Thesis (Ph. D.)--University of Wisconsin--Madison, 1949. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 53-55).

Thesis (M.A.)--Utah State University, 2008. / Title from title screen (viewed Dec. 15, 2008). Department: History Includes bibliographical references. Archival copy available in print.

Research was conducted near the Starkey Experimental Forest and Range in northeastern Oregon. Effects of defoliating bluebunch wheatgrass (Agropyron spicatum (Pursh) Scribn. and Smith) to increase the quality of regrowth available on elk (Cervus elaphus nelsoni) winter range were studied from 1988 through 1990. Clipping treatments were implemented to condition the forage regrowth. Treatments were no defoliation, spring defoliation (7.6 cm stubble height) in June, and fall defoliation (7.6 cm stubble height) in September. Percent calcium, phosphorus, in vitro dry matter digestibility (IVDMD), and available forage (kg/ha DM) of regrowth present on control, spring defoliated, and fall defoliated plots were determined in November and April of both years. Conditioned forage that was again defoliated in the winter was also analyzed for nutrient quality and available forage. Spring conditioning did not affect (p > 0.05) the forage in percent calcium, phosphorus, or available forage, and only slightly increased the IVDMD, when compared to the control in November. In November, the control and spring conditioned forages were deficient in meeting elk requirements for phosphorus, and contained wide calcium to phosphorus ratios. The forages were below 50% IVDMD, and digestible energy levels were below animal requirements in year 1, indicating that spring conditioning did not have an effect on the quality of winter range forage. Defoliation in the vegetative phenology stage allowed the regrowth to complete the growing season similarly as undefoliated plants. Fall conditioning significantly increased the percent phosphorus and IVDMD, while decreasing the available forage compared to the control and spring conditioned forage in November. Fall conditioned forage exceeded elk requirements in both calcium and phosphorus. The calcium to phosphorus ratio was near the optimum absorption range. Digestibility was high, and digestible energy levels were above animal requirements for both years. Fall conditioning however, may create a severe deficit of forage if regrowth is not achieved. In April, there were no differences among treatments in percent calcium, phosphorus, or available forage. Forage from all treatments exceeded elk requirements in calcium and phosphorus, and the calcium to phosphorus ratio would allow optimum absorption of both minerals. Digestibility was high for forage from all treatments. This indicated that the previous years defoliation did not effect forage quality the following spring. Conditioned forage that was again defoliated in the winter was not different in percent calcium or phosphorus when compared to the control in April. Depending on the year and conditioning treatment, there were statistically significant differences in IVDMD and available forage between the control and the winter defoliated samples in April. Conditioned forage that was not defoliated in the winter (April (U)) and winter defoliated samples (April (W)) were comparable in forage quality and available forage in April, though statistical differences were calculated for the spring conditioned samples in year 1, and fall conditioned samples in year 2. / Graduation date: 1992

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 86-93). Also available on the World Wide Web.

