Date of Award:

5-1996

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Animal, Dairy, and Veterinary Sciences

Committee Chair(s)

Randall D. Wiedmeier

Committee

Randall D. Wiedmeier

Committee

Jeffrey Walters

Committee

Lyle McNeal

Committee

Frederic D. Provenza

Committee

Kenneth Olson

Committee

Robert C. Lamb

Abstract

The evaluation of ammoniation of mature grass (1/3 Festuca sp, 1/3 Bromus and 1/3 Dactylis sp) as a basal diet for pregnant ewes and its effects on ruminal fermentation were studied. Ammoniation increased the forage dry matter intake (DMI), crude protein (CP), and gross energy digestibility. Ruminal pH and total volatile fatty acid were not affected by ammoniation (P > .05). Individual VFA concentrations were affected significantly.

In a third experiment, ammoniated wheat straw was evaluated as a basal diet for wintering pregnant ewes. Ammoniated straw replaced grass hay in the diet. Dry matter intake was not different (P > .05). Final body weight total gain, and fleece weight were higher for controls (P < .05). Lamb birth weight was not affected by forage type (P > .05).

A fourth experiment evaluated how rehydrating wheat straws prior to ammoniation affected utilization by pregnant western white-face ewes. These treatments increased dry matter and crude protein intakes significantly (P < .01), and also improved body weight (P < .05). Lamb birth weight was not affected by treatment (P = .874) and fleece weight increased (P < .05).

Nutritive value of 5 barley and 10 wheat straw varieties was evaluated for ruminants with the in situ technique. Fiesta and Kombar barley varieties exhibited the highest dry matter disappearance (P < .05). Malcom, Manning, Ute, and 1549-19 wheat varieties exhibited the highest dry matter disappearance (P <.05). These varieties were Dwarf type and presented higher nutrient availability for ruminants.

In a final study, nitrogen and energy balance was measured on lactating western white-face ewes during early and late lactation. Milk production was .683 and .711 L/d during early and late lactation. Efficiency of milk production was .429 and .338 milk L/kg DM consumed for early and late lactation, respectively. Nitrogen balance was positive during both stages of lactation. Milk gross energy and metabolizable energy were 15.13 and 14.16% for early and late lactation, respectively.

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