Productive response of lambs fed with fresh or dehydrated spineless cactus (Opuntia ficus-indica L.)

The objective of this study was to evaluate the effect of cactus (Opuntia ficus indica L.) supplementation on lamb animal performance, during a 11 week period. For this purpose, 27 male lambs of commercial crossbreeds were used, with initial live weight mean of 21.4 +/- 3.8 kg. They were distributed homogeneously into three groups of nine each, and then randomly assigned to each of the following treatments: (T1) control diet, (2) diet with 17% (dry matter basis) of dehydrated cactus, and (3) diet with 17% (dry matter basis) of fresh cactus. Digestibility in situ of the diet, dry matter intake (DMI), daily gain weight (DGW), feeding conversion (FC) and efficiency (FE), back fat, hot and cold carcass yield, biological hot and cold carcass yield, and carcass pH at slaughtering and 24h post mortem, were evaluated. A completely random design using Proc GLM was used, and when statistical differences were observed, a mean comparison was done using the Tukey test. There were significant differences (P <= 0.001) on DM digestibility, with higher value (42.0%) on the control diet during the first 6 hours of incubation, but after 48 hours, the highest digestibility (88.6%) was on the fresh cactus diet. There were not significant differences (P>0.05) between treatments on animal performance, except on back fat, being higher (P<0.001) on dehydrated (4.1 mm) and fresh (3.3 mm) diets, compared to the control one (7.8 mm). The means for hot and cold carcass yield, biological hot and cold carcass yield, and carcass pH at slaughtering and 24h post mortem were 50.6%, 47.0%, 55.4%, 49.5%, 6.6% and 5.8%, respectively. Diet including cactus had similar effect on productive parameters than that of the commercial one, which makes it a viable feeding strategy, and from the economical point of view, could be attractive to the farmer, since the cactus is a plant that grows over the year. However, there is a need of doing more research to confirm these results, not only on fattening lambs, but also on the different animal life stages, considering different levels of cactus, and working on different animal breed and species.