Derek W. Bailey

Characteristics of spatial memory in cattle

Two studies were conducted to examine spatial memory of cattle. In Study 1, six heifers were trained and observed in a radial- and parallel-arm maze at two levels of complexity. Grain was placed at the end of each arm, and heifers were released individually and allowed to choose arms freely until all grain was consumed. Incorrect choices occurred when heifers entered a previously entered arm. At the 4-arm level, the mean number of correct choices in the first four entrances was 3.83 and 3.60 for the radial and parallel mazes, respectively. At the 8-arm level, the number of correct choices in the first eight entrances was 7.78 and 7.36, respectively. Heifers were slightly more efficient (P < 0.05) in the radial maze in which directional and distal cues were more pronounced. In Study 2, two sets of monozygous twin steers were trained in a radial-arm maze using similar procedures as Study 1. The mean number of correct choices in the first eight entrances was 7.68. A variable delay interval was then imposed between Choices 4 and 5. Steers rarely made errors after delay intervals from 5 min to 4 h. Performance appeared to decline (P < 0.1) after an 8-h delay interval. Accuracy declined dramatically (P < 0.001) after a 12-h delay interval. The mean number of correct choices in the first eight entrances was 7.63, 7.29 and 5.80 for delay intervals of 4, 8 and 12 h, respectively. Cattle appear to have the ability to associate several locations with food resources and to remember the locations for periods of up to 8 h.

Identification and Creation of Optimum Habitat Conditions for Livestock

Abstract Optimum habitat condition is a concept typically used for wildlife rather than livestock. The definition for optimal livestock habitat will vary with management objectives. Abiotic factors, such as topography, water availability, and thermal cover, affect animal performance and uniformity of grazing. Livestock usually prefer gentle slopes and avoid traveling long horizontal and vertical distances to water. Shade and nearby water are used for thermoregulation when temperatures are high, and topographic relief and woody vegetation can be used for thermal cover during cooler temperatures. Biotic factors, such as forage quality and quantity, influence spatial grazing preferences and affect animal performance. Livestock prefer areas with higher forage quality and quantity. Uniformity of grazing may be greater in homogeneous vegetation, but animal performance may be greater in heterogeneous vegetation, especially at lower stocking rates. Livestock grazing patterns have been predicted using multiple regression and other models, but their success has typically been limited to a specific site. Managers can improve livestock habitat conditions by changing abiotic attributes of the pastures, such as developing water, building structures for thermal cover, and changing biotic attributes of the pasture through burning, fertilizing, varying stocking rates, and manipulating grazing systems. Managers can also choose animals that are more adapted to specific rangeland conditions. Practices such as strategic supplementation and herding can modify livestock behavioral patterns to use more of the available habitat. The spatial and temporal variability of rangeland requires multiple management practices to optimize use of livestock habitat.

Climate Change and North American Rangelands: Trends, Projections, and Implications

Abstract The amplified “greenhouse effect” associated with increasing concentrations of greenhouse gases has increased atmospheric temperature by 1°C since industrialization (around 1750), and it is anticipated to cause an additional 2°C increase by mid-century. Increased biospheric warming is also projected to modify the amount and distribution of annual precipitation and increase the occurrence of both drought and heat waves. The ecological consequences of climate change will vary substantially among ecoregions because of regional differences in antecedent environmental conditions; the rate and magnitude of change in the primary climate change drivers, including elevated carbon dioxide (CO2), warming and precipitation modification; and nonadditive effects among climate drivers. Elevated atmospheric CO2 will directly stimulate plant growth and reduce negative effects of drying in a warmer climate by increasing plant water use efficiency; however, the CO2 effect is mediated by environmental conditions, especially soil water availability. Warming and drying are anticipated to reduce soil water availability, net primary productivity, and other ecosystem processes in the southern Great Plains, the Southwest, and northern Mexico, but warmer and generally wetter conditions will likely enhance these processes in the northern Plains and southern Canada. The Northwest will warm considerably, but annual precipitation is projected to change little despite a large decrease in summer precipitation. Reduced winter snowpack and earlier snowmelt will affect hydrology and riparian systems in the Northwest. Specific consequences of climate change will be numerous and varied and include modifications to forage quantity and quality and livestock production systems, soil C content, fire regimes, livestock metabolism, and plant community composition and species distributions, including range contraction and expansion of invasive species. Recent trends and model projections indicate continued directional change and increasing variability in climate that will substantially affect the provision of ecosystem services on North American rangelands.

