Submitted to: Animal Feed Science And Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/4/2009
Publication Date: 6/27/2009
Publication URL: http://hdl.handle.net/10113/34924
Citation: Pina, D.S., Tedeschi, L.O., Filho, S., Azevedo, J., Detmann, E., Anderson, R.C. 2009. Influence of calcium oxide level and time of exposure to sugarcane on in vitro and in situ digestion kinetics. Animal Feed Science and Technology. 153:101-112. Interpretive Summary: Sugarcane is an important alternative roughage source for cattle, sheep, and goats under some feeding conditions. However, sugarcane contains a high amount of digestion-resistant fiber, and its slow digestibility can sometimes limit the amount of feed an animal can eat. The present set of experiments was carried out to see if an alkali treatment of the sugarcane would make its fiber component more digestible for the animal. Results showed that treatment of sugarcane with 0.5% or 1.0% of the alkali treatment calcium oxide for 24, 48, or 72 h positively affected the digestibility of some of the hard to digest components of sugarcane but had no effect on most of the easy to digest components. These results indicate that calcium oxide treatment makes sugarcane a better feedstuff for cattle, sheep, and goats. Ultimately, this research may allow farmers with access to this feedstuff to produce high quality meat at less cost for the American consumer.
Technical Abstract: Experiments were carried out to evaluate, using in vitro and in situ techniques, the effects of three inclusion levels of calcium oxide (0, 5, and 10 g/kg of sugarcane fresh matter) and four exposure times (0, 24, 48, and 72 h) of sugarcane to calcium oxide on the chemical composition and digestive kinetic parameters of sugarcane. The treatments were arranged in a 3 by 4 factorial design. Freshly-cut sugarcane (whole plant) was treated with calcium oxide and separated into 12 piles inside a barn to prevent direct exposure to sunlight, rain, and wind. Every day, before and after animal feeding, the calcium oxide was proportionally hand-mixed with approximately 150 kg of freshly-cut sugarcane to make up the dietary treatments. The lowest (Ti) and greatest (Ts) temperature and pH of the treated sugarcane piles were measured immediately before and after sampling, respectively. The ether extract (EE) and DM were not affected (P>0.05) by either exposure time or inclusion level. However, CP increased linearly (P=0.01) and OM decreased linearly (P<0.0001) as the exposure time and calcium oxide inclusion level increased. Interactions between inclusion level and exposure time on DM, OM, CP, EE, Ti, and Ts were not observed. However, significant interactions were detected for non-fiber carbohydrate (NFC), neutral detergent fiber (aNDF), and pH. A quadratic effect of exposure time on the Ti and Ts was observed (P=0.001 and P=0.001, respectively). The maximum temperature was reached with approximately 51 h of exposure time. Calcium oxide positively affected the insoluble, potentially digestible fraction of sugarcane DM and aNDF (P=0.001 and P=0.001, respectively) and the indigestible fraction of sugarcane aNDF (P=0.001). Interactions between inclusion level and exposure time on soluble and indigestible fractions of sugarcane DM (P=0.0001 and P=0.01, respectively) were found. However, no interactions (P>0.27) were found between inclusion level and exposure time on aNDF digestive kinetic parameters. The fractional digestion rate (kd) of sugarcane DM and aNDF was not influenced by treatments (P>0.05). The mean values of kd for sugarcane DM and aNDF were 0.0235 and 0.0215/h, respectively. The gas production kinetics parameters were not affected (P>0.05) by treatments. In conclusion, the inclusion of calcium oxide improved the in situ potentially digestible fraction of sugarcane DM and aNDF; however, it did not influence the fractional digestion rate. No effects were observed on the in vitro digestive kinetic parameters.