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Item Influence of barley inclusion method and protease supplementation on growth performance, nutrient utilisation, and gastrointestinal tract development in broiler starters(Elsevier B.V. on behalf of KeAi Communications Co. Ltd, 2022-03) Tari LM; Perera WNU; Zaefarian F; Abdollahi MR; Cowieson AJ; Ravindran VThe influence of the method of barley inclusion (fine, coarse and whole barley) in a wheat-based diet and protease supplementation (0 and 0.20 g/kg) on growth performance, nutrient utilisation and gastrointestinal tract development of broilers (d 1 to 21) was evaluated in a 3 × 2 factorial arrangement. Whole barley (WB) grains were ground in a hammer mill to pass through the screen sizes of 2.5 and 8.0 mm to achieve fine (FB) and coarse (CB) barley particle sizes, respectively. A total of 288, one-day-old male broilers were allotted to 36 cages (6 cages/treatment; 8 birds/cage). There was no significant (P > 0.05) interaction between barley inclusion method and protease for any growth performance or nutrient utilisation parameters. Birds fed diets containing CB and WB showed higher (P < 0.05) weight gain, and digestibility of dry matter, nitrogen, calcium, gross energy, and ileal digestible energy compared to those fed FB diets. Compared to the birds fed FB diets, feed per gain was lower (P < 0.05) in birds fed diets made of WB. Fat digestibility of the birds fed CB was higher (P < 0.05) than those fed FB and WB birds. Compared to FB and CB diets, inclusion of WB resulted in heavier (P < 0.05) gizzards but reduced (P < 0.05) gizzard pH. Supplemental protease, however, had no effects (P > 0.05) on growth performance and nutrient utilisation, most likely due to the well balanced digestible amino acids and high inherent digestibility of protein in the basal diet, and/or the presence of exogenous carbohydrase and phytase. In conclusion, the present results showed that the inclusion of coarsely ground and whole barley in a wheat-based diet can enhance nutrient and energy utilisation and is beneficial to the growth performance of young broilers.Item Influence of feed processing and enzyme supplementation on performance, nutrient utilisation and gut morphology of poultry fed barley-based diets : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Poultry Nutrition at Massey University, Palmerston North, Manawatu, New Zealand(Massey University, 2020) Perera, Wellawattage Nipuna UdayaniThe first experiment (Chapter 3) determined the metabolisable energy and standardised ileal digestible amino acids of two barley cultivars (NSH [normal starch hulled barley] and WSHL [waxy starch hull-less barley]) and wheat for broilers. These values were used to formulate the experimental diets in subsequent experiments that evaluated the optimum barley inclusion rate in wheat-based diets (Chapters 4 and 5), optimum barley particle size (Chapter 6) and conditioning temperature (CT; Chapter 7), and potential interaction of carbohydrases with each processing parameter. In Chapter 3, wheat and WSHL had the highest and lowest metabolisable energy and digestible amino acid contents, respectively, with NSH being intermediate. Supplemental carbohydrases increased the energy utilisation with a pronounced effect in WSHL. Data reported in Chapter 4 showed that optimum inclusion level of NSH was 283 g/kg of diet. Nutrient utilisation linearly improved with increasing inclusions of NSH. Carbohydrases improved feed per gain (F/G) and nutrient utilisation. Chapter 5 suggested that WSHL could be safely included up to 260 g/kg in a wheat-based diet with no adverse effect on growth performance. Carbohydrases improved the F/G and, starch and energy utilisation. In Chapter 6, particle size effect was preserved after pelleting and, coarse barley and carbohydrases improved the F/G and nutrient utilisation. The combination of carbohydrase and phytase produced no further improvements in nutrient utilisation. The final experiment (Chapter 7) demonstrated that better pellet quality achieved by increasing CT to 88 °C failed to ameliorate the negative impacts of high CT on nutrient utilisation and broiler performance. Carbohydrases improved weight gain, F/G and, starch and energy utilisation. The lack of interaction between the carbohydrases and CT indicated that carbohydrase had similar efficacy at each CT. The primary finding of this thesis research was that if cultivar-specific values for metabolisable energy and digestible amino acids are used in feed formulations, barley has the potential to substitute up to 50% of wheat in broiler diets. Coarse particle size (8.0 mm) and conditioning the diets up to 74 °C is recommended for the tested barley type. Supplemental carbohydrases improved the feeding value of barley for broilers.Item Quantitative genetics of resistance to net bloch of barley (Hordeum vulgare L.) