Theme 2-3: Forage Production and Utilization--Poster Sessions
Description
Low ratio of readily fermentable carbohydrate to soluble protein concentrations in lucerne (Medicago sativa L.) leads to inefficient use of herbage N by ruminants. To improve the energy to protein balance in lucerne-grass herbage, four proportions of lucerne:red clover (Trifolium pratense L.) were compared in mixtures with and without grasses: timothy (Phleum pratense L.) and tall fescue (Schedonorus arundinaceus Schreb. Dumort.) in Quebec (QC, Canada). In the first post-seeding year, red clover proportion averaged (across grasses and four harvests) 0, 37, 59, and 74% in herbage mixtures. Increasing the proportion of red clover caused a slight but significant decrease in herbage total nitrogen (TN) concentration (32 to 31 g kg-1 DM) but substantial decreases in non-protein N (PA), rapidly (PB1) and moderately (PB2) degraded protein fractions, and a significant increase in the slowly degraded protein fractions (PB3+PC) (157 to 308 g kg-1 TN). With the inclusion of 74% of red clover, the ratio of soluble sugar to crude protein (CP) in herbage increased from 0.25 to 0.36 because of the increase in the soluble sugar concentration (48 to 66 g kg-1 DM). The inclusion of red clover in mixture with lucerne improved the energy to CP balance compared to lucerne alone, and caused a linear increase in the herbage in vitro neutral detergent fiber digestibility from 568 to 639 g kg-1 aNDF with similar herbage dry matter yield (10.3 Mg ha-1).
Included in
Red Clover Improves the Energy to Protein Balance of Lucerne-Grass Herbage
Low ratio of readily fermentable carbohydrate to soluble protein concentrations in lucerne (Medicago sativa L.) leads to inefficient use of herbage N by ruminants. To improve the energy to protein balance in lucerne-grass herbage, four proportions of lucerne:red clover (Trifolium pratense L.) were compared in mixtures with and without grasses: timothy (Phleum pratense L.) and tall fescue (Schedonorus arundinaceus Schreb. Dumort.) in Quebec (QC, Canada). In the first post-seeding year, red clover proportion averaged (across grasses and four harvests) 0, 37, 59, and 74% in herbage mixtures. Increasing the proportion of red clover caused a slight but significant decrease in herbage total nitrogen (TN) concentration (32 to 31 g kg-1 DM) but substantial decreases in non-protein N (PA), rapidly (PB1) and moderately (PB2) degraded protein fractions, and a significant increase in the slowly degraded protein fractions (PB3+PC) (157 to 308 g kg-1 TN). With the inclusion of 74% of red clover, the ratio of soluble sugar to crude protein (CP) in herbage increased from 0.25 to 0.36 because of the increase in the soluble sugar concentration (48 to 66 g kg-1 DM). The inclusion of red clover in mixture with lucerne improved the energy to CP balance compared to lucerne alone, and caused a linear increase in the herbage in vitro neutral detergent fiber digestibility from 568 to 639 g kg-1 aNDF with similar herbage dry matter yield (10.3 Mg ha-1).
