Sugarcane juice can partially or completely replace cereal grains in pig diets under commercial conditions, as demonstrated in a number of studies. Successful experiments and commercial applications of feeding cane juice to pigs have been reported from the Caribbean islands, Mexico, Colombia, the Philippines, Vietnam, Africa and other tropical areas (see Pérez, 1997 for a comprehensive review of those studies; Mena, 1988; Speedy et al., 1991; Sarria et al., 1990; Sarria et al., 1992; Motta et al., 1994; Paula et al., 1994).
Diets including sugarcane juice must be formulated using the metabolizable or net energy systems in order to avoid excessive carcass fatness. It is necessary to include protein-rich ingredients to compensate for the low protein content of the sugarcane juice (Mena, 1987). In small-scale farming systems, tropical foliages such as ensiled cassava leaves or cocoyam leaves (Xanthosoma sagittifolium) can be used as a protein source in pigs fed sugarcane juice (Du Thanh Hang et al., 1997; Rodriguez et al., 2006). In commercial conditions, sugarcane juice can be used as the main source of energy in growing-finishing pigs and lactating sows with no limit to the inclusion rate. For example, sugarcane juice fed to finishing pigs and pregnant sows completely replaced maize grain and resulted in better animal performance, better health and a lower weaning-to-mating interval (Chaves, 2008; Paula et al., 1994). In young pigs, the inclusion level of sugarcane juice must be limited to avoid diarrhea. The principal disadvantage of feeding pigs with sugarcane juice is its high and rapid rate of fermentation (about 12 hours), which causes storage issues on the farm.
The apparent energy digestibility of sugarcane juice is close to 100%, due to its high content of water soluble sugars, which are entirely digestible. The average digestible and metabolizable energy values for sugarcane juice are 17.3 and 17.1 MJ/kg DM (Xandé et al., 2010). Due to the very low DM content of the juice, and based on the ME content of sugarcane juice and maize grain, about 4.5 L of juice is required to substitute for one kg of maize (Pérez, 1997).
The juice is normally fed to pigs in a drinking trough. A halved 50 cm plastic drain pipe set into cement is ideal because it can be easily and thoroughly cleaned. Ad libitum intake of juice will range from 5 litres per day at 20 kg to 15 litres per day at 100 kg live weight. A dry supplement must be fed separately, preferably in the morning in order to be totally consumed before feeding the juice (Pérez, 1997).
For small-scale cane producers who raise only a few pigs, feeding sugarcane juice requires too much work to be practical. In the Philippines, some farmers preferred to partially evaporate (boil) the fresh juice, place the resultant syrup in a covered drum alongside the pig pen and reconstitute this syrup with three parts of water whenever the pigs needed to be fed. These farmers obained an average daily gain of 450 g with a diet based on sugarcane syrup and soybean meal (Pérez, 1997).