Nguyen Van Thu
Faculty of Agriculture, Cantho University, Vietnam
Two experiments were carried out on four fistulated swamp buffaloes to evaluate local feed resources using the in sacco method to study degradability and effects of the rumen environment. Promising feeds included: water plants (duckweed, azolla, Eleocharis dulcis, Blyxa Javenicey, and Sacciolepis indica), natural grasses (Bbrachiaria mutica and Panicum repens), legume tree leaves (Sesbania sesban, Sesbania grandiflora, and Leucaena leucocephala), crop residues and agro-industrial by-products (rice straw, sugarcane tops, maize stover and pine apple peel) and protein and energy-rich supplements (coconut and ground nut cake, rice bran, broken rice and maize).
The rumen environment study was a Latin square arrangement with four different diets: rice straw (RS), rice straw and molasses-urea cake (MUC), rice straw, MUC and grass (0.5% body weight), and rice straw and grass (0.5%DM of body weight). The results in the above order of diets were: ruminal NH3-N 9.17, 13.7, 12.3, 10.2 mg/100ml (SE=±1.19, P=0.032); bacteria population 0.84, 1.01, 1.07, 0.98* 109 (SE=±0.03, P=0.002); Protozoa population 2.49, 3.03, 3.38, 2.84* 105 (SE=±0.12, P=0.002). Feed intake was 96.0, 99.0, 113 and 109 gDM/W0.75 (SE=±2.10, P=0.001), respectively. There was an indication of improvement in feed degradability when the rice straw was supplemented with molasses-urea cake and grass.
It is concluded that there is an abundance of local feeds available for buffalo production in the Mekong delta and that supplementation of rice straw with Molasses-urea cake and grass has beneficial effects on the rumen environment of swamp buffaloes.
Key words: Swamp buffaloes, local feed resources, rice straw, molasses-urea cake, grass, ruminal ammonia, bacteria, protozoa, feed degradation.
Swamp buffaloes have played an very important role of providing draught power and beef for people in the Mekong delta of Vietnam. Farmers have benefited much from swamp buffalo production, but feeding systems are traditional and there are few studies aimed at improving the performance of buffaloes and how to enhance profit for farmers who keep these animals.
In recent years the buffalo population has seriously decreased due to the limitation on grazing land areas and the increased use of tractors. In many cases farmers sold buffaloes to buy tractors for work, then they had to sell tractors to buy buffaloes for work again (Ogle et al 1994). By the end of the dry season, in many areas buffaloes have only rice straw to eat. Then their working performance and health is poor. In many serious cases, they have been sold for slaughter.
A multi-nutritional supplement-molasses-urea cake (MUC) - produced at Cantho University improved the swamp buffalo performance in working, growth rate and milk production (Nguyen Van Thu 1996). The aim of this study was to produce some basic data on the nutritive value of local feed resources for swamp buffalo and to study the effect small amounts of low-cost supplements such as molasses-urea cake and grass on the rumen ecosystem.
Materials and methods
In the first experiment, for buffaloes with permanent rumen fistulas, two years of age, were used to investigate feed selection, composition and relative rumen degradation rate of natural grasses, water plants, agro-industrial by-products, and energy and protein supplements available in the Mekong delta. he samples of feeds were oven-dried and ground through a 2–3mm screen. The procedure for measuring degradability was that descibed by Ørskov et al (1980) and Ørskov and Shand (1997). Bags were removed from the rumen at 6, 12, 24, 36, 48, 72 and 96 hours. In the second experiment four dietary treatments were compared in a 4*4 Latin square arrangement using the same animals as in the first experiment. The diets were: rice straw (RS); rice straw and molasses-urea cake (MUC) fed at 350 g/day, rice straw plus fresh grass at 0.5% of body weight (dry basis) (RSG) and the combination of rice straw, molasses-urea cake and grass (RSMG). Rumen fluid was collected at 06:30 hours prior to feeding. pH was measured with a glass electrode and ammonia by steam distillation. Protozoa were counted in a 0.2 mm deep chamber under 100* magnification. Numbers of bacteria were counted in a Neubauer chamber under 1200* magnification following the procedure decribed by Hernander (1989). The rumen degradation rates of reference feed samples (rice straw, sugar cane bagasse, banana leaves and leaves and stems of Sesbania grandiflora) were determined using the in sacco method. The samples were oven-dried and then cut into 2–3 mm pieces. Feed intake was recorded.
Results and discussion
Of the feed resources tested (Table 1), the water plant Blyxa Javenicey had the highest value (60%) for 24 hour degradability. Two other water plants -duckweed and Saciolepis indica - had degradabilities of 56 amd 50%, respectively. Azolla was very poor with a 24 hour degradability of only 29% The two grasses were similar to duckweed (about 50% degradable at 24 hours).
