Abstract #T390

# T390
Associations of behavior and production in lactating dairy cows.
Carleigh Johnston1, Trevor J. DeVries*1, 1Department of Animal and Poultry Science, University of Guelph, Guelph, ON, Canada.

Identification of the associations of cow behavior with productivity is important for supporting recommendation of strategies that optimize milk quality, efficiency, and yield. Thus, the objective of this study was to collate data from studies of the behavior of lactating dairy cows and identify associations between measures of behavior of dairy cattle and milk production and efficiency. 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 ± SD) 1.8 ± 0.9 lactations, 108.4 ± 42.7 DIM, and 654.6 ± 71.4 kg BW during each observation week. Production data included: DMI (27.0 ± 3.1 kg/d), milk yield (43.0 ± 7.0 kg/d), milk fat content (3.60 ± 0.49%), milk fat yield (1.53 ± 0.30 kg/d), milk protein content (3.05 ± 0.25%), milk protein yield (1.29 ± 0.17 kg/d), and production efficiency (1.60 ± 0.22 kg milk/kg DMI). 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), rumination time (516.0 ± 90.7 min/d), and lying time (621.5 ± 142.8 min/d). Data were analyzed in multivariable mixed-effect regression models to identify which behavioral variables, when accounting for other cow-level factors (DIM, parity, BW), were associated with measures of production. DMI was associated with feeding time (+0.02 kg/min; P = 0.002) and tended to be associated with rumination time (+0.003 kg/min; P = 0.1) and meal frequency (+0.2 kg/meal; P = 0.06). Similarly, milk yield was associated with feeding time (+0.03 kg/min; P = 0.005) and rumination time (+0.02 kg/min; P < 0.001), and tended to be associated with meal frequency (+0.3 kg/meal; P = 0.1). Milk fat yield was associated with meal frequency (+0.02%/meal; P = 0.05). Efficiency of production was associated with rumination time (+0.0006/min; P < 0.001) and tended to be associated with meal time per day (+0.0005/min; P = 0.09). Overall, our results indicate that nutrition, management, and housing factors that improve time spent feeding, in more frequent meals, and time spent ruminating may have a positive impact on milk yield and component production, as well as production efficiency.

Key Words: behavior, production, rumination