## 1 Introduction  
The lamb industry plays an important role in the Australian economy accounting for 7% ($4.2 billion) of the gross value of agricultural production and 6% ($2.8 billion) of the agricultural export income in 2018-19 [1]. The Australian lamb industry benefits from the large grazing land area of approximately 341 million hectares [2] because animal production based on grazing systems is relatively low cost compared to more intense production systems [3]. Meat from lambs finished on green pastures is generally regardedas a good source of iron, zinc and omega-3 polyunsaturated fatty acids (n-3 PUFA) [4]. However, lamb production based on grazing systems is dependent on pasture quantity and quality, which in turn, is dependent on seasonal patterns and climate variability [5]. In addition, export markets in Asia and the USA, which represent more than 50% of the total Australian lamb export volume [6], prefer carcasses of heavier weight specifications (22 kg or more) [7]. Therefore, there is a need to evaluate the effect of legumes, improved pastures and specialized forages in lamb finishing systems on growth rate, carcass characteristics and fatty acid profiles of grazing lambs. The additional use of supplementation with diverse oils of plant origin and subsequent effects on growth rate and carcass traits also needs to be evaluated in order to support lamb producers in the production of high quality and heavier carcasses for meeting the requirements of specific export markets [8].  
Cocksfoot cv. porto (_Dactyliss glomerta_ L. cv. Porto) (CFP) was released in Tasmania in 1972 [9]. This grass has the potential to produce healthy, premium quality meat with high contents of n-3 PUFA and n-3 long-chain (\(\geq\)C\({}_{20}\)) PUFA (n-3 LC-PUFA) [10]. However, there is a scarcity of available published information on the effect of CFP on lamb performance and carcass characteristics. Lucerne dominant pastures have been shown to consistently produce premium lamb carcasses for both the Australian local and export markets [7]. Nevertheless, available knowledge on the effect of lucerne pasture on prime lamb production and carcass characteristics in Tasmania characterized by a cool, temperate climate and considered as Australia's coolest state with a 'clean, green image' [11; 12], is generally limited.  
Canola oil is commercially extracted from canola seeds [13]. Rice bran oil is a by-product of rice processing [14]. Canola and rice bran oils have been studied for their effect on prime lamb performance and carcass characteristics in a confined system. Supplementation of lambs with rice bran oil and canola oil in confined systems had comparatively lower feed costs, without compromising average daily gain (ADG), carcass characteristics and over the hooks (OTH) trade income [15]. It has been demonstrated previously that supplementation of prime lambs with canola oil infused pellets in a confined system did not cause significant differences in daily feed intake, growth performance and carcass characteristics compared with supplementation with a none-oil containing pellet [16]. However, there is no peer-reviewed and published information on the effect of rice bran and canola oil supplementation on the performance and carcass characteristics of prime lambs managed on cocksofot and lucerne dominated grazing systems. Therefore, the objective of this study was to evaluate the effects of CFP and lucerne pastures and supplementation with pellets with or without plant oil infusion on lamb performance and carcass characteristics.