Physical Effectiveness of the Neutral Detergent Fiber of Whole Linted Cottonseed Relative to that of Alfalfa Silage at Two Lengths of Cut

Abstract

The effectiveness of the neutral detergent fiber (NDF) of whole linted cottonseed to stimulate chewing was examined relative to the effectiveness of the NDF of alfalfa silage at two lengths of cut. Twelve Holstein cows (125 d of lactation) were fed diets containing alfalfa silages differing in theoretical length of cut, with or without cottonseed substituted for alfalfa silage at 27% of alfalfa NDF. The experiment was a replicated (n =3) 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Length of cut had no effect on milk production or composition, and substitution of cottonseed increased milk production but did not affect milk composition. An interaction was observed between treatment effects for dry matter intake, total chews per day, and total chewing time (minutes per day). Physical effectiveness of cottonseed NDF was calculated by dividing the total chewing time per unit of cottonseed NDF by total chewing time per unit of alfalfa silage NDF. Physical effectiveness of cottonseed NDF was calculated to be 50% of long-cut and 127% of short-cut alfalfa silage NDF. The interaction observed between main effects for total chewing time per day indicated that the physical effectiveness of whole linted cotton-seed was relative and depended on the characteristics of the forage that it replaced.