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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 NH₃ and anhydrous NH₃ (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 NH₃ 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^0.75 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 NH₃ treatment. Rate and extent of DM loss from whole grains incubated in the rumen were increased by NH₃ treatment of the WCB. Distribution of anhydrous NH₃ 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.

Two open-circuit indirect-calorimetry ventilated hoods were built for measuring the energy exchanges of cattle nourished wholly be continuous intragastric infusions of mixtures of volatile fatty acids and casein. In Expt. 1 the energy costs of eating and ruminating oat husks were measured. The energy costs of eating and rumination were estimated to be 11.4 J/kg live weight and 9.3 J/kg live weight per minute spent eating and ruminating respectively. The energy cost of standing above that of lying was calculated to be 6.6 kJ/kg live weight per day. In the subsequent four experiments, the effect of abomasal infusions of various amount of glucose on the heat production, nitrogen metabolism and blood metabolites of Friesian steers was investigated. In Expt. 2, the abomasal infusion of 350 g of glucose/d after a five day fast, decreased the urinary nitrogen excretion to the endogenous nitrogen loss values. In Expt. 3 the infusion of glucose at low rates (16, 25 or 50 kJ/kg W^0.75/d) had virtually no nitrogen-sparing effect. In Expts. 4 and 5 the response in heat production to abomasal infusions of glucose differed between steers. Two steers had consistent heat decrements whereas one steer showed mostly heat increments. Fasting urinary nitrogen excretion was gradually reduced by glucose infusion, demonstrating the nitrogen-sparing effect of glucose. Plasma insulin was decreased during the fast in Expt. 4, but it was not affected by glucose infusion in both Expts. 4 and 5, suggesting that nitrogen-sparing is not mediated by insulin. Plasma free fatty acids and β-hydroxybutyrate concentrations were increased several-fold during the fast and were decreased by the infusion of glucose. It is concluded that the increased loss of nitrogen in fasting cattle is unrelated to a specific requirement for glucose precursors during the fast.

A programme of work was undertaken to assess the efficacy of a new automated ad libitum feed delivery system for newly weaned pigs; to investigate the effects of liquid feeding on their performance and to explore the possibilities for reducing diet cost by using lower cost liquid components. A series of 28 day feeding trials was conducted using pigs weaned at 24 ± 4 days and fed ad libitum on liquid diets. Compared with pigs fed dry diets, liquid feeding increased feed intake by 109 ± 10 g dˉ¹ (P<0.001) and daily gain by 57± 14 g dˉ¹ (P<0.001). Pig growth and feed conversion ratio was not significantly influenced by dry matter content over the range of 255 - 149 g DM kgˉ¹. However, diets containing less than 220 g DM kgˉ¹ increased effluent output per kg of liveweight gain. Within the liquid feed system a natural lactic acid fermentation occurred which reduced diet pH ≤ 4.0 and inhibited the growth of coliform bacteria. Pigs fed diets in which pH was reduced to ≤ 4.0 by acidification with either lactic acid or Pediococcus acidilactici had daily gains of 496 and 474 ± 17 g dˉ¹ and feed conversion ratios of 1.11 and 1.15 ± 0.06 respectively. A series of laboratory studies was conducted with the aim of upgrading and controlling fermentation of food industry liquid residues for use in liquid diets for weaners. Steeping was investigated as a method for reducing glycoalkaloid levels in reject raw potatoes. A combination of natural fermentation and hydrolysis reduced the levels of α-solanine by 16.6 mg kgˉ¹ (35%) and α-chaconine by 28.7 mg kgˉ¹ (51%) respectively. Diets based on the food industry liquid residues (Whey, 'C'-Starch and Greenwich Gold), were either allowed to ferment naturally or inoculated with Enterococcus faecium or Pediococcus acidilactici. Inoculation with either Enterococcus faecium or Pediococcus acidilactici did not result in a significant difference in the final pH of the diets or in the final populations of microorganisms examined compared with the control. The series of studies demonstrated the potential for improving weaner pigs performance using fermented liquid diets. However, it highlighted the need for further studies to obtain a greater degree of control over fermentation patterns.

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