Author : Mom Seng

Summary : Like in other developing countries in the region, ruminant feeding in Cambodia rely mainly on rice straw with addition of other crop residues and grass from infertile land. The available feed resources are poor quality, which result in low production. Rumen manipulation with removal of protozoa appears to have a considerable potential to improve ruminant productivity. Lipid can be used as a defuanating agent. The effect of a single drench of locally available cooking oil on local "yellow" cattle fed rice straw and cassava foliage on rumen ecosystem and animal performance was tested. Twelve growing local "yellow" cattle of 114 kg. (SE+- 4.35), received a basal diet of adlibitum rice straw and 300 g/head and day of rumen supplement (15% area). The 4 treatments, arranged according to a 2*2 factorial design, were the basal diet (RS), basal diet with single oil drench of 5ml/kg LW (RSO), basal diet with fresh cassava foliage at 3% LW or about 25% (DM basis) of the diet (RSC) and RSC with oil drench (RSCO). Rumen samples were taken by stomach tube at 7th, 14th, 28th and 84th day related to oil drench to determine pH, ammonia and protozoa count. daily feed intakes and fortnightly liveweight were recorded for 4 months. The result showed that oil drench had a negative effect on protozoa population in the rumen. However, there was a rapid re-infestation by the small protozoa (mainly entodinia) but only a large protozoa (mainly polyplastrons and holotrichs) were observed, being present in significantly (P<0.01) smaller numbers than in non-oil groups. The overall protozoa biomass throughout the 84 days trial was estimated to be at least 4 times lower than in animals that did not receive the oil treatment. Cassava supplement had no significant effect on protozoa. Rumen ammonia concentrations were significantly (P<0.01) lower in the cattle that received the oil drench. Feed intake increased significantly (P<0.01) in both oil and non-oil animals as cassava foliage was supplemented but there was not affected by oil drench. However, growth rates were significantly increased by the oil drench (P<0.05) and by supplementation with cassava foliage (P<0.01). The mean values were 53,124,210 and 302 g/day (SEM+- 30) for RS, RSO, RSC and RSCO, respectively. The result suggests that cooking oil, available in the market of Cambodia (vegetable cooking oil Cabbage Brand), can be used as defaunation agent. Oil drench and/or cassava foliage supplement at 3% LW (fresh matter) will have positive effect on animal performance. However, the number of animals employed was small ad the results from larger scale experiments are needed before confidence can be expressed in the level of performance. Furthermore, continuous works should be done on the level of oil to be used and frequency of drench, which give the highest benefit on farm level in long run. It would also be interesting to test the oil content of local available by-products such as rubber seed as defaunating agents.