Chlormequat can be applied to winter barley for growth manipulation with a view to increasing ear number per m<SUP>2</SUP> and hence grain yield, but, reviewing the literature on field trials showed the effects were not consistent. Previous work showed that the grain yield per m<SUP>2</SUP> of winter barley was strongly correlated with the number of grains per m<SUP>2</SUP> which itself was shown to be mostly influenced by the number of ears per m<SUP>2</SUP>. Three agronomic factors, cultivar, sowing date and nitrogen fertiliser, were identified from the literature as important influences on ear production in winter barley. These were therefore considered to have the potential to modify plant response to chlormequat, in terms of ear production, and might thus account for some of the inconsistency of the effect of chlormequat on grain yield in field trials. The intention of these studies was to move towards a description of winter barley production systems into which chlormequat may be integrated to consistently increase grain yield. Because little information was available on the growth, development and grain yield components of field grown modern winter barley cultivars, these attributes were monitored and analysed in detail for a range of modern cultivars grown at two sites in north-east Scotland in the harvest years 1984 and 1985. Tipper and Maris Otter were identified as strongly contrasting cultivars, being good examples of the extremes of the range of growth parameters found. In addition, the analyses identified the extreme importance of high cultivar biomass per plant for the attainment of high cultivar grain yield per plant. Evidence that increases in biomass have already contributed to the higher grain yields of modern cultivars of both spring barley and winter wheat was also found within the literature. The effect of chlormequat at a range of application times in the spring on early and late sowings of Igri, Tipper (low ear production) and Maris Otter (high ear production) was tested. When averaged over all cultivars and sowing dates chlormequat applied prior to stem extension significantly increased the number of ears per m<SUP>2</SUP> in 1983--4 which led to increases in grain yield. In 1984--5 chlormequat applied at the start of stem extension significantly increased the number of grains per ear and significantly increased grain yield; within-plant uniformity, in terms of shoot contribution to grain yield, was also increased. Chlormequat had no consistent effect on the grain yield of the cultivars Igri and Tipper, but did increase the grain yield of both early and late sown Maris Otter by increasing the number of grains per m<SUP>2</SUP>. These higher grain numbers were achieved through consistent increases in the number of ears per m<SUP>2</SUP> which were nearly always associated with increases in the number of grains per ear on the main stem and early primary tillers. These larger sink sizes of Maris Otter followed temporary reductions in shoot height which were offset by compensatory increases in shoot growth. The growth, development and grain yield components of Maris Otter were described in detail with a view to enabling cultivars with similar growth characteristics to be identified. Application of nitrogen fertiliser did not modify the effect of chlormequat on shoot height or shoot dry weight. In these experiments chlormequat increased neither ear number per m<SUP>2</SUP> nor grain number per ear; therefore, the effect of nitrogen application strategy on the ability of chlormequat to increase in sink size could not be evaluated. It was suggested that application of chlormequat to Igri winter barley receiving more than 100 kg N/ha is unlikely to reduce grain yield. These investigations confirmed the extreme importance of high crop biomass for the attainment of high grain yield. The findings of these investigations together with the findings of a re-analysis of advisory service field trial data on the effect of chlormequat on winter barley are discussed in relation to commercial winter barley production. Finally, it is suggested that more consistent increases in grain yield may be achieved by restricting the use of chlormequat for tiller manipulation to cultivars of the Maris Otter type such as Halcyon and Pipkin which are slow developing, produce relatively large numbers of tillers and eventually many ears per plant.

No description available.

No description available.

Feeding value of dried distillers grains with soluble (DDGS) as an energy source for lactating dairy cows was evaluated in two studies. A diet in which barley grain was replaced by DDGS at 20% of dietary dry matter (DM) did not affect milk yield but tended to increase rumen pH compared with the control diet. Diets in which barley silage was replaced by DDGS at 20% of dietary DM increased milk yield and decreased chewing time compared with the control diet in both studies, but decreased rumen pH and milk fat concentration in the second study, and the inclusion of alfalfa hay in place of barley silage at 10% of dietary DM did not alleviate those depressions. In conclusion, DDGS can be used as an energy source as a partial replacement of barley grain or barley silage in diets for lactating dairy cows. / Animal Science

