Nutritive Value of Alfalfa Haylage-Dairy Waste Fiber Mixtures for Dairy Heifers

Abstract

The objective was to study the influence of adding dairy waste fiber to alfalfa of two maturities on nutrient intake and digestibility by Holstein heifers. Changes associated with delayed harvest of first spring-growth alfalfa also were characterized. Spring growth of alfalfa from a common field was cut at two maturities, late bud and 50% flower. Fresh dairy waste fiber was obtained by processing manure, by a roller press liquid/solid separator, from lactating Holstein cows fed a 57% roughage diet. Alfalfa haylage was mixed and ensiled with three concentrations of dairy waste fiber (0, 20, or 40% dry matter). Thirty-five Holstein heifers (initial weight 339 kg) consumed one of six diets (early cut control, no waste; early cut, low waste; early cut, high waste; late cut control, no waste; late cut, low waste; late cut, high waste) ad libitum in a 19-day digestion study. Delaying first harvest of alfalfa increased concentrations of stems, neutral detergent fiber, acid detergent fiber, and acid detergent lignin and decreased concentrations of leaves, total nitrogen, and calcium. Increasing dietary concentrations of dairy waste fiber decreased dry matter intakes and digestibilities and increased dietary fiber concentrations and ratios of acetate:propionate. Apparent nitrogen digestibility decreased as dairy waste fiber increased. Heat damage was in all diets with controls containing .87% acid detergent insoluble nitrogen. It appears that alfalfa-dairy waste fiber mixtures can be ensiled successfully but that utilization of the mixtures by dairy heifers is impaired because of either heat damage or nature of the fiber in dairy waste. © 1983, American Dairy Science Association. All rights reserved.