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In 1953 to 1971, Thai rural areas were covered with buffalo because most of the rural families had 2 – 4 buffaloes each. According the Thailand agricultural statistical center (1971 – 1981), Thailand owned the largest buffalo population and was the buffalo champion in South East Asian countries. The buffaloes were used as draft animals. Thai people have deep relationship with the buffalo in the life. Before 1971 the buffalo was a very important domestic animal in Thailand. According of statistics from Thailand, Agricultural Statistical Center showed that Thailand had about 5.5 – 6.5 million buffalo during 1971 and 1981. The buffalo population declined to 1.8 million in 1999, if compared to the presence is 1.6 million heads. As shown only 1 year the numbers of buffalo population were decreased 0.2 million. There are several reasons for the reduction in the number of Thai swamp buffalo and were as follows; the reduction of rice producing areas, the replacement of buffalo by small tractors, the castration of good male buffalo, the industry invasion into the rural area. Therefore, the role of buffaloes to sustainable agriculture should be more concern. Buffalo could be extinct from Thailand in 20 years, if no considerable public attention was received. In Northeast Thailand, swamp buffalo were traditionally raised mainly under extensive grazing. Additional roughage cut by hand is sometimes given to swamp buffalo, especially in the dry season, in order to satisfy their requirements. In the dry season the animals used to often graze in the forest or be given only rice straw.
It has previously been reported that when buffalo and cattle are kept under similar conditions, buffalo utilize feed more efficiently with the digestibility of feed being typically 2-3 percentage units higher than cattle (Kennedy and Hogan, 1994; Wanapat et al., 1999). In paper II, dry matter intake of buffalo was relative high at 2.1-2.4% BW. Comparisons made between buffaloes and cattle suggest that buffaloes may achieve better balance between protein and energy and hence a better potential to synthesize glucose than cattle (Kennedy and Hogan, 1994). Similar to (Ludri and Razdan, 1987, cited by David 1998) who suggest those ruminal characteristics of buffaloes are more favorable to ammonia-nitrogen utilization, buffaloes digest less crude protein than cattle but increased their body nitrogen more and they were being fed only 40% of the recommended daily intake of crude protein. The abilities of buffaloes to digest fiber efficiently may be partly due to the microorganisms in their rumen. The microbes in the buffalo rumen convert feed into energy more efficiently than do those of cattle (as measured by the rate of production of volatile fatty acids in the rumen) (David, 1998). Buffaloes and cattle have a different physiology in term of live weight gain at the same stage of growth (Johnson and Charles, 1975) cited by Granum et al. (2003). Buffaloes have a superior digestive capacity over cattle in situations where the feed supply is of low quantity and/or quality (Wanapat, 1999). In paper II, DM digestibility of buffalo also was high at 71.0-78.4%.
The number of bacteria per ml rumen fluid varies with time after feeding and substrate. Hungate (1966) reported that total count of bacteria per ml rumen fluid of cows ranged from 10.3x109, 22.2x109 and 31.3x109 cells/ml when fed alfalfa hay ad libitum, 12 lb grain mixed with 25 lb alfalfa meal or 25 lb grain mixed with 9 lb alfalfa meal, respectively. The cellulolytic bacteria are sensitive to pH. When a high level of grain fed, the pH may decrease below 6.0. At this pH the cellulolytic bacteria are inhibited and the feed intake decrease (Russell and Wilson, 1996). Optimum pH for maximum microbial growth is between 6.5 and 7.0 (Hungate, 1966). Ruminal in paper II were in normal range (6.4-6.8) as suggested by Hungate (1966). NH3-N is an essential source of nitrogen for microbial protein synthesis. Song and Kennelly (1989) found that total mixed bacteria tended to increase with increasing level of ammonia nitrogen in the rumen fluid of cattle; this pattern has also been reported in buffaloes (Suwanlee and Wanapat, 1994). The ranges of NH3-N level for optimal rumen ecology has been reported to be 15-30 mg% (Leng, 1999; Wanapat and pimpa, 1999)
Fungi is closely associated with the more slowly digested vascular lignin-containing tissues and they may play a role in the rumen digestion of low quality of roughages that turn over slowly in rumen, as the complete life of fungi requires 24 hours (Demeyer, 1981). Rumen fungi produce high level of enzymes capable of degrading the total cell wall (celluloses, hemicelluloses and xylanses), which are regulated by substrates (especially soluble sugars) available to the organism (Grenet et al., 1989). Fungi could alter the fibrous residue for easier mastication by the animal and may also be associated with proteolytic activity (Ho and Abdullah, 1999).
Locally available feed resources will continue to be important in the feeding systems of livestock for small-holder farmers in the tropics; especially during the dry season to cope with scarced feed resources and prevailing increased number of livestock (Wanapat, 2002).Ruminants have been fed on low good-quality protein. This leads to low digestibility and voluntary feed intake, and an imbalance in the absorbed -quality roughages, agricultural crop-residues, and industrial by-products which basically contained high levels of ligno-cellulosic materials, a low level of fermentable carbohydrate and a low level of nutrients (protein to energy ratio, P/E) and, as a consequence, growth, reproductive rate, and milk production are low.
However, feed resources and crop residues are enormously available locally for use to increase livestock production in the tropic and subtropics areas. Cassava chips/pellets and cassava hay, baby corn stovers, broken rice, leucaena, and kapok meal are good examples feed resources, while rice straw and urea treated rice straw are excellent roughage for ruminant during the dry season.
