Postgraduate Program in Animal Production, Institute of Agricultural Sciences, Federal University of Minas Gerais, Av. Universitária, Montes Claros, Minas Gerais, 1000, 39404-547, Brazil.
Faculty of Veterinary Medicine, Federal University of Uberlândia, Av. João Naves de Ávila, Uberlândia, Minas Gerais, 2121, 38408-100, Brazil.
Trop Anim Health Prod. 2024 Oct 2;56(8):316. doi: 10.1007/s11250-024-04176-8.
The residual intake and gain (RIG) aims to select animals that present low feed intake in relation to the expected. This study aimed to evaluate the associations of selection for RIG with performance and carcass traits in Nellore cattle. Initially, residual feed intake (RFI) and residual gain (RG) were determined. From this, the RIG was calculated, and the animals were classified as efficient and inefficient for RIG. The efficient animals for RIG showed higher daily weight gain (DWG), Longissimus muscle area (LMA), and mid-test metabolic body weight (MMBW) than the inefficient ones. No significant correlations were found between subcutaneous fat thickness (SFT), marbling (MAR), LMA, MMBW, and the RIG. Thus, it's concluded that the RIG is a measure that can be used to identify and select animals with higher rates of DWG and LMA without changes in the dry matter intake (DMI), SFT, and MAR. However, this index should still be observed with caution, as it may be dependent on body size. Based on the findings, the selection of animals according to the RIG can be an important factor to generate phenotypic evolution in characteristics such as weight gain and rib eye area without adverse effects on the carcass fat deposition.
残留采食量和增益（RIG）旨在选择采食量低于预期的动物。本研究旨在评估选择 RIG 与内罗尔牛性能和胴体特征的相关性。最初，确定了残留采食量（RFI）和残留增益（RG）。由此计算出 RIG，并将动物分为 RIG 高效和低效。RIG 高效动物的日增重（DWG）、背最长肌面积（LMA）和中测代谢体重（MMBW）均高于低效动物。皮下脂肪厚度（SFT）、大理石纹（MAR）、LMA、MMBW 和 RIG 之间没有显著相关性。因此，得出结论，RIG 是一种可以用来识别和选择具有更高 DWG 和 LMA 率的动物的方法，而不会改变干物质采食量（DMI）、SFT 和 MAR。然而，该指数仍应谨慎观察，因为它可能依赖于体型。基于这些发现，根据 RIG 选择动物可以成为在不影响胴体脂肪沉积的情况下产生增重和眼肌面积等特征表型进化的重要因素。
