Journal of Integrative Agriculture ›› 2025, Vol. 24 ›› Issue (4): 1234-1245.DOI: 10.1016/j.jia.2024.12.037

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放牧率对典型草原滩羊生长性能、能量与氮利用效率、甲烷排放以及放牧行为的影响

  

  • 收稿日期:2023-09-25 接受日期:2024-11-29 出版日期:2025-04-20 发布日期:2025-03-14

Effects of stocking rate on growth performance, energy and nitrogen utilization, methane emission, and grazing behavior in Tan sheep grazed on typical steppe

Hairen Shi, Pei Guo, Jieyan Zhou, Zhen Wang, Meiyue He, Liyuan Shi, Xiaojuan Huang, Penghui Guo,  Zhaoxia Guo, Yuwen Zhang, Fujiang Hou#   

  1. State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems/Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs/Engineering Technology Research Center for Ecological Restoration and Utilization of Degraded Grassland in Northwest China, National Forestry and Grassland Administration/College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China

  • Received:2023-09-25 Accepted:2024-11-29 Online:2025-04-20 Published:2025-03-14
  • About author:Hairen Shi, Tel: +86-931-8913047, E-mail: shihr21@lzu.edu.cn; #Correspondence Fujiang Hou, Tel: +86-931-8913047, E-mail: cyhoufj@lzu.edu.cn
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (32161143028), the Key Technology of Grassland Ecological Civilization Demonstration Area in Ningxia Hui Autonomous Region, China (20210239), and the Northwest Shelterbelt Construction Bureau of the National Forestry and Grassland Administration, China.

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摘要：

背景和目的：放牧是一种投资少、收益高的草地经营模式。但是，与单胃动物相比，反刍动物是低生产效率高CH4排放的代表，其排放量约占人为活动CH4排放总量的30%~32%，造成显著的能量损失。优化放牧管理对提升反刍牲畜饲料转化率，缓解动物CH4排放具有较大的潜力和空间。因此，本研究旨在评估不同放牧率对滩羊生长性能、能量与氮利用效率、甲烷排放以及放牧行为的影响。方法：为期两年（2018-2019）的放牧试验在一个长期轮牧系统中开展，该放牧系统从2001年开始，每年6月上旬至9月上旬夏季放牧。放牧地共有9个放牧小区，每个面积为100 m×50 m，每个小区分配4只、8只和13只滩羊（6月龄，平均体重：23.15±1.32 kg），每个处理设3个空间重复，得出放牧率分别为2.7、5.3和8.7羊/公顷。结果：不同放牧年份牧草中性洗涤纤维和酸性洗涤纤维的含量存在差异（P<0.05），放牧率与牧草粗纤维含量呈正相关（P<0.05）；随着放牧率增加，滩羊干物质采食量下降（P<0.05），2.7羊/公顷平均日增重最高（P<0.05）；与2.7和8.7羊/公顷相比，5.3羊/公顷干物质消化率最低（P<0.05）；8.7羊/公顷时粪氮处于最低水平（P<0.05），而沉积氮/总氮在8.7羊/公顷时最高；当8.7羊/公顷时，消化能、代谢能、及消化能/总能和代谢能/总能最高（P<0.05），而甲烷排放量、甲烷/干物质采食量和甲烷能/总能在2.7羊/公顷最高（P<0.05）；年份对放牧行为影响不显著，随着放牧率增加，行走时间和反刍/休息分配时间均下降，而放牧时间与放牧率呈负相关。结论：增加放牧率可能使动物选择性采食策略改变，迫使它们采食不喜食牧草以满足其能量需求。虽然导致滩羊干物质采食量下降，但消化率提高，最终减少了氮排泄和CH4排放。创新性：提出根据牧草营养价值和组成重新评估和调整放牧率，以优化动物生产性能以及甲烷减排途径。

Abstract:

Understanding livestock performance in typical steppe ecosystems is essential for optimizing grassland-livestock interactions and minimizing environmental impact.  To assess the effects of different stocking rates on the growth performance, energy and nitrogen utilization, methane (CH4) emissions, and grazing behavior of Tan sheep, a 2-year grazing experiment in the typical steppe was conducted.  The grazing area was divided into 9 paddocks, each 0.5 ha, with 3 spatial replicates for each stocking rate treatment (4, 8, and 13 sheep per paddock), corresponding to 2.7, 5.3, and 8.7 sheep ha–1.  The results showed that the neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents of herbage varied between grazing years (P<0.05), with a positive correlation between stocking rate and crude fiber content in the herbage (P<0.05).  Dry matter intake (DMI) decreased with increasing stocking rate (P<0.05), and the average daily gain (ADG) was highest at 2.7 sheep ha–1 (P<0.05).  Compared to 2.7 and 8.7 sheep ha–1, the 5.3 sheep ha–1 treatment exhibited the lowest nutrient digestibility for dry matter, nitrogen, and ether extract (P<0.05).  Fecal nitrogen was lowest at 8.7 sheep ha–1 (P<0.05), while retained nitrogen as a proportion of nitrogen intake was highest.  Digestive energy (DE), metabolic energy (ME), and the ratios of DE to gross energy (GE) and ME to GE were highest at 8.7 sheep ha–1 (P<0.05).  In contrast, CH4 emissions, CH4 per DMI, and CH4E as a proportion of GE were highest at 2.7 sheep ha–1 (P<0.05).  Stocking rate and grazing year did not significantly affect rumen fermentation parameters, including volatile fatty acids, acetate, propionate, and the acetate/propionate ratio.  At 8.7 sheep ha–1, daily grazing time and inter-individual distance increased, while time allocated to grazing, walking, and ruminating/resting decreased as stocking rates increased (P<0.05).  This study highlights the importance of adjusting stocking rates based on the nutritional value of forage and grazing year to optimize grazing management. 


Key words: stocking rate , methane emissions , energy and nitrogen utilization ,  grazing behavior