Sheep grazing bladder clover (Trifolium spumosum L.) had similar productivity and meat quality to sheep grazing subterranean clover (Trifolium subterraneum L.)

Abstract

An accession of bladder clover, a new species to agriculture, was selected for commercial release in Australia with the cultivar name of AGWEST Bartolo. As part of a duty-of-care assessment, we tested the hypothesis that sheep grazing the bladder clover cultivar will have similar liveweight, condition scores and wool production to sheep grazing a widely adopted subterranean clover cultivar (cv. Dalkeith). Further, we hypothesised that sheep grazing bladder clover and subterranean clover will have similar meat quality (after 48 days of grazing) and health as indicated by muscle, liver and kidney panel analysis. The data supported the hypotheses. While there were significant initial differences in liveweight between the two groups of sheep, there were no significant differences in liveweight at later time points during the grazing period and no significant differences in mean daily growth rate between weighing times. There were no differences in wool growth between sheep grazing the bladder or subterranean clover cultivars. Sheep in the subterranean clover plots had significantly higher condition scores after the first 24 days of grazing; however, these differences were not apparent after another 24 days of grazing. There were some differences in indications of animal health; however, there were no significant detrimental effects associated with bladder clover and sheep grazing both species had mean plasma indicators that were deemed ‘healthy’. There were no differences in meat eating quality as estimated by a consumer panel for tenderness, juiciness or flavour. Dry seasonal conditions limited biomass growth and the sheep were removed from the subterranean clover plots on Day 48 of grazing. The sheep grazing the bladder clover plots remained on the plots for a further 26 days. The data indicate that, for the conditions of this experiment, the clovers had the same relative feeding value. Laboratory analysis of herbage from across the clover plots (bulked before analysis) suggest that the bladder clover had higher in vitro digestibility, crude protein and lower fibre than the herbage sample from the subterranean clover plots. The biomass data indicate that the bladder clover cultivar can support more grazing days per ha in a relatively dry season than the subterranean clover cultivar.