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)

Abstract

ObjectiveTwo 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.MethodsThree 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.ResultsDry 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).ConclusionDigested 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.

Intake, digestibility, growth performance, and enteric methane emission of Brazilian semiarid non-descript breed goats fed diets with different forage to concentrate ratios

“…This is especially true where concentrates have high starch contents. Though there remain apparent inconsistencies for goats, as witness the comparison between our results and those of Lima et al (2016) and Na et al (2017). As data have accumulated on this topic, opportunities should be taken to exploit the variation in differences among feed qualities that have been used in different experiments to interrogate cognate datasets together so as to tease out dietary variables that have major impact.…”

“…However, there were no reductions in methane emissions from goats in response to decreased forage:concentrate ratio in two recent studies, in which a corn and soybean meal-based concentrate was used (Lima et al 2016;Na et al 2017). These conflicting results could be due to differences in forage quality between studies.…”

“…Low forage:concentrate ratio in ruminant diets has been one efficient strategy to reduce enteric methane emission (Kumar et al 2013;Granja-Salcedo et al 2016;Na et al 2017). Changes in the proportion of short-chain fatty acids are reported to be one of the main mechanisms explaining this effect because the fermentation of starch-rich concentrate and soluble sugars produces a higher proportion of propionate compared to the fermentation of fiber-rich forage, which in turn produces greater proportion of acetate (Knapp et al 2014).…”

“…The use of diets with low forage:concentrate ratio is one of the major management strategies to reduce enteric methane emissions from ruminants through changes in ruminal fermentation (Hristov et al 2013). Despite this, few studies have been conducted to evaluate the effect of different forage:concentrate ratios on enteric methane emissions in goats (Lima et al 2016;Na et al 2017).…”

Effects of feeding level on nutrient digestibility and enteric methane production in growing goats (<i >Capra hircus hircus) and Sika deer (Cervus nippon hortulorum)

“…Although a large number of goats and Sika deer inhabit East Asia [ 2 ], few studies have estimated enteric CH 4 production of goats and Sika deer. Enteric CH 4 production by ruminants is generally influenced by various dietary factors such as the forage-to-concentrate ratio [ 3 ], carbohydrate type [ 2 , 4 ], forage processing [ 5 ], fat addition [ 6 ], and ionophore addition [ 7 ]. Fundamentally, because enteric methane production is a part of the energy utilization process of ruminants, the amount of feed intake has been suggested as the major factor driving enteric CH 4 production.…”