Table 1: Relative degradation of natural grasses and water plants after different incubating time in buffalo rumen
There were marked improvements in degradability for incubation periods of 72 hours with all the tested feeds reaching values between 70 and 80%. It is generally considered that rumen turnover time is slower in buffaloes than in cattle thus 72 hour values may be a more appropriate indicator of potential fermentability of feeds in the former species.
Table 2: Mean values for pH, ammonia and protozoa and bacterial population of rumen fluid of swamp buffaloes fed rice straw without (RS) and with supplements of molasses-urea cake (MUC), grass (G) and both (RSMG)
|Feed intake, gDM/W0.75||96.0||99.0||113||109||±2.1/0.001|
In the second experiment the result showed that there was a significant increase in ruminal pH when the molasses-urea cake was fed. Ammonia concentration, and populations of protozoa and bacteria populations, were higher on all supplemented diets compared with unsupplemented rice straw. Feed intake was increased by supplementation with grass but not with the molasses-urea cake (Table 2).
None of the supplementation treatments affected the rumen degradabilities of the reference feeds (Table 3). These findings with swamp buffalo are different from what has been recorded for cattle fed rice straw and supplements. Bui Xuan An et al (1992) reported a 16% increase in rumen degradability of rice straw in nylon bags (48 hour incubation) in cattle when their rice straw diet was supplemented with a molasses-urea block. Similar findings were reported by Wanapat et at (1991) when Brahman cattle fed rice straw were supplemented with a feed block. Kabatange and Shayo (1991) showed increases in rumen degradability of a fibrous feed (maize stover) in cattle when a maize stover basal diet was supplemented with leucaena hay. Addition of grass to the diet of sisal waste fed to sheep also increased fibre degradability in nylon bags (Guttierrez et al 1984).
Table 3: Relative degradability at 24 and 72 hours of reference feeds in the rumen of swamp buffaloes fed rice straw without (RS) and with supplements of molasses-urea cake (MUC), grass (G) and both (RSMG)
It appears that swamp buffaloes may have lower requirements for rumen ammonia than cattle (Ørskov E R 1997, personal communication) which could explain the lack of effect of the supplements on feed degradability despite the fact that most criteria of an effective rumen ecosystem were improved by molasses-urea supplementation (Table 2).
Conclusions and recommendations
Local feed resources available for swamp buffalo production in the Mekong delta were abundant. Supplementation of a rice straw basal diet with a molasses-urea cake and small amounts of natural grass (0.5% of liveweight, DM basis) improved the rumen environment of swamp buffaloes but there were no benefits on rumen degradabilities of rice straw, sesbania leaves or banana leaves.
Swamp buffaloes fed on rice straw may respond differently to supplementation compared with cattle which is a topic meriting further research.
The research described here was financed in part by the International Foundation for Science (IFS) whose support is gratefully acknowledged (Grant B2296-1)
Bui Xuan An, Ngo Van Man and Luu Trong Hieu 1992 Molasses-Urea block (MUB) and Acacia mangium as supplements for crossbred heifers fed poor quality forages. Livestock Research for Rural Development. Volume 4, Number 2:1–6
Gutierrez E and Elliott R 1984 Interaccion digestiva de la pulpa de henequen (Agave fourcroydes) y el pasto estrella de Africa (Cynodon plectostachyus). In: Alternatives y valor nutritivo de algunos recursos alimenticios destinados a produccion animal. Informe provisional No 16 Fundacion Internacional para la Ciencia: Stockholm pp 229–246
Kabatange M A and Shayo C M 1991 Rumen degradation of maize stover as influenced by leucaena hay supplementation. Livestock Research for Rural Development. Volume 3, Number 2: 19–22
Nguyen Van Thu, Nguyen Van Cu, N, Pearson R A and Preston T R 1996 Effect of work and supplementation on performance of lactating buffaloes in Vietnam. In Proceedings of the 2nd Asian Buffalo Congress held in Philippines in Oct. 9–12, 1996. p 104–116.
Ørskov E R, Hovell F D De B and Mould F 1980 The use of nylon bag technique for the evaluation of feedstuffs. Tropical Animal Production 5: 195–213.
Ørskov E R and Shand W J 1991 Use of the nylon bag technique for protein and energy evaluation and for rumen environment studies in ruminants. Livestock Research for Rural Developement. Volume 9, Number 1 (15Kb)
Preston T R 1995 Identifying priortity areas for research on tropical feed resources. Tropical Animal Feeding. FAO Animal Production and Health paper 126. P 21–34.
Wanapat M 1991 Effect of HQFB supplementation on intake, rumen fermentation characteristics in ruminants fed rice straw based diets. In Proceedings of Internetional workshop on increasing Livestock production by making better use of local feed resource (Editors: T R Preston, B Ogle, Luu Trong Hieu and Le Viet Ly), Nov. 25–30, 1991, Vietnam.