Tedera proves its value as a summer and autumn feed for sheep in Mediterranean-like climates

Abstract

Tedera (Bituminaria bituminosa C.H Stirt. vars. albomarginata and crassiuscula) is a traditional forage species for goats in the Canary Islands, Spain. It has agronomic characteristics ideally suited to Mediterranean-like climates that allows it to provide high quality green forage for grazing animals during summer and autumn. It can be used to extend the growing season into late spring and early summer and/or to reduce or eliminate the need for expensive hand feeding of grain and hay to sheep to fill the ‘feed gap’ during the dry season in southern Australian farming systems. Three sheep grazing experiments were carried out with the objective to evaluate sheep production during summer and autumn with tedera as the sole diet. A 3-ha site at Dandaragan, Western Australia was grazed during the summer and autumn of 2014–2015 and 2016 and a 2.4-ha site was grazed at Kojonup, Western Australia during the same period in 2016. At each site, two grazing treatments were evaluated, continuous grazing and rotational grazing with six plots (14 days of grazing and 70 days of recovery). The first hypothesis tested was that tedera plants would not survive continuous grazing during summer and autumn. The second hypothesis tested was that without hand feeding, 10 dry sheep equivalents/ha would be able to at least maintain weight and condition score during summer and autumn. The third hypothesis tested was that rotational grazing would improve the production of the sheep (liveweight and condition score) compared with continuous grazing. The first hypothesis was rejected, the population of tedera plants did not significantly decline due to being continuously grazed during summer and autumn. The second hypothesis was confirmed, at the three experimental sites, 10 dry sheep equivalents/ha were able to at least maintain weight and condition score without any hand feeding. The third hypothesis was partially rejected; continuous grazing had a better performance of the sheep than rotational grazing. However, the rotational grazing plots had more tedera on offer in the remaining grazing plots in the rotation with the potential for a longer grazing time. These three experiments clearly demonstrate that tedera can be used to reduce or eliminate expensive hand feeding during summer and autumn using the simplest and least expensive grazing management; continuous grazing.