Lamb performance in hardwood silvopastures, II: animal behavior in summer.

Benjamin F Tracy,Gabriel J Pent,John F Munsell,John H Fike,Scott P Greiner

doi:10.1093/tas/txz177

Abstract

Integrating trees into pastures, a practice known as silvopasture, may benefit livestock in the summertime through the provision of shade. The purpose of this project was to compare the behavioral patterns of sheep grazing in silvopastures and open pastures. Black walnut (Juglans nigra L.) and honeylocust (Gleditisia triacanothose L.) based silvopasture systems were compared with open pastures in a randomized complete block design with three blocks over two summers. 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 wideband audio-recording device to detect prehension events. Time-lapse cameras documented sheep behavior every 60 s. In the silvopastures, the lambs spent over 90% of daylight hours within shade from trees. Lambs in silvopastures spent more time lying down than animals in the open pastures (P ≤ 0.01), while lambs in the open pastures spent more than 2 h longer each day standing (P < 0.0001). Lambs in the black walnut silvopastures spent more time grazing (488 ± 14 min · d−1) than lambs in the honeylocust silvopastures (438 ± 14 min · d−1; P = 0.0493) and lambs in the open pastures (417 ± 14 min · d−1; P = 0.0026). There was no difference in grazing time for lambs in the latter two systems (P = 0.5597). Spectral analysis of the imagery revealed that the lambs in the black walnut silvopastures grazed more frequently than the lambs in the other systems for both years. The acoustic analysis, though limited by recorder durability to 47 complete recordings, revealed no difference in total bites taken per day (P ≥ 0.7222) or in the morning (P ≥ 0.2069), afternoon (P ≥ 0.5816), and evening periods (P ≥ 0.9337). Silvopastures provide an opportunity to improve lamb comfort in the summer.

Highlights

IntroductionWhile temperate silvopastures may differ from open pastures in terms of forage yield, composition, or nutritive value, these responses do not necessarily track differences in animal performance between silvopastures and open systems (Peri et al, 2001; Lehmkuhler et al, 2003; Kallenbach et al, 2006; Pent et al, 2019)
Altered animal behaviors—such as grazing time, rumination, standing up, and lying down—and consequences to energy expenditure may be an important driver of the similar animal gains observed between open and silvopasture systems
Fasting—or time since the last rotation in a rotational stocking system—is a major driver of grazing time in ruminants (Newman et al, 1994), and it seems that this effect precluded our ability to detect differences between treatments in addition to the low number of complete recordings included in the final analysis

Summary

Introduction

While temperate silvopastures may differ from open pastures in terms of forage yield, composition, or nutritive value, these responses do not necessarily track differences in animal performance between silvopastures and open systems (Peri et al, 2001; Lehmkuhler et al, 2003; Kallenbach et al, 2006; Pent et al, 2019). Research with sheep (Ovis aries) and cattle (Bos taurus) grazing in hardwood tree-based silvopasture systems suggests animal performance is comparable to that from open pastures, even when forage yield is reduced (Kallenbach et al, 2006; Fannon et al, 2017; Pent et al, 2019). The mechanisms behind these responses have not been clearly defined. Lamb productivity and forage characteristics are available in a corresponding article (Pent et al, 2019)

Objectives

Methods

Results

Discussion

Conclusion