Jeff Powell

Mountain big sagebrush browse decreases dry matter intake, digestibility, and nutritive quality of sheep diets.

A metabolism study evaluated the influence of increasing quantities (0-30% dry matter basis) of mountain big sagebrush (Artemisia tridentata ssp. vaseyana Rydb. Beetle) on dry matter intake and in vivo digestibility of wether diets. Diets consisted of hand-harvested, coarse-ground and frozen current years growth of mountain big sagebrush leaves and twig tips mixed with chopped native grass hay. Dry matter intake decreased from 93 to 23 g dry matter day-1 kg metabolic weight-1 and in vivo dry matter digestibility from 59 to 0% with increasing levels of sagebrush in the diet. With increasing levels of sagebrush in the diet, water, lignin, and nitrogen contents increased in the diet, but decreased in the dung, while fiber components decreased in both the diet and dung. Total nitrogen intake decreased from 1.58+/-0.041 to 0.406+/-0.070 g day-1 kg metabolic weight-1, and nitrogen retention decreased from 0.80 g day-1 kg metabolic weight-1 with no sagebrush to a slight loss of nitrogen with 30% sagebrush in the diet. Mountain big sagebrush was not readily consumed by wethers when fed together with grass; as low as 10% sagebrush in the diet seems to adversely influence intake and digestibility. Therefore, when other more favorable forages are not available, sheep and other ruminants with similar physiological responses to mountain big sagebrush may not meet their nutrient requirements through increased sagebrush consumption.

Range animal diet composition in southcentral Wyoming

Because of the ongoing controversy about shrub forage value for different ungulates and significance of the shrub communities for spring-fall grazing in southcentral Wyoming, the relative importance of various forage classes was determined by fecal analyses in the spring, summer, and fall diets of pronghorn (Antilocarpa americana Ord), mule deer (Odocoileus hemionus hemionus), elk (Cervus elaphus), cattle (Bos taurus), and domestic sheep (Ovis aries) in the mountain brush and Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young) plant communities. Mountain big sagebrush (A.t. ssp. vaseyana Rydb. Beetle) comprised 76% of pronghorn spring diets in the mountain brush plant community, and Wyoming big sagebrush comprised 91% of the pronghorn spring diets in the Wyoming big sagebrush plant community. Antelope bitterbrush (Purshia tridentata Pursh.) comprised about 80 to 90% of the pronghorn and deer summer and fill diets in the mountain brush plant community. Graminoids, primarily Bromus, Carex, Juncus, and Stipa spp., made up 80+% of elk, cattle, and sheep diets in either plant community. Forbs and shrubs other than sagebrush or bitterbrush were a minor component of either plant community and diets of any of the 5 kinds of animals. A shrub management program to maintain species diversity while increasing bitterbrush and graminoid production under common use grazing by both browsers and grazers is recommended for this area.

Large ungulate habitat preference in Chobe National Park, Botswana.

Both large ungulates and wildlife tourists tend to concentrate along the Chobe River in Chobe National Park, Botswana, during the dry season causing concern for wildlife habitat and the recreational experience for wildlife viewers. Therefore, ground reconnaissance inventory data of 5 most common large ungulates were collected during the early morning and late afternoon hours along tourist routes in 5 different habitat types every second month for a period of 24 months in Chobe National Park to determine their relative, seasonal habitat preference and availability for viewing by vehicular tourists. A total of 909 herds: greater kudu (Tragelaphus strepsiceros), 285; impala (Aepyceros melampus), 209; elephant (Loxodonta africana), 200; giraffe (Giraffa camelopardalis), 138; and buffalo (Syncerus caffra), 77 were observed during the 760 observation periods. The average frequency of observation of a herd of 1 or more of these 5 ungulates per habitat type was alkali flats, 3.42; floodplain grassland, 2.67; shrub savanna, 2.29; tree savanna, 1.04; and woodland, 0.30. This order of frequency of observation is highly correlated with nearness to the Chobe River, the major water source during the dry season. Elephant and giraffe were more wide-ranging than buffalo, impala, and kudu. During the dry season, all animals were seen more often on the floodplain grassland in the afternoon than in the morning. Giraffe were never seen in any habitat type in December, and impala were never seen in the woodland in any month. Our data confirm that tour operators interested primarily in providing their guests with a view of the greatest numbers of animals in a limited period of time are justified in congregating along the Chobe River during the dry season. However, as in most public wildlife reserves, Chobe National Park management is faced with the decision of how best to optimize the biological needs of Park animals and their habitat with the economic and recreational desires of Park users. DOI:10.2458/azu_jrm_v55i4_omphile

Brush Management Influences Preference Values of South Texas Woody Species for Deer and Cattle.

Highlight All mechanical brush control practices excepi rooi plowing increased preference values and forage ratings of South Texas brush species for deer and cattle the first year following treatment. Preference values for shrubs declined with length of fime following treatment. Increased pref erence values were associated with increased availability, the amouni of new regrowth, and crude profein content of fhe shrubs.

Increasing bitterbrush nutrient quality with 2,4-D, mowing, and burning in southcentral Wyoming.

