Masters Theses

Date of Award

6-1972

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Husbandry

Major Professor

M. J. Montgomery

Committee Members

K. M. Barth, D. O. Richardson

Abstract

Three stages of maturity of orchardgrass hay which were harvested at the boot stage, 14 days after the boot stage, and 26 days after the boot stage were studied in order to determine the effect of stage of maturity on its productive and nutritive values. Due to mold contamination in the boot-stage hay of the first cutting, the boot-stage hay of the second cutting was used in the feeding and digestion trials. Total dry matter yield which was estimated at each stage of maturity by weighing the forage from a known area and determining the percent dry matter increased with advancing stage of maturity. A decrease in percent crude protein and an increase in percent of acid-detergent fiber, acid-insoluble lignin, and cell-wall constituents were found with an increase in stage of maturity. Nutritive value was determined by a feeding trial with dairy heifers and effectively demonstrated that a decrease in body weight gain and voluntary feed intake occurred with increasing maturity of hay, A digestion trial conducted with sheep showed that the hay cut at the late stage of maturity had lower digestibility coefficients for every nutrient than those of hays cut at an early and the medium stage of maturity. With advancing stage of maturity, digestible dry matter (DDM) obtained by in vivo digestion trial and dry matter disappearance (DMD) obtained by in vitro fermentation technique and nylon bag technique decreased. It also appeared that dry matter disappearance (DMD) values by in vitro technique and nylon bag technique could produce reasonable estimates of the nutritive value of these forages.

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