Submitted to: American Society of Agricultural and Biological Engineers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2009
Publication Date: 10/20/2009
Publication URL: http://asae.frymulti.com/toc_journals.asp?volume=25&issue=4&conf=aeaj&orgconf=aeaj2009
Citation: Pandey, V., Kiker, G.A., Campbell, K.L., Williams, M.J., Coleman, S.W. GPS Monitoring of Cattle Location Near Water Features in South Florida. American Society of Agricultural and Biological Engineers. Applied Engineering in Agriculture. Vol.25(4) Interpretive Summary: Nonpoint source pollution from animal production operations is a matter of concern in Florida, where cattle and calf inventory is 1.69 million head. The majority of these cattle are located in south and central Florida, especially in the Lake Okeechobee watershed, where cow-calf operations and dairy farming are major agricultural activities. This region is characterized by flat topography with sandy soils that consist of mixtures of pastureland and wetlands that are connected and drained by shallow ditches. These networks collect runoff from this watershed and eventually drain into Lake Okeechobee. Located in south-central Florida, this large, shallow (average depth 2.68 m) eutrophic lake has a drainage basin of more than 11,913 km2. The lake has been threatened by large inputs of nutrients, especially Phosphorus (P) from the agro-ecosystems north of lake that have adversely impacted its water quality. One of the key sources of high P loads in the watershed is suspected to be runoff from dairy farms and direct stream access by large numbers of beef cattle from improved pastures. Beef cattle activity in animal production operations in south Florida may result in direct nutrient loading of important water resource locations. If BMPs are needed to minimize the impact of beef cattle production on water bodies in south Florida, a better understanding of beef cattle utilization of natural (wetland) and artificial (ditches and water trough) water sources is necessary. This research study attempted to quantify the amount of time spent by grazing cattle near or in water locations by the use of GPS collars. These collars were used to measure the amount of time spent near water-filled location in the pasture landscape. There was some indication of higher presence of cattle near water locations during warm periods than in cool periods (11.45±0.39% vs. 6.09± 0.69%). On a daily basis, cattle utilization of all water sources (as determined by % time present) was relatively low (<15% in a 24-h period). Cattle seemed to utilize water troughs in a fairly consistent manner, going to water troughs earlier (late morning) and staying in the area longer during warm periods, compared to cool periods when they went later (afternoon) in the day and for shorter periods of time. The presence of cattle in the wetlands was generally well distributed across all warm and cool periods as well as all times of day (approx. 4% in a 24-h period). During cooler periods, cattle were present in wetlands when grazing would be expected to occur (late morning), indicating the need for feed might be the driving factor. In contrast, during the warm periods, cattle were present when grazing was not an expected occurrence (afternoon), suggesting that cooling may be the reason the cattle were in the wetlands. Presence of cattle in ditches was generally higher in the warm periods than the cool periods, although there was no consistent pattern for time of day within warm or cool periods. The low utilization of water bodies would not suggest cattle as the major factor affecting surface water quality.
Technical Abstract: A study was conducted to quantify the amount of time spent by grazing cattle near or in water locations (wetlands, ditches, and water troughs) across seasons of a cow-calf production ranch in South Florida. Prolonged hot summers in these regions can cause physiological heat stress in cattle and drive them into water-filled ditches and wetlands in order to cool down. Because of the numerous ranches in the region, it is perceived that this activity is contributing towards the phosphorus loading into the receiving water body, Lake Okeechobee. Cattle position data was monitored continuously using GPS collars. Data was recorded every 15 min during a 5-day period in spring (March), summer (June), fall (late August), and winter (November or December) from 2001 to 2003. The average percentage of daily time spent by cattle near/in water locations (water trough, wetland, and ditch) during the warm season (summer + fall) was 11.45± 0.39% and 6.09± 0.69% during the cool season (winter + spring). Overall, the cattle utilized water-filled features somewhat more during warm seasons, with some exceptions under higher temperatures found in southern Florida winters. Temporal, sub-daily analysis of the use of water troughs revealed very little usage during early morning and night and increased use as the day progressed. Similar analysis of wetlands use showed greater utilization during late morning and nights in the cool season. Utilization of ditches was fairly consistent through out all years; more during warm seasons and less during cool. Current hydrological modeling systems that are actively used to represent the nutrient-enriched agricultural enterprises in South Florida lack the ability to comprehensively represent the dynamics of the animal-plant-soil system. This study will provide crucial information for model developers who may utilize these results to develop more detailed hydrological and nutrient loading models.