Cow gut permeability under heat stress linked to reduced milk yield and a nutritional remedy
Researchers from Cornell University, alongside colleagues from the University of Bologna, have demonstrated that extreme heat can cause leaky gut in dairy cows and have identified a nutritional supplement that partially restores milk production. The findings appear in the Journal of Dairy Science, highlighting a direct connection between heat exposure, intestinal integrity, and milk output.
In hot conditions, Holstein cows show a marked decline in milk production, with potential losses ranging from 30 to 70 percent. Scientists observed that heat stress leads to reduced feed intake, which in turn lowers milk yield. More importantly, the research points to an immune system response triggered by elevated temperatures. This response is associated with increased intestinal permeability, or perforation of the intestine, allowing gut microorganisms to enter the bloodstream. The energy required to fuel the immune reaction diverts resources away from milk synthesis, contributing to the drop in production.
On the brighter side, the study identifies a gut-health supplement that can raise milk yield by about 3 liters per day during heat spells. The supplement combines a blend of organic acids and select plant extracts designed to support intestinal barrier function and overall gut health in dairy cows.
The concept that heat-related reductions in milk yield may be linked to intestinal barrier disruption has been a topic of discussion for some time. This latest research provides experimental support for that hypothesis, showing how a brief period of heat can initiate changes in gut permeability and immune activity, with real consequences for production. The authors emphasize that these findings open pathways for nutritional interventions that could help mitigate production losses during heat waves. Source: Journal of Dairy Science.