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Simple Summary: Incorporating forage plantain into the diet of grazing dairy cows has the potential to reduce nitrogen (N) losses from pastoral systems. One of the key mechanisms for reduced N loss from plantain-fed cows is through increased urine volume and diluted urine N concentration, which increases the % of urine N used for plant growth. The aim of this study was to determine whether lower proportions of plantain in the diet would be effective in achieving changes in urination. The results showed that compared to cows grazing traditional perennial ryegrass and white clover pastures, cows with 25% plantain in their apparent dietary intake increased urine volume and urination frequency and reduced urine N% in the morning. When dietary plantain was less than 20%, there was only a small effect on increased urine volume, though morning urine N% was reduced. Ensuring more than 20% plantain in the diet has the potential to reduce N leaching risk via reduced urinary N load from grazing dairy cows. The objective of this study was to determine the effect of grazing plantain-based pastures on urine volume, urination frequency, and urinary nitrogen (UN) concentration of dairy cows under a typical pastoral dairy practice offering approximately 25% supplemented feeds. The experiment was a completely randomised design with three pasture treatments (perennial ryegrass–white clover (RGWC); RGWC + low plantain rate (PLL); and RGWC + high plantain rate (PLH)), five replicate plots, and repeated in two sequential grazing periods. Forty-five lactating Friesian × Jersey cows were randomly assigned into three groups of 15 animals each to graze over six days in adaptation paddocks and three days in experimental plots. Urine flow sensors were used to measure urine volume and urinary frequency, while spot urine sampling was conducted to determine nitrogen (N) concentration in cow urine. The results showed that including 25% plantain in the diet (PLH) increased daily urine volume by 44% and the daily number of urinations by 28%, compared to grazing the RGWC pasture. In addition, N concentration in cow urine was decreased by 18 and 29% when the diet contained 18% and 25% plantain, respectively. In conclusion, under a typical dairy farm practice, incorporating plantain into the RGWC pasture with the proportion of 25% plantain in the diet can increase the number of urine patches and reduce the concentration of N in the urine, thereby providing the opportunity to decrease N leaching from pastoral systems. [ABSTRACT FROM AUTHOR]

Plantain (Plantago lanceolata L.) is a forage that produces secondary metabolites with one, aucubin, known to inhibit soil nitrification. This study aimed to quantify the exudation of aucubin and catalpol by plantain root systems in a hydroponic experiment; evaluate the effect of aucubin on nitrogen (N) leaching and nitrous oxide (N2O) emissions from urine applied to plantain and ryegrass-white clover swards; and compare N losses from a ryegrass-white clover sward after urine from cows fed plantain and cows fed ryegrass-white clover was applied. Nitrate ( NO 3 − ) leaching and N2O losses were measured in a lysimeter experiment. Catalpol, but not aucubin, was exudated by plantain roots. N2O emissions were decreased by plantain swards and by ryegrass-white clover swards to which aucubin was also applied. Aucubin had no effect on NO 3 − leaching. Urine from cows grazing plantain had no effect on N2O emissions, and N leaching when compared to the urine from cows grazing ryegrass-white clover with the same N content. We conclude the plantain sward and the aucubin applied to the ryegrass-white clover sward decreased N2O emissions via mechanisms in the soil separate from the decreased emissions resulting from the lower N concentration of urine derived from cows grazing plantain. [ABSTRACT FROM AUTHOR]

Incorporating plantain with perennial ryegrass and white clover (RGWC) can improve the quality and quantity of grazing pastures; however, the sowing rate could affect the persistence of plantain, pasture yield, and nutritive value in different seasons. The objective of this study was to evaluate the effect of increasing sowing rates of plantain when established with RGWC on the dry matter (DM) yield, botanical composition, nutritive value, and bioactive compounds of the pasture over the first two years after sowing; and to determine the relationship between plantain content and nutritive characteristics in different seasons. The pasture treatments were RGWC, RGWC + low plantain rate (PLL), RGWC + medium plantain rate (PLM), and RGWC + high plantain rate (PLH). The results showed that annual DM yield was similar between treatments. The average plantain content (including leaves and reproductive stem) was 32, 44, and 48% in PLL, PLM, and PLH, respectively. The plantain composition increased in the first 15 months, then declined rapidly to about 20–30% at day 705 after sowing. Compared with RGWC, the plantain-RGWC pastures (PLL, PLM, PLH) had a higher content of organic matter digestibility (OMD), ash, starch, non-structural carbohydrates (NSC), P, S, Ca, Mg, Na, Cl, Zn, B, Co, aucubin, acteoside, and catalpol, while they contained a lower composition of DM%, acid detergent fibre (ADF), neutral detergent fibre (NDF), crude fat (CF), Fe, and Mn. These differences were linearly associated with the content of plantain leaves in the pasture and were higher in summer and autumn than in spring. In conclusion, incorporating plantain into the RGWC pasture can improve herbage nutritive quality, thus potentially increasing farm productivity and environmental benefits. However, further work is required to investigate management interventions to sustain plantain content beyond two years from sowing. [ABSTRACT FROM AUTHOR]

