Short communication: Intensive measurements of standing time of dairy calves housed in individual pens within a naturally ventilated, unheated nursery over different periods of the year

Holstein calves, 2 to 5 d of age initially (42.8 ± 2.1 kg of body weight) from a single dairy farm, were transported 3.5 h to southwest Ohio. Calves were housed in 1.2 × 2.4 m individual pens with wire mesh sides within a curtain sidewall barn with no added heat. Pens were bedded with long straw and fed 0.68 kg (as-fed) of milk replacer powder reconstituted to a 14% dry matter daily in 2 equal meals at 0615 and 1600 h. Starter and water were offered ad libitum. Calves were weaned at 42 d with measurements made until d 56. Ten calves per period in 4 periods of the year (spring/summer, SS; summer, S; fall, F; winter, W) were used to measure standing and lying behavior using an electronic data logger attached to the medial side of the right rear leg of calves. In period SS, loggers were attached from d 2 to 6, 10 to 17, 25 to 32, and 33 to 56. In periods S, F, and W, the logger was attached from d 4 to 56. Standing time was estimated from 5-min interval recordings. Data from the first 2 d after attachment were not used. Standing time did not differ among periods and averaged 303 ± 52.8 min/d. These measurements were low, and approximately 2 h/d less than other measurements found in the literature. Standing time differed among sections of the day and was greatest during a.m. and p.m. feeding, intermediate during midday and evening, and least at night. No interaction of period of year by time of day was noted. Standing time increased by 0.52 ± 0.063 min/d with increasing age of calf (approximately 26 min per 7 wk). Variances of standing time within period of year due to calf and variances across periods were compared and did not differ. In summary, calves averaged approximately 300 min/d standing, and time standing increased by approximately 0.5 min/d with age and did not differ with period of year.