Effects of dietary forage-to-concentrate ratio on nutrient digestibility and enteric methane production in growing goats (Capra hircus hircus) and Sika deer (Cervus nippon hortulorum)

Asian-Australas J Anim Sci. 2017 Jul;30(7):967-972. doi: 10.5713/ajas.16.0954. Epub 2017 Mar 21. Na Y1, Li DH1, Lee SR1. Author information 1 Department of Animal Science and Technology, Konkuk University, Seoul 05029, Korea. Abstract OBJECTIVE: Two experiments were conducted to determine the effects of forage-to-concentrate (F:C) ratio on the nutrient digestibility and enteric methane (CH4) emission in growing goats and Sika deer. METHODS: Three male growing goats (body weight [BW] = 19.0±0.7 kg) and three male growing deer (BW = 19.3±1.2 kg) were respectively allotted to a 3×3 Latin square design with an adaptation period of 7 d and a data collection period of 3 d. Respiration-metabolism chambers were used for measuring the enteric CH4 emission. Treatments of low (25:75), moderate (50:50), and high (73:27) F:C ratios were given to both goats and Sika deer. RESULTS: Dry matter (DM) and organic matter (OM) digestibility decreased linearly with increasing F:C ratio in both goats and Sika deer. In both goats and Sika deer, the CH4 emissions expressed as g/d, g/kg BW0.75, % of gross energy intake, g/kg DM intake (DMI), and g/kg OM intake (OMI) decreased linearly as the F:C ratio increased, however, the CH4 emissions expressed as g/kg digested DMI and OMI were not affected by the F:C ratio. Eight equations were derived for predicting the enteric CH4 emission from goats and Sika deer. For goat, equation 1 was found to be of the highest accuracy: CH4 (g/d) = 3.36+4.71×DMI (kg/d)-0.0036×neutral detergent fiber concentrate (NDFC, g/kg)+0.01563×dry matter digestibility (DMD, g/kg)-0.0108×neutral detergent fiber digestibility (NDFD, g/kg). For Sika deer, equation 5 was found to be of the highest accuracy: CH4 (g/d) = 66.3+27.7×DMI (kg/d)-5.91×NDFC (g/kg)-7.11× DMD (g/kg)+0.0809×NDFD (g/kg). CONCLUSION: Digested nutrient intake could be considered when determining the CH4 generation factor in goats and Sika deer. Finally, the enteric CH4 prediction model for goats and Sika deer were estimated. KEYWORDS: Capra hircus hircus; Cervus nippon hortulorum; Forage-to-concentrate Ratio; Greenhouse Gas; Methane PMID: 28335097 PMCID: PMC5495675 DOI: 10.5713/ajas.16.0954 Free PMC Article