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Plant Science at Massey University(Massey University, 1982) Douglas, Grant BrodieA half diallel cross was made amongst five barley (Hordeum vulgare L.) genotypes (Zephyr, Hassan, Mata, Kaniere and Manchuria) which exhibited differential resistance to net blotch disease, incited by the fungus, Drechslera teres. The 15 genotypes (5 parents and 10 F₁'s) were grown to physiological maturity under two nitrogen regimes (20 mg 10̄³ m̄³ and 105 mg 10̄³ m̄³ N) , 14 hour photoperiod, light intensity of 170Wm̄²PAR, 22°C (day)/16°C (night) and relative humidities of 70% (first seven weeks) and 95 to 100%. All genotypes were first inoculated (9,000 conidia 10̄⁶ m̄³ ) at 14 days and thereafter ten times at approximately weekly intervals. Infection occurred only in the high nitrogen environment. Absence of net blotch at the lower nitrogen level was probably due to insufficient plant nitrogen concentrations for growth of the fungus. The procedures of Mather and Jinks were used to analyse the half diallel cross for net blotch resistance of the following intact plant parts: (1) top canopy (2) bottom canopy (3) flag leaf and (4) second leaf. Resistance of leaf sections in petri dishes was also analysed. Biometrical analyses for all net blotch data sets showed that additivity was of much greater importance than dominance in controlling resistance. Epistasis and/or correlated gene distributions were trivial. Resistance was conditioned by a partially dominant, single effective factor which was suggested as one gene. Heritability estimates were moderate. In the high nitrogen environments, net blotch had no significant effect on plant height, tillers per plant, spikelet and grain numbers per ear, grain yield, 100 kernel weight and intensity of physiological brown spot. However heading date of diseased plants was significantly earlier than for fungicide treated plants. Nitrogen concentration had a marked effect on most characters. Significant genotype-nitrogen (G x E) interactions occurred for plant height, spikelet number per ear, grain yield, 100 kernel weight and physiological brown spot. Further biometrical analyses showed that additivity was most important for plant height, tillers per plant, spikelet and grain numbers per ear, and physiological brown spot. Dominance was noteworthy for heading date, grain yield and 100 kernel weight. Epistasis was relatively unimportant. Keywords: biometrics, barley, diallel analysis, disease resistance, growth stages, inoculation, intensity, leaf area diagrams, net blotch, pathogen, quantitative genetics, susceptibility.Item Variations in lipid composition of perennial ryegrass (Lolium perenne) and barley (Herdeum vulgare) with special reference to galactolipids : a thesis ... M. Agr. Sc.(Massey University, 1965) Gray, Ian KeithIn New Zealand, dairy cows are fed mainly on pasture in situ. This is in contrast to feeding practices in other countries where lactating cows are normally fed diets containing appreciable proportions of food products, other than fresh pasture. Although lipids form only 4-6% of the dry weight of leaf tissue (Hilditch and Williams, 1965) it has been estimated that a cow by eating 9 kg. of dry matter of grass per day may consume up to 700 g. of lipid (Hawke, 1963). The nature of dietary lipid and its modification in the rumen (Reiser and Reddy, 1956) is of particular interest as it may influence the composition of the depot and milk fats of ruminants. Only a few investigators have studied possible relationships between the composition of the milk fat and dietary lipids when ruminants are fed entirely on pasture species. (McDowall and McGillivray, 1963; Hawke, 1963).The latter worker demonstrated that young succulent short rotation ryegrass (Lolium multiflorum x Lolium perenne) contained a higher content of lipid (β of dry wt.) than mature grass which contained appreciable stalk material. Furthermore the lipid from the new growth contained higher proportions of linolenic acid and lower proportions of linoleic and palmitic acids. When pairs of monozygous twin cows were grazed on these two types of pasture, the cows feed on the young grass had higher levels of unsaturated fatty acids in the milk fat. This was thought to be related to higher levels of unsaturated fatty acids in the young grass and to the degree of hydrogenation of the unsaturated fatty acid components of the dietary lipid in the rumen. A large proportion of the dietary lipid of ruminants fed on pasture would consist of galactosyl glycerides since these components are the major lipids of photosynthetic tissue (Weenink, 1961 ; Sastry and Kates, 1964). Consequently the comparative levels of galactosyl glycerides and changes in their fatty acid composition in L. perenne leaf tissue of varying age has been investigated. The present investigation also includes a study of the effect of the light environment on the levels and composition of lipid, especially the galactolipids, and on the biosynthesis of fatty acids. [From Introduction]Item Lipid biosynthesis in isolated barley protoplasts : a thesis ... for the degree of Master of Science in