Strategic grouping of dairy beef calves on arrival at a rearing unit

There is an increasing trend in the number of dairy beef cross calves being born on dairy farms in the United Kingdom. The majority of these calves are sold off farms pre-weaned for further rearing on dedicated calf rearing units where they enter the dairy-beef production cycle. On these rearing units, such calves are exposed to new environmental and disease challenges as well as often being mixed with other calves from multiple farms. The aim of this preliminary study was to strategically group calves when they arrived on a rearing unit and assess their health and performance after a period of time on the rearing unit. One hundred and forty calves were sourced from seventeen dairy farms within a seventy-mile radius of the rearing unit. The calves ranged from 10 to 67 days of age (mean 26 days). On arrival, the calves were lung ultrasound scanned (LUS) and scored on a scale from 0 (normal aeriated lungs) to 5 (consolidation observed in three or more lung lobes). The calves were also Wisconsin health scored (WS) and weighed. Using this information, calves were then assigned to one of five groups: (i) ‘High health’ (HH) (LUS 0/1 & WS ≤2), (ii) ‘Low health’ (LH) (LUS ≥3 & WS ≥3), (iii) ‘Intermediate health’ (INT) (LUS 2/3 & WS≤ 2), (iv) ‘Mixed health’ (MIX) (a proportion of calves (50%) LUS ≤2 & WS ≤2 along with a proportion of calves (50%) with LUS 4/5 & WS ≥2) and (v) ‘Normal farm practice’ (NFP). The NFP for grouping calves was to keep calves from the same source farm together in the same pen. All calves were weighed, LUS and WS again after 22 days of being on the rearing unit to coincide with the farms routine for handling calves, thus allowing a daily liveweight gain (DLWG; kg/d) to be calculated. A relatively large proportion of the calves (62%) were observed with signs of lung consolidation (LUS≥3) on arrival at the rearing unit. Younger calves had lower LUS on arrival at the rearing unit. Calves grouped as LH had a higher DLWG compared to calves grouped as HH but lower than NFP. The results of this preliminary study highlight some areas of interest that require further investigation.