# Effects of an optimized dairy calf-rearing protocol on performance and health in the subsequent fattening period on Swiss veal farms

## TL;DR

An optimized calf-rearing protocol improved weight gain and reduced time to reach carcass weight but did not improve health or reduce antibiotic use in veal farms.

## Contribution

Demonstrated that optimized rearing protocols can enhance performance without affecting health or antimicrobial use in veal calves.

## Key findings

- Optimized rearing increased daily weight gain on dairy farms compared to control calves.
- Preconditioned calves reached optimal carcass weight faster on veal farms.
- No improvement in clinical health or reduction in antimicrobial use was observed.

## Abstract

•We tested the optimized rearing of calves on dairy farms.•This optimized rearing improved daily weight gain on dairy farms.•On veal farms these calves reached an optimal carcass weight in shorter time.•However, neither clinical health was improved, nor antimicrobial use was reduced.

We tested the optimized rearing of calves on dairy farms.

This optimized rearing improved daily weight gain on dairy farms.

On veal farms these calves reached an optimal carcass weight in shorter time.

However, neither clinical health was improved, nor antimicrobial use was reduced.

We conducted a prospective field study to characterize the effects of an optimized rearing protocol of calves on dairy-farms on the subsequent performance, health and antimicrobial use (AMU) at the veal-farm. On 19 dairy-farms a total of 55 matched pairs of calves (same gender and breeding type, born within the same period and farm) were randomly assigned to the treatment group P (“preconditioned”) or C (“control”) during five two-week enrollment periods. The P-calves were fed milk ad libitum, received parenteral selenium and iron supplementation, wore calf jackets at low temperatures, and were vaccinated intranasally against bovine respiratory disease. The C-calves were fed restrictively and received no additional measures. At an average of 30 days of life, calves were transported directly to one of two veal-farms. Body weight and health score were determined between days 2 and 5 of life, at transport and in weeks 4 and 12 after arrival on the veal farm. All applications of antimicrobials were recorded. Mixed-effect models were applied for statistical analyses. While born with similar body weights, daily weight gain of the calves differed between groups on the dairy-farms (P: 1.10[0.96–1.25] vs. C: 0.70[0.55–0.84]kg/day; p < 0.001) but not on the veal-farms (P: 1.34[1.24–1.44] vs. C: 1.29[1.19–1.39]kg/day). A similar carcass weight was reached in shorter time for P-calves compared to C-calves (104[99–110] vs. 115[109–120] days on the veal-farm; p = 0.04). Neither clinical health nor AMU differed between the groups. Thus, while preconditioning was effective regarding performance parameters, a significant advantage in respect of health status and AMU could not be demonstrated.