Vargas Juan de J, Swenson Maya, Gomez-Salmoral Macarena, Garcia Liza, Paula Eduardo M, Sitorski Leo G, Campos Leticia M, Carvalho Pedro H V, Stackhouse-Lawson K R, DiLorenzo Nicolas, Place Sara E
AgNext, Department of Animal Sciences, Colorado State University, Fort Collins, CO 80523, USA.
North Florida Research and Education Center, University of Florida, Marianna, FL 32446, USA.
Transl Anim Sci. 2025 Aug 20;9:txaf111. doi: 10.1093/tas/txaf111. eCollection 2025.
Dry matter intake () estimation in ruminants is important for providing a balanced diet, increasing animal performance, and reducing nutrient excretion. Gas flux ( and production) is related to DMI; however, there is limited information regarding the use of gas flux production when estimating DMI in growing steers. This study aimed to 1) determine the relationship of animal growth performance and gas flux variables with DMI of growing steers fed a backgrounding diet, and 2) evaluate the DMI accuracy of eight equations to predict DMI from growing steers fed a forage-based diet. The relationship between DMI, animal growth performance, and gas flux variables was evaluated in 130 backgrounding steers, and two equations were generated to predict DMI. Then, six retrieved equations from the literature and the two new equations were used to determine the prediction accuracy using an independent dataset. Models were compared based on the mean square prediction error (), the decomposition of the root MSPE (), and the concordance correlation coefficient (). In backgrounding steers, DMI had a positive and significant relationship (0.01) with shrunk body weight (), average daily gain, and CO and CH production. The production of CO and CH independently explained 48.1% and 40.9% of the observed DMI in growing steers, respectively. One equation retrieved from the literature had an excellent agreement with the observed DMI, with a CCC value of 0.93 and an RMSPE of 0.19 kg/d, representing 2.5% of the average DMI. That equation used SBW and dietary energy concentration. The use of CO production had adequate agreement with the observed DMI, with a CCC value of 0.73 and an RMSPE of 0.45 kg/d, representing 6% of the average DMI. Other equations had null to moderate agreement with the observed DMI, with CCC values ranging from 0.00 to 0.47 and an RMSPE from 0.51 to 4.40 kg/d. In conclusion, there is a positive relationship between DMI, animal growth performance, and gas flux in growing steers fed a backgrounding diet. In addition, CO production has the potential to be used to predict DMI in growing steers fed a forage-based diet. Future research is required to evaluate the relationship between CO production and DMI, especially under grazing conditions.
反刍动物干物质摄入量（）的估测对于提供均衡日粮、提高动物生产性能以及减少养分排泄至关重要。气体通量（和生成量）与干物质摄入量相关；然而，在估测生长阉牛的干物质摄入量时，关于气体通量生成量应用的信息有限。本研究旨在：1）确定采食育成前期日粮的生长阉牛的生长性能和气体通量变量与干物质摄入量之间的关系；2）评估八个方程从采食牧草型日粮的生长阉牛预测干物质摄入量的准确性。在130头育成前期阉牛中评估了干物质摄入量、动物生长性能和气体通量变量之间的关系，并生成了两个预测干物质摄入量的方程。然后，使用文献中检索到的六个方程和两个新方程，利用一个独立数据集来确定预测准确性。基于均方预测误差（）、根均方预测误差（）的分解以及一致性相关系数（）对模型进行比较。在育成前期阉牛中，干物质摄入量与体缩体重（）、平均日增重以及二氧化碳和甲烷生成量呈显著正相关（0.01）。二氧化碳和甲烷的生成量分别独立解释了生长阉牛中观察到的干物质摄入量的48.1%和40.9%。从文献中检索到的一个方程与观察到的干物质摄入量具有极好的一致性，一致性相关系数值为0.93，均方根预测误差为0.19 kg/d，占平均干物质摄入量的2.5%。该方程使用了体缩体重和日粮能量浓度。二氧化碳生成量的应用与观察到的干物质摄入量有适当的一致性，一致性相关系数值为0.73，均方根预测误差为0.45 kg/d，占平均干物质摄入量的6%。其他方程与观察到的干物质摄入量的一致性从无到中等，一致性相关系数值范围为0.00至0.47，均方根预测误差为0.51至4.40 kg/d。总之，采食育成前期日粮的生长阉牛的干物质摄入量、动物生长性能和气体通量之间存在正相关关系。此外，二氧化碳生成量有潜力用于预测采食牧草型日粮的生长阉牛的干物质摄入量。未来需要开展研究来评估二氧化碳生成量与干物质摄入量之间的关系，尤其是在放牧条件下。
