A bromoform based Investigational Veterinary Product fed twice daily to lactating dairy cows had no adverse effects on eating, rumination, or locomotion behaviours.

An Investigational Veterinary Product (IVP) containing synthetic bromoform has emerged as a promising technology for reducing livestock enteric methane emissions. However, the effects of feeding the bromoform-based IVP on eating, rumination and locomotion behaviour (critical animal welfare indicators) remain unclear. This study assessed the response of supplementing twice daily an IVP at two bromoform inclusion rates to lactating dairy cows at milking on i) eating and rumination behaviour; and ii) locomotion behaviour. Thirty multiparous, Holstein-Friesian cows (214 ± 15.2 days in milk) were allocated to one of three treatments; CON (0 mg bromoform/cow per day), LowBR (227 mg bromoform/cow per day) and HighBR (455 mg bromoform/cow per day). The IVP was mixed with 3.1 kg dry matter of grain and offered during each milking. The basal diet consisted of vetch hay offered ad libitum. Cows were equipped with a RumiWatch System noseband pressure sensor and pedometer (ITIN + HOCH GmbH, Liestal, Switzerland) for 11 days. Data were analysed by CRD-based repeated measures split-plot ANOVA using Genstat 24 (VSN International, Hemel Hempstead, UK). Results showed no significant effect of the IVP on eating, rumination, lying or standing behaviour. Although cows fed the IVP showed an increase in walking duration, the difference was negligible in practical terms (twelve minutes per day). These findings indicate that feeding dairy cows with the bromoform-based IVP does not change their behaviour, resulting in a potential technology to reduce enteric methane emissions without compromising animal welfare.