SHEEP PERFORMANCE, GRAZING BEHAVIOR, AND BODY TEMPERATURESIN SILVOPASTURE SYSTEMS

摘要

Silvopasture systems integrate trees for timber or fodder with forages for grazing ruminants. Reports of forage and animal productivity from these systems have been variable. In some cases, animal gains are similar or better despite lower forage yield. We explored the relationship between grazing system, body temperature, grazing behavior, and animal performance in this study. Black walnut (Juglans nigra) and honeylocust (Gleditsia triacanthos) based silvopasture systems were compared with open pastures in a randomized complete block design (r = 3). Pastures were rotationally stocked with six or seven lambs depending on forage availability. All sheep were weighed and fecal samples from a subset of the lambs were taken every four weeks. Body temperatures and grazing behavior measures were recorded within a replicate within a week, and these measures were taken sequentially within three experimental periods. Ewe lambs (n=3) within each experimental unit were equipped with a vaginal temperature sensorand a wideband audio recording device to detect prehension events. Time lapse cameras documented sheep behavior every 60 seconds. Forage availability measurements taken with a rising plate meter indicated no difference between the honeylocust silvopasture (4400 ± 70 lbs/acre) and the open pasture (4300 ± 70 lbs/acre; P = 0.9916), though forage availability in the black walnut silvopastures (3100 ± 70 lbs/acre) was lower than that within the other treatments (P < 0.0001). Animal gains were highest inthe honeylocust silvopastures (27.8 ± 2.12 lbs/period), and were significantly different from the gains of the open pastures (20.8 ± 2.20 lbs/period; P = 0.0254) and the gains of the black walnut silvopastures (18.7 ± 2.22 lbs/period; P = 0.0046), though no difference was found between the latter two systems (P = 0.5173). Observations indicate that sheep in silvopastures had extended foraging periods and, in some cases, lower body temperatures.