Short communication: Associations of feeding behavior and milk production in dairy cows.

Identification of the associations of cow feeding behavior with productivity is important for supporting recommendations of strategies that optimize milk yield and composition. The objective of this study was to identify associations between measures of feeding behavior and milk production using data collated from studies of the feeding behavior of lactating dairy cows. A database containing behavior and production data for 132 dairy cow-week observations (mean of 7 d of consecutive data per cow) was assembled from 5 studies. Cows averaged (mean ± standard deviation) 1.8 ± 0.9 lactations, 108.4 ± 42.7 d in milk, and 654.6 ± 71.4 kg of body weight during each observation week. Production data included dry matter intake (27.0 ± 3.1 kg/d), milk yield (43.0 ± 7.0 kg/d), milk fat content (3.60 ± 0.49%), and milk protein content (3.05 ± 0.25%). Behavioral data included feeding time (230.4 ± 35.5 min/d), feeding rate (0.13 ± 0.03 kg/min), meal frequency (9.0 ± 2.0 meals/d), meal size (3.2 ± 0.9 kg/meal), daily mealtime (279.6 ± 51.7 min/d), and rumination time (516.0 ± 90.7 min/d). Data were analyzed in multivariable mixed-effect regression models to identify which behavioral variables, when accounting for other cow-level factors (days in milk, parity, and body weight) and dietary characteristics (forage level, nutrient content, and particle distribution), were associated with measures of production. Dry matter intake was associated with feeding time (+0.02 kg/min) and tended to be associated with rumination time (+0.003 kg/min) and meal frequency (+0.2 kg/meal). Similarly, milk yield was associated with feeding time (+0.03 kg/min) and rumination time (+0.02 kg/min), and tended to be associated with meal frequency (+0.3 kg/meal). Milk fat yield was associated with meal frequency (+0.02 kg/meal). Overall, our results suggest that milk yield and component production may be improved in situations where cows are able to increase their time spent feeding, in more frequent meals, and time spent ruminating.