Parsons Cory T, Dafoe Julia M, Wyffels Samuel A, DelCurto Timothy, Boss Darrin L
Northern Agricultural Research Center, Montana State University, Havre, MT 59501, USA.
Department of Animal and Range Sciences, Montana State University, Bozeman, MT 59717, USA.
Animals (Basel). 2021 May 23;11(6):1518. doi: 10.3390/ani11061518.
The objectives of this study were to evaluate the influence of RFI and cow age on the supplement intake and grazing behavior of beef cattle. Average daily supplement intake (kg/cow/d) displayed an RFI × cow age interaction ( < 0.01), with a linear increase in average daily supplement intake with increasing RFI of 3-year-old cows ( < 0.01). Average daily supplement intake (g ∙ kg BW ∙ d) displayed an RFI × cow age interaction ( < 0.01), with a quadratic effect on supplement intake of 3-year-old cows ( = 0.01). Cow age displayed a quadratic effect on variation of supplement intake ( < 0.01), where 1-year-old cows had a greater CV of supplement intake than all other cow ages ( < 0.01). Distance traveled displayed a cow age × RFI interaction ( = 0.02), where high-RFI 5-year-old cows traveled further per day than low 5-year-old RFI cows. The probability of grazing site selection was influenced by cow age ( ≤ 0.03). In summary, heifer post-weaning RFI had minimal effects on beef cattle performance, grazing behavior, or resource utilization; however, cow age impacted both grazing behavior and resource use.
本研究的目的是评估剩余采食量（RFI）和母牛年龄对肉牛补充料摄入量及放牧行为的影响。平均每日补充料摄入量（千克/头/天）呈现出RFI×母牛年龄的交互作用（P＜0.01），对于3岁母牛，随着RFI的增加，平均每日补充料摄入量呈线性增加（P＜0.01）。平均每日补充料摄入量（克·千克体重·天）呈现出RFI×母牛年龄的交互作用（P＜0.01），对3岁母牛的补充料摄入量有二次效应（P = 0.01）。母牛年龄对补充料摄入量的变异有二次效应（P＜0.01），1岁母牛补充料摄入量的变异系数（CV）高于所有其他年龄的母牛（P＜0.01）。行走距离呈现出母牛年龄×RFI的交互作用（P = 0.02），高RFI的5岁母牛每天行走的距离比低RFI的5岁母牛更远。放牧地点选择的概率受母牛年龄影响（P≤0.03）。总之，断奶后小母牛的RFI对肉牛生产性能、放牧行为或资源利用的影响最小；然而，母牛年龄对放牧行为和资源利用均有影响。
