Sheep Preference for Fresh Leaf and Stem of Seven Accessions of Tedera Was Not Influenced by Prior Grazing Experience and Wilting Made No Difference

Abstract

Tedera is a valuable high-quality forage for sheep during summer–autumn. There is evidence that prior grazing experience of novel forages influences preference and haymaking of tedera improves preference by goats. In the first experiment, it was hypothesised that the voluntary feed intake (VFI) of fresh leaves and stems of tedera by sheep would be greater for experienced vs. naïve sheep. In the second experiment, it was hypothesised that the VFI of naïve sheep fed wilted leaves and stems of tedera would be greater than fresh leaves and stems of tedera. To test these hypotheses, adult Merino sheep were fed seven accessions of tedera, in two outdoor pen feeding experiments conducted consecutively. Each of six pens had 14 feeders, two for each accession, and two sheep. In experiment 1, three pens had sheep that had previously grazed tedera (experienced) and three pens had sheep with no experience (naïve), and all were fed fresh leaves and stems of the seven tedera accessions. Experiment 2 involved only naïve sheep, with three pens fed fresh leaves and stems and three pens fed wilted leaves and stems of the seven tedera accessions. Preference was measured each day for six days in experiment 1; and for five days in experiment 2 by calculating the average differences of feed offered and feed remaining from the feeders. In experiment 1, experienced sheep showed no difference in preference (average percentage eaten) in the first hour of each day compared to naïve sheep (70% vs. 56% DM intake (kg), p = 0.27). There was an increase in the amount eaten from the first to the last day for both groups, except for the intake of one accession that was reduced for the experienced sheep. In experiment 2, there was no statistical difference in preference between accessions. However, when the average percentage eaten by the experienced and naïve groups are combined, they are strongly correlated, with significant differences between accessions. Sheep did not eat more wilted tedera compared to fresh, which did not support our hypothesis. The only differences we found in sheep preference for tedera accessions occurred in experiment 1. Further studies to investigate seasonal differences in sheep preference between accessions is required and increased replication is needed to better determine the effect of prior grazing experience on the preference for tedera accessions.

Keywords

• grazing
• feed-gap
• forage
• plant secondary compounds
• post-ingestive effects