An animal house study on utilisation of fresh tedera (Bituminaria bituminosa var. albomarginata and crassiuscula) by Merino wethers

Bituminaria bituminosa is a drought-tolerant, perennial legume that has been used for centuries as a part of the mixed sward in grazing systems around the Mediterranean sea and ‘cut and carried’ to feed as hay to dairy goats in the Canary Islands; varieties albomarginata and crassiuscula, commonly known as tedera, are native only to the Canary Islands. In south-western Australia, tedera will likely be directly grazed as green plants to help fill the feed gap in summer–autumn, due to its drought tolerance and capacity to retain green leaves. There are no reports of ill-effects of grazing tedera in its native environment; however, tedera is never the sole diet there. Hence, before proceeding to grazing trials it was important to conduct pen feeding studies with a sole diet of tedera. Sheep fed fresh tedera exclusively for 34 days readily consumed the forage and remained in good health, as reflected by a standard set of blood chemistry parameters. Furthermore, while the intake of the sheep fed tedera may not have been ad libitum (~1.0 kg DM/head.day), they maintained their liveweight (42.5 kg) and body condition (condition score 3) throughout the experiment. This is the first experiment to measure the in vivo digestibility and nitrogen balance of sheep fed ‘fresh’ tedera forage. During the metabolism study, the in vivo digestibility of organic matter in the dry matter of the fresh tedera was similar to that of lucerne chaff (59% vs 55%) when the sheep fed lucerne chaff had their intake restricted to that of those fed tedera.