Two trials were conducted to evaluate the effects of titrated levels of wheat-based dried distillers grains on feedlot performance, carcass characteristics and rumen fermentation parameters of cattle fed wheat-based dried distillers grains with solubles (DDGS). In trial 1, a barley grain-based diet (0% DDGS) was used as a control. It was formulated to 12% CP and 1.52 and 0.93 Mcal kg-1 net energy of maintenance (NEm ) and net energy of gain( NEg) respectively, during the backgrounding period and to 13% crude protein (CP) and 1.90 and 1.26 Mcal kg-1 NEm and NEg respectively, during finishing. Wheat-based DDGS replaced on a dry matter basis (DM) barley grain at levels of 8, 16, 24 and 32% during backgrounding and 6, 12, 18 and 23% during finishing. During backgrounding dry matter intake (P = 0.02), ADG (P = 0.04), and ultrasounded (US) longissimus. dorsi gain (P = 0.02) exhibited a cubic response to DDGS inclusion level with theoretical minima at 6.9, 8.1 and 6.9% DDGS respectively, and theoretical maxima responses at 27.2, 30.8 and 23.9% DDGS, respectively. Feed efficiency exhibited a quadratic response (P = 0.02) to DDGS inclusion level with a theoretical poorest response at 13.1% DDGS. Similar responses were noted during the first 56 d of the finishing period, however over the course of the finishing period no effect of DDGS inclusion level was noted on average daily gain (ADG), DMI, feed efficiency (FE), ultrasound measurements or on any carcass traits. <p>Trial 2 examined the effects of graded levels of wheat-based DDGS (0, 7, 14, 21% DM basis) on rumen fermentation characteristics using rumen cannulated heifers. Rumen pH measurements indicated that the pH mean at or below 5.8 and 5.5 decreased as DDGS inclusion level increased to 14% DM. The highest values (P<0.05) for pH area between the benchmarks of 5.5 and 5.2, pH area below 5.2 and time below pH 5.2 were found at the 14% DDGS inclusion level, pointing to rumen fermentation characteristics associated with severe rumen acidosis. Ammonia nitrogen levels, percent acetate, percent butyrate and the acetate: propionate ratio increased linearly (P < 0.0001) with DDGS. Propionate concentration decreased linearly (P = 0.006) as the level of DDGS increased. In situ rumen degradation kinetics showed that the DM and CP soluble fraction of DDGS to be significantly higher than that of rolled barley, however effective degradability of dry matter (EDDM) and effective degradability of crude protein (EDCP) were greater for barley. The results of this trial indicate that wheat-based DDGS has an energy value at least equal to that of barley grain with no adverse effects on cattle performance or carcass quality. Furthermore, since all treatments showed equal susceptibility to sub-acute ruminal acidosis (SARA) and therefore, wheat-based DDGS as a dietary ingredient is unable to mitigate rumen fermentation conditions associated with SARA.

Two trials were conducted to evaluate the effects of titrated levels of wheat-based dried distillers grains on feedlot performance, carcass characteristics and rumen fermentation parameters of cattle fed wheat-based dried distillers grains with solubles (DDGS). In trial 1, a barley grain-based diet (0% DDGS) was used as a control. It was formulated to 12% CP and 1.52 and 0.93 Mcal kg-1 net energy of maintenance (NEm ) and net energy of gain( NEg) respectively, during the backgrounding period and to 13% crude protein (CP) and 1.90 and 1.26 Mcal kg-1 NEm and NEg respectively, during finishing. Wheat-based DDGS replaced on a dry matter basis (DM) barley grain at levels of 8, 16, 24 and 32% during backgrounding and 6, 12, 18 and 23% during finishing. During backgrounding dry matter intake (P = 0.02), ADG (P = 0.04), and ultrasounded (US) longissimus. dorsi gain (P = 0.02) exhibited a cubic response to DDGS inclusion level with theoretical minima at 6.9, 8.1 and 6.9% DDGS respectively, and theoretical maxima responses at 27.2, 30.8 and 23.9% DDGS, respectively. Feed efficiency exhibited a quadratic response (P = 0.02) to DDGS inclusion level with a theoretical poorest response at 13.1% DDGS. Similar responses were noted during the first 56 d of the finishing period, however over the course of the finishing period no effect of DDGS inclusion level was noted on average daily gain (ADG), DMI, feed efficiency (FE), ultrasound measurements or on any carcass traits. <p>Trial 2 examined the effects of graded levels of wheat-based DDGS (0, 7, 14, 21% DM basis) on rumen fermentation characteristics using rumen cannulated heifers. Rumen pH measurements indicated that the pH mean at or below 5.8 and 5.5 decreased as DDGS inclusion level increased to 14% DM. The highest values (P<0.05) for pH area between the benchmarks of 5.5 and 5.2, pH area below 5.2 and time below pH 5.2 were found at the 14% DDGS inclusion level, pointing to rumen fermentation characteristics associated with severe rumen acidosis. Ammonia nitrogen levels, percent acetate, percent butyrate and the acetate: propionate ratio increased linearly (P < 0.0001) with DDGS. Propionate concentration decreased linearly (P = 0.006) as the level of DDGS increased. In situ rumen degradation kinetics showed that the DM and CP soluble fraction of DDGS to be significantly higher than that of rolled barley, however effective degradability of dry matter (EDDM) and effective degradability of crude protein (EDCP) were greater for barley. The results of this trial indicate that wheat-based DDGS has an energy value at least equal to that of barley grain with no adverse effects on cattle performance or carcass quality. Furthermore, since all treatments showed equal susceptibility to sub-acute ruminal acidosis (SARA) and therefore, wheat-based DDGS as a dietary ingredient is unable to mitigate rumen fermentation conditions associated with SARA.

