Milk production and urinary nitrogen excretion of dairy cows grazing plantain in early and late lactation

Can alternative forages substantially reduce N leaching? findings from a review and associated modelling

“…However, Wang et al (2015) noticed, in insect herbivores feeding on plantain, an increase in IG did not reduce intake rate but lowered growth rate, leading to the suggestion that PSM reduce the efficiency of nutrient utilisation. Interestingly, a similar effect has occasionally been observed in dairy cows grazing plantain or grass-clover pastures as a control, whereby greater apparent intake was measured for plantain but milk production was similar to the control (Box et al 2017b;Mangwe et al 2018). The theory that PSM may alter intake and nutrient use efficiency has been explored in greater detail for phenolics such as condensed tannins which will be addressed later in this review.…”

“…While animal species do vary in their urination patterns (Domingue et al 1991), we have also observed examples of diuresis occurring in dairy cows grazing plantain. Box et al (2017b) reported increased urine volumes with 50 or 100% plantain diets. Similarly Mangwe et al (2019) also showed increased urine volumes from cows grazing plantain compared with ryegrass clover.…”

“…PSM in plantain (aucubin and catalpol) have shown to be highest in concentration in autumn, supporting the hypothesis that these terpenoids are responding to cooler temperatures or increased insect pressure late in the milk production season. Anecdotal evidence that the palatability of plantain by livestock is lower in autumn (Bryant et al 2018) is likely to be linked to fluctuations in these compounds, and cow adaptation has been demonstrated to the overcome initial avoidance of plantain (Box et al 2017b). The advantage of high PSM which reduce rumen degradability in autumn may reduce the risk of high urinary N loading during this high risk period (Figure 1) and suggests plantain as a potential forage for reduced N losses.…”

Milk yield and urinary-nitrogen excretion of dairy cows grazing forb pasture mixtures designed to reduce nitrogen leaching

“…For example, changes in urine N concentration from spot samples could be due to differences in urine volume. Evidence of a diuresis effect of plantain had previously been demonstrated in sheep (O'Connell et al, 2016), dairy heifers (Cheng et al, 2017) and dairy cows (Box et al, 2016(Box et al, , 2017. Although no specific plant mechanism has been attributed to the observed increases in urine volume from ruminants fed plantain (O'Connell et al, 2016;Box et al, 2017), it is accepted that, generally, urine volume is influenced by water and/or mineral intake such as sodium (Spek et al, 2012).…”

Establishment of plantain into existing pastures

“…Animal and lysimeter studies have demonstrated the efficacy of forages such as plantain (Plantago lanceolata) and Italian ryegrasses (Lolium multiflorum) to reduce N losses (Bryant et al 2018;Totty et al 2013;Woods et al 2016). When plantain accounts for 30-50% of the diet of dairy cows, urinary N concentration and estimated N excretion is reduced by more than 20% with no compromise in milk yield per cow compared with conventional ryegrass clover pastures (Woodward et al 2012;Box et al 2017;. Ease of adoption of plantain-based pastures within farm systems is not yet known, but initial data from commercial farms indicate that high plantain contents in mixed-species pastures can be achieved in the first years after pasture renewal, but cannot be maintained .…”