Herbage selection by cattle on sub-alpine wood pastures

On botanically diverse sub-alpine wood pastures, the quantity and quality of the herbage available and consumed by cattle was investigated. Seven forest ranges located between 1560 and 2000 m a.s.l. in the Swiss Canton of Grisons were stocked with heifers, lactating and non-lactating cows. On average, the ranges consisted of 44% woodland, 25% half-open area (with young trees and shrubs) and 31% open area. The ranges were grazed applying a wide range of stocking rates (0.4-2.8 livestock units ha-1) and grazing periods (12 to 114 days), with 6 to 65% of the herbage resources being exploited. Vegetation surveys were performed before and after grazing to determine the frequency of functional botanical groups in the herbage available and in that consumed. Herbage intake, selection and digestibility were determined using the double alkane technique applying controlled release capsules. On average, the daily herbage dry matter intake rates amounted to 1.3 and 1.8 kg 100 (kg live weight)(-1) in heifers and cows, respectively. Grass species were browsed on nearly half of the plots on which they occurred, whereas legumes, forbs and shrubs were browsed on approximately 20% of the plots. Although the herbage quantity provided by the pastures was quite small in some cases, cattle selected herbage of relatively constant digestibility throughout the approximately weekly pasture measurement periods (short-term response) and also after about I month of grazing of the same site (long-term response). The results show that the wood pastures, in conjunction with the ability of the animals to select sufficiently digestible plants, provide feed of a quality high enough to satisfy the requirements of livestock, at least in comparably extensive systems. (C) 2003 Elsevier Science B.V. All rights reserved.