A part of efficient supplementation of locally mixed concentrate, grain or protein foliage demonstrated well to improve rumen ecology, dry matter intake and subsequent meat, milk quantity and quality (Wanapat, 1999). The extent to which tree foliages protein is degraded in or escapes the rumen is extremely important. If the tree foliage protein is totally degraded them it provides ammonia and microbial growth (Leng, 1993). Greater many tropical foliages or legumes contain secondary plant compounds which many diminish their potential value as high quality feed, and there is an increasing awareness that the effects of these compounds on feed quality and animal production need further study. Roughages used in Experiment II, also contained secondary compound namely condensed tannins which could act to protect protein from rumen digestion, thereby could increase by-pass protein.
In situations where concentrate feed supplementation are expensive, farmers should be capable of formulating their own feeds based on available farm resources and their economic viability (Wanapat, 1999). Preston and Leng (1987) pointed out that the integration of livestock with crop production was a mean of establishing sustainable farming system at optimizing resources use. The supplements needed to balance these feed resources for ruminants can be obtained from the home-grown protein supplements on the farm. Small-holder and family mixed farming will remain predominant for some time to come, with livestock production driven by by-products and surplus products of crop agriculture. Important productivity gains will be achieved by further enhancing nutrient and energy cycles between the two components. The environmental and economical stability that this system provides make it the prime focus for continuing technology generation, transfer and expansion. Livestock’s role, in addition to production, is to enhance and substitute natural resources, and also to produce efficiently at minimal environment cost.
Urea-treatment is using 5 kg of urea mixed in to 100 kg of water and poured over a pile or stack of rice straw covering with plastic sheets or ensiling in a cement block for at least 10 days before being fed as fresh to ruminants has been demonstrated to be the best chemical treatment in the topics resulting in improved digestibility, fermentation end–products, overall intake, reduce rumen retention time and the subsequent performances (Wanapat, 1995, Hart and Wanapat, 1992). More importantly, on- farm trials employing these technologies verified with satisfactory results and acceptance especially by dairy farmers during the dry season. The major constraint using urea- treated rice straw addressed by engaged farmers were as follows: frequent labor utilization and variable cost of urea. Nevertheless, the technology is practically simple and cost- effective as apposed to other fibrous treatments. Urea-treated rice straw was used in the Paper II, and CP content was improved up to 8% of DM and the value was similar with those by Wanapat (1995).
Cassava or tapioca (Manihot esculenta, Crantz) is grown widely in tropical and sub-tropical countries. In Thailand cassava is the second most important crop after rice in terms of planting area, generating farmers’ income, rural employment and export earnings. The production of cassava roots in 2004 was 21.4 million tons and the planted area cover 1.08 million hectares. The average fresh root yield was 20.3 tons/ha (Office of Agricultural Economics, 2004). Many varieties are being cultivated in different locations, and the most common cassava varieties are Rayong 1, Rayong 5, Rayong 60, Rayong 90, Kasetsart 50 etc. The starch content in the roots is 17.7 to 35%, depending on variety, age of planting, planting area, planting and harvesting season (Sinthuprama et al., 1983; Settasuk, 1994; Sriroth, 2000). The results revealed high DM intake (11.2kg/hd/d, 3.2% BW) and DM digestibility (71%; Wanapat et al., 1997). Furthermore, cassava hay supplementation is not only a protein source but it also apparently contains a gastrointestinal anthelmintic agent which can reduce total nematode egg counts in grazing cattle and buffaloes by the action of condensed tannins in cassava hay (Netpana et al., 2001). According to Wanapat et al., (1997) who reported that cassava foliage yield was 1.0 ton DM/ha and was lower than in Paper I (2.6 tons DM/ha). This might be due to different in soil type and time of planting. Wanapat et al. (1997) planted in the dry season but the result of Paper II was in the rainy season. In addition, yield of cassva foliage depends on soil fertility, planting season, varieties of cassava, spacing between stems of cassava for planting and subsequent harvesting. Dung et al. (2005) reported that total yield of cassava foliage was 6.75 tons DM/ha when the first harvesting was at 3 months after planting and followed by re-growth (from 56-75 days). Cassava foliage yield was higher than in Paper I. However, Wanapat et al. (1997, 2000a, 2000b) suggested that cassava hay could be produced from initial harvest of plant tops at 3-4 months after planting and subsequent harvests at a month intervals.
Cassava in Thailand can be planted year round since there is usually sufficient soil moisture. Previous research revealed that planting cassava in the rainy season between May to October gave a root yield that was higher than in the dry season (November to April; Kathong, 1994). However, there are commonly two planting periods, on the first period cassava is planted in the beginning of the rainy season (April to middle of June) and the second planting period is late in rainy season or early in the dry season (October to December). Land preparation is by ploughing by farm tractor with 8 to 12 inches depth. It was suggested that ploughing 2 times before planting resulted in higher root yield and economical returns (Kathong, 1994). The land is ridged after ploughing. Mature cassava a stem of 8-12 months of age with 15-20 cm length is used as a planting material. The spacing of planting material is 70-100 cm between the rows and 50-100 cm between stems. Cassava cultivation for several years in the same piece of land and without application of fertilizer resulted in a decline in soil fertility and root yield. In contrast, the application of chemical fertilizer results in slightly increased root yield in the long term (Wongwiwatchai et al., 2001; Nakviroj et al., 2001 cited by Wongwiwatchai et al., 2002). The average amounts of fertilizers are comparable to the general recommendation of 100 kg N, 50 P2O5 and 100 K2O/ha (Sittibusaya et al., 1993). Weed control is traditionally done by hand with a hoe. The number of weeding necessary for cassava varies considerably depending on soil fertility, climate factors and varieties. Weeding cost varies according to the planting season, the cost being much higher when cassava is planted in the early rainy season than when planted in the early dry season.
Cassava could be cultivated to produce mainly cassava leaves to make hay, which has a high nutritive value. Intercroppi