Three experiments were conducted to determine the effects of source (experiment 1), frequency, and level (experiments 2 and 3) of energy supplementation on performance, forage utilization and intake, productivity, rumen fermentation, and nutrient digestibility of growing beef cattle fed stockpiled forage. In experiment 1 (EXP1) and experiment 2 (EXP2), 45 cross bred yearling steers were managed on stockpiled crested wheatgrass pasture over 70 days during summer/fall of 2011 and 2012. Steers were stratified by IBW (EXP1 = 334±1.2 kg; EXP2 = 358±1.8 kg) and allocated randomly to 1 of 9 crested wheatgrass pastures (5 steers/pasture). Each pasture was randomly assigned to 1 of 3 replicated (n = 3) treatments. In EXP1, two isonitrogenous and isocaloric by-product feed pellets that differed in starch and degradable fiber content were used in one of three supplementation strategies: 1) no supplement (CON), or supplemented at 0.6 % of BW with 2) low starch/high fibre (LS/HF) pellet (40.3% starch; 29.5% NDF DM basis) pellet, or 3) high starch/low fibre (HS/LF; 48.6% starch; 22.8% NDF DM basis) pellet. In EXP2 a by-product feed pellet was formulated to provide ruminal and post-ruminal energy (30.3 % NDF; 32.0 % starch; 7.2 % fat) supplementation strategies included: 1) daily (DLY) supplementation at 0.6 % of BW, 2) low-alternate (LA) supplementation at 0.9 % of BW, and 3) high-alternate (HA) supplementation at 1.2 % of BW. There was no effect (P > 0.05) of treatment on forage utilization in either experiment. In EXP 1, final BW and ADG were not different (P > 0.05) between LS/HF (435 kg; 1.4 kg d-1) and HS/LF (439 kg; 1.5 kg d-1). However, supplemented cattle had higher (P < 0.05) final BW and ADG than CON cattle (402 kg; 1.0 kg d-1). Supplementation increased production costs by 450 %. In EXP 2, no difference (P > 0.05) was observed for final BW and ADG among DLY (435 kg; 1.1 kg d-1), LA (424 kg; 0.9 kg d-1), and HA (428 kg; 1.0 kg d-1). Production costs were reduced by 23 % with alternate supplementation and LA had 19 % less production costs than HA. In experiment three (EXP 3), four ruminally cannulated beef heifers were individually fed a stockpiled grass hay and offered the same pelleted supplement as in EXP2. Treatments consisted of 4 supplementation strategies: 1) no supplement (CON), 2) daily (DLY) supplementation at 0.6% BW, 3) low-alternate (LA) supplementation at 0.9 % of BW, and 4) high-alternate (HA) supplementation at 1.2 % of BW. Forage intake, rumen fermentation parameters, and apparent total tract digestibility were measured. Three data sets were analyzed: 1) overall (average of all collection days), 2) day of supplementation (DS) and 3) non-supplementation day (NSD) for alternating treatments. Overall, hay DMI (kg d-1) was lower (P = 0.04) for DLY (7.1) vs. CON (8.1), but no different (P ≥ 0.11) for DLY vs. LA (6.9), or vs. HA (6.4). On DS, hay DMI (kg d-1) of DLY (7.3) differed (P < 0.05) vs. HA (6.0), but was not different (P = 0.16) vs. LA (6.4). On NSD, hay DMI (kg d-1) of DLY (7.0) was not different (P ≥ 0.48) to those of LA (7.3) and HA (6.9). Overall, total VFA concentration (mM) was lower (P < 0.01) for CON (69.2) vs. DLY (77.1); but not different (P ≥ 0.45) for DLY vs. LA (75.8) or HA (75.1). Rumen NH3 (mg/dL) was lower (P < 0.01) for CON (3.4) and higher (P < 0.01) for LA (5.8) vs. DLY (4.6), but not different (P = 0.37) for DLY vs. HA (4.3). Overall, ruminal pH was lower (P ≤ 0.04) for DLY (6.65) vs. CON (6.75) and HA (6.72), but similar (P = 0.18) for DLY vs. LA (6.70). On DS, ruminal pH was lower (P = 0.04) for HA (6.59) vs. DLY (6.64), but higher (P < 0.01) on NSD for HA (6.85) vs. DLY (6.67). Apparent DM, OM and GE digestibility coefficients were lower (P ≤ 0.03) for CON and LA vs. DLY, but no difference (P ≥ 0.36) for DLY vs. HA. These results indicate that beef steers grazing stockpiled crested wheatgrass were limited in energy intake and that supplementation of metabolizable energy improved animal performance regardless of the source of energy. Reducing the frequency of energy supplementation and level offered on alternate days do not affect animal performance and reduces the production costs of the system. Negative effects of alternate day supplementation on forage intake and rumen fermentation are reduced when a lower level is offered relative to simply doubling the daily amount of supplement.

No description available.

