub>3</sub> in crops < 600g DM was uneven. The final trial used steers of liveweight 150, 250 and 350 kg to test the hypothesis that smaller cattle digest whole grain more fully than do large cattle. The influence of animal size on starch digestibility coefficient was found to be significant when a multiple regression analysis was performed on the data. However faecal grain loss was still high (digestibility coefficient of starch < 0.85) for all diets and animal categories. Urea effectively preserved WCB of 675g DM /kg, the resulting material being readily consumed. It is concluded that WCB harvesting with subsequent chemical treatment, and feeding to cattle cannot be justified because of the high faecal grain loss which occurs at productive levels of intake, but the possibility does exist for inclusion in complete diets for sheep.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:483198 |
| Date | January 1987 |
| Creators | Davis, M. |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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