Calf presence in the cow herd: Associations with growth, health, and herd horn status in a cow-calf contact system

• The amount of time calves spent in the herd decreased with increasing age • Whole-day contact calves had higher weight gains than calves with half-day contact • Calves spent less time in the herd with horned cows • Health status of calves with or without contact to the dairy herd did not differ Prolonged cow-calf contact in dairy farming is receiving considerable attention. However, research on systems that allow calves to access the whole dairy herd has been limited. This study investigated the time that German Holstein calves spent daily within the dairy herd of their dams, its association with calf growth and health, and the effect of herd (horned vs. polled). The calves with whole-day contact (WDC, n = 23) could enter the herd at any time during the day, except during milking; the calves with daytime contact (DTC, n = 26) had only access between morning and evening milking. Calves with no herd contact (NOC, n = 42) served as a control. Calves were weighed weekly and their health status was assessed. Between the 2 nd and 11 th weeks of life, the time spent in the cow herd decreased in WDC calves (h d -1 , horned WDC: - 10.9, polled WDC: - 3.7, P < 0.001), but did not differ in DTC calves ( P > 0.1). More time in the herd was associated with higher growth rates ( P = 0.003). However, no effect of the herd was observed on calf growth or health. WDC calves had the highest growth rate compared to DTC and NOC (g d -1 , 991 ± 36, 718 ± 35, 869 ± 28, respectively, P < 0.05). Unrestricted access to the cow herd resulted in individual variation in the time calves spent within the herd, with no observed effects on growth or health.