The problems of ruminant feeding have received considerable attention in the tropics and sub-tropics. Most of the research has focused on treating roughage in the late dry season when the quality and quantity of food supply from natural pastures become limiting. Moreover, ruminant animals have evolved the ability to utilize and digest fibrous materials. In contrast to the situation in the tropics and sub-tropics, in many developed countries, foods that are suitable for human consumption are very often used for feeding both monogastrics and ruminant animals. Nitrogen deficiency is the most important limiting factor in these feeds. Maize stover is a major animal feed resources in Nigeria. Maize stover is categorized under the high fiber-low protein feed resources available for livestock production in the tropics. High fiber-low protein feeds include fibrous residues arising from crops grown for human consumption, such as straws and stovers from rice, millet, sorghum and maize, and sugarcane bagasse. Though maize stovers is the most abundant of all agricultural residues and has a great potential as a feed-stuff for ruminants, it appears that 1ivestock production based on these stovers are rather low (Tesfayohannes, 2003).
Urea treatment of cereal straws and stovers has received considerable attention due to its simplicity in usage, nitrogen enrichment and improvement in the digestibility of fibrous feeds due to cleavage of linkages between different structural components, which leads to easy action of microbial enzymes and eventually improves the nutritional status of animals and their performance (Fall et al., 1987). The advantage of urea treatment of roughages is that it urea is easily available as a fertilizer grade urea, is cheaper and not hazardous to use compared to NaOH NaoH and NH3, the two most effective treatment chemicals. Moreover, it has the added advantage of increasing the nitrogen content of the feed for use by the micro flora in the rumen to synthesize microbial protein, other conditions in rumen being right (Said and Wanyoike, 1987).
Chemical up-grading of maize stovers by means of ammoniation with gaseous or liquid ammonia has received considerable attention in many countries (Sundstol and Coxworth, 1984). An alternative method of ammoniation, using urea as the source of ammonia has been reported by several research workers (Saadullah et al., 1981; Hadjipanayiotou, 1982; Cloete and Kritzinger, 1984; Dias-Da-Silva and Sandstol, 1986). According to Davis et al. (1983), of all the alkalis tested, ammonia is the most preferred because it provides both the alkaline effect and a source of nitrogen. However, alkali treatments are generally expensive and the chemicals are not readily available in many parts of developing countries (Tesfayohannes, 2003).
Urea treatment or supplementation of urea through crop residues increases the nutrient digestibility as well as the rumen ammonia nitrogen concentration and microbial protein synthesis. Urea treatment / supplementation could force the ruminal microorganisms to use NPN more effectively and maximize the availability of amino acids for absorption through the intestine (Woyengo et al., 2004). The amounts of these maize by-products generated annually in the country continue to increase as more people venture into the cultivation of maize, but these by-products have low feeding value because of their poor protein content, energy, minerals and vitamins. Fortunately, the current trend indicates that which maize stovers and cobs are no longer considered as wastes, but are now being converted to animal protein for human consumption (Akinfemi et al., 2010).
Generally, crop residues and by-products are deficient in fermentable energy, fermentable nitrogen, protein and several of the required micronutrients. Brand et al. (1991) postulated that urea-ammoniated diets such as barley, maize stover, oat, wheat straw and oat hay may not be adequate for production functions like growth, pregnancy and lactation. It has been suggested that crop residues and by-products, even when treated, should be fed along with the concentrates. The concentrates was expected to provide the required concentration of protein as well as other nutrients (Singh, 2005).
1.2 GENERAL OBJECTIVE
This study is designed to determine the concentrate supplementation effect on in vitro gas production characteristics of urea treated maize stovers
1.3 SPECIFIC OBJECTIVES
These are to investigate:
- Concentrate supplementation effects on in vitro gas production characteristics of untreated maize Stover
- Concentrate supplementation effects on in vitro gas production characteristics of urea-treated maize Stover
- Urea treatment and concentrate supplementation effects on in vitro gas production characteristics of maize Stover