Mom Seng et al., 2001. Livest. Res. Rural Dev., 13 (4)

The following study aimed to improve the utilization of available resources and develop a system for fattening local cattle in Cambodia. It is based on two principles: ruminants use their feed more efficiently when protozoa are absent from the rumen and cassava foliage has been found to be a source of by-pass protein for ruminants. Twelve growing local "Yellow" cattle of mean weight 114 kg (SE ±4.35) received a basal diet of ad libitum rice straw and a rumen supplement (13% urea; 3% diammonium phosphate) at 300g/head/day. The 4 treatments, arranged according to a 2×2 factorial design, were the basal diet alone (RS), or RS plus fresh cassava foliage at 3% of LW (fresh basis) (RSC), RS plus a single oil drench (cooking oil at 5ml/kg LW) (RSO), or RSC with oil drench (RSCO). Rumen samples were taken at the 7th, 14th, 28th, 56th and 84th day related to the day of the oil drench to determine pH, ammonia concentration and protozoa count. Daily feed intakes and fortnightly live weights were recorded for 4 months. The oil drench reduced the protozoa population. However, there was a rapid re-infestation of the small protozoa (mainly Entodinia) to a level comparable to the control groups. Only a few large protozoa (mainly Polyplastron and Holotrichs) were observed, being present in significantly smaller numbers than in non-oil animals. The overall protozoal biomass in the oil groups throughout the 84 day trial was estimated to be at least 4 times lower than in the non-oil groups. Rumen ammonia concentrations were significantly lower in oil-drenched animals. Feed intake increased significantly in both oil and non-oil animals when cassava foliage was given but was not affected by the oil drench. Growth rates were increased significantly by the oil drench and the cassava supplement. The mean values were 53, 124, 210 and 302 g/day (SEM ± 30) for RS, RSO, RSC and RSCO, respectively.