Biochemistry at Massey University(Massey University, 1983) Bell, Louise CynthiaIn most studies of fatty acid and lipid synthesis in plants there has been poor incorporation of radioactive label from acetate into linoleic (18:2) and linolenic (18:3) acids. Consequently the amounts of these fatty acids found in the galactolipids in such studies are much less than their observed endogenous levels. In the present study incorporation of H 14 CO 3 - and (1 14 C) acetate into lipids of barley protoplasts was examined. CO 2 -dependent O 2 evolution rates of the protoplasts were around 180 µmol O 2 /h/mg Chl and intactness was also ascertained by phase contrast microscopy. Incubating proto- plasts with 1mM H 14 CO 3 - or 50 µM (1- 14 C) acetate resulted in 146.2 and 17 nmol/mg Chl being incorporated into lipids respectively after 1 hour. A concentration of 10 mM was optimal for HCO 3 - incorporation and up to 580 nmol/mg Chl was incorporated into lipids at the end of 1 hour. Mg ++i ions used at 2 mM had little effect on HCO 3 - incorporation while PP i appeared to be slightly inhibitory. Acetate assimilation and its incorporation into lipids was markedly affected by pH and pH 5.8 was chosen for the assay medium. In 20 hour incubations 162 nmol acetate/mg Chl was incorporated. About 33% of label from acetate was found in each of palmitic (16:0) and oleic (18:1) acids with less than 9% in each of stearic (18:0), linoleic and linolenic acids. There was little or no incorporation of acetate into DGDG and less than 10% into each of PG, MGDG, PE and U (unknown lipid). Incorporation into PC after 2 1/2 hours was 36.8% then decreased to 8.9%. Acetate incorporation was most significant into U SF (another unknown lipid), being 73.4%. Although acetate was incorporated into a range of glycerolipids, incorporation into constituent 18:2 and 18:3 of these lipids was not significant.Item The effect of nitrogen management and paddock history on growth and yield of barley (Hordeum vulgare L.) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Plant Science at Massey University(Massey University, 1985) Shuhaimen bin IsmailA field experiment was conducted during spring 1983/1984 at four adjacent sites on marginal the cropping soil Tokomaru silt loam to study the effect of nitrogen management and paddock history on growth and yield of barley (Hordeum vulgare L.) cv. Magnum. Six nitrogen treatments were tested in three replications in a randomised complete block design at each site. The treatments were no-N (control), 60 kg N/ha either applied at sowing, growth stage (G.S.) 3, G.S.6 or equally split between G.S.3 and G.S.6 and a higher rate based on soil test results (70-90 kg N/ha depending on site) applied at sowing. Site histories were immediately out of pasture and previously cropped with barley for 1 , 2 and 3 years. Crop nitrogen status was monitored by nitrate sap test and plant analysis. Control plot yield decreased almost linearly from 5.78t/ha directly out of pasture to 3.55 t/ha on the site previously cropped for three years. This indicated that regular cropping without fertiliser nitrogen on this soil could substantially reduce the yield of barley. Application of nitrogen significantly increased yield over control at all sites. The response in the first year of cropping was probably because of the low accumulation of nitrogen during the pasture phase on this soil. Average yield of plots receiving nitrogen were similar for the first two year of cropping (7.09 and 6.86 t/ha respectively) but declined rapidly for the third and fourth year of cropping (5.90 and 5.94 t/ha respectively). Plots receiving the high nitrogen rate were also unable to maintain yield as cropping increased. The yield decline could have been caused by deteriorated soil physical conditions under continuous cropping. Maintaining adequate nitrogen toward later stages of growth by late or split application was found to be as effective as applying the higher nitrogen rate at sowing especially as soil fertility reduced. Ear density was the main component affecting yield. Grain number/ear was also an important yield component for crop grown under lower fertility and was increased when nitrogen was applied at sites cropped for 3 and 4 years. There was differences between predicted yield based on soil test results and actual yield of control plots across the sites. Sap nitrate concentration showed a good relationship with total nitrogen analysis. Both measurements of plant nitrogen at earlier stages of growth were related to the yield. Highest yield (7t/ha) was found to be associated with 4.5% total nitrogen and >6000ppm sap nitrate concentration at about G.S.3.Item Effects of ℓ-glucan and non-starch polysaccharides on ileal and faecal energy, nitrogen, ileal apparent and true amino acid digestibility in the growing pig : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science at Massey University, Palmerston North, New Zealand(Massey University, 1999) Kim, Jae CheolIt is generally accepted that soluble