225and 3 ). This is because, when ruminants are offered a diversity of plants, they
increase their daily intake and their productivity rises (Baumont et al. 2000 ). Thus,
in Australia, it has been demonstrated that the live weight of sheep is greater if they
are offered a diversity of plants rather than a monoculture (Fig. 4 ).
Complex silvopastoral systems can also improve animal health and welfare
(Broom et al. 2013 ) because, in a complex landscape, feeding behaviour is more
rewarding with the animals eating more as well as eating a variety of plants of dif-
ferent flavours (Provenza et al. 1996 ; Scott and Provenza 1998 ). Moreover, native
shrubs, being wild and unbred, contain an array of natural plant secondary com-
pounds (Tables 2 and 3 ). Such compounds are typically removed by plant breeding
because they can, for example, be responsible for poor palatability and thus intake.
However, some of the bioactive secondary compounds can be most valuable – they
have antimicrobial and anthelmintic properties, reduce methane emissions, and
improve the efficiency of rumen fermentation (Kotze et al. 2009 ; Vercoe et al. 2009 ;
Durmic et al. 2010 ; Li 2013 ). They also have the potential to reduce the risk of lactic
acidosis (Hutton et al. 2010 ) and to modify rumen biohydrogenation, thus driving
the fatty acid profiles in meat and milk towards healthier products (Wallace 2004 ,
Durmic et al. 2008 ).
Fig. 3 Various scenarios illustrating the risks to landscapes in grazing systems, with and without
shrubs. (a) Effect of an out-of-season (summer) rainfall event in the northern agricultural region of
western Australia (photo courtesy of D.K. Revell); (b) and (c) typical scenarios of overgrazed pad-
docks during the ‘feed gap’ in summer and autumn in south western Australia (photos courtesy of
P.E. Vercoe and D.K. Revell); (d) and (e) examples of the ‘Enrich’ system on two farms in Pingelly,
Western Australia, where a mixture of native shrub species has been incorporated into the grazing
system. Plate ‘d’ was taken in autumn, 8 months after the perennial shrubs had been planted as
seedlings (photo courtesy of D.K. Revell) and plate ‘e’ (Pingelly, Western Australia) was taken in
winter (photo courtesy of P.E. Vercoe)
Integrated and Innovative Livestock Production in Drylands