Many grazing-management challenges stem from poor livestock distribution resulting in overuse of some areas and low utilization of others. Managing livestock-distribution patterns requires knowledge of pasture characteristics and animal behavior patterns. Behavioral patterns result from recognizable processes that include inherited attributes, individual and social learning systems, cue-consequence specificity, predispositions toward novel stimuli, and spatial memory. Through these behavioral mechanisms, animals form and revise preferences and aversions for specific locations in their foraging landscape. To accomplish habitat selection, domestic herbivores use sight and sound cues to seek and return to high-quality foraging locations. Nested within habitat selection are learned diet preferences and aversions by which ungulate herbivores associate taste with positive or negative postingestive feedback. The deliberate and careful modification of animal attributes and habitat characteristics could yield options for adaptive rangeland management. In this article, we describe the basic principles that underlie how animals make decisions about where to forage and how long to stay in a particular habitat. We also suggest management practices designed to modify animal behavior and alter habitat-use patterns. Resumen Muchos de los retos en el manejo de apacentamiento tienen su origen en la pobre distribució n del ganado que resulta en la sobreutilizació n de algunas á reas y la subutilizació n de otras. El manejo de los patrones de distribució n del ganado requiere del conocimiento de las propiedades del potrero y los patrones de comportamiento del ganado. Los patrones de comportamiento resultan de procesos reconocibles que incluyen atributos heredados, sistemas de aprendizaje individuales y sociales, especificidad de consecuencias, predisposició n hacia un estímulo novedoso y la memoria espacial. A través de estos mecanismos de comportamiento, los animales forman y revisan las preferencias y aversiones para localidades especificas en el paisaje donde apacientan. Para lograr la selecció n del há bitat, los herbívoros domésticos usan señ ales visuales y de sonidos para buscar y regresar a localidades de apacentamiento de alta calidad. Incluidas dentro de la selecció n del há bitat está n las preferencias de la dieta y aversiones aprendidas, mediante las cuales los herbívoros ungulados asocian el sabor con una retroalimentació n post-ingestiva negativa o positiva. La modificació n deliberada y cuidadosa de los atributos animal y las características del hábitat pudiera producir opciones para el manejo adaptativo del pastizal. En este artículo describimos los principios bá sicos que determinan como los animales toman decisiones acerca de donde apacentar y cuanto permanecer en un há bitat particular. También sugerimos prá cticas de manejo diseñ adas para modificar el comportamiento animal y alterar los patrones de uso del há bitat.

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Plants possess a wide variety of compounds and growth forms that are termed "anti-quality" factors because they reduce forage value and deter grazing. Anti-quality attributes can reduce a plant's digestible nutrients and energy or yield toxic effects. Herbivores possess several adaptive mechanisms to lessen the impacts of anti-quality factors. First, herbivores graze selectively to limit consumption of potentially harmful plant compounds. Grazing animals rely on a sophisticated system to detect plant nutritional value or toxicity by relating the flavor of a plant to its positive or negative digestive consequences. Diet selection skills are enhanced by adaptive intake patterns that limit the deleterious effects of plant allelochemicals; these include cautious sampling of sample new foods, consuming a varied diet, and eating plants in a cyclic, intermittent, or carefully regulated fashion. Second, grazing animals possess internal systems that detoxify or tolerate ingested phytotoxins. Animals may eject toxic plant material quickly after ingestion, secrete substances in the mouth or gut to render allelochemicals inert, rely on rumen microbes to detoxify allelochemicals, absorb phytochemicals from the gut and detoxified them in body tissues, or develop a tolerance to the toxic effects of plant allelochemicals. Understanding the behavioral and metabolic abilities of herbivores suggests several livestock management practices to help animals contend with plant anti-quality characteristics. These practices include offering animals proper early life experiences, selecting the appropriate livestock species and individuals, breeding animals with desired attributes, and offering nutritional or pharmaceutical products to aid in digestion and detoxification.

Utilization patterns of cattle were related to pasture chrracteristics in a nonrandom and complex manner. Six mixed brush pastures on the Rio Gnndc PIrills (2&356 ha) that were topographically flat and homogeneous in soil type and range sites were studied. Two experiments were conducted: the first experiment was conducted when green forage was abundant and the second under conditions of little vegetative regrowth. A total of 340 random points were characterized for amount, frequency, and greenness of both grasses and forbs, brush and shade tree density, and distnnce to nearest fence, road, md water. These are vrriables that can be altered with management practices. When green forage was abundant, factor analysis identified 5 orthogonal factors (green herbage availability, grass quantity, brush abundance, remoteness from roads, and water availability) which accounted for 70% of the communal variation. Six factors (brush abundance, grass qurnthy, green forb frequency, road locntion, fence proximity, and water availability) accounted for 70% of the communal variation when herbrge was limited. Regression analyses predicting percent utilization from the orthogonal factors indicated that when green forage was abundant, utilization was related largely to green herbage availnbllity, grass quantity, brush abundance, and remoteness (R* = 0.54, RSD = 0.114). Remoteness, brush abundance, green forb frequency, and water availability were the factors associated with utilization when forage was limited (R* = 0.45, RSD = 0.152). Green herbage availabiiity was less important under conditions of limited forage. In mixed brush communities, the actual amount of grass, brush abundance, end remoteness were the major factors affecting utilization.