non-starch polysaccharides (NSP) in cereals such as barley have a negative influence on the digestibility of energy, nitrogen, and amino acids in broiler chickens. However, the evidence in growing pigs for a similar effect of barley NSP on nutrient digestibility is less convincing. A major reason for this is that detailed investigations into the effect of barley NSP, predominantly β-glucan, have not been conducted. Therefore, the overall aim of this study was to elucidate the effect of NSP from a cohort of Australian barleys on the ileal and faecal digestibility of energy, nitrogen, and amino acids in growing pigs. This study was a collaborative project with the South Australian Research and Development Institute (SARDI). Eleven Australian barley varieties (including a control barley) were fed as the sole source of protein and energy to Landrace X Large White male pigs (35-55kg) fitted with a T-piece PVC cannula. Celite® was added as the indigestible marker. All diets were cold-press pelleted. Test diets were given to pigs based on a Latin Square design for five days prior to a two day collection period. An enzymically-hydrolysed casein (EHC) diet was fed to pigs for quantitative determination of endogenous amino acid flows at the terminal ileum. Ileal nitrogen, energy, apparent and true amino acid digestibilities were determined with reference to the marker. Faecal nitrogen and energy digestibilities were determined in six of the barley diets that were examined in New Zealand. An experiment with five barley varieties and one control barley was conducted in South Australia, and the same experimental protocol was followed at Massey University. The range in nutrient composition of Australian barley varieties was 7.6-14.2% CP, 12-21% NDF, 3-6% ADF, 0.5-1.5% Lignin, 2-4% total β-glucan, 0.21-0.34% soluble β-glucan, and 6-12% total amino acids on a dry matter basis. The six barleys that were examined in New Zealand were analysed for NSP and contained 11-17% total NSP, 7-11% insoluble NSP, and 2-7% soluble NSP. The contents of total NSP, soluble NSP, and soluble β-glucan were significantly correlated to CP content in barley (p<0.01, p<0.001, p<0.05, p<0.01, respectively). The ileal and faecal energy digestibilities of the barleys ranged from 53.6 to 71.0% and from 79.2 to 82.5%, respectively. Ileal and faecal nitrogen digestibilities ranged from 52.5 to 76.0% and from 64.3% to 75.6%, respectively. The mean apparent and true amino acid digestibilities were 69.7% and 84.1%, respectively. The mean endogenous Lysine flow determined under conditions of EHC/Ultrafiltration was 472μg/g dry matter intake. Correlation analysis between the chemical composition of the barleys and nutrient digestibility found significant positive relationships between ileal nitrogen digestibility and crude protein content (p<0.05), soluble μ-glucan (p<0.05), soluble NSP (p<0.05), and faecal nitrogen digestibility (p<0.05). Ileal energy digestibility was negatively correlated to insoluble NSP (p<0.05). No correlation was found between the chemical composition of barley and faecal nitrogen digestibility, while faecal energy digestibility was negatively correlated with NDF, ADF, and hemicellulose (p<0.05). The apparent ileal digestibility of essential amino acids was positively (p<0.05 - 0.01) correlated to ileal nitrogen digestibility, whereas no relationship (p>0.05) was found between true digestibility of essential amino acids and chemical composition of barley. Mathematical investigations found that the ileal (r2=0.66) and faecal energy digestibility (r2=0.73) could be predicted from the concentration of insoluble NSP and hemicellulose contents of barleys, respectively. Ileal nitrogen digestibility (r2=0.80) could be predicted from the concentration of CP and faecal nitrogen digestibility. Also, apparent ileal digestible lysine content (r2=0.99) could be predicted from faecal nitrogen digestibility along with the content of lysine in the barley. The anti-nutritive effects of NSP of Australian barleys were not observed in apparent ileal and faecal digestibilities of energy, nitrogen, and amino acids. However, a consistent tendency of the negative influence (p<0.05 - p>0.05) of NSP to true amino acid digestibility was demonstrated.Item Evaluation of the anti-nutritive and hypocholesterolemic effects of a [beta]-glucan preparation extracted from New Zealand barley : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutritional Science at Massey University(Massey University, 1999) Maqueda de Guevara, Maria de LourdesThe present study evaluated the anti-nutritive as well as the hypocholesterolemic effects of barley β-glucan through the use of a commercially prepared barley β-glucan extract. Two experiments with broiler chickens were performed. In the first experiment (Chapter 3), a commercially prepared barley β-glucan extract was added (15 g/kg diet) to a synthetic diet based on cornstarch and casein. In addition, the diet was heated to evaluate the effects of heat treatment on the anti-nutritive