Abstract
Alfalfa (Medicago sativa L) is a high-quality forage for ruminants and the main stem is the dominant morphological component contributing to the forage nutritive value in mature alfalfa forage. Shearing force, a fracturing property of plant stem, is an important indictor of forage value. The objectives of this study were to investigate the effects of morphological characteristic on shearing force, the relationship between shearing force and chemical composition, and the relationship between shearing force and in situ digestibility of alfalfa stem. The results showed that linear density (weight per unit length of stem) was more important than chemical composition in affecting shearing force. There was a positive relationship between lignin content and shearing force (r = 0.78). Correlations were not found between shearing force and other chemical components such as neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose and hemicelluloses. In situ digestibility (of dry matter and NDF) was related to shearing force. A negative correlation was found between shearing force and dry matter (DM) digestibility (r = -0.70), and there was also a negative correlation between shearing force and NDF digestibility (r = -0.87). When shearing force was standardized for stem diameter or stem linear density, the relationship between shearing force and digestibility was consistent regardless of stem diameter and stem linear density. Shearing force was significantly correlated with lignin content and in situ digestibility (of DM and NDF), and was a more direct indicator for estimating forage nutritive value related to animal performance, so it can be used to predict the forage value of alfalfa.
Highlights
Forage intake and digestibility of ruminants are major determinative factors of animal performance
Forage intake was affected by the action of thirst-controlling peptides and related to saliva secretion (Sunagawa et al, 2007)
We studied the correlations of shearing force with chemical composition
Summary
Forage intake and digestibility of ruminants are major determinative factors of animal performance. Forage intake was affected by the action of thirst-controlling peptides and related to saliva secretion (Sunagawa et al, 2007). Ba et al (2008) reported that forage intake declined as concentrate intake increased. There are many factors affected forage digestibility. Studies show that forage digestibility were significantly affected by meal frequency and decreased as the number of meals increased (Assoumaya et al, 2009). Variable feed supply would decrease forage digestibility (Habib et al, 2008). Forage quality was an important factor which could affect forage intake and digestibility . Iwaasa et al (1996) found that the physical properties of forages are related to voluntary feed intake of ruminants.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call