Effect of different rubber seed levels on digestibility and nitrogen retention in growing goats fed a basal diet of wheat bran and brewers grain

Hoang Huong Giang

lengaing@hotmail.com

 Abstract

Four Bach Thao growing male goats of approximately 14 kg live weight were used in a 4x4 Latin square design to determine total digestibility and N retention of diets of wheat bran and brewer grains (3:1) where the wheat bran was replaced with graded levels of whole rubber seed meal (0, 20, 40 and 60% in dry basis). In addition, the animals were offered cassava (Manihot esculenta Crantz) foliage at a rate of 0.5 kg/goat per day.

The whole rubber seed meal was from the Cambodian province of Kompong Cham and contained DM 82.5 %, NDF 65.9 %, crude protein 13.9 % in dry basis respectively.

Daily feed intake was from 211 to 396.g DM/kg live weight, and tended to decrease when the rubber seed level increased in the diets (P<0.01). This effect was quadratic in nature (R² 0.96)  There was no symptoms of animal discomfort during the entire trial. There was no treatment effect (P>0.05) on DM, N and NDF digestibility. N retention expressed as percentage of consumption were significantly influenced (P<0.05) by the inclusion of graded levels of rubber seed in the diet.

Ruminal ammonia concentration and pH as measured at the end of every collection period showed no significant differences among treatments. (overall values, 6.75 and 855 mg/L).

It is suggested that digestibility indices are not impaired when high levels of rubber seed meal are given in the diet to the goat. Moreover, rubber seed meal appears to exhibit a similar nutritive value to that of a mixture of wheat bran and brewers grain. Although further studies related to the determination of the feeding value of rubber seed meal in goats are recommended, the use of local available feeds such as rubber seed is highly encouraged in integrated farming systems.