A thorny species, Acacia farnesiana is eaten by small ruminants and camels rather than by cattle. Small ruminants browse branches and leaves from the tree. They might also receive some parts, like seeds and hulls. It is palatable to deer that might be in competition for food with small ruminants (Ramirez et al., 1997b). The nutritive value of huizache can be of interest during the dry season in Mexico compared to the other plants available at that time (Landa-Becerra et al., 2016).
Foliage
Compared to other locally available plants, huizache is of nutritional interest for small ruminants due to its high protein content, low fibre content and high digestibility (Garcia-Montes de Oca et al., 2011; Corniaux et al., 1996). Huizache shrubs are of interest as supplementary feed for goats : the nitrogen utilization and intake levels were similar to those of goats offered lucerne hay (Ramirez et al., 1997a).
Digestibility
OM digestibility values of huizache browse estimated with the gas production method are quite low, in the 26-37% range. Treatment with polyethylene glycol (PEG), which counteracts the defaunating effect of tannins and reduces their astringency, increased OM digestibility up to 40% (by 14 percentage points in one case) (Olivares-Pérez et al., 2014; Monforte-Briceño et al., 2005).
Palatability
Huizache is one of the preferred browse plants by goats in Mexico because it shows smooth and waxy leaf surfaces without trichomes (Foroughbakhch et al., 2012; Franco-Guerra et al., 2011; Franco-Guerra et al., 2008; Ramirez et al., 1997a). It was found to be palatable to goats in Zimbabwe (Reiss et al., 1990), though less palatable than Guazuma ulmifolia in Mexico (Villa-Herrera et al., 2010).
Mineral composition
The mineral composition of Acacia farnesiana foliage was found to be less variable than that other browse species in Mexico, and the Ca, Mg, K and Mn levels meet adult goat requirements, but animals need to be supplemented in P, Zn and Cu (Ramirez et al., 2001)..
Pods
Huizache pods are relished by sheep and goats and are a good source of protein source that can be incorporated into small ruminant feeding systems in arid and semi-arid regions. In Mexico, sheep preferred them to pods of Acacia macilenta but preferred those of Acacia cochliacantha (Rojas-Hernandez et al., 2016; Quiroz-Cardoso et al., 2015). Dry and ground pods of huizache could be utilized in the feeding of wool sheep up to 40% of the diet in combination with maize stover, without signs of toxicity (Velázquez Avendaño et al., 2005). With isoproteic diets incorporating up to 40 % pods, the optimal inclusion rate was 20% to obtain the highest voluntary intake and wool growth at the lowest cost (Velázquez et al., 2011a). However, authors recommended a maximum inclusion rate of 12% (Garcia-Winder et al., 2009).
Huizache pods included in nutritional blocks as a feed supplement increased DM intake in sheep, without affecting diet digestibility and weight gain (Rojas-Hernandez et al., 2015). Low amounts of Acacia farnesiana pods affected positively the digestibility and feed intake of low quality roughage by sheep due to their high protein content (Ramirez et al., 1998).
