Biofuel co-products as livestock feed - Opportunities and challenges

Utilization of co-products of the biofuel industry as livestock feeds – a synthesis 513ine, stressing that methanol should be removed as far as istechnically possible and that the methanol content of eachbatch should be declared.Pongamia cake (Braid, 25; Abbeddou and Makkar, 19)is similar to soybean meal in many respects, but containsanti-nutritional factors (karanj and pongamol) that alsomake it unpalatable, although Abbeddou and Makkar (19)consider it a safe feed within limits after detoxification.However, because of the anti-nutritional characteristicsand relative unpalatability, Braid (25) suggests Pongamiapinnata as a useful tree for incorporating into extensivepasture because of a relatively low risk of grazing damage.Feeding of untreated pongami or karanj cake to livestockreduced dry matter intake and caused histological changesto vital organs of ruminants and poultry, and this has ledto various attempts to detoxify it, although they havebeen general rather than targeting a specific toxin (Dutta,Panda and Kamra, 22; Braid, 25). The most successful ofthese was de-oiling to ensure removal of the toxins duringthe extraction process, which is achieved through treatmentwith an alkali solution (1.5% NaOH plus 3% lime)or ammoniation with urea (Dutta, Panda and Kamra, 22).Carcass weight of lambs was reduced more with expellercake than with solvent-extracted karanj, but chemical andphysical attributes of the lambs were not affected. Bothforms of karanj resulted in lighter carcasses than de-oiledgroundnut meal (Dutta, Panda and Kamra, 22). The sameauthors reported that masking the taste of neem or ureaammoniation improved intake of neem seed kernel cake(NSKC) in ruminants. Neem seed cake (NSC) was found toreduce growth, impair the male reproductive system and,in some cases, result in haematuria. Treatments showingpositive results with neem seed kernel cake include addingNaOH (1 percent) and boiling (this can reduce CP)and washing with water, which can result in a loss of drymatter. Another approach is to ensile the NSKC with either2 percent NaOH for 24 hours or 2.5 percent urea for 5–6day, followed by sun drying and grinding (Dutta, Pandaand Kamra, 22). Although responses in feeding trials havebeen mixed, there are no reports of changes in rumen pHor total volatile fatty acids. Dutta, Panda and Kamra (22)suggest that both karanj and neem seed cake, if properlyprepared, could replace 50 percent of the nitrogen in thediets of lambs. Although farmers in India show reluctanceto feed castor meal (this could be related in part to a higheconomic return from sugar cane), there is evidence thatruminants can use it (Anandan, Gowda and Sampath, 20;see also Table 7 in Chapter 20), in some cases withoutdetoxification of the ricin.The two major by-products from palm oil processing arepalm kernel cake (PKC), also known as palm kernel expeller(PKE), and crude palm oil (CPO) (Wan Zahari, Alimon andWong, 13). There are two dominant processing methodsused: solvent extraction and expeller. These result in palmproducts with a range of nutritive values arising from differencesin agronomic factors and processing procedures.Expeller palm kernel meal (PKM) has a substantially higheroil content than the solvent-extracted material and the AAprofile shows deficiencies in lysine, methionine and trytophan,which are currently being addressed (Wan Zahari,Alimon and Wong, 13). PKC is free of aflatoxins, heavymetals and chemicals, and can be stored for up to threemonths. However, the Malaysian palm oil industry also producesvaluable by-products resulting directly from the fieldoperations. These include oil palm fronds (OPF) from pruning,felling and harvesting that are available throughout theyear, the yield being around 82.5 kg/palm/year (Wan Zahari,Alimon and Wong, 13). The fronds can be chopped and fedfresh, which is the common practice, ensiled, or processedfor cubing or pelletting. Freshly chopped OPF is a commonsource of forage and can be fed at 40 percent of the diet,often with some added PKC, to buffalo, cattle and sheep.If ensiled, the diet will benefit from a urea supplement tooffset the low level of CP in the silage. The second fieldresidue is oil palm trunks (OPT), the life of a tree being25–30 years (the criteria for felling and clearing are heightof palm >13 m and/or a diminishing yield). The trunks canbe chipped and ensiled, and, with added urea, have a similarnutritive value to that of rice straw, with the parenchymabeing an excellent source of roughage for beef cattle (WanZahari, Alimon and Wong, 13). With beef cattle, a maximuminclusion of 85 percent PKC is recommended, andfor dairy cows 30–50 percent PKC is recommended, oftenfed as a pellet with grass and other concentrates. However,with sheep, 30 percent PKC should be regarded as themaximum because of the high Cu content of the cake,which can cause long-term problems in this species (WanZahari, Alimon and Wong, 13).Other products from the oil palm industry, which eitherhave some use at present or merit research for future use,include palm oil mill effluent (POME), which after decantationcan be used for ruminants; empty fruit branches,a field product, suitable for coarse forage, mulching andfibreboard production; palm press fibre (PPF), used for fuel,paper, fibreboard, etc., as well as for coarse forage (treatmentwith alkali or steam is not assured of success); andcrude palm oil (CPO) is rich in vitamins A and D and can beused to reduce dustiness in the diet. Derivatives from CPOinclude palm fatty acid distillates (PFAD) and spent bleachedearths (SBEs) (Wan Zahari, Alimon and Wong, 13).Non-ruminantsCrude glycerine contains similar energy to that of maize forpigs. If affordable, sow diets can contain up to 9 percentand weaners at least 6 percent glycerine, which can beincreased up to 15 percent for finishers. Inclusion of