Horses and Cattle Grazing in the Wyoming Red Desert, I. Food Habits and Dietary Overlap

Abstract

The sagebrush-grass rrnge in southcentral Wyoming presently summer and winter grazing seasons of 198 I. supports large numbers of feral homes and domestic livestock. Diets of feral horses and cattle during summer and winter grazing Study Area were evaluated using fecal analydr under 2 stocking levels in small pastures. Horses and cattle consumed primarily grasses during the Study sites were located in the Red Desert, northeast of Rock summer and winter. However, shrubs and forbs were also impor-Springs, Wyo., in Sweetwater County(Fig. I). A semiarid climatic tant dietary components. Needleandthread, Sandberg bluegrass, thickspike wheatgrass, Indian ricegrass, gray horsebrush, and winterfat were the maJor foods of horses and cattle during the summer anti wfnter. Dietary overlap between horses and cattle during the summer averaged 72% and Increased to 84% during the winter. Horses and cattle selected foods in a simllrr order. Large increases in feral horse (Equus cubaflus) numbers have occurred in the western United States since passage of the Wild Free-Roaming Horse and Burro Act of 1971 (Artz 1977, Wolfe 1980). These increases have become a major concern to public land managers, livestock producers, and animal welfare groups. Cook (1975) reported a 20-30% annual increase in feral horse populations in the western United States yearly from 1973 through 1975. This increase in population has forced public land administration agencies to reduce domestic livestock grazing in localized areas to accommodate the grazing pressure feral horses have added on Fig. 1. Locations ofsummer and winrer sites in the Wyoming Red Lksert. western ranges (Artz 1977). In 1974 the feral horse population in pattern prevails over both areas. Yearly precipitation averages 21.5 Wyoming was estimated at 4,434 animals; however a recently cm with approximately 40% falling from April to June. Snowfall completed census estimates the population at 10,448 animals usually occurs from October to May (BLM 1978 a,b). (USDI-BLM and USDA-FS 1980). Three distinct vegetation types cover most of the summer study An important factor in determining proper animal stocking area. The sagebrush-grass type on sandy and loamy range sites is levels for a given range is the botanical composition of diets of characterized by a shrub layer of big sagebrush (Artemisia tridenmajor herbivores and the relationship of diets to available forages. tata subsp. tridentata, vaseyanu, Wyomingensis), Douglas rabbit-Animal Science, University of Wyoming, assistant professor, Division of Range greasewood (Sarcobatus vermiculatus), rubber rabbitbrush (Chrymanagement, an! associate profeso~, Division of Animal Science, University of sothamnus nauseosus), fourwing saltbush (Atriplex canescens), Wypming, Laranue 8207 I. Mr. Krysl IS currently a graduate assistant! Department of ;;&?I and Range Scwnces. Box 3-1. New Mexxo State Universl(y, Las Cruces spiny hopsage (Grayia spinosa), Sandberg bluegrass, Indian ricegrass, needleandthread, lambsquarter (Chenopodium alba), west-This study was ...

Comparison of long-chain fatty acids and alkanes as markers to estimate diet composition of equines and cattle consuming heathland vegetation species

“…), it seems that they present a high degree of dietary overlap and, consequently, a high competition for the available biomass. In fact, overlap levels higher than 70% have been recorded between these animal species in very different ecosystems such as North American sagebrush steppe (Krysl et al, 1984), African thornbush savannah (Lechner-Doll et al, 1995) and European Pyrenean pastures (Aldezabal, 2001), with an intensive utilization of the grass biomass in all situations. Their co-existence in very diverse ecosystems results of different digestive strategies (Duncan et al, 1990;LechnerDoll et al, 1995), conferring them alternative abilities to use the same feed resources (Menard et al, 2002;Loucougaray et al, 2004).…”

Can horse riding induce the introduction and establishment of alien plant species through endozoochory and gap creation?

“…Vallentine 1990). Although graminoids are the dominant component of a horse's diet, shrubs and forbs are also important dietary components (Krysl et al 1984). In our study carried out in genuine boreal forest habitat, there were 15 species of seedlings introduced via horse manure.…”

Horses and Cattle Grazing on the Wyoming Red Desert, III

“…Three distinct vegetation types; sagebrush-grass, saltbrush, and greasewoodrabbit brush, cover most of the area. For a more complete description of the study area see Krysl et al (1984).…”

“…Animal numbers and stocking rates for the winter study by treatment were; horses grazed alone, 14 horses and 2 colts (3.3 AU/ha); cattle grazed alone, 12 cattle (2.3 AU/ha); horses and cattle grazed in combination, 12 cattle, 14 horses and 1 colt (2.8 AU/ ha). Detailed information on grazing treatments is found in Krysl et al (1984).…”