1826
Evaluating Daily Variation in Body Weight, Milk Production, and Rumination Activity on a Commercial Dairy with Robotic Milking
Emerging technologies allow commercial dairy producers to collect a wide array of individual cow data on a daily basis, with the potential to profoundly influence managerial and nutritional decision-making on a pen basis. The objective of this study was to utilize daily body weights, rumination activity, and milk production data from lactating dairy cows to evaluate random variation that exists on a commercial dairy. Data were obtained from a commercial robotic dairy farm in Melrose, WI via the Lely T4C© herd management system for either a whole year (daily body weights and daily milk production) or one week (rumination). Data from approximately 500 cows in seven pens (1 pen per robot, approximately 70 cows per pen) was utilized. Cows were assigned to a pen post-calving and remained there until dry off. All data is presented as mean ± standard deviation. On this dairy, milk production averaged 37.4 kg, with a standard deviation of 1.0 kg among days within a pen, 14.4 kg among individual cows within a pen, and 21.2 kg among days within individual cows. Body weight averaged 689.2 kg, with a standard deviation of 4.5 kg among days within a pen, 75.6 kg among individual cows within a pen, and 34.6 kg among days within individual cows. Rumination (min per day) averaged 461.1 min, with a standard deviation of 6.1 min among days within a pen, 128.0 min among individual cows within a pen, and 43.6 min among days within individual cows. A statistical power calculation would suggest that with 7 pens and 95% confidence, a difference of 1.5 kg mean milk production, 6.5 kg mean body weight, or 8.0 min mean rumination time could be deemed statistically significant from day to day within this herd. Understanding the magnitude of the variability among these parameters could be a powerful tool to monitor pen level changes over a short period of time and implement immediate managerial modifications.
Keywords:
body weight, milk production, rumination