Range Behavior of Hereford, Hereford X Holstein and Holstein Non-Lactating Heifers

Abstract

Ten each of Hereford, Hereford X; Holstein and Holstein non-lactating heifers were observed on native tallgrass range during eight 24-hr, periods, two each in winter (February, March), spring (May, June), summer (July, August) and fall (November, December). Each 24-hr, period was divided into four 6-hr, intervals: (1) 12 am to 6 am; (2) 6 am to 12 pm; (3) 12 pm to 6 pm; and (4) 6 pm to 12 am. Activities, observed every 15 min., were grazing, ruminating (standing and lying), idling (standing and lying), drinking, walking, sleeping and feeding. Significant (P<.001) F tests for breed, season, day, interval and all their interactions were noted for all major activities. Interval effects were the largest and breed effects the smallest source of variation. Grazing occupied more time than any other activity, 43.9, 41.5 and 41.2% on a yearly basis for Hereford, Hereford X; Holstein and Holstein heifers, respectively. Grazing time tended to increase from winter to fall, and was greatest during intervals 2 and 3 (6 am to 6 pm). Here fords grazed more than other breeds in interval 1. Grazing time was not highly related to forage intake, based on a comparison of grazing time with seasonal and yearly weight gains. Rumination times of 32.2, 29.7 and 31.2% on a yearly basis were observed for the three respective breeds; approximately 83% of the ruminating was done in the lying position. Peak intervals for rumination (1 and 4), 6 pm to 6 am, were exactly opposite the peak intervals for grazing (2 and 3). Rumination time did not increase from winter to fall as grazing time did, suggesting initially an increase in forage quality and subsequently greater selectivity in grazing. Idling time, 18.4, 22.4 and 22.1% on a yearly basis for the respective breeds, tended to decrease as grazing time increased (winter to fall). Herefords tended to idle more in the standing position and their idling pattern was more uniformly distributed across the four daily intervals, compared to the other breeds. Minor activities consumed 5.5, 6.4 and 5.5% of the time on a yearly basis for the respective breeds. The behavior patterns and concurrent weight gains observed in this study indicate that Holstein and Hereford X; Holstein non-lactating heifers were generally similar to Hereford heifers in range behavior activities of grazing, ruminating, idling, drinking, walking and sleeping.