Abstract The objective was to evaluate the accuracy of predicting 24-hour milk yield and composition from a single morning (AM) or evening (PM) milk weight and composition. A calibration dataset of 37,481 test-day records with both AM and PM yields and composition was used to generate the prediction equations; equations were validated using 4,644 test-day records. Prediction models were developed within stage of lactation and parity while accounting for the inter-milking time interval. The mean correlation between the predicted 24-hour yields and composition of milk, fat and protein and the respective actual values was 0.97 when based on just an AM milk yield and composition with a mean correlation of 0.95 when based on just a PM milk yield and composition. The regression of predicted 24-hour yield and composition on the respective actual values varied from 0.97 to 1.01 with the exception of 24-hour fat percentage predicted from a PM sample (1.06). A single AM sample is useful to predict 24-hour milk yield and composition when the milking interval is known.

中文翻译：

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从单日产奶量和样本预测奶牛的 24 小时产奶量和成分

摘要 目的是评估从单个早晨 (AM) 或晚上 (PM) 的牛奶重量和成分预测 24 小时产奶量和成分的准确性。使用包含 AM 和 PM 产量和成分的 37,481 个测试日记录的校准数据集来生成预测方程；使用 4,644 个测试日记录验证方程。预测模型是在泌乳阶段和胎次阶段开发的，同时考虑了两次挤奶的时间间隔。当仅基于 AM 产奶量和成分时，预测的 24 小时产量和牛奶、脂肪和蛋白质的组成与各自的实际值之间的平均相关性为 0.97，而仅基于 PM 产奶量和组成时的平均相关性为 0.95。作品。除了从 PM 样本预测的 24 小时脂肪百分比 (1.06) 之外，预测的 24 小时产量和成分对各自实际值的回归从 0.97 到 1.01 不等。当挤奶间隔已知时，单个 AM 样本可用于预测 24 小时的牛奶产量和成分。