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The Potential Utilization of Short Rotation Biomass Produced Trees as a Feed Source for Ruminants

Document Type

Thesis/Dissertation

Volume

41

Issue

12

Publisher

Michigan State University

Publication Date

1980

Abstract

Recently, there has been a resurgence in research interest in the potential use of alternative, nonconventional feed sources for animal production. Cellulose is the most abundant energy feed in the world but its full potential is yet to be exploited.

In this study, as examination was made on very short rotation hardwood biomass trees as a potential feed source for ruminants. The specific objectives of this study were to (l) characterize and quantitate the gross chemical com— position of rapidly produced tree species (2) quantitate fiber components (celluose, hemicellulose and lignin) (3) to assess the fermentation of these rapidly produced tree species in the rumen by nylon bag technique (u) evaluate dry matter consumption, digestibility, rumen pH, rumen ammonia, VFA profiles and nitrogen balance of poplar biomass vs. alfalfa (5) to evaluate above objectives in terms of differing stages of growth and regrowth.

EXPERIMENT I - CHEMICAL COMPOSITION. The selected chemical analyses indicated that biomass produced trees may be a nutritious forage source for ruminant animals. Five of the eleven biomass trees averaged over 20% crude protein with the average for all samples being 18.81% crude protein. The estimates of hemicellulose, cellulose, lignin and hemi- cellulosic sugars indicated that biomass tree samples were generally higher in cellulose, lignin and zylosezarabinose ratios when compared with alfalfa. The mineral contents of the biomass substrates over both harvest periods were comparable with alfalfa in both macro and micro minerals measured. Gross energy values were higher for alfalfa within both the early and late harvest periods. The biomass samples consisting of poplar, honey locust, black locust and aspen were all similar in their gross energy values over both harvests.

EXPERIMENT II - ENSILEMENT STUDY. The fermentation paramenters measured within the ensilement study suggested adequate fermentation and preservation for all samples ensiled except elm, birch and willow which all exhibited significantly higher butyric acid values.

EXPERIMENT III — NYLON BAG DEGRADABILITY. The degradability of samples incubated in the rumen of steers over a 6, 12, and 2H hour period exhibited a higher percentage of sample degraded for the early harvested substrates plus those biomass species which were lowest in lignin within each harvest group. This trend was evident for dry matter, nitrogen, and acid detergent fiber disappearance.

EXPERIMENT IV - INTAKE AND DIGESTIBILITY TRIAL. Within the feeding trial, as the percent of poplar increased from 66.6% to 100%, the intake of dry matter, crude protein, and energy decreased significantly vs. the 100% alfalfa and 33.3% poplar. However, the intake for the 66.6% poplar ration could be considered adequate for dry matter, protein, and energy as this diet was significantly higher (P<.05) for intake values than the 100% poplar. The apparent digestibility coefficients suggested that the diets containing poplar were significantly less digestible in dry matter, crude protein, ADP and energy. However, both the 33.3% and 66.6% rations displayed dry matter digestibilities over 60%. Nitrogen retention and retention as percent of total intake were lower in value as the percentage of poplar increased in the diet. Differences in rumen fluid and blood parameters for lambs fed varying levels of poplar tended to be greater for the 100% alfalfa and 33.3% poplar, although no significant differences were reported.

Comments

This thesis was submitted to Michigan State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Animal Husbandry.

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