Animal & Range Sciences
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The curricula in animal science provide students with a firm foundation in the biological and natural sciences, animal breeding, reproductive physiology, nutrition, and livestock production and management. Natural Resources & Rangeland Ecology focuses on managing the interaction of livestock, and wildlife and their rangeland habitats. Emphasis is placed on soil, water and vegetation attributes which influence habitat ecology and management of livestock and wildlife.
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Item Habitat Relations of Mule Deer in the Texas Panhandle.(1985-11-27) Koerth, Benjamin H.; Sowell, Bok F.; Bryant, Fred C.; Wiggers, Ernie P.Telemetric observations of mule deer (Odocoileus hemionus) does were used to determine seasonal relationships between deer use and availability of habitats on two study areas in the Panhandle region of west Texas. Juniper breaks was the only type used in greater proportion than its availability on the Canadian River study area (CRSA). On the Clarendon study area (CSA) mule deer shifted seasonal preferences between riparian, cultivated fields, and juniper breaks. Annual and seasonal home ranges were considerably larger on the CSA. Larger home ranges and variability in seasonal use of the habitat types on the CSA were attributed largely to the presence of cultivated winter grain fields. Shifts in home ranges coincided with the season when production in the cultivated fields was highest and native forage availability was lowest. Comparisons of indirect deer observations (pellet groups and bed sites) with random measurements within each habitat type characterized deer use sites as east and north facing slopes, located close to a canyon rim, and receiving light livestock and human use. The placement of cultivated grain fields could be used to influence overall range use and attract deer to or away from localized sites. Also, consideration should be given to directing heavy livestock and human traffic away from sites that are used by mule deer.Item Horses and Cattle Grazing on the Wyoming Red Desert, III.(1984-03) Plumb, G. E.; Krysl, L. J.; Hubbert, M. E.; Smith, M. A.; Waggoner, J. W.Vegetative cover losses due to trampling near watering sites in the summer and winter are compared for horses grazed alone, cattle grazed alone and horses and cattle grazed in combination. There were significant differences (p<.05) found in the rates of total cover loss as a function of distance to water in both the summer and winter. Grasses sustained heavy trampling losses in all treatments in both seasons. Forbs sustained heavy losses in all treatments during summer. Shrub losses were moderate to low in all treatments during both seasons. Total cover loss was similar in all summer and winter treatments.Item Horses and Cattle Grazing in the Wyoming Red Desert, II. Dietary Quality.(1984-05) Krysl, L. J.; Sowell, Bok F.; Hubbert, M. E.; Plumb, G. E.; Jewett, T. K.; Smith, M. A.; Waggoner, J. W.Botanical composition of horse and cattle diets from fecal analysis and nutrient quality of hand-harvested forages used by these herbivores were evaluated to assess dietary quality during the summer and winter seasons of 1981 in the Wyoming Red Desert. Dietary crude protein estimates averaged 7.5±0.1% and 9.0±0.5% during the summer for horses and cattle, respectively. Dietary crude protein estimates in the winter were lower, averaging 6.1±0% and 6.0±0% for horses and cattle, respectively. Estimated dietary calcium levels for both herbivores were high through the summer and winter, while dietary phosphorus levels appear to be deficient during both seasons. Average in vitro dry matter disappearance coefficients for horses and cattle during the summer were 52±2% and 52±2%, respectively. During the winter these values dropped to 39±1% and 40±1% for horses and cattle, respectively.Item Estimating Digestibility and Faecal Output in Lambs Using Internal and External Markers.(1988-08-01) Krysl, L. J.; Galyean, M. L.; Estell, R. E.; Sowell, Bok F.Twenty fine-wool, ruminally cannulated lambs (average weight 45–9 kg) were used in a completely random design to evaluate the ability of three internal markers to predict dry matter digestibility and two external markers to estimate faecal output. Lambs were allotted randomly to one of four diets: 100% prairie hay (PH), 100% lucerne hay (LH), 50% prairie hay:50% sorghum grain (PS) and 50% lucerne hay: 50% sorghum grain (LS). The trial consisted of a 14-day adaptation period followed by a 7-day total faecal collection period. Feed and faecal samples were subjected to 96 h ruminal fluid and 48 h acid-pepsin digestions, followed by extraction with acid detergent (IVADF) or neutral detergent (IVNDF) solution. Dry matter digestibility (DMD) calculated from feed:faeces ratios of IVADF, IVNDF and acid detergent lignin (ADL) was compared with in vivoapparent digestibility. Ytterbium-labelled forage (YLF) and dysprosium-labelled faeces (DLF) were pulse-dosed via ruminal cannulae, and faecal Yb and Dy excretion curves were fitted to a one-compartment, agedependent model for estimation of faecal output, paniculate passage rate (PPR) and mean gastrointestinal retention time. In vivoDMD in lambs fed PH was greater (P <005) than DMD calculated from IVNDF, IVADF and ADL. In lambs fed LH and LS, in vivoDMD did not differ (P >005) from marker estimates. In vivoDMD for lambs fed PS did not differ from IVNDF or IVADF estimates but was greater than (P <005) the ADL estimate. No differences (P> 005) were observed in recovery among the three internal markers for any of the diets. Faecal output for lambs fed PH did not differ {P >005) from marker estimates but was overestimated by 15 to 20% by YLF and DLF. Faecal output for lambs fed LH was similar to the estimate from YLF, but less than (P <0–05) the estimate with DLF. For lambs fed PS, faecal output did not differ from marker estimates, but YLF and DLF values were 16% lower and 17% higher, respectively. No significant differences were observed in actual and estimated faecal output for lambs fed the LS diet. Estimates of PPR with DLF were numerically greater than YLF estimates for all diets except LS. Correspondingly, mean gastrointestinal retention time was less (P <005) for DLF compared with YLF for all diets except LS.Item Horses and Cattle Grazing in the Wyoming Red Desert(1984-01) Krysl, L. J.; Hubbert, M. E.; Sowell, Bok F.; Plumb, G. E.; Jewett, T. K.; Smith, M. A.; Waggoner, J. W.The sagebrush-grass range in southcentral Wyoming presently supports large numbers of feral horses and domestic livestock. Diets of feral horses and cattle during summer and winter grazing were evaluated using fecal analysis under 2 stocking levels in small pastures. Horses and cattle consumed primarily grasses during the summer and winter. However, shrubs and forbs were also important dietary components. Needleandthread, Sandberg bluegrass, thickspike wheatgrass, Indian ricegrass, gray horsebrush, and winterfat were the major foods of horses and cattle during the summer and winter. 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 similar order.