• Diets of goats grazing oak shrubland of varying cover in northern Greece

      Papachristou, T. G.; Nastis, A. S. (Society for Range Management, 1993-05-01)
      The effects of 3 brush cover proportions (Low Brush pasture: 52% brush/32% herbage, Medium Brush pasture: 62% brush/20% herbage, and High Brush pasture: 66% brush/12% herbage) on dietary selection of goats in northern Greece were investigated. Diet samples were collected from esophageally fistulated goats during 14 grazing periods at monthly intervals from June 1987 to July 1988. Kermes oak foliage (Quercus coccifera L.) was the main component of the available forage in all pastures during all grazing periods. The herbaceous component contributed more than 50% for the goats' diet during spring for Low Brush pasture, 46% for Medium Brush pasture, and 40% for High Brush pasture. In the remaining grazing periods, goats selected larger quantities of browse. For Low Brush pasture browse contribution ranged from 48% to 66%, for Medium Brush from 54% to 77%, and for High Brush from 66% to 80%. Leaves of all forage species contributed more than 56% during all test periods. The quantities of twigs from shrubs and stems from herbaceous species were low but constant during all test periods. Fruits and flowers, despite representing low percentages of the overall production, were important for the animals' nutrition, since they provided a high percentage of nutrients. Our results indicated that goats adapted diets to forage class availability.
    • Nutrient composition of whitetop

      McInnis, M. L.; Larson, L. L.; Miller, R. F. (Society for Range Management, 1993-05-01)
      Whitetop or heart-podded hoary cress (Cardaria draba (L.) Desv.) is an Eurasian native of the Cruciferae actively invading rangelands throughout western North America. The plant is reported to be unpalatable to livestock and contain potentially toxic glucosinolates. Practical experience indicates sheep consume whitetop during its early growth stages and cattle ingest large quantities of seedheads. Chemical analysis of whole plants from rosette to hard seed, respectively, indicated the following trends: crude protein (28.8 to 7.9%), neutral detergent fiber (13.1 to 52.8%), acid detergent fiber (12.0 to 41.8%), cellulose (9.9 to 32.1%), lignin (1.9 to 9.4%), ether extract (1.6 to 2.4%), in vitro organic matter digestibility (77.3 to 49.1%), digestible energy (2.9 to 1.8 Mcal/kg), and total glucosinolates (28.4 to 84.0 micromoles/g). Leaves were higher than stems in crude protein, ether extract, in vitro organic matter digestibility, and digestible energy. Analysis of 11 micro- and macroelements revealed sulfur (S) levels ranged from 0.73 to 2.69% and were therefore higher than the reported maximum tolerable level (0.4%). High S levels likely reflected the S moiety of glucosinolates and their hydrolysis products. Whitetop has some forage value, but until further research establishes the toxicity of this species to sheep and cattle, prudence suggests managers use caution when allowing animals to graze whitetop-infested rangelands by providing supplemental iodine, utilizing mature and nonlactating animals, and reducing opportunities for animals to consume the plant.
    • Technical Notes: Botanical components of annual Mediterranean grassland as determined by point-intercept and clipping methods

      Glatzle, A.; Mechel, A.; Va, M. E. (Society for Range Management, 1993-05-01)
      Three methods for determining proportions of botanical components, i.e., grasses, legumes, and forbs (nonleguminous dicots), of continuously grazed Mediterranean pastures were compared. Percentage contribution to dry matter yield was determined by sample clipping and separating into botanical components. Both percentage of sward and specific contribution were determined by the point-intercept method. These were defined by the relative contribution of 1 botanical component to the total number of counted intercepts between 200 pins inserted vertically into the sward and all botanical components. For specific contribution only the number of pins contacted by the various botanical components were considered, whereas for percentage of sward even multiple contacts between a pin and plant parts of a particular botanical component were taken into account. Percentage contribution was highly significantly correlated with percentage of sward (R = 0.92) and specific contribution (R = 0.93) running the analyses across all botanical components, although there was a significant trend to underestimate forbs and overestimate legumes by the point-intercept methods. It is concluded, however, that for most practical purposes determination of specific contribution, the least laborious method, should give satisfactory estimates of percentage contribution.