Bur clover is frequently used in sheep production systems in all Mediterranean climatic regions, such as southern Europe, North Africa, South America and Australia, due to its adaptation to a wide range of edaphic conditions (Porqueddu et al., 2006). Bur clover is an important pasture plant and its dry fruits are a valuable concentrated fodder for pasture animals during the dry season. They are not suitable for sheep pasture as the fruits become entangled in the wool. Consumption of the pods is most noticeable after the spiny burs have been softened by fall rain (USDA NRCS, 2002).
In vitro digestibility of bur clover pastures was reported to be as high as that of subterranean clover or sulla (Hedysarum coronarium) pastures (Sölter et al., 2007). Bur clover pods have a low apparent OM digestibility (40-50%) (Porqueddu, 2001).
No information found (2016).
Voluntary intake of fresh bur clover fed alone to lactating ewes may be as high as 102 (winter) or 107 (spring) g/kg BW0.75, which was greater by 55 and 36% to voluntary intake of fresh annual ryegrass in winter and spring, respectively (Addis et al., 2005). When fed fresh with 350-450 g concentrate/day, a voluntary intake of 108 to 175 g/kg BW0.75 has been observed, greater than that observed with annual ryegrass or sulla fed as the main forage (Cabiddu et al., 2006). In winter (vegetative stage), high feeding levels coupled with a high nutritive value allowed a level of milk production from lactating ewes fed on fresh bur clover similar or greater to those fed on fresh sulla. In spring (reproductive stage), despite a higher intake level, milk production of ewes fed on bur clover was lower than those fed on sulla, probably due to its large drop in nutritive value between the vegetative and reproductive stages (Cabiddu et al., 2006).
Supplementing wethers fed on wheat straw with pods of bur clover increased total intake from 57 to 73 g DM/kg BW0.75 (of which half was medic pods), i.e. a 27% increase in total intake level and a global substitution rate of 54% between pods and straw (Chriyaa et al., 1997). This positive effect was similar to that measured with alfalfa hay or old man saltbush (Atriplex nummularia) foliage used as supplements. However, introducing bur clover pods did not increase DM, OM or fibre digestibility of the diet (Chriyaa et al., 1997).
Grazing sheep (vegetative bur clover)
In pastures containing 49% bur clover, an intake level of 120 g/kg BW0.75 has been observed, which was greater than that observed on subterranean or sulla-based pastures (+13%; Molle et al., 2008). Milk yield of lactating ewes also tended to be greater when grazed on bur clover pastures (1640 mL/d, +6%). Milk production of dairy ewes grazing bur clover may be greater than 1500 g/d throughout the grazing season (Fois et al., 2005). In Italy, similar milk yields were observed between lactating ewes grazing either safflower, chicory or bur clover, with greater milk fat and protein concentrations with bur clover (Landau et al., 2005).
Summer grazing sheep (dead bur clover)
Mature bur clover (pods and dry stubble) may form the basis of the diet of grazing sheep, allowing maintenance of weight and body condition score throughout the summer. An intake level of 1200 g/d may be achieved, of which 50% are pods (more than 500 g pods consumed per day) (Fois et al., 2000).
Wool quality degradation
When sheep graze bur clover, the burs entangle in the wool, causing a significant drop in quality of the Australian wool clip, thus reducing its economical value. Burs are difficult to remove. Carding may break them into smaller pieces and their coils tend to unwind into thin eyebrow-shaped pieces, which are even more difficult to remove and can persist into the finished product (Popay, 2014).
No information found (2016).