Lombardi Mayara Campos, Neto Hilton do Carmo Diniz, Coelho Sandra Gesteira, Machado Fernanda Samarini, Pereira Luiz Gustavo Ribeiro, Tomich Thierry Ribeiro, Campos Mariana Magalhães
Department of Animal Science, Veterinary School, Universidade Federal de Minas Gerais, Belo Horizonte 30161-970, MG, Brazil.
Brazilian Agricultural Research Corporation, Empresa Brasileira de Pesquisa Agropecuária-Embrapa Gado de Leite, Juiz de Fora 36038-330, MG, Brazil.
Animals (Basel). 2022 Jan 29;12(3):331. doi: 10.3390/ani12030331.
The objectives of this study were: (1) to identify and rank phenotypically divergent animals for residual feed intake (RFI) regarding their efficiency (high: HE or low: LE); (2) to evaluate their relationships with ingestive behavior, ruminal and blood parameters, performance, and infrared thermography; and (3) to determine if such measurements can be used as feed efficiency markers in rearing dairy heifers. Thirty-eight heifers, 143 d ± 4 (Mean ± SD) of age and 108.7 kg ± 17.9 of body weight were used. The animals were fed with a total mixed ration during the 91 d of the trial. A phenotypic divergence of DMI for RFI was observed between -0.358 and 0.337 kg/d for HE and LE, respectively. Dry matter intake (DMI) was lower in the HE (2.5 kg DMI/d vs. 3.1 kg DMI/d), as was the number of visits to the feed bin with consumption (59 vs. 71). Feed intake was the best predictor of said divergence. Water intake and number of visits to the feed bin were presented moderate correlations with RFI. The ruminal fermentation variables, blood metabolites, blood hormones (such as the other ingestive behavior variables), and infrared thermography were not able to accurately predict HE or LE animals.
（1）根据剩余采食量（RFI）的效率（高：HE或低：LE）识别并对表型差异较大的动物进行排名；（2）评估它们与采食行为、瘤胃和血液参数、生产性能以及红外热成像的关系；（3）确定这些测量是否可作为饲养奶牛小母牛的饲料效率指标。使用了38头小母牛，年龄为143天±4（平均值±标准差），体重为108.7千克±17.9。在91天的试验期间，给动物饲喂全混合日粮。观察到HE和LE的RFI在干物质采食量（DMI）上的表型差异分别为-0.358至0.337千克/天。HE的干物质摄入量（DMI）较低（2.5千克DMI/天对3.1千克DMI/天），采食时到饲料槽的访问次数也较低（59次对71次）。采食量是上述差异的最佳预测指标。饮水量和到饲料槽的访问次数与RFI呈中等相关性。瘤胃发酵变量、血液代谢物、血液激素（如其他采食行为变量）和红外热成像无法准确预测HE或LE动物。
