Date of Award:

5-1984

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Animal, Dairy, and Veterinary Sciences

Committee Chair(s)

Paul V. Fonnesbeck

Committee

Paul V. Fonnesbeck

Committee

Jeffrey L. Walters

Committee

Ronald L. Boman

Committee

Jim L. Bushnell

Abstract

Water was applied to swaths of cut alfalfa forage with oscillating sprinklers to stimulate rain damage to field drying alfalfa hay to determine the changes in chemical composition, loss of yield, and acceptability of rain damaged hay to sheep. An additional objective was to develop models to estimate yield losses form experimental hay. The experimental hay was prepared with a 2x2x4x4x2 factorial design. The factors were two different cuttings (July and September), two width of swath (3.05 m and 4.27 m), four times of applying artificial rain (3h, 8h, 13h, and 24h after cutting), four levels of artificial rain (no rain, 12.5 mm, 25.0 mm, and 50.0 mm), and two applications of artificial rain (initially and repeated 24h after first application).

The hay was dried in favorable weather conditions during the summer season. Fair weather, was observed in the fall season.

Chemical composition of the fresh forage at each of the seasons of cutting was closely comparable. Main factors (cut, swath width, time, level, and application of water) and their respective interactions (cut x swath, cut x time, cut x level, time x level) affected chemical composition and voluntary intake of the experimental hay. Samples were analyzed for dry matter, ash, crude protein, plant cell walls, hemicellulose, cellulose, lignin, and acid detergent fiber.

No significant changes in the chemical composition occurred when the artificial rain was applied on the fresher forage ( < 3 h after cutting). However, substantial losses were observed after the forage wilted ( > 13h after cutting).

Plant cell contents (100% minus plant cell wall %) decreased while plant cell wall constituents increased with increasing levels of water applied after cutting, and with double application of water. Cell wall content of the hay increased more from rain damage during the fall season than during summer period.

Most of the loss of soluble components (cell contents) occurred with the initial application (12.5 mm) of water. Protein content proved to be a poor indicator of rain damage in alfalfa hay.

The width of the swather used to harvest the hay (P < .0001), and amount of water applied (P < .0001) were negatively correlated with voluntary intake by lactating ewes.

Models for estimating loss of yield from the experimental hay were developed. The amount of rainfall and other descriptive factors were useful to estimate of yield from specific lots of rain damaged alfalfa hay.

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