Abstract
Abstract
Background
Premature culling reduces dairy farm profitability and increases the environmental footprint of milk production by shortening productive lifespan and increasing replacement animal requirements. This study evaluated whether treatment with a live consortium of rumen-native microbes was associated with improved herd retention across controlled commercial dairy trials. Cull outcomes (sold or died vs. retained in herd) were analyzed across twenty trials encompassing more than 40,000 dairy cattle housed across 110 experimental pens, with each trial conducted for at least 5 months. Treatment pens received a defined daily dose of Galaxis® Frontier (“GF”, Native Microbials, San Diego, CA), containing
Pichia kudriavzevii
,
Clostridium beijerinckii
,
Ruminococcus bovis
, and
Butyrivibrio fibrisolvens,
incorporated into the ration; control and treatment groups were otherwise managed equivalently. Cow-level time to culling was modeled within each trial, accounting for pen-level clustering, and trial estimates were combined using random-effects meta-analysis.
Results
Supplementation with rumen-native microbes was associated with a 9% lower hazard of culling across 20 trials (hazard ratio = 0.91, 95% confidence interval: 0.86-0.96; P
Conclusion
Across diverse commercial dairy environments, feeding a defined consortium of rumen-native microbes was associated with improved dairy cow retention. Recorded health events suggested that improved metabolic stability may contribute to this effect. Extending productive lifespan reduces replacement requirements and the number of non-lactating heifers needed to maintain herd size, thereby reducing the economic burden and carbon footprint associated with replacement animals that do not directly contribute to milk production. These results demonstrate rumen-native microbial supplementation as a practical strategy to enhance the economic and environmental sustainability of dairy production.