BACKGROUND: Feeding of high glucosinolate rapeseed–mustard cakes (RMCs) imparts adverse effects on dry matter (DM) intake, health and overall performance of animals. Recently, plant breeding efforts have resulted in many cultivars of RMCs containing low to moderate levels of glucosinolate in India. The feeding value of RMC cultivars with high and low glucosinolate was evaluated relative to commonly used soybean meal as a protein supplement in growing crossbred calves.
RESULTS: Eighteen growing crossbred calves (62.9 ± 3.8 kg body weight) were randomly allocated to three dietary treatments SBM, LG and HG containing soybean meal, low glucosinolate B. napus (15 µmol glucosinolates g−1) and high glucosinolate B. juncea (135 µmol glucosinolates g−1), respectively. Although daily intake of total DM and wheat straw did not differ (P > 0.05) among the dietary treatments, intake (g/kgW0.75) of concentrate moiety decreased quadratically (P < 0.01) with increasing glucosinolate levels in diets. Nutrient digestibility and balances of N, Ca and P by calves were similar (P > 0.05) among dietary treatments. However, average daily gain (g) decreased and feed conversion ratio values increased quadratically (P < 0.05) with increasing glucosinolate levels. Serum metabolic profile and triiodothyronine remained within the normal range; however, thyroxine changed quadratically.
CONCLUSION: The results suggested that while high glucosinolate RMCs may reduce the palatability and consequently growth rate in crossbred calves, SBM can be replaced completely by low glucosinolate rapeseed without compromising their performance. Copyright © 2008 Society of Chemical Industry