Nutritive value and palatability of cladodes of spiny cactus (Opuntia Amyclae) or spineless cactus (Opuntia Ficus-Indica F. Inermis) measured on adapted and non-adapted goats

This experiment aimed to compare the nutritive value and palatability of spineless (Opuntia ficus-indica f. inermis) and spiny (Opuntia amyclae) cactus cladodes measured on goats previously adapted or not to the consumption of cactus. Nine local goats (initial BW 30.6+/-3.7 kg) were allotted into three equal groups and housed in individual boxes. These animals came from a previous 3-month experiment in which goats received either a cactus-free diet (group not adapted, NA), a spineless cactus-based diet (group adapted to spineless cactus, A-OFI) or a spiny cactus-based diet (group adapted to spiny cactus, A-OA). In the current experiment these three groups received during 9 consecutive days (from 24 April to 2 May 2006) 500 g of oaten hay. Group NA (n=3) did not receive additional feeds. However, both A-OFI (n=3) and A-OA (n=3) groups received daily 3 kg of spineless cactus and spiny cactus cladodes (fresh weight basis) at the same time in separate troughs. Both cactus species were high in oxalate (ca. 100 g/kg DM) but spiny cactus was higher in crude protein (76 vs. 45 g/kg DM) and NDF (383 vs. 279 g/kg DM). Gas production from in vitro fermentation of spiny cactus was slightly higher than that from spineless cactus. In the first day of this experiment, NA-goats consumed more (P<0.05) spineless than spiny cactus (11.4 vs. 6.2 g DM/kg BW(0.75)). However, A-OFI and A-OA goats had better preferences for spiny cactus (14.5 vs. 6.4 g DM/kg BW(0.75), A-OFI group; 15.8 vs. 5.8 g DM/kg BW0.75). At the end of the experiment (Day 9) spineless cactus was much more consumed that spiny cactus. Irrespective of early adaptation, the average DM intake for the whole trial period was highest with spineless cactus (ca. 25 vs. 15 g DM/kg BW(0.75)) in the three goat groups. Early adaptation had no effect on the average DM intake of spineless and spiny cactus (P>0.05). Cactus palatability was not affected by its nutritive value. The rapid burning of cladodes to take out spines could have changed their taste and advocated a repulsive odor which might explain the low palatability of spiny cactus as compared to spineless cactus.