I couldn't have done this last year, but this year with the wet spring and 100mm in November, the kikuyu is green and suitable for tissue testing. So I grabbed the opportunity and will also be getting blood tests on two mobs of lambs this week. This is to just check on a few observations of some lines of lambs growing slowly, and others that are growing much faster.
As you can see in the photos below, which are all from one paddock on the same day, there are distinct differences in the pasture growth.
Some areas where the ryegrass has been eaten down less and the kikuyu is smaller, are where I have added too much lime (it's where I first practiced driving the tractor and calibrating the lime spreader). I noticed zinc deficiency earlier in the year in those areas, even though plenty of zinc had been spread. So I spread more and did a foliar spray in early spring.
In other areas where it is wetter, clovers are still growing, and in other areas, the ryegrasses have been grazed much better and allowed the kikuyu to thrive better.
What I am looking for in the plant tissue tests, and the blood tests in different lamb mobs, is to see if a nutrient is too high, or something is still too low. Or both could be happening - example zinc too low because of the high lime in areas, and molybdenum being too high for the same reason. Molybdenum is more available in higher pH soils.
Or it could all be ok and genetics could be the main cause. We'll know in the coming weeks.