Thesis (Ph. D.)--University of Adelaide, Dept. of Agronomy and Farming Systems, 1997. / Includes bibliographical references (leaves 290-324).

The fibrous barley hull is the main reason for barleys low available energy relative to corn. Barley grain contains hydroxycinnamic acids (mainly ferulic acid (FA) and ñ-coumaric acid (PCA)) which are cross-linked to polysaccharides, therefore, limit cell wall degradability in the rumen. Paricle size of barley grain also affects the digestion of barley in the rumen. The objective of this study was to evaluate a set of barley varieties grown in Saskatchewan (Canada) and provided by Crop Development Center (CDC, Canada) and find a variety with low hull, FA, PCA and fiber content, while maintaining large particle size after mechanical processing, and having high nutrient availability.<p> Three studies were conducted to determine the content of barley hull, FA, PCA, neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) in various barley varities. Mean/median particle size of the barley grain after coarse dry-rolling was also determined. The relationships among these parameters and the digestibility of barley grain in ruminants were then assessed. Six barley varieties (AC Metcalfe, CDC Dolly, McLeod, CDC Helgason, CDC Trey and CDC Cowboy) from samples grown in three years (2003, 2004 and 2005) were evaluated in each study.<p> The first study determined the original content of barley hull, FA, PCA, NDF, ADF, ADL, and mean/median particle size of barley grain and evaluated the effects of barley variety. The results showed barley variety had a significant impact on the chemical and physical profiles of barley grain, with CDC Helgason and CDC Dolly showing relatively lower content of barley hull, FA, PCA, NDF, ADF, ADL, hemicellulose and cellulose, and moderate mean/median particle size, whereas McLeod and CDC Cowboy showed the opposite.<p> The second study involved two consecutive trials. Trial 1 was to assess differences in the in situ rumen degradability of dry matter (DM), FA, PCA, NDF, ADF and ADL at 12 and 24 h of rumen incubations. Results revealed that CDC Dolly consistently showed relatively lower rumen residues of DM, FA, PCA, NDF, ADF and ADL at 12 and 24 h, with McLeod being opposite. Barley variety displayed some effects on the digestibility of DM, FA, PCA, NDF, ADF and ADL at 12 and 24 h. Since CDC Dolly demonstrated relatively less content of hull, FA, PCA, NDF, ADF, ADL and mean/median particle size and higher rumen digestibility among the six barley varieties, while McLeod was the opposite, CDC Dolly and McLeod were selected for the third trial in order to compare differences in the rumen degradation kinetics of DM, FA and PCA. Trial 2 did not show significant differences in effective degradation of DM, FA, except for PCA. In general, CDC Dolly exhibited better degradability of DM, FA and PCA than McLeod.<p> The third study analyzed the correlation and regression between the original content of barley hull, FA, PCA, NDF, ADF, ADL and mean/median particle size in barley grain and rumen residual content of the corresponding parameters at 12 and 24 h of rumen incubation. Results showed that FA content in barley grain had a predominantly negative effect on DM degradability, while barley hull content affected the degradability of NDF and ADF.<p> In summary, the present studies show that hull and FA content in barley grain have negative effects on the degradability of barley grain in ruminants and also showed that CDC Dolly could be an ideal feed barley grain for ruminants due to its lower hull and FA content and higher rumen dry matter degradability.

The fibrous barley hull is the main reason for barleys low available energy relative to corn. Barley grain contains hydroxycinnamic acids (mainly ferulic acid (FA) and ñ-coumaric acid (PCA)) which are cross-linked to polysaccharides, therefore, limit cell wall degradability in the rumen. Paricle size of barley grain also affects the digestion of barley in the rumen. The objective of this study was to evaluate a set of barley varieties grown in Saskatchewan (Canada) and provided by Crop Development Center (CDC, Canada) and find a variety with low hull, FA, PCA and fiber content, while maintaining large particle size after mechanical processing, and having high nutrient availability.<p> Three studies were conducted to determine the content of barley hull, FA, PCA, neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) in various barley varities. Mean/median particle size of the barley grain after coarse dry-rolling was also determined. The relationships among these parameters and the digestibility of barley grain in ruminants were then assessed. Six barley varieties (AC Metcalfe, CDC Dolly, McLeod, CDC Helgason, CDC Trey and CDC Cowboy) from samples grown in three years (2003, 2004 and 2005) were evaluated in each study.<p> The first study determined the original content of barley hull, FA, PCA, NDF, ADF, ADL, and mean/median particle size of barley grain and evaluated the effects of barley variety. The results showed barley variety had a significant impact on the chemical and physical profiles of barley grain, with CDC Helgason and CDC Dolly showing relatively lower content of barley hull, FA, PCA, NDF, ADF, ADL, hemicellulose and cellulose, and moderate mean/median particle size, whereas McLeod and CDC Cowboy showed the opposite.<p> The second study involved two consecutive trials. Trial 1 was to assess differences in the in situ rumen degradability of dry matter (DM), FA, PCA, NDF, ADF and ADL at 12 and 24 h of rumen incubations. Results revealed that CDC Dolly consistently showed relatively lower rumen residues of DM, FA, PCA, NDF, ADF and ADL at 12 and 24 h, with McLeod being opposite. Barley variety displayed some effects on the digestibility of DM, FA, PCA, NDF, ADF and ADL at 12 and 24 h. Since CDC Dolly demonstrated relatively less content of hull, FA, PCA, NDF, ADF, ADL and mean/median particle size and higher rumen digestibility among the six barley varieties, while McLeod was the opposite, CDC Dolly and McLeod were selected for the third trial in order to compare differences in the rumen degradation kinetics of DM, FA and PCA. Trial 2 did not show significant differences in effective degradation of DM, FA, except for PCA. In general, CDC Dolly exhibited better degradability of DM, FA and PCA than McLeod.<p> The third study analyzed the correlation and regression between the original content of barley hull, FA, PCA, NDF, ADF, ADL and mean/median particle size in barley grain and rumen residual content of the corresponding parameters at 12 and 24 h of rumen incubation. Results showed that FA content in barley grain had a predominantly negative effect on DM degradability, while barley hull content affected the degradability of NDF and ADF.<p> In summary, the present studies show that hull and FA content in barley grain have negative effects on the degradability of barley grain in ruminants and also showed that CDC Dolly could be an ideal feed barley grain for ruminants due to its lower hull and FA content and higher rumen dry matter degradability.

Atrazine (2-chloro-4, ethylamino-6-isopropylaminos- triazine) applied to Hordium vulgare L. variety barbless in low concentrations (0.001, 0.01, 0.1 uM) was shown to in--­ crease the activity of D-ribulose-1, 5-diphosphate carboxylase (RuDPCase) and phosphoribulokinase (PRuK) up to 23% and 30% respectively and increase the amount of chlorophyll and extractable protein up to 18% and 21% respectively over the control plants. These results indicate that sub-toxic levels of atrazine significantly stimulate plant growth. Barley plants given higher concentrations of atrazine (1.0 and 10 uM) showed up to a 78% and 42% decrease in the activity of RuDPCase and PRuK respectively as well as a decrease in the amount of chlorophyll and extractable protein--72% and 19% respectively as compared to control plants. Zea mays L. variety PX 545 plants treated with the higher concentrations of atrazine (1.0 and 10.0 uM) showed no deleterious effects of the herbicide and in fact showed some enhancement of growth. Treatment of corn with the lower concentrations of atrazine (0.001, 0.01, and 0.1 uM) resulted in little or no significant differences from the control plants.