Forage plantain (Plantago lanceolata L.): Meta-analysis quantifying the decrease in nitrogen excretion, the increase in milk production, and the changes in milk composition of dairy cows grazing pastures containing plantain

Summary

Plantain (Plantago lanceolata L.) has been increasingly used as a forage component in dairy grazing systems due to its capacity to reduce nitrogen (N) losses, while improving or maintaining milk production. A meta-analysis was conducted to quantify the effect of plantain on milk production and urinary nitrogen (UN) excretion by dairy cows. The main outcomes of this analysis included the yield, solids (fat + protein), protein and fat components of milk, and N concentration in urine, daily urine volume, and total UN excretion by dairy cows. Overall, grazing pastures containing plantain significantly increased milk yield (weighted mean difference (WMD) = 1.02 kg/cow/day, 95% confidence interval (CI) = 0.55–1.46), milk solids yield (WMD = 0.07 kg/cow/day, 95% CI = 0.02–0.12), and milk protein