Effects of burning, mowing, and 2,4-D on antelope bitterbrush (Purshia tridentata Pursh.) nutrient contents were evaluated in southcentral Wyoming. During the first growing season following treatments, spraying of 2,4-D increased bitterbrush nitrogen (N) contents from 1.5 to 1.9%, phosphorus (P) from 0.12 to 0.15%, and in vitro digestible dry matter (IVDDM) from 44.1 to 48.4%. Mowing increased N from 1.5 to 1.7%, P from 0.12 to 0.16%, and IVDDM from 44.1 to 46.1%. Burning increased N from 1.4 to 1.9%, P from 0.11 to 0.17%, ash from 3.7 to 5.3%, and IVDDM from 47.4 to 51.0%, and decreased gross energy from 4,640 to 4,380 kcal/g. There were no differences in N and IVDDM contents among treatments at the end of the second growing season, but P content was still greater in mowed bitterbrush regrowth than on untreated bitterbrush. Ash contents were not affected by treatments, but were higher in summer (3.9%) than in winter (2.4%). Gross energy contents varied only 5 to 10% among all treatments and seasons. Correlation coefficients between N, P, ash, and IVDDM contents varied from +0.54 to +0.76, and all of these nutrients were negatively correlated with gross energy. Bitterbrush nutrient contents can be increased by shrub management practices, but short-term responses require that small portions of the total area be treated annually in a rotational shrub management program.

Site factor relationships with volatile oils in big sagebrush.

The volatile oil content in big sagebrush leaves varied greatly on different sites, ranging form 3.5% of the air-dry weight in short plants on poor sites to 6.0% in tall plants on favorable sites. A regression equation using selected site factors accounted for 91% of the variation in oil content. Oil content was most highly correlated with sagebrush size and the amounts of magnesium and phosphorus in the A horizon. Short big sagebrush plants on poor sites should be maintained as forage plants, but tall big sagebrush plants on favorable sites should be replaced with other more palatable species. Chemicals which can reduce or retard volatile oil production should be studied.

Mechanical Control and Fertilization as Brush Management Practices Affect Forage Production in South Texas.

LITERATURE CITED HULL, A. C., JR. 1954. Rating seeded stands on experimental range plots. J. Range Manage. 7:122-124. HULL, A. C., JR. 1959. Pellet seeding of wheatgrasses on southern Idaho rangelands. J. Range Manage. 12: 155-163. HULL, A. C., JR., AND G. J. KLOMP. 1966. Longevity of crested wheatgrass in the sagebrush-grass type in southern Idaho. J. Range Manage. 19:5-11. WEINTRAUB, FRANCIS. 1953. Grasses introduced into the United States. U. S. Dep. Agr. Handbook 58. 79 p.

Sites, mowing, 2,4-D, and seasons affect bitter- brush twig morphology

Effects of site factors, mowing, 2,4-D, and seasons on antelope bitterbrush (Purshia tridentata Pursh.) twig length, basal and tip diameters, and weight were evaluated in southcentral Wyoming. Linear regression coefficients for twig length regressed on basal diameter were greater on productive sites than on less productive sites, greater on mowed areas than on sprayed or untreated areas, and greater in late fall because of leaves than in late winter. Twig elongation continued after data collection in early November. Twig length was more variable and more sensitive to different environmental conditions than twig basal diameter, tip diameter, or weight. Twig length accounted for 80-86% of the variation in twig weight. Sites, shrub management practices, and seasons do affect bitterbrush twig morphology, but habitat managers can use twig length-diameter-weight relations in this vegetation type to estimate utilization if the sampling is stratified along environmental gradients.

Deer browsing and browse production of fertilized American elm sprouts.

winter, and spring. Twig tips of first-year elm sprouts were readily Mariposa manzanita (Arctosfaphylos mariposa) (Gibbens and browsed by deer after succulent cool season, berbaceous plants F’ieper 1962), and Douglasfir (Pseudotsuga menziesii) (Longhad matured in May. Browsing and browse production were burst et al. 1968) were browsed to a greater extent than ungreater on fertilized sprouts if trees were cut and fertilized in the fertilized Plants. previous late summer or current late spring seasons. Fertilization Based on the information concerning increased utilization of and lateral branching after browsing increased total twigs per sprout which, in turn, increased browse production and use as the woody plants as sprouts and from fertilization, we combined the

Effect of atrazine, fertilizer, and 2,4-D on winter grazing preferences of beef cows on northcentral Oklahoma tallgrass prairie.

A good condition, tallgrass prairie experimental area was treated with selected combinations of atrazine, 2,4-D, and NPK fertilizer in spring 1975 and 1976. Crude protein contents in November herbage ranged from 3.401, to 6.3% in treated samples. Untreated herbage contained 5.0% crude protein. Nonlactating beef cows were allowed to graze freely on the area during December, 1976. Utilization of herbage ranged from 43% to 87%. Utilization was greatest on NPK areas (82%), 3.4 kg atrazine + NP areas @SO/O), and 3.4 kg atrazine -I- NPK areas (87%). Decreaser species comprised a larger percentage of the total production on atrazine i- NP, atrazine -I- NPK, and 2,4-D -I- NPK areas than on fertilizer-only areas. Tallgrass prairie treated with atrazine and fertilizer or 2,4-D and fertilizer was preferred by beef cows as winter forage over untreated herbage. There was a 15% increase in herbage utilization for every 1% increase in crude protein in the