Effect of prepartum physical activity on behavior and immune competence of dairy cows

Abstract Text: The objective was to determine the effect of prepartum exercise, pasture turnout, or total confinement on activity and immune competence of dairy cows. Sixty pregnant, non-lactating cows were assigned to control (Holstein=19; Jersey×Holstein=1), exercise (Holstein=19; Jersey×Holstein=1), or pasture (Holstein=20) treatments using rolling enrollment from Jan to Nov 2015 at dry-off. Cows were balanced by parity (1.8±0.9), projected metabolizable energy fat-corrected milk yield (13,831±2,028 kg per lactation) and projected due date. Cows were housed in a naturally ventilated, 4-row deep-bedded sand freestall barn at the University of Tennessee’s Research Unit (Walland, TN). Cows were moved to a maternity pen with a rubber mattress to calve. Fitted 3 d before dry-off, accelerometers determined lying time (h/d), lying bouts (n/d), lying bout duration (min/bout), and steps (n/d) at 1-min intervals. Data were averaged by four periods relative to actual calving date: -58 to -15 d (FO), -14 to -1 d (CU), d 0 (CA), and 1 to 14 d (PP). Exercise was done on five consecutive days per wk for 1.4 ± 0.1 h/d (targeted 1.5 h/d), at a pace of 1.88 ± 0.58 km/h. Pasture turnout occurred on a grassy paddock five consecutive days per wk for 1.8 ± 0.3 h/d (targeted 1.5 h/d). Control cows remained in the home pen throughout the dry period. Blood was sampled on d -3 and 42, relative to dry-off to assess immune competence via ROS generation using PMA. A mixed model determined the effects of treatment, period, and treatment×period on daily lying behavior and steps and the effect of treatment, day, PMA level, and their interactions on ROS generation. Cow within treatment was the random variable. Exercise cows lay down less frequently at CA (11.6±1.0 bouts/d) compared to control cows (14.6±0.9 bouts/d; P=0.03). However, lying bout duration and lying time did not differ among treatments at CA (P>0.31). Exercise cows were more active at FO, CU, and CA (2,895.4±107.6, 2,614±125.2, and 2,824.6±224.4 steps/d, respectively) than control (1,788.8±103.9, 1,840.8±120.7, and 1,969.3±216.2 steps/d), and pasture (2,132.0±103.6, 1,951.6±120.9, and 2,234.9±216.3 steps/d; P<0.01). ROS production was not affected (P=0.63).  Exercised cows took more steps, but had fewer lying bouts around calving, suggesting more comfort during calving. Furthermore, physical activity did not alter immune competence. Prepartum exercise may be a viable management strategy to improve calving performance.

Keywords: dairy cow; immune competence; physical activity