Sedating calves for disbudding hits growth rates, RVC study finds

Researchers at the Royal Veterinary College (RVC) are urging vets to reconsider sedating calves when carrying out disbudding, raising concerns over its effectiveness and wider health impacts.

The research, which looked at the impact of sedation versus conscious disbudding on calves, was led by Dr Sophie Mahendran, lecturer in farm animal health and welfare at the RVC.

The research team monitored the disbudding of 485 calves in Somerset between April and August 2024 and their welfare thereafter.

See also: How stress-free disbudding can benefit calf units

It found that sedation using xylazine might not be that effective and have longer-term health implications, resulting in lower subsequent growth rates.

“The use of sedation for disbudding calves is becoming very common practice, so understanding the effects that xylazine use has is important,” said Dr Mahendran.

She added that “knockdown disbudding” is often used when calf handling facilities are poor, or to try and increase efficiency when disbudding large numbers of calves.

“This work has shown that it causes reduced calf growth rates for approximately 20 days following disbudding, and that this effect was worse in calves that only experienced a light plane of sedation and were able to enter sternal recumbency during the procedure,” she said.

Key findings

The findings revealed that sedated calves grew 0.14kg a day less in the 20 days after disbudding compared to conscious calves.

Within the sedated group, calves that entered sternal recumbency had the greatest reduction in growth at 0.89kg a day compared to 0.98kg a day for lateral recumbency.

Almost one in five calves (19.3%) showed either movement or ended up in sternal recumbency, suggesting that this type of sedation was not always deep enough.

The researchers say that these findings are not only an economic concern for farmers, but may also indicate stress or welfare compromise for the animal.

Vital insight for vets

Dr Mahendran now encourages vets to carefully consider whether to use sedation for disbudding, particularly when sedation quality cannot be guaranteed.

“Vets should consider whether sedation should be used as a standard restraint method, or whether investment into appropriate calf handling facilities should be encouraged on farms,” she added.