Pineapple leaves are a medium-quality roughage for ruminants. It is possible to let cattle graze pineapple leaves but this practice tends to compact the soil and it is recommended to cut the leaves instead (Py et al., 1987). Pineapple leaves can be used fresh, artificially dried or ensiled. They must always be chopped before use. It is recommended to ensile pineapple leaves with molasses. Though the silage is relatively low in protein and high in fibre, ruminants can be daily fed 15-20 kg of fresh or ensiled plants when other feed is scarce. The dried leaves can be advantageously pelleted (Morton, 1987; Göhl, 1982).
Because pineapple leaves have a low and poorly digestible protein content, supplementation with protein sources is necessary (Kellems et al., 1979).
Pineapple hay can be used as a roughage source of medium quality for lactating dairy cows (Prachyalak et al., 2000; Snitwomg et al., 2000; Otagaki et al., 1961). Whatever the ration (fresh grass or total mixed ration), cows fed on pineapple hay have slightly higher intake, slightly lower milk production, and equal or slightly higher butterfat levels (Prachyalak et al., 2001; Prachyalak et al., 2000). Pineapple hay is not detrimental to animal health or to milk flavour (Dronawat et al., 1966; Otagaki et al., 1960).
Dairy cows rations containing a mix of pineapple hay (pelleted or not) and pineapple bran resulted in lower milk yields of similar protein content and higher milk fat than rations based on pineapple bran alone (Dronawat et al., 1966).
In a long-term experiment covering several lactations, pineapple silage was fed as the sole roughage to dairy cows. After the second lactation, it caused lower milk yield, lower appetite, weight losses, lighter calf weights, coat abnormalities and pica. Milk production and abnormalities were corrected with a supplement of alfalfa hay. These problems were not considered to be specific to the pineapple silage but rather to the effect of prolonged silage feeding as the only form of roughage (Bishop et al., 1974).
Fattening and growing cattle
Pineapple leaves fed alone to fattening cattle resulted in higher intakes but lower daily weight gains and lower carcass characteristics resulting in reduced financial returns for farmers (Prachyalak et al., 2001). When pineapple leaves were mixed with fresh grass or offered with total mixed rations the results were different: the fattening cattle had increased intakes but also higher daily weight gain and better dressing characteristics, thus resulting in more profit (Prachyalak et al., 2001; Prachyalak et al., 1999). Good growth results (0.77 kg daily weight gain/animal) were obtained in steers fed on pineapple leaf silage supplemented with soybean meal as a source of protein, though this diet did not compare favourably with the control maize grain/alfalfa diet in terms of average daily gain and feed conversion (Kellems et al., 1979). The value of feeding both pineapple canning by-products and pineapple crop residues (leaves and stems) was demonstrated in the Philippines, where large scale feeding trials on cattle given pineapple pulp and pineapple leaf silage, together with a 35% protein concentrate at 0.6% body weight, gave daily live-weight gains of between 0.38 and 0.48 kg (Albarece, 1979 cited by Devendra, 1985).
In sheep, an aqueous extract of pineapple leaves was found to have a moderate anthelmintic effect against gastrointestinal nematodiasis (Khalid et al., 2005).