Publication Date

1985

Location

Kyoto Japan

Description

To revise the conventional method of forage evaluation, digestion trials were conducted at the level of voluntary intake. Dry matter (DM), crude protein and Neutral Detergent Fibre (NDF) contents in offered and residual feeds were measured, using suffolk wethers which were fed with grass silage and hay. A lower content of crude protein and a higher content ofNDF in residual feeds were detected when compared with those of offered feeds. Then, crude protein and NDF values of intake feeds were calculated from the composition of offered and residual feeds. It was suggested that the reason for different contents of crude protein and ND Fin intake and supplied feeds may be due to that the ruminants fed palatable parts of forage preferentially. Higher crude protein and lower NDF percentages in intake feeds than in offered were confirmed. To indicate the values of contents in offered feeds, Available Intake Ratio (AIR) was adopted. AIR defines the ratio of contents of intake to offered feeds. AIR values were 77-89% in dry matter, 82-94% in crude protein and 76-89% in NDF, respectively. AIR digestibility (AIR X digestibility of voluntary intake) is in conformity with the digestibility of feed on voluntary intake appropriately. Therefore it is considered that AIR digestibility could be applied for forage evaluation in voluntary intake of ruminants.

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Evaluation of Forage at the Level of Voluntary Intake

Kyoto Japan

To revise the conventional method of forage evaluation, digestion trials were conducted at the level of voluntary intake. Dry matter (DM), crude protein and Neutral Detergent Fibre (NDF) contents in offered and residual feeds were measured, using suffolk wethers which were fed with grass silage and hay. A lower content of crude protein and a higher content ofNDF in residual feeds were detected when compared with those of offered feeds. Then, crude protein and NDF values of intake feeds were calculated from the composition of offered and residual feeds. It was suggested that the reason for different contents of crude protein and ND Fin intake and supplied feeds may be due to that the ruminants fed palatable parts of forage preferentially. Higher crude protein and lower NDF percentages in intake feeds than in offered were confirmed. To indicate the values of contents in offered feeds, Available Intake Ratio (AIR) was adopted. AIR defines the ratio of contents of intake to offered feeds. AIR values were 77-89% in dry matter, 82-94% in crude protein and 76-89% in NDF, respectively. AIR digestibility (AIR X digestibility of voluntary intake) is in conformity with the digestibility of feed on voluntary intake appropriately. Therefore it is considered that AIR digestibility could be applied for forage evaluation in voluntary intake of ruminants.