Background:This study investigated greenhouse gas (GHG) emission characteristics of lactating Holstein dairy cows in East China and provided a basis for formulating GHG emission reduction measures. GreenFeed system was used to measure the amount of methane (CH4) and carbon dioxide (CO2) emitted by the cows through respiration. Data from a commercial cow farm were used to observe the effects of parity, body weight, milk yield, and milk component yield on CH4 and CO2 emissions. Results:Mean herd responses throughout the study were as follows:111 cows completed all experimental processes, while 42 cows were rejected because they were sick or had not visited the GreenFeed system 20 times. On average, lactating days of cows was 138 ± 19.04 d, metabolic weight was 136.5 ± 9.5 kg, parity was 2.8 ± 1.0, dry matter intake (DMI) was 23.1 ± 2.6 kg/d, and milk yield was 38.1 ± 6.9 kg/d. The GreenFeed system revealed that CH4 production (expressed in CO2 equivalent, CO2-eq) was found to be 8304 g/d, CH4eCO2?eqT/DMI was 359 g/kg, CH4eCO2?eqT/energy-corrected milk (ECM) was 229.5 g/kg, total CO2 production (CH4 production plus CO2 production) was 19,201 g/d, total CO2/DMI was 831 g/kg, and total CO2/ECM was 531 g/kg. The parity and metabolic weight of cows had no significant effect on total CO2 emissions (P>0.05). Cows with high milk yield, milk fat yield, milk protein yield, and total milk solids yield produced more total CO2 (P<0.05), but their total CO2 production per kg of ECM was low (P<0.05). The total CO2/ECM of the medium and high milk yield groups was 17％and 27％lower than that of the low milk yield group, respectively. Conclusions:The parity and body condition had no effect on total CO2 emissions, while the total CO2/ECM was negatively correlated with milk yield, milk fat yield, milk protein yield, and total milk solids yield in lactating Holstein dairy cows. Measurement of total CO2 emissions of dairy cows in the Chinese production system will help establish regional or national GHG inventories and develop mitigation approaches to dairy production regimes.

Peng Jia;Yan Tu;Zhihao Liu;Qi Lai;Fadi Li;Lifeng Dong;Qiyu Diao

State Key Laboratory of Grassland Agro-ecosystems,Key Laboratory of Grassland Livestock Industry Innovation,Ministry of Agriculture and Rural Affairs,Engineering Research Center of Grassland Industry,Ministry of Education,College of Pastoral Agriculture Science and Technology,Lanzhou University,Lanzhou 730020,People's Republic of China;Institute of Feed Research,Chinese Academy of Agricultural Sciences/Sino-US Joint Lab on Nutrition and Metabolism of Ruminant,Beijing 100081,People's Republic of China;College of Animal Science and Technology,Henan University of Science and Technology,Luoyang 471003,People's Republic of China;College of Animal and Veterinary Sciences,Southwest Minzu University, Chengdu 610041,People's Republic of China

畜牧与生物技术杂志（英文版）

[1]Peng Jia;Yan Tu;Zhihao Liu;Qi Lai;Fadi Li;Lifeng Dong;Qiyu Diao-.Characterization and mitigation option of greenhouse gas emissions from lactating Holstein dairy cows in East China)[J].畜牧与生物技术杂志（英文版）,2022(06):1959-1972

GreenFeed,CH4eCO2,eqT,Cows

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