| Abstract
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Two feeding trials involving 32 cattle and 32 buffaloes or 137 to 149 kg body weight (BW) and 103 to 150 kg BW, respectively were conducted over a period of 14 months in Malaysia. In the first trial, maintenance requirements and efficiencies of energy use for tissue storage in Kedah-Kelantan (KK) cattle (Bos indicus) and swamp buffalo (SB) (Bubalus bubalis) were measured in a double 4 x 4 latin square trial, replicated four times for each species. The animals were fed on palm kernel cake at maintenance (M), 1.4M, 1.8M and ad libitum intakes. Retained energy (RE) was estimated for each animal from the difference between initial and final body fat and protein compositions for each period using the tritiated water dilution procedure. Energy maintenance requirement for KK (335 kJ ME kg BW) was (p < 0.05) than that for SB (313 kJ ME kgBW). Efficiencies for maintenance and RE for KK (0.64 and 0.30, respectively) were higher (p < 0.05) than for SB (0.48 and 0.25, respectively). Microbial N yield per kg digestible DM intake, predicted using urinary allantoin excretion for KK (18.4 g) was higher (p < 0.01) than for SB (10.4 g), but net N depositions were not significantly different between the two species. The second trial examined differences between two breeds of cattle (KK and Sahiwal x Friesian crossbred, SF) and two breeds of buffalo (SB and Murrah buffalo, MB) fed at 700 kJ ME kg BW and ad libitum intake levels. Efficiency for RE was higher (p < 0.05) for beef breeds (averaged 0.20) than for dairy breeds (averaged 0.17). Ad libitum food intake (kJ ME kg BW per day) was highest for SF (905), followed by MB and KK (averaged 850) and SB (701). The Maximal RE for the corresponding intakes were 141, 115, 135 and 118 kJ kg BW per day. However, RE (kJ kg BW per day) at a standardised intake level of 700 kJ ME kg BW per day was highest for SB (118), followed by SF (105), KK (102) and MB (89).
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