Effects of Feeding Wastes from Brassica Species on Growth of Goats and Pesticide/Insecticide Residues in Goat Meat

The effects of feeding Brassica vegetable market wastes on intake, body weight changes and pesticide/insecticide residues in products of goats were evaluated in two experiments. In the first experiment (Exp. 1) 16 goats (Bach Thao, 9 to 10 kg, 3 months old, 9 males and 7 females) were fed four diets with leaves either from cabbage (Brassica oleracea var. capitata), cauliflower (Brassica oleracea var. botrytis) or Chinese cabbage (Brassica campestris subsp. pekinensis) with 30% of Para grass. The control group was fed 100% Para grass. All diets contained soybean waste as a supplement and the experiment lasted for 136 days. In the second experiment (Exp. 2) 24 goats (Bach Thao, 12 to 14 kg, all males) were assigned to three treatments in a completely randomised block design based on initial body weight. The goats were fed cabbage waste supplemented with 200 g or 100 g DM (dry matter) of concentrate. Para grass with 100 g DM concentrate supplementation was used as a control group. The experiment lasted for 90 days and at the end of the study, 12 goats were slaughtered for pesticide/insecticide analysis. Due to low DM content (5.3 and 3.7%, respectively) feed intakes of cabbage and Chinese cabbage groups were lower than those of other groups in the experiment. The highest feed intake and body weight gain was obtained when the goats were fed cauliflower (529 g DM/day and 87.5 g/day, respectively). In Exp. 2 total intake of cabbage and concentrate was similar (484 g and 453 g DM/day) whether the goats were fed 100 or 200 g concentrate/day but lower than that of Para grass and concentrate probably due to the low DM content of the cabbage (5.9%). Crude protein intake (79 g to 86 g/day) and body weight gain (70 g to 88 g/day) was not significantly different between treatments. Adding concentrate consequently resulted in higher DM intake than in Exp. 1 but did not result in any higher growth rate. Three of the pesticide/insecticide residues tested were found in cabbage, Alpha-Cypermethrin, Bassa-Fenobucarb and Dimethoate with levels of 0.175, 0.074 and 0.028 mg/kg fresh cabbage respectively. Weight of livers from goats fed cabbage was about 90 g higher than from goats fed Para grass but no pesticide/herbicide residues were found in meat or liver.