Theme 09: Forage Quality
Description
The objective of this study was to evaluate dry matter ruminal degradation kinetics, of prairie grass (Bromus catharticus Vahl.) and annual ryegrass (Lolium multiflorum), by using in sacco technique, on seven different harvesting dates. The forage was incubated in nylon bags, suspended in the rumen of four Hereford steers with a rumen fistula. The dry matter ruminal degradation was calculated through the exponential model P=a+b(1-exp(-ct)). Potential degradabilities (PD) were high and reduced across a temporal trend, ranging between 92,31 and 81,79g 100g -1 of dry matter (DM) for prairie grass (PG) and 95,06 and 77,44g 100g -1 DM for annual ryegrass (AR). Effective degradabilities (ED) had the same tendency as PD, ranging between 75,85 and 53,80g 100g -1 DM for PG and 79,68 and 53,60g 100g -1 DM for AR. For both parameters and most of the harvesting dates, AR was superior to PG. Except on two harvesting dates, both species presented similar degradation rates, ranging between 16,30% h-1 and 5,35% h-1. It was concluded that, during its main period of utilization, AR showed more ED and PD than PG, though, except on October, differences were of scarce magnitude. However, PD and ED decay across a temporal trend were more pronounced in RG. On the last harvest dates PG tended to stabilize its degradabilities.
Included in
In Situ Dry Matter Ruminal Degradation Kinetics of Prairie Grass and Annual Ryegrass Forage
The objective of this study was to evaluate dry matter ruminal degradation kinetics, of prairie grass (Bromus catharticus Vahl.) and annual ryegrass (Lolium multiflorum), by using in sacco technique, on seven different harvesting dates. The forage was incubated in nylon bags, suspended in the rumen of four Hereford steers with a rumen fistula. The dry matter ruminal degradation was calculated through the exponential model P=a+b(1-exp(-ct)). Potential degradabilities (PD) were high and reduced across a temporal trend, ranging between 92,31 and 81,79g 100g -1 of dry matter (DM) for prairie grass (PG) and 95,06 and 77,44g 100g -1 DM for annual ryegrass (AR). Effective degradabilities (ED) had the same tendency as PD, ranging between 75,85 and 53,80g 100g -1 DM for PG and 79,68 and 53,60g 100g -1 DM for AR. For both parameters and most of the harvesting dates, AR was superior to PG. Except on two harvesting dates, both species presented similar degradation rates, ranging between 16,30% h-1 and 5,35% h-1. It was concluded that, during its main period of utilization, AR showed more ED and PD than PG, though, except on October, differences were of scarce magnitude. However, PD and ED decay across a temporal trend were more pronounced in RG. On the last harvest dates PG tended to stabilize its degradabilities.
