Delaying postpartum separation by 3, 5, or 7 days compared with immediate separation: A pilot study on production and health indicators in Holstein cows and their calves.

Taking the calf away from the mother is common practice in global dairy production systems. This practice is to prevent disease in new-born calves due to pathogens shed by cows, for better control of colostrum management and milk intake, and to maximize milk yield, improve efficiency of milking, prevent intra-udder infections in cows, and minimize separation stress after the bond between cow and calf has been formed. Available evidence though, suggests that longer maternal contact may be neutral or even beneficial rather than detrimental to the calf and udder health, while also promoting natural behaviour. The public is generally not well informed about farming, including immediate cow-calf separation, and when made aware, typically rejects this management practice, because it fails to conform with societal values. To make informed decisions when considering longer cow-calf contact procedures while also taking in account farm profitability, dairy farmers must be able to understand the effects on animal health and productivity to estimate income and costs. This is particularly the case in light of the potentially substantially infrastructure changes needed to successfully implement a system of longer cow-calf contact. To study this further, the objectives of the study cited were to investigate the effect of full cow-calf contact for three, five, or seven days after calving, compared with immediate separation on milk production and components, cow metabolic indicators, milking characteristics, and intra-udder bacterial infection status, as well as calf transfer of passive immunity (TPI), milk intake, and health scores.

Twenty-three Holstein cows with a single calf were enrolled, and their calves included in a randomized block design. The cows were housed in identical box stalls regardless of treatment assignment and milked twice daily from calf birth to day eight. In pairs assigned to the zero day (0D) group, calves were separated immediately after birth, whereas in the 3D, 5D, and 7D treatment groups, calves were separated three, five, or seven days after birth, respectively. All calves were fed colostrum at 8.5% of birth body weight (BBW).

Contact calves had access to the cow’s box stall except during milking, when they were confined to a connected calf creep area. Separated calves were fed whole milk twice daily, up to a total of 25% of BBW per day, and housed in identical pens in a different section of the same barn. Milk yield was measured at each milking, and milk components were determined on day 0, 1, 3, 5, and 7. Quarter-level milk was taken for microbial cultures on day 0 and 8. Vacuum aspects were measured daily using a portable vacuum recorder to detect bimodal milk flow curves. Serum samples of cows and calves were analysed for metabolic markers and immunoglobulin (IgG) concentration, respectively. Calf health was scored daily, and their hip and withers heights measured.

Milk production was lower during the respective contact periods in the 3D, 5D, and 7D groups, but rebounded to the level of the 0D group after separation, respectively. Lactose concentration was lower in the 5D group compared with the 0D group. Bimodality was only found in milking observations of the contact groups but not in the 0D group. Quarter-level new IMI or risk of cure, as well as metabolic indicators did not differ between groups. Successful TPI was shown in all groups, and calf health and growth indicators did not differ between the groups. Median milk intake in the separated calves ranged from 9 to 9.8 kg on day 7.

In summary, the cows with delayed separation of their calves showed a transient reduction in milk yield, occurrence of bimodality, and lower milk lactose concentration, whereas metabolic indicators and IMI risk did not differ. The calves showed no difference in health scores or growth, and the separated calves voluntarily consumed a daily amount of milk equal to 18% to 20% of BBW. The delayed separation of the calves from their mothers resulted in differences in milk production, bimodality and milk components, whereas under the controlled colostrum feeding conditions, the calves showed no difference in TPI, health outcomes, or injury risk. While this is significant, the long term effects on milk production, bimodality, calf growth, and health merit further investigation.