effects of β-glucan. The diet was fed to twenty 15-day-old male broilers for 7 days. Diets containing β-glucan reduced (P<0.01) nitrogen (N) and carbon (C) digestibility, increased in the full weight of the whole gut (P=0.08) and the caeca (P<0.05)? and increased (P<0.01) the insoluble solids volume (ISV) and water holding capacity (WHC) of digesta of birds. Heating the diets decreased (P<0.01) N digestibility and increased the ISV of the digesta. In the second experiment (Chapter 4), different amounts of the β-glucan extract were added to a barley-based diet to provide three different levels of dietary β-glucan (low (19.8 g β-glucan /kg diet), medium (50.7 g β-glucan/kg diet), and high (68.3 g β-glucan/kg diet)). In addition, a β-glucanase was added to each of the diets to assess its influence on digestibility, performance, and digesta physico-chemical properties. The diets were fed to 36, 15-day-old male broilers for seven days. Results showed variable responses. The values obtained for gross energy (GE) digestibility, and the weights of the whole gut empty and the second part of the small intestine full and empty were similar between diets of low and medium β-glucan content, but lower (P<0.05) than the values obtained with diet high. In the case of WHC and ISV, the values obtained with diets medium and high were similar, but higher (P<0.01 for WHC; P<0.005 for ISV) than the values obtained with diet low. For viscosity, the higher (P<0.01) values were obtained with diet low, while the values obtained with diets medium and low were similar. The variable responses were attributed to the soft gelatinisation of β-glucan when dispersed in water, which could have encapsulated the native β-glucan from barley, hindering any anti-nutritive effect it could have. Another possibility suggested was in terms of the threshold level of β-glucan needed to elicit its anti-nutritive effects, which was not reached in some of the diets. The β-glucanase inclusion improved N, C (P<0.05), and GE (P<0.01) digestibility, decreased the viscosity of the digesta (P<0.01) and the weights of the whole gut and the second part of the small intestine (P<0.01), and improved the weight gain and feed conversion ratio (FCR) of the birds (P<0.05). The experiment also suggested that viscosity is not the main mechanism needed for the anti-nutritive effects of β-glucan because although the viscosity of most of the diets was low, the β-lucan still elicited some anti-nutritive effects. It is possible that the gelling capacity of the β-glucan extract was one of the main factors influencing the anti-nutritive effects of the extract. In addition to these two studies, an in vitro digestibility method simulating the chicken's gut was developed to evaluate the anti-nutritive effects of β-glucan on N and C digestibility as well as on the physico-chemical properties of the digesta (Chapter 5). The method showed acceptable accuracy (r=0.93, P<0.01) in the prediction of N digestibility in vivo in a wide range of diets. In the case of C digestibility, although a significant correlation (r=-0.64, P<0.05) between the in vitro and in vivo values was found, the in vitro digestion did not reflect what happened during the in vivo digestion. This was possibly due to the fact that the in vitro assay was not designed to analyse C digestibility, and the results obtained were in fact an artifact of the data set. The physico-chemical properties of the digesta were not predicted accurately by the in vitro method because conditions such as the churning effect of the intestine and the action of the microorganisms present in the intestine, which greatly affect digesta, could not be replicated in the method. The hypercholesterolemia effects of the β-glucan extract were evaluated in growing male rats through the inclusion of β-glucan in synthetic diets based on cornstarch and casein (Chapter 6). In addition, the effects of coconut oil (rich in saturated fatty acids (SFA)), and flax oil (rich in polyunsaturated fatty acids (PUFA)) in blood lipids were also evaluated. The diets were fed to 36 28-day-old male rats for 28 days. The results of this experiment showed a reduction (P=0.07) in total cholesterol (TC) levels by the inclusion of β-glucan. The kind of oil used in the diets did not affect TC levels(P>0.05). Serum TG levels were decreased (P<0.01) by inclusion of β-glucan. When coconut oil was used, β-glucan inclusion decreased (P<0.05) serum TG levels. However, when flax oil was used, β-glucan inclusion did not have any effect on TG (P>0.05). In addition, it is suggested that the hypocholesterolemic effects of the β- glucan extract used were due to a decrease in lipid absorption in the small intestine,which was caused by the β-glucan inducing a gel formation, which delayed nutrient absorption. This gel formation induced by the β-glucan extract is considered to be one of the main factors responsible for the hypocholesterolemic effects of the β-glucan extract. It is concluded that the anti-nutritive and hypocholesterolemic