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).
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 CH4emission. 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 CH4emissions 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 CH4emissions expressed as g/kg digested DMI and OMI were not affected by the F:C ratio. Eight equations were derived for predicting the enteric CH4emission 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).


CONCLUSIONS
Digested nutrient intake could be considered when determining the CH4generation factor in goats and Sika deer. Finally, the enteric CH4prediction model for goats and Sika deer were estimated.
Department of Animal Science and Technology, Konkuk University, Seoul 05029, Korea.
Youngjun
Y
Na
Department of Animal Science and Technology, Konkuk University, Seoul 05029, Korea.
Dong Hua
DH
Li
Department of Animal Science and Technology, Konkuk University, Seoul 05029, Korea.
Sang Rak
SR
Lee
Capra hircus hircus; Cervus nippon hortulorum; Forage-to-concentrate Ratio; Greenhouse Gas; Methane