Aharoni, Y., Beef Cattle Section, Agricultural Research Organization, Newe Yaar Research Center, PO Box 1021, Ramat Yishay 30095, Israel
Henkin, Z., Beef Cattle Section, Agricultural Research Organization, Newe Yaar Research Center, PO Box 1021, Ramat Yishay 30095, Israel, Department of Natural Resources, Agricultural Research Organization -the Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Ezra, A., Beef Cattle Section, Agricultural Research Organization, Newe Yaar Research Center, PO Box 1021, Ramat Yishay 30095, Israel
Dolev, A., MIGAL - Galilee Technological Center, Qiryat Shemona, PO Box 90000, Rosh Pina 12100, Israel
Shabtay, A., Beef Cattle Section, Agricultural Research Organization, Newe Yaar Research Center, PO Box 1021, Ramat Yishay 30095, Israel
Orlov, A., Beef Cattle Section, Agricultural Research Organization, Newe Yaar Research Center, PO Box 1021, Ramat Yishay 30095, Israel
Yehuda, Y., MIGAL - Galilee Technological Center, Qiryat Shemona, PO Box 90000, Rosh Pina 12100, Israel
Brosh, A., Beef Cattle Section, Agricultural Research Organization, Newe Yaar Research Center, PO Box 1021, Ramat Yishay 30095, Israel

The grazing behavior, diet intake, and energy costs of activity of 2 types of cows grazing a Mediterranean pasture were compared. Fifteen largeframe Beefmaster × Simford (BM) cross cows and 13 small Baladi (Ba) mature cows were allocated to the paddock and monitored during 3 seasons throughout 2006; spring (April), summer (June), and autumn (September). Cows were not given supplemental feed during the spring and summer, but had free access to a poultry litter supplement (25% CP, DM basis) during the autumn. Fecal output and digesta kinetics and feed intake were estimated using indigestible double-marker technique. Cows were fitted for 3 to 4 d in each season with global positioning system (GPS) monitors, with activity monitors attached to one of their hind legs, and with heart rate (HR) monitors harnessed to their chests. Oxygen consumption per heart beat was determined for each cow during each season to enable conversion of the diurnal HR patterns to heat production (HP) units. All the GPS data of cattle locations and the activity, HR, and HP data were synchronized to produce a simultaneous record at 5-min intervals. Partition of time spent by the cows lying down, standing, grazing, and walking without grazing, the horizontal and vertical distances walked per day, and the number of steps taken per day were summed from these records. Multiple regression models were adjusted to refer these activities to the HP and to estimate the specific HP costs per unit of each activity. Accordingly, the daily energy costs of activity were calculated for the 2 cattle breeds on each season as the product of the specific activity and the number of units of each activity per day. Feed intake by Ba cows per unit of metabolic BW was greater (P < 0.001) than that of BM cows in both spring and summer and their apparent selection of greater-quality herbage in spring was greater (P < 0.1) than that of BM cows. The smaller framed Ba cows grazed more hours per day and walked longer distances than the BM cows among all seasons. The specific costs for locomotion were less for the Ba cows. © 2009 American Society of Animal Science.