Bell M J, Potterton S L, Craigon J, Saunders N, Wilcox R H, Hunter M, Goodman J R, Garnsworthy P C
School of Biosciences,The University of Nottingham,Sutton Bonington Campus,Loughborough LE12 5RD,UK.
Animal. 2014 Sep;8(9):1540-6. doi: 10.1017/S1751731114001530. Epub 2014 Jun 19.
Methane (CH4) emissions by dairy cows vary with feed intake and diet composition. Even when fed on the same diet at the same intake, however, variation between cows in CH4 emissions can be substantial. The extent of variation in CH4 emissions among dairy cows on commercial farms is unknown, but developments in methodology now permit quantification of CH4 emissions by individual cows under commercial conditions. The aim of this research was to assess variation among cows in emissions of eructed CH4 during milking on commercial dairy farms. Enteric CH4 emissions from 1964 individual cows across 21 farms were measured for at least 7 days/cow using CH4 analysers at robotic milking stations. Cows were predominantly of Holstein Friesian breed and remained on the same feeding systems during sampling. Effects of explanatory variables on average CH4 emissions per individual cow were assessed by fitting a linear mixed model. Significant effects were found for week of lactation, daily milk yield and farm. The effect of milk yield on CH4 emissions varied among farms. Considerable variation in CH4 emissions was observed among cows after adjusting for fixed and random effects, with the CV ranging from 22% to 67% within farms. This study confirms that enteric CH4 emissions vary among cows on commercial farms, suggesting that there is considerable scope for selecting individual cows and management systems with reduced emissions.
奶牛的甲烷（CH₄）排放量会因采食量和日粮组成而有所不同。然而，即使在相同采食量下饲喂相同日粮，不同奶牛之间的CH₄排放量差异也可能很大。商业农场中奶牛CH₄排放量的变化程度尚不清楚，但目前方法学的发展使得在商业条件下能够对个体奶牛的CH₄排放量进行量化。本研究的目的是评估商业奶牛场挤奶期间反刍CH₄排放的个体差异。在21个农场中，使用机器人挤奶站的CH₄分析仪对1964头个体奶牛的肠道CH₄排放量进行了至少7天/头的测量。奶牛主要为荷斯坦-弗里生品种，在采样期间保持相同的饲养系统。通过拟合线性混合模型评估解释变量对每头个体奶牛平均CH₄排放量的影响。发现泌乳周、日产奶量和农场存在显著影响。产奶量对CH₄排放的影响因农场而异。在调整固定效应和随机效应后，观察到奶牛之间的CH₄排放量存在相当大的差异，各农场内的变异系数范围为22%至67%。本研究证实，商业农场中奶牛的肠道CH₄排放量存在个体差异，这表明在选择个体奶牛和减排管理系统方面有很大空间。
