Minnee and DairyNZ scientist Julia Lee trialled crops of Agricom’s Choice Chicory in 2010-11 and 2011-12 and evaluated the effect of supplementing a perennial ryegrass-based diet with chicory at various levels in late summer and early autumn.
The trial compared cows eating chicory for 20-40% of their diet, against cows eating only ryegrass and white clover pasture.
Cows with chicory in their diet had an average 19% increase in milk yield (litres/cow/day) and 17% increase in milksolids (MS) (kg MS/cow/day).
“We did see a trend of increasing milk yield per cow per day with increased amount of chicory in the diet, but this did not always translate to greater MS yield,” Minnee said.
The milk yield largely depended on the quality of the pasture fed alongside chicory. Gains were achieved through a greater quality of chicory and/or greater drymatter (DM) intake.
Cows with chicory in their diet ate 0.6-1.2kg more DM than cows on pasture-only. This was an average 6% more DM intake.
The milk production response would require further research in a farm system context to take into account the full effect of incorporating crops, such as the time between spraying out pasture and when feed was available, Lee said.
“But we see chicory as a good option in a pasture renewal programme, as a break crop to improve soil structure and reduce weed and grass-specific pests.”
Chicory could make up to 60% of a cows’ diet with no observed ill-effects on rumen health, Minnee said.
Chicory had high digestibility and was quickly broken down in the rumen, which could result in low rumen pH, but there was no indication of this, she said.
‘We see chicory as a good option in a pasture renewal programme, as a break crop to improve soil structure and reduce weed and grass-specific pests.’
Allocating chicory must be done carefully. The DM% ranges from 10% to 15% so yields can vary and there is the potential for both over- and under-estimation.
DairyNZ recommends cutting 0.25m2 quadrants to a 5cm height at four different sites in the paddock. Weighing the four samples and then multiplying by 10,000 gives an estimate of the fresh weight per hectare. Drying a 200g sub-sample of the fresh chicory in the microwave and then weighing the dry weight. Dividing the dry weight by 200g (the fresh weight of the sample) generates an estimate of DM%. Multiplying the fresh weight/ha by this DM% calculates the average DM/ha for the chicory crop.
There is another, less accurate, rule of thumb recipe – a pre-grazing height of 25cm roughly corresponds to 3000kg DM/ha, though this would depend on plant density, and a residual grazing height is about 1500kg DM/ha. This equates to 1500kg DM/ha of chicory available. If the target daily allocation is 6kg DM/cow, dividing the 1500kg DM/ha available by 6kg DM/cow gives the number of cows that could be accommodated per hectare – in this example 250 cows/ha. To calculate area per cow required for 6kgDM/ha, dividing 10,000m2 – one hectare – by 250 cows/ha, generates 40m2/cow.
For the first couple of grazings while the crop is still establishing, whole paddock grazings might be the best approach, before transitioning to back-fenced (if required) breaks. To maintain a daily allocation of 5-6kg DM/cow/day, 5-6ha of chicory is required for every 100 cows. If carrying through to a second season, the impact of this amount of area out of winter production, as chicory is dormant over the winter, needs to be considered.
If considering taking the crop through to a second year, DairyNZ guidelines suggest a minimum plant density of 25-30/m2. A lower population density could affect yields. Pre-grazing plant height for the first post-winter grazing should not exceed 50cm. Second-season plants have a stronger tendency to bolt and go to seed, potentially impacting on feed value and palatability if not managed properly.
Get the latest information and advice from DairyNZ on growing and feeding chicory.
