In arid regions, domestic (sheep, goats and camels) and wild (gazelles) ruminants eat the leaves and flowers of Calotropis procera during droughts, but they graze on it sparingly. If the leaves are chopped and mixed with other feed, consumption greatly increases with no ill effects (Abbas et al., 1992, Nehra et al., 1987; Gallacher et al., 2006).
In nutritional terms, this species provides important nutrients with emphasis on protein, average value of 20% DM, and an in vitro digestibility above 70% (Fall Touré, 1991; Cruz et al., 2007; Costa et al., 2009). No tannins were detected in Calotropis procera (Cruz et al., 2007). In vivo OM digestibility of Calotropis procera hay measured in sheep reached 75%, and voluntary intake reached 60 g DM/kg LW0.75 (Silva et al., 2001).
Several trials in Brazil have highlighted the potential and the limits of Calotropis procera hay in meat-producing lambs. Calotropis hay replacing sorghum hay was found to be an attractive and technically viable option at the inclusion rate of 17%, but higher inclusion rates (33% and 50%) affected negatively the growth rate, the health of the animals and meat pH (Madruga et al., 2008). Calotropis hay could also replace up to 30% (18% of the total diet) of the maize grain and soybean meal in the diet without compromising performance and nutrient consumption (Torres et al., 2010). The same inclusion rate did not affect the tissue composition, ratios and muscularity index of leg and physical-chemical parameters. Substitution levels above 30% affected negatively the sensory attributes of the meat (juiciness, flavour and overall acceptability) (Costa et al., 2011).
In dairy goats, Calotropis procera hay included at up to 22% in the diet may increase intake and nutrient digestibility (Pereira et al., 2010). It could be included at up to 60% without depressing the essential fatty acids content of the milk (Pereira et al., 2009).
Anthelmintic and anticoccidial activity
An aqueous extract of Calotropis procera flowers was shown to have a good anthelmintic activity against nematodes in sheep (Iqbal et al., 2005). Calotropis latex given to sheep in single oral doses of 0.01 ml or 0.02 ml/kg body weight reduced, but did not suppress, nematode egg production (Al-Qarawi et al., 2001). Calotropis procera latex also had an anticoccidial activity in adult sheep (single oral doses of 0.02 ml/kg body weight), and repeated treatment of lambs with Calotropis procera latex and sulfadimidine was suggested (Mahmoud et al., 2001).