The level of energy in pasture plants during spring has a marked influence on the total season’s production.
Cows that do not lose weight after calving are able to produce more during the coming season. It is simply more efficient to maintain or gain weight during lactation than losing it in spring and attempting to gain it again at some other time.
Short frost damaged grass abundant on properties monitored this spring is highly palatable and contains much of what cows need soon after calving. Fibre levels are relatively high, dry matter is low, and stock are easily satisfied on what appears to be a meagre amount.
More rapidly grown grass has recently been measured at 14% – 20% dry matter with brix levels of 9.5. Slower growing grass was measured at 20 –28% dry matter with brix levels of 11 – 13.5.
We are still learning the relevance of brix to animal performance however properties monitored where stock are grazing high brix pasture this spring have low somatic cell counts, very few cases of clinical mastitis, and a low incidence of calcium/magnesium related metabolic disorders.
Pasture energy levels are directly related to sunshine hours and the ability of the plant to photosynthesise. Photosynthesis is the process by which plants utilise sunshine to build energy, which is then fed to animals to produce food.
Soil temperatures largely govern the increase in the rate of growth in spring, with the greatest influence being direct sunshine hours. Springs following dry frosty winters usually receive more direct sunlight.
It may therefore be that the apparent low pasture covers worrying many this spring contain as much energy as greener, taller, lower dry matter pastures typical of August, and energy is the key to production.
Regular monitoring of brix levels on properties using Golden Bay Dolomite based nutrient programmes over the last two years has indicated that as brix levels in pasture increase so too does animal weight and total production. There also appears to be a corresponding decrease in somatic cell counts and the incidence of clinical mastitis.
The