Mechanisms Determining Large-Herbivore Distribution

Grazing distribution is an important component of the foraging ecology of large herbivores. Recognising the differences in foraging behaviours that occur along spatial and temporal scales is critical for understanding the mechanisms that result in grazing distribution patterns. Abiotic factors such as topography, water availability and weather and biotic factors such as forage quantity and quality affect the distribution of large herbivores. Numerous empirical studies have shown that large herbivores typically match the time spent in an area with the quantity and quality of forage found there. Although the observed grazing patterns have been documented, the underlying behavioural processes are still being elucidated. Cognitive foraging mechanisms assume that animals can use spatial memory to remember the levels of forage resources in various locations, while non-cognitive mechanisms require that behaviours such as intake rate, movement rate and turning frequency vary in response to forage resource levels. The ability of animals to use spatial memory during foraging has been demonstrated in several species including livestock, which suggests cognitive mechanisms are possible. Optimal-foraging theory can also be used to help explain behavioural processes. Giving-up rules based on marginal-value theorem appear to work well for large herbivores when a patch or feeding site can be noticeably depleted within an appropriate temporal scale such as a grazing bout or when forage availability is limited. However, givingup rules do not always explain movements among feeding sites when forage is plentiful. The satiety hypothesis has been used to explain the avoidance of toxins and the acquisition of nutrients in diet selection. We suggest the satiety hypothesis can be expanded to account better for the variability in feeding-site selection. Large herbivocres should move among feeding sites when forage availability becomes limiting or when animals become satiated. Satiation with feeding sites may occur because of the presence of toxins or nutrient imbalances or because of aversive external stimuli. Large herbivores may return to sites that were previously considered aversive due to a combination of individual animal variation and social factors. Large herbivores can now be readily tracked using global positioning system (GPS) technology, which will allow us to test predictions of the satiety and other hypotheses and to better understand behavioural processes associated with foraging

Daily selection of feeding areas by cattle in homogeneous and heterogeneous environments

Abstract Yearling steers were observed in a two-part study to evaluate movement patterns in homogeneous and heterogeneous areas. Previous grazing and fertilization were used to create three heterogeneous patches that varied in forage quality and quantity. Three homogeneous patches were also established. Two groups of steers were released daily from a holding pen and allowed to choose within either the homogeneous area or the heterogeneous area. During the first trial, steers selected patches from a central decision area, and fences divided the patches. During the second trial, division fences were removed. No patch preferences developed in the homogeneous area if data were pooled within a day. However, time spent in patches was not consistent throughout the day. Steers grazed patches nearest to water during midday, but avoided those patches during the morning and evening. Animals developed preferences for the most nutritious patches, as indexed by crude protein concentration, in the heterogeneous area. They avoided a patch with lower forage quality for 21 consecutive days. Cattle tended to return to a particular patch more often in the heterogeneous area, but in both the heterogeneous and homogeneous areas, animals returned to the same patch on consecutive mornings less than 48% of the time. Cattle moved among patches more frequently in the homogeneous area during Trial 2 after fences were dismantled. One or two individuals may have influenced the initial patch selection for the remainder of the group. Uneven grazing distribution patterns associated with cattle grazing heterogeneous environments may occur because they select feeding areas with higher forage quality more frequently than feeding areas with lower forage quality.

Climate Change and North American Rangelands: Assessment of Mitigation and Adaptation Strategies

Abstract Recent climatic trends and climate model projections indicate that climate change will modify rangeland ecosystem functions and the services and livelihoods that they provision. Recent history has demonstrated that climatic variability has a strong influence on both ecological and social components of rangeland systems and that these systems possess substantial capacity to adapt to climatic variability. Specific objectives of this synthesis are to: 1) evaluate options to mitigate greenhouse gas emissions and future climate change; 2) survey actions that individuals, enterprises, and social organizations can use to adapt to climate change; and 3) assess options for system transformation when adaptation is no longer sufficient to contend with climate change. Mitigation for carbon sequestration does not appear economically viable, given the small and highly variable carbon dioxide fluxes of rangeland ecosystems and the high transaction costs that would be incurred. In contrast, adaptation strategies are numerous and provide a means to manage risks associated with climate change. Adaptation strategies are diverse, including altered risk perception by individuals, greater flexibility of production enterprises, and modifications to social organizations that emphasize climatic variability, rather than consistency. Many adaptations represent “no regrets” actions because their implementation can be justified without emphasis on pending climate change. Adaptations specific to livestock production systems can include flexible herd management, alternative livestock breeds or species, innovative pest management, modified enterprise structures, and geographic relocation. Social-ecological systems in which adaptation is insufficient to counter the adverse consequences of climate change might undergo transformative change to produce alternative ecosystem services, production enterprises, and livelihoods. The rangeland profession is in a pivotal position to provide leadership on this global challenge because it represents the intersection of management and scientific knowledge, includes diverse stakeholders who derive their livelihoods from rangelands, and interacts with organizations responsible for rangeland stewardship.

Association of relative food availabilities and locations by cattle.

Four yearUng steers were trained and observed in a parallel-arm maze. Tbe purpose was to determine if cattle bad tbc ability to associate locations witb relative food availabilities. Tbc study consisted of 3 phases. In phase 1, ail 5 arms contabred 0.4 kg of gabt. In phase 2, the amount of grahr hr each arm was systematicilly varied from 0.1 to 0.8 kg. In phase 3, placement of grain was reversed. Steers performed efficiently in all 3 phases of tbe study. The overaIl-mean number of correct cboicee in tbe first 5 entrancea was 4.69 as compared to 3.73 by chance. Arms selected for choices 2,3, and 4 during tbe Iast 5 MaIs of pbase 2 were dIffercut (p<O.O5) from those selected during tbe last 5 trials of pbase 3. For tbe last 5 triah of phases of 2 and 3, arms selected in choices 1,2, and 3 contained 0.4,0.6 and 0.8 kg of grabr on 85% of tbe MaIs. Steers appeared to order their choices from larger to smaller rewards. Steers apparently can remember not only where they have foraged, but aIso tbe amount of food found there.

Research observation: Daily movement patterns of hill climbing and bottom dwelling cows

Abstract Individual animal selection has been proposed as a tool for increasing uniformity of grazing on rugged rangeland. Daily grazing patterns of cows previously identified as preferring steeper slopes and higher elevations (hill climbers) were compared to cows preferring gentler slopes and lower elevations (bottom dwellers). Cows were ranked for slope use and vertical distance traveled to water during late summer in 1997 using horseback observers. In 1998, 9 extreme cows based on 1997 rankings (4 hill climbers and 5 bottom dwellers) were tracked using Global Positioning System (GPS) collars for 3 weeks during late summer on foothill rangeland. Hill climbers (1027 hours) arrived at water about 1 hour later (P = 0.04) than bottom dwellers (0928 hours). Hill climbers and bottom dwellers left water at the same time (1801 hours, P = 0.3). During this interval, 90% and 98% of the observations were within 100 and 200 m of water, respectively. While cattle were away from water (1901 to 0846 hours), 56%, 77%, and 87% of the observations were within 200, 300, and 400 m, respectively, from the cows location at 0700 hours. Hill climbers spent 14% of their time on steeper slopes (20 to 30 degrees) while bottom dwellers spent 7% (P = 0.01), and hill climbers (41%) tended (P = 0.07) to spend less time on gentler slopes (0 to 10 degrees) than bottom dwellers (47%). Hill climbers (1323 m) were observed at higher elevations (P = 0.01) than bottom dwellers (1277 m). Horizontal distance traveled to water (633 m) was similar (P > 0.1) for hill climbers and bottom dwellers. Cow location during the early morning (0700 hours) was a good predictor of terrain used during the morning and previous evening grazing bouts. Cows tracked in this study did not appear to regularly associate with each other. They usually grazed in different areas of the pasture and regularly used different water sources. Individual cows within a herd can use different terrain even though many aspects of the grazing patterns are similar. Location of cows during the early morning and perhaps the time that cows travel to water can be used to identify differences in terrain use among individual animals.

Rotational Grazing Systems and Livestock Grazing Behavior in Shrub-Dominated Semi-Arid and Arid Rangelands

Abstract Rotational grazing systems (RGS) are often implemented to alleviate undesirable selective grazing by livestock. At both fine and coarse scales, livestock selectively graze individual plants, patches, communities, and landscapes. Smaller pastures, increased stocking density, and rotation allow managers to constrain livestock movement and determine season and frequency of grazing, potentially limiting selectivity and preventing repeated grazing of preferred plants. However, in arid and semi-arid rangelands, forage growth is limited primarily by precipitation rather than defoliation frequency. When soil moisture is adequate, forage is abundant and defoliation levels are typically low, and repeated, intensive defoliation of preferred plants is less likely than in more mesic areas where more consistent precipitation and soil moisture storage allows animals to establish and maintain spatial hierarchies of grazing patterns. Many southwestern rangelands contain diverse vegetation, which provides quality forage during different times of the year. These spatial and temporal patterns of forage distribution may not be amenable to manipulation with RGS. Tracking data show that livestock often alternate among locations within pasture boundaries and can opportunistically exploit areas with higher quality forage when they are available. Higher stock densities combined with higher stocking rates can increase livestock use of less preferred areas, but overall distribution patterns of intensive-rotational and extensive grazing systems are often comparable at similar stocking rates and distances from water. Management that ensures that grazing of riparian areas does not occur during the critical late summer period may be more beneficial than RGS that periodically defers livestock use throughout the grazing season. In arid and semi-arid shrublands, timely adjustments to animal numbers and practices that improve grazing distribution at regional and landscape scales are more likely to be effective in maintaining or improving rangeland health than fencing and RGS.

Cattle use visual cues to track food locations

We tested the hypothesis that cattle aided by visual cues would be more efficient than uncued animals in locating and consuming foods placed in either fixed or variable locations within a 0.64-ha experimental pasture. Eight yearling steers were randomly selected and trained to associate traffic barricades and traffic cones with high- (oat-barley mixture) and low- (straw) quality foods, respectively. Initially steers were randomly assigned to 1 of 4 food location/visual cue treatments: fixed locations/with cues (F/C), variable locations/with cues (V/C), fixed locations/no cues (F/NC), or variable locations/no cues (V/NC). High- and low-quality foods and their respective cue (or no cue) were placed in the experimental pasture. Individual animals were allowed to explore the pasture for 10 min twice per day every other day for 1 week. Minutes until feeding, first feed type consumed (i.e., high-quality, low-quality, or no food consumed), animal location and activity (i.e., feeding, standing, or moving), and total intake of high- and low-quality feed were recorded during each 10-min trial. At the end of each week, location/visual cue treatments were randomly assigned to another 2 steers, which permitted an independent test of each animal in each treatment over a 4-week period. Animals in the F/C and V/C treatments took about 2 min to initially locate and consume a food, compared to F/NC and V/NC animals who took nearly 4 and 6 min, respectively. The high-quality food was the first food located and consumed by F/C, V/C, F/NC, and V/NC animals during 79, 77, 67, and 54% of sampling occasions, respectively. Cued animals typically spent more time feeding (P=0.0004) and less time standing (P=0.005) than uncued animals. Cued animals had a higher mean intake than uncued animals of high- (P=0.001) and low- (P=0.04) quality food. Mean high-quality intake for F/C, V/C, F/NC, and V/NC treatments was 266, 245, 214, and 126 (+/-22) g, respectively; mean low-quality intake for the same treatments was 36, 32, 12, and 10 (+/-10) g. Cued animals also consumed more food per distance traveled than uncued animals (P=0.005). Animals located food quicker (P=0.03) and consumed more high-quality food (P=0.02) when food locations were constant than when they were variable. Our data strongly indicate that cattle can learn to associate visual cues with disparate food qualities and use this information to forage more efficiently in both fixed and variable foraging environments.