Reintke Jessica, Brügemann Kerstin, Yin Tong, Engel Petra, Wagner Henrik, Wehrend Axel, König Sven
Institute of Animal Breeding and Pet Genetics, University of Giessen, 35390 Giessen, Germany.
Clinic for Obstetrics, Gynaecology and Andrology of Large and Small Animals with Veterinary Ambulance, University of Giessen, 35392 Giessen, Germany.
Arch Anim Breed. 2020 Apr 16;63(1):113-123. doi: 10.5194/aab-63-113-2020. eCollection 2020.
The aim of the present study was to derive individual methane ( ) emissions in ewes separated in respiration and eructation traits. The generated longitudinal data structure was used to estimate phenotypic and genetic relationships between ewe records and energy efficiency indicator traits from same ewes as well as from their lambs (intergenerational perspective). In this regard, we recorded emissions via mobile laser methane detector (LMD) technique, body weight (EBW), backfat thickness (BFT) and body condition score (BCS) from 330 ewes (253 Merinoland (ML), 77 Rhön sheep (RH)) and their 629 lambs (478 ML, 151 RH). The interval between repeated measurements (for ewe traits and lamb body weight (LBW)) was 3 weeks during lactation. For methane concentration ( L L ) determinations in the exhaled air, we considered short time measurements (3 min). Afterwards, emissions were portioned into a respiration and eructation fraction, based on a double normal distribution. Data preparation enabled the following trait definitions: mean concentration during respiration and eructation ( ), mean concentration during respiration ( ), mean concentration during eructation ( ), sum of concentrations per minute during respiration ( ), sum of concentrations per minute during eructation ( ), maximal concentration during respiration ( ), maximal concentration during eructation ( ), and eructation events per minute ( ). Large levels of ewe emissions representing energy losses were significantly associated with lower LBW ( ), lower EBW ( ) and lower BFT ( ). For genetic parameter estimations, we applied single- and multiple-trait animal models. Heritabilities and additive genetic variances for traits were small, i.e., heritabilities in the range from <0.01 ( , , , ) to 0.03 ( ). We estimated negative genetic correlations between traits and EBW in the range from 0.44 ( ) to 0.05 ( ). Most of the traits were genetically negatively correlated with BCS ( 0.81 for ) and with BFT ( 0.72 for ), indicating same genetic mechanisms for output and energy efficiency indicators. Addressing the intergenerational aspect, genetic correlations between emissions from ewes and LBW ranged between 0.35 ( ) and 0.01 ( , ), indicating that breeding on reduced emissions (especially eructation traits) contribute to genetic improvements in lamb weaning performance.
本研究的目的是得出根据呼吸和嗳气特征区分的母羊个体甲烷（ ）排放量。所生成的纵向数据结构用于估计母羊记录与来自同一母羊及其羔羊（代际视角）的能量效率指标性状之间的表型和遗传关系。在这方面，我们通过移动激光甲烷探测器（LMD）技术记录了330只母羊（253只美利奴兰德羊（ML），77只罗恩羊（RH））及其629只羔羊（478只ML，151只RH）的 排放量、体重（EBW）、背膘厚度（BFT）和体况评分（BCS）。泌乳期间重复测量（针对母羊性状和羔羊体重（LBW））的间隔为3周。对于呼出气体中甲烷浓度（ L L ）的测定，我们采用短时间测量（3分钟）。之后，基于双正态分布将 排放量分为呼吸部分和嗳气部分。数据处理得出了以下性状定义：呼吸和嗳气期间的平均 浓度（ ）、呼吸期间的平均 浓度（ ）、嗳气期间的平均 浓度（ ）、呼吸期间每分钟 浓度总和（ ）、嗳气期间每分钟 浓度总和（ ）、呼吸期间的最大 浓度（ ）、嗳气期间的最大 浓度（ ）以及每分钟嗳气次数（ ）。代表能量损失的母羊 排放量的高水平与较低的LBW（ ）、较低的EBW（ ）和较低的BFT（ ）显著相关。对于遗传参数估计，我们应用了单性状和多性状动物模型。 性状的遗传力和加性遗传方差较小，即遗传力范围从<0.01（ 、 、 、 ）到0.03（ ）。我们估计 性状与EBW之间的遗传相关性在 -0.44（ ）到 -0.05（ ）之间。大多数 性状与BCS（ 为 -0.81）和BFT（ 为 -0.72）呈遗传负相关，表明 排放和能量效率指标具有相同的遗传机制。从代际角度来看，母羊 排放量与LBW之间的遗传相关性在 -0.35（ ）到0.01（ 、 ）之间，这表明针对减少 排放（尤其是嗳气性状）进行选育有助于羔羊断奶性能的遗传改良。
