Institute of Animal Science, Beef Cattle Research Center, Sertãozinho, SP, Brazil.
São Paulo State University (Unesp), School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil.
PLoS One. 2021 Oct 14;16(10):e0257964. doi: 10.1371/journal.pone.0257964. eCollection 2021.
Enteric methane (CH4) emissions are a natural process in ruminants and can result in up to 12% of energy losses. Hence, decreasing enteric CH4 production constitutes an important step towards improving the feed efficiency of Brazilian cattle herds. The aim of this study was to evaluate the relationship between performance, residual feed intake (RFI), and enteric CH4 emission in growing Nellore cattle (Bos indicus). Performance, RFI and CH4 emission data were obtained from 489 animals participating in selection programs (mid-test age and body weight: 414±159 days and 356±135 kg, respectively) that were evaluated in 12 performance tests carried out in individual pens (n = 95) or collective paddocks (n = 394) equipped with electronic feed bunks. The sulfur hexafluoride tracer gas technique was used to measure daily CH4 emissions. The following variables were estimated: CH4 emission rate (g/day), residual methane emission and emission expressed per mid-test body weight, metabolic body weight, dry matter intake (CH4/DMI), average daily gain, and ingested gross energy (CH4/GE). Animals classified as negative RFI (RFI<0), i.e., more efficient animals, consumed less dry matter (P <0.0001) and emitted less g CH4/day (P = 0.0022) than positive RFI animals (RFI>0). Nonetheless, more efficient animals emitted more CH4/DMI and CH4/GE (P < 0.0001), suggesting that the difference in daily intake between animals is a determinant factor for the difference in daily enteric CH4 emissions. In addition, animals classified as negative RFI emitted less CH4 per kg mid-test weight and metabolic weight (P = 0.0096 and P = 0.0033, respectively), i.e., most efficient animals could emit less CH4 per kg of carcass. In conclusion, more efficient animals produced less methane when expressed as g/day and per kg mid-test weight than less efficient animals, suggesting lower emissions per kg of carcass produced. However, it is not possible to state that feed efficiency has a direct effect on enteric CH4 emissions since emissions per kg of consumed dry matter and the percentage of gross energy lost as CH4 are higher for more efficient animals.
肠道甲烷(CH4)排放是反刍动物的一种自然过程,可导致高达 12%的能量损失。因此,减少肠道 CH4 产生是提高巴西牛群饲料效率的重要步骤。本研究旨在评估生长型内罗尔牛(Bos indicus)的性能、剩余饲料摄入量(RFI)和肠道 CH4 排放之间的关系。从参与选择计划的 489 只动物(中试年龄和体重分别为 414±159 天和 356±135 千克)中获得了性能、RFI 和 CH4 排放数据,这些动物在 12 个个体围栏(n = 95)或集体围场(n = 394)中进行了评估,这些围场配备了电子饲料槽。使用六氟化硫示踪气体技术测量每日 CH4 排放量。估计了以下变量:CH4 排放率(g/天)、残留甲烷排放量和代谢体重、干物质摄入量(CH4/DMI)、平均日增重和摄入总能(CH4/GE)每中试体重的排放量。被归类为负 RFI(RFI<0)的动物,即更有效的动物,消耗的干物质较少(P <0.0001),每天排放的 CH4 量较少(P = 0.0022)比正 RFI 动物(RFI>0)。然而,更有效的动物排放更多的 CH4/DMI 和 CH4/GE(P <0.0001),表明动物之间的每日摄入量差异是每日肠道 CH4 排放量差异的决定因素。此外,被归类为负 RFI 的动物每公斤中试体重和代谢体重排放的 CH4 较少(P = 0.0096 和 P = 0.0033),即效率最高的动物每公斤胴体排放的 CH4 较少。总之,与效率较低的动物相比,效率较高的动物每天和每公斤中试体重产生的甲烷较少,表明每公斤胴体产生的甲烷排放量较低。然而,不能说饲料效率对肠道 CH4 排放有直接影响,因为对于更有效的动物,每消耗的干物质和作为 CH4 损失的总能的比例更高。