Simple Summary: Plantain (Plantago lanceolata) has emerged as a forage with the ability to reduce nitrogen (N) losses, in particular N leaching, from grazing dairy systems. For farmers to confidently incorporate plantain into their farms, research needs to demonstrate that these environmental benefits sustain similar production and farm profit than traditional ryegrass (Lolium perenne)–white clover (Trifolium repens, wc)-based pasture. The effect of changing the cows' diet to plantain-based pastures was evaluated over two lactation seasons in comparison to ryegrass–wc pastures. Cows grazing plantain-based pastures produced the same milk solids production, but a urine with a lower N concentration when compared to ryegrass–wc pastures. Plantain reduced the urinary N loads from individual urine patches via higher urine volume and reduced the total N loading onto pastures via a lower urinary N excretion to mitigate the N leaching losses from grazed pastures. Plantain pastures could be employed by farmers to reduce the nitrate leaching from dairy farms. The use of plantain pasture in dairy systems can potentially reduce nitrogen (N) leaching losses via the lower N concentration in the urine (UNc) of cows. Reducing the urinary N load while cows graze pastures can reduce the risk of N leaching losses from urine patches. Research needs to demonstrate that these environmental benefits are not at the expense of milk production and farm profit. Three groups of 20 cows grazed in the following three pasture treatments: (i) plantain, (ii) plantain–clover mix (plantain, red [Trifolium pratense] and white clover), or (iii) ryegrass-white clover (wc) pastures, from spring to autumn for two years. Each year, pasture intake, diet quality, milk production and animal N (milk and urine) excretion were evaluated in spring, summer, and autumn. The cows grazing the plantain and plantain–clover mix pastures produced similar milk solids as cows grazing ryegrass–wc pasture but reduced their UNc during summer and autumn, when compared to those grazing the plantain–clover mix and ryegrass–wc pastures. Plantain reduced urinary N loads onto pastures by a greater number of urine patches with lower urinary N loading rates. The results demonstrate that plantain pastures do not diminish milk solids production from cows, and the lower UNc from summer to autumn could reduce N being lost to the environment. [ABSTRACT FROM AUTHOR]

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 yield (WMD = 23.4 g/cow/day, 95% CI = 11.3–35.5), maintained milk protein concentration and milk fat yield, but reduced milk fat concentration (WMD = −0.24%, 95% CI = −0.31 to −0.17). Feeding pastures containing plantain reduced total UN excretion by 22% (95% CI = 15–28), which was associated with a decrease of 30% in UN concentration (95% CI = 20–38) and an increase of 17% in daily urine volume (95% CI = 7–29). Subgroup analysis showed that cows grazing pastures containing plantain had a significantly higher milk yield in late lactation (WMD = 1.4 kg/cow/day, 95% CI = 0.8–1.9), but a similar milk yield in early lactation, compared to grazing control pastures. In addition, meta-regression analysis found statistical associations between the content of plantain in the diet and N concentration in urine (P < 0.001), daily urine volume (P < 0.001), and total UN excretion (P = 0.036). The results suggest that incorporating plantain into grazing pastures is a potential strategy for improving farm productivity, while reducing the environmental impact of dairy farms. • Pastures containing plantain decrease urinary nitrogen excretion by dairy cows. • The decrease in urinary nitrogen excretion is associated with plantain content. • Pastures containing plantain increase milk yield in late lactation. • Plantain inclusion reduces milk fat concentration but maintains milk fat yield. [ABSTRACT FROM AUTHOR]

Plantain (Plantago lanceolata L.) has been identified by the New Zealand dairy sector as an option for reducing nitrogen losses from grazed pastures. However, there is growing concern over its poor persistence. Reports have suggested that plantain does not tolerate waterlogged soils; however, there is little scientific evidence to support those claims. Thus, the present study aimed to investigate the impact of waterlogging on plantain growth and survival. In a glasshouse, three water treatments were applied to plantain plants in pots: control (soil water below field capacity but not limited), wet (soil water marginally above field capacity), and waterlogged (water table 5 cm below the surface) for 39 days, followed by 27 days under the control watering treatment. Leaf elongation and photosynthesis were measured during the experiment. The mean leaf elongation rate of waterlogged plants was 37% lower than control plants during the stress period, but not significantly different than control plants during the recovery period. Waterlogging reduced the rate of photosynthesis in plantain leaves by 15% on average in comparison with control watering during the stress period; however, waterlogged and control plants had a similar mean photosynthesis rate during the recovery period. The results show that plantain growth and photosynthesis were significantly limited under waterlogging; however, the rapid recovery of both processes following the removal of stress suggests that important physiological functions remained intact under waterlogging, possibly due to tolerance mechanisms. These findings suggest that while waterlogging may cause limitations for plantain growth, there is no evidence to suggest that it alone could cause irreversible damage to plants and thus prevent their recovery. Rather, waterlogging stress could undermine the ability of plantain to compete with species that are tolerant of waterlogging within mixed pastures. [ABSTRACT FROM AUTHOR]

Plantain (Plantago lanceolata L.) is recognised for its ability to improve summer feed productivity as well as mitigate nitrous oxide (N2O) emissions from grazed pastoral soils. This study aims to determine the proportion of plantain required in perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), or RWC, mixed swards to maintain yield stability and to quantify N2O emission reductions. The botanical composition was monitored when plantain was sown at different rates of 0%, 30%, 50% and 70% in RWC pastures under grazing by dairy cows over 2 grazing years. Urine from cows grazing RWC (6.15 g N L−1), 30% (5.40 g N L−1) and 50% (4.40 g N L−1) plantain mixed pastures was used to measure N2O emissions (n = 5) from the pastures of their origin and to assess the impact of the plantain rhizosphere on N2O emissions by applying the RWC urine to the 50% plantain mixed pasture, and vice versa, in late summer–autumn using the static chambers technique. After declining in spring, the plantain content recovered in early autumn and reached a peak of 40% in the 30% plantain mixed pasture and around 50% in the 50% and 70% plantain mixed pastures in winter. A lower N content in urine, and therefore a lower urine N-loading rate from cows grazing in the 50% plantain mixed pasture, resulted in 39% lower total N2O emissions compared to RWC urine treatment. In conclusion, 30% to 50% plantain in mixed pastures was stable throughout the 2 years, and it not only reduced the urinary N concentration in grazing cattle but also contributed to reduced N2O EFs. [ABSTRACT FROM AUTHOR]