The objectives of this study were to quantitatively summarize factors associated with cow milk yield (MY) and calf growth response in pasture-based beef cow-calf suckler systems and to discern how cow genotype and parity influenced these responses. A dataset of 344 treatment mean observations was compiled from 69 studies that reported data on cow MY, and calf pre-weaning average daily live weight gain (ADG) and/or weaning weight (WW). Data were analysed using linear mixed effects models with study and region included as random effects. Models were developed for cow MY, calf ADG and WW response and each model was evaluated based on different model fit statistics. The final cow MY model included cow origin (Dairybeef or Beef), cow maturity (early-maturing (EM) or late-maturing (LM) genotypes) and parity. Dairybeef produced 35.4% more milk (8.64 vs. 6.38 kg/day) than Beef cows, and LM produced 20.9% more milk (8.20 vs. 6.78 kg/day) than EM genotypes (P < 0.001). Multiparous cows had a 14.8% higher MY (8.11 vs. 7.06 kg/day) compared to primiparous cows (P < 0.001). Lactation curve persistency was better (P < 0.05) for Beef and EM compared to Dairybeef and LM genotype cows, respectively. The final models of calf ADG and WW included cow origin, cow maturity and parity. Calves from Dairybeef and LM cows were 14 and 20 kg heavier (P < 0.001) at weaning (210-day adjusted) compared to those from Beef and EM genotype cows, respectively. Calves from multiparous cows were 13 kg heavier at weaning than those from primiparous cows (P < 0.001). The response in calf ADG associated with a 1 kg increase in cow daily MY was 47 and 53 g for Dairybeef and Beef cows, respectively (P < 0.001). Corresponding responses for EM and LM cows were 51 and 55 g (P < 0.001). In conclusion, the relationships between cow MY and calf pre-weaning growth, as well as the quantitative impact of cow genotype and parity were determined for pasture-based beef suckler systems; the coefficients generated can be used for improving beef cow-calf management strategies, beef cattle breeding programmes and bio-economic modelling purposes.

本研究的目的是定量总结基于牧场的肉牛犊牛吮吸系统中与牛奶产量（MY）和小牛生长反应相关的因素，并了解奶牛的基因型和均价如何影响这些反应。从69项研究中收集了344个治疗平均观察值的数据集，这些研究报告了奶牛MY和断奶前小牛平均日增重（ADG）和/或断奶体重（WW）的数据。使用线性混合效应模型分析数据，其中研究和区域作为随机效应。针对奶牛MY，小牛ADG和WW反应开发了模型，并根据不同的模型拟合统计量对每种模型进行了评估。最终的奶牛MY模型包括奶牛出身（Dairybeef或Beef），奶牛的成熟度（早熟（EM）或晚熟（LM）基因型）和均等。乳牛的牛奶产量增加了35.4％（8.64 vs.P <0.001）。与初产母牛相比，多产母牛的MY（8.11比7.06 kg /天）高14.8％（P <0.001）。与奶牛和LM基因型奶牛相比，牛肉和EM的泌乳曲线持续性更好（P <0.05）。小牛ADG和WW的最终模型包括母牛的出身，母牛的成熟度和胎次。与牛和EM基因型母牛相比，断奶（调整210天）时，Dairybeef和LM母牛的犊牛分别重14和20 kg（P <0.001）。断奶时来自多头母牛的犊牛比初生母牛的犊牛重13 kg（P <0.001）。奶牛和奶牛的小牛日增重与奶牛每日MY增加1公斤有关，分别为47和53克（P <0.001）。EM和LM母牛的相应响应分别为51和55 g（P <0.001）。总之，确定了基于牧场的牛肉吸盘系统的奶牛MY与断奶前断奶生长之间的关系，以及奶牛基因型和胎次的定量影响。所产生的系数可用于改善肉牛犊牛管理策略，肉牛育种计划和生物经济建模目的。