Agropyron scribneri Vasey (spreading wheatgrass) is endemic to the Rocky Mountains of the Intermountain West. Each distinct population is widely separeated by valley and desert floors. It is morphologically similar to the hybrid between Agropyron trachycaulum (Link) Malte and Sitanion hystrix between Agropyron trachycaulum (Link) Malte and Sitanion hystrix (Nutt.) J. G. Smith as well as the hybrid, A. trachycaulum x A. scribneri. It appears that A. scribneri may have originated de novo from hybidization products of A. trachycaulum and S. hystrix. Agropyron scribneri appears to be morphologically similar to the population of S. hysterix with which it is associated. There is some fertility in the A. trachycaulum x S. hysterix hybrids, and back-crossing onto both A. trachucaulum and S. hysterix is common. Sterile backcross derivatives, (A. trachycaulum x S. hysterix) x S. hysterix, were found which possess characters similar to A. scribneri and which phenotypically resemble A. scribneri. These are considered to be stabilized hybrid segregants which indicate that the incipient formation of A. scribneri is in progress.

Agropyron spicatum (Pursh) Scribn, and Smith, an important forage grass distributed primarily throughout western United States and northward into Canada, exhibits considerable ecological, cytological, and genetic variation. Twenty-five populations of 100 plants each were scored to obtain data on morphological and ecological variation. Statistical analysis of the data from fourteen of the populations showed that correlations between awn divergence and length, rhizomes with number of culms, adn diameter with number of culms were inconsistent or not significant. However, the correltion between rhizomes and diameter was significant in all populations.

A comparative index to digestible nutrients was established for Russian wildrye, crested wheatgrass, and intermediate wheatgrass seeded on foothill areas of Utah. The nutritive values of these grasses were compared by the lignin ratio method, the chlorophyllan ratio method, and the in vivo rumen bag process. Average digestion coefficients computed by the lignin ratio method for dry matter, ether extract, cellulose, and gross energy were highest for intermediate wheatgrass. Protein was more digestible for Russian wildrye. Digestible energy was adequate in all species to meet requirements for late lactation. Results from the chlorophyllan ratio method were excessively high and were not considered valid. Dry matter loss of Russian Wildrye was greater than losses from either of the wheatgrasses. Losses of dry matter due to 24-hour in vivo rumen fermentation and rinsing only of nylon bags were closely correlated.

The effects of grazing and moisture availability on the competitive interactions of intermediate wheatgrass (Thinopyrum intermedium (Host) Barkw. & D.R. Dewey) and western wheatgrass (Pascopyrum smithii (Rhydb.) A. Love) were examined under a short-duration grazing system in central Utah. The fate of tiller cohorts was observed at approximately monthly intervals at the interface between patches of these two rhizomatous grasses and in monospecific stands. The effects of short-duration grazing, clipping of western wheatgrass following grazing to achieve levels of utilization equivalent to that of intermediate wheatgrass, irrigation, and removal of the competitor were assessed in terms of the recruitment, longevity, and mortality of ramets of both species. The effects of severance of clonal connections and defoliation on the performance of young shoots of both species were also studied. The tiller dynamics of the two species differed greatly. Maximum life span of intermediate wheatgrass tillers was approximately 18 months, while that of western wheatgrass tillers exceeded the 3.5-year observation period. Tiller turnover was higher in intermediate wheatgrass than in western wheatgrass. Defoliation tended to increase the mortality risk of intermediate wheatgrass ramets but not that of western wheatgrass ramets. Supplemental water had the opposite effect. Irrigation increased the probability of ramet survival for intermediate wheatgrass during the growing season but led to higher winter mortality for western wheatgrass ramets. During the four years of this study (1987-1990), western wheatgrass was the competitive dominant species. Recruitment of intermediate wheatgrass ramets at the interface was reduced compared to monospecific stands while that of western wheatgrass was enhanced. The mortality of intermediate wheatgrass tillers increased as a result of competition with western wheatgrass but only when plants were grazed. Competition had little effect on the mortality of western wheatgrass ramets. The competitive ability of intermediate wheatgrass versus western wheatgrass improved when both species were grazed heavily and when plants were irrigated.