effects of barley β-glucans were demonstrated through the use of a commercially prepared barley β-glucan extract, and that the gel formation induced by the β-glucan extract could be one of the main mechanisms responsible for the anti-nutritive and hypocholesterolemic effects of this NSP, which could be equally important to increases in viscosity induced by intact β-glucan.Item Aspergillus flavus and the deterioration of farm-stored barley grain : a thesis presented in partial (30%) fulfilment of the requirements for the degree of Master of Philosophy in Veterinary Pathology & Public Health at Massey University(Massey University, 1983) Hussein, Hassan MFor many years there was a tendency to regard moulds in grains destined for animal consumption as of little significance other than as gross spoilage organisms. Investigations of the possible role of toxic fungi in diseases of grain-fed animals was confined in the main to problems of restricted local significance (Forgacs and Carll, 1962). However, it was the discovery of aflatoxin in 1961 and the widespread concern which it generated, which inspired a vast amount of research into the natural production of mycotoxins and the consequent mycotoxicoses affecting both animal and human health, aspects of which have been fully reviewed in a number of recent publications (Purchase, 1974; Rodricks, 1976; Rodricks et at., 1977; Wyllie and Morehouse, 1978 and Cole and Cox, 1981). Mycotoxin production can occur anywhere, in the field, or during harvest, processing, storage and shipment, or during the feeding period on the farm. Commodities grown and stored in areas where high levels of insect damage and poor farming and storage practices prevail appear to be the most susceptible (Ciegler, 1978). Nevertheless, natural contamination with a variety of mycotoxins has been reported for most of the major agricultural commodities in the world (Hesseltine, 1974) and those mycotoxins currently of most concern are: aflatoxin, trichothecenes, zearalenone, ochratoxin, citrinin and some tremorgens (Ciegler, 1978). However, there are over 23 known mycotoxins which can be associated with grains and some of those currently less well known may prove to be significant in the future.Item Prediction of the in vivo digestible energy value of barley for the growing pig on the basis of physical and chemical characteristics and in vitro digestible energy : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University(Massey University, 1997) Chen, JiaiThe study aimed to develop statistical relationships to allow the prediction of apparent digetible [sic] energy in barley based on simple physical and chemical measures. A second aim was to evaluate a recently developed in vitro energy digestibility assay. Seventeen barley samples representing nine varieties were obtained throughout New Zealand during the 1995 harvest. The samples were subjected to chemical analysis and several physical attributes were determined. Ten barley samples were selected on the basis of their crude protein and fibre contents to cover the range in gross chemical composition and digestible energy contents were determined after sampling faecal contents from 30 kg liveweight pigs, given barley as the sole source of energy. In vitro dry matter digestibility of the barley samples was determined using a multi-enzyme assay. The physical characteristics of the barley samples were variable, especially the level of screenings (ranging from 1 to 11.6%) and to a lesser extent the moisture content (ranging from 12 to 16.2%) and 1000 seed weight. The chemical composition of the barley samples differed with the crude protein content ranging from 7.8 to 11.7%. The mean levels of Neutral Detergent Fibre (NDF), Acid Detergent Fibre (ANF) and lignin were 16.4 %, 4.2%, and 1.1%, respectively. Total β-glucan and Gl extracted β-glucan contents were also determined with mean values of 4.5% and 1.4%, respectively. The in vivo apparent digestibility of energy (DE) ranged from 72.5% to 78.4% with a mean digestibility of 75.8%. Among the physical and chemical characteristics, only the seeding rate was significantly correlated with in vivo energy digestibility (r = 0.73, P< 0.05). The gross energy (GE) content was significantly correlated with apparent digestible energy content (r = 0.78). When the gross energy value of a sample is known, an approximation of the apparent digestible energy (ADE) content can be made using a simple prediction equation: ADE MJ/kg dry matter = -10.48 ± 1.33 GE MJ/kg dry matter. Repeatability of the in vitro digestibility of dry matter (DDM) was high (r =0.68) but the correlation coefficient between in vivo DE and in vitro DDM for the barley samples (r = 0.29) was not statistically significant. However, when combined with results for several wheat milling by-products, the in vitro DDM was significantly (p<0.01) correlated to the in vivo DE (r = 0.96) indicating that in vitro DDM is a good predictor for in vivo DE across feedstuffs but not within a feedstuff.