Fattening Cattle with Sugar Cane: Effect of Supplementation with Final Molasses

Two growth trials are reported. In the first (of 141 days) , 42 bulls of initially about 220 kg and 2 years of age were given: (A) chopped whole sugar cane ad libitum plus 300 g/d extracted soya bean meal; (B), © and (D) as (A), but with 100, 200 or 300 g molasses/urea (2.5%) per kg fresh cape mixed into the cane; (E) as (D) , but with 600 g soya/d; (F) , chopped whole cane plus 1 kg/d wheat bran; or (G), as (F) plus 150 g soya/d. All animals received 9 g urea and 2.5 g ammonium sulphate/kg fresh cane. Two pens of three animals were allocated to each treatment. Growth rates and cane intakes were (± SEx): 61, 172, 190, 239, 122 148, 166 ± 39 g/d and 3.2, 3.2, 3.6, 3.3, 3.2, 3.4 and 3.6 ± 0.15kg DM/d for treatments (A; to (G) respectively. Molasses intakes were 0.9, 1.8, 2.6 and 2.6 kg DM/d for treatments (B) to (E) respectively. The growth response to the additional molasses was thus very poor and this was not rectified by additional protein (E). The response to wheat bran (F) and (G) was also poor (less than half that expected). In the second experiment (of 135 days), 24 bulls of initially about 170 kg and 2 years old were given chopped whole sugar cane plus 300 g/d soya (plus minerals, urea and ammonium sulphate as above) and molasses/urea (5%) in separate feeders (H) or mixed into the cane (I), or molasses/urea (10%) in separate feeders (J) or mixed into the cane (R) . The amount of molasses mixed into the cane was defined by the voluntary intake when given separately. Two pens of 3 animals were allocated to each treatment. Growth rates and food intakes (± SEx) were: 457, 446, 475 and 554 ± 42 g/d, 2.3, 2.7, 3.1 and 3.3 ± 0.12 kg cane DM/d; and 1.2, 1.6, 0.8 and 0.9 ± 0.03 kg molasses DM/d for treatments (H) to (K) respectively. Differences in growth rates or total DMI were not significant although at the higher level of urea, the animals eat less molasses (P 0.003) , and more cane (P 0.007) . It is concluded that the method of presenting the molasses (mixed or separate) was not important, and that the partition of the voluntary consumption of cane and molasses/urea can be trolled by varying the urea content of the molasses. No explanation can be offered for the very poor responses in Expt One, although it is suggested that the reason may be due to inefficiencies within the animal|microbial complex of the ruminant.