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.

Palynology, the study of organic microfossils, is an important tool for improving our understanding of past environments and landscapes. Palynology provides a wealth of information from which climatic and environmental conditions can be inferred. However, inferred climatic and environmental conditions are often open to interpretation. Assumptions made about past climate conditions from pollen assemblages often rely on qualitative understanding of modern-day vegetation distributions, rather than empirical relationships. Historic anthropogenic impact on the environment must also be inferred, and assessments made as to whether vegetation changes are a result of climate change or human impact. This study seeks to address some of the questions that arise through the interpretation of pollen assemblages, by establishing empirical relationships between the geochemistry of modern pollen and climate or environmental controls. It focuses on the pollen of the climatically sensitive montane conifer Cedrus atlantica, which is distributed across the mountains of Morocco and Algeria. The study investigates aspects of modern pollen geochemistry and morphology and finds a strong relationship between the stable carbon isotope composition of modern pollen and mean annual precipitation (r2 = 0.54, p &lt;0.001) and summer precipitation (r2 = 0.63, p &lt;0.0001). Furthermore, a stronger relationship exists with aridity measured using the self-calibrating Palmer Drought Severity Index (r2 = 0.86, p &lt;0.0001), suggesting that the stable carbon isotope composition of Cedrus atlantica pollen is influenced by environmental moisture availability. The study also finds there is an increased abundance of ultraviolet absorbing compounds (UACs) in modern Cedrus atlantica pollen with increasing summer UV-B flux. This relationship was evident with samples growing in their native range (r2 = 0.84, p &lt;0.0001), but not with samples from outside this range (r2 = 0.00, p = 0.99), suggesting a possible genetic influence. Lastly, the study finds that grain size of Cedrus atlantica pollen is highly variable within and between samples, and we rule out climatic control on pollen grain size. These results suggest that quantitative relationships can be established between the geochemistry of Cedrus atlantica pollen and environmental and climatic influences. Stable carbon isotope analysis of fossil pollen could be used as a proxy for reconstruction of summer moisture availability, while analysis of UACs in fossil pollen could be used as a proxy for the reconstruction of summer UV-B flux. These proxies will enhance our understanding of climatic and environmental change in Northwest Africa and will complement existing palynological techniques for environmental and climate reconstruction. Palynology, the study of organic microfossils, is an important tool for improving our understanding of past environments and landscapes. Palynology provides a wealth of information from which climatic and environmental conditions can be inferred. However, inferred climatic and environmental conditions are often open to interpretation. Assumptions made about past climate conditions from pollen assemblages often rely on qualitative understanding of modern-day vegetation distributions, rather than empirical relationships. Historic anthropogenic impact on the environment must also be inferred, and assessments made as to whether vegetation changes are a result of climate change or human impact. This study seeks to address some of the questions that arise through the interpretation of pollen assemblages, by establishing empirical relationships between the geochemistry of modern pollen and climate or environmental controls. It focuses on the pollen of the climatically sensitive montane conifer Cedrus atlantica, which is distributed across the mountains of Morocco and Algeria. The study investigates aspects of modern pollen geochemistry and morphology and finds a strong relationship between the stable carbon isotope composition of modern pollen and mean annual precipitation (r2 = 0.54, p &lt;0.001) and summer precipitation (r2 = 0.63, p &lt;0.0001). Furthermore, a stronger relationship exists with aridity measured using the self-calibrating Palmer Drought Severity Index (r2 = 0.86, p &lt;0.0001), suggesting that the stable carbon isotope composition of Cedrus atlantica pollen is influenced by environmental moisture availability. The study also finds there is an increased abundance of ultraviolet absorbing compounds (UACs) in modern Cedrus atlantica pollen with increasing summer UV-B flux. This relationship was evident with samples growing in their native range (r2 = 0.84, p &lt;0.0001), but not with samples from outside this range (r2 = 0.00, p = 0.99), suggesting a possible genetic influence. Lastly, the study finds that grain size of Cedrus atlantica pollen is highly variable within and between samples, and we rule out climatic control on pollen grain size. These results suggest that quantitative relationships can be established between the geochemistry of Cedrus atlantica pollen and environmental and climatic influences. Stable carbon isotope analysis of fossil pollen could be used as a proxy for reconstruction of summer moisture availability, while analysis of UACs in fossil pollen could be used as a proxy for the reconstruction of summer UV-B flux. These proxies will enhance our understanding of climatic and environmental change in Northwest Africa and will complement existing palynological techniques for environmental and climate reconstruction.