Use of gps and gis for monitoring of cattle´s grazing on a silvipasture of Tolima (Colombia)

Cattle behavior and grazing distribution is probably related to the available food, although it could also be influenced by the canopy shade, ambient temperature and access to water. The objective of this study was to evaluate the interaction among tree cover (TC) and cattle positions (CP) when searching for food and comfort areas, under warm and hot weather, in a silvopasture system. Analyses were conducted on Pajonales farm, located in the municipality of Ambalema (lat. 4° 45’ 25.9” N; 74° 52’ 20.8” W) in Colombia, from December 2009 to January 2010. The farm has an average elevation of 300 masl. Mean precipitation is 1270 mm.year-1, and temperatura 28°C. The pasture used for this study had an area of approximately 54 ha, with topography from flat to gently sloping. TC was determined from digital orthophotos QuickBird using ArcGIS® 9.1. The paddock was segmented into a 0.25 ha grid cell lattice and all sapling canopies within grid cells and animal movement were mapped.Six cows (3 Brahman and 3 F1, Brahman x Holstein) equipped with GPS-collars (Garmin eTrex-Vista) configured to record and store position, were tracked during 60 days at 5‐min intervals. Average values indicate that cows, generally, traveled greater distances in warm period (7.4 km) and 6.1 km in the hot period. Cows prefer areas with low TC (˂ 20%) and intermediate TC (20-40%); these areas had more biomass of fodder dry matter. The study is an important contribution to understanding the dynamics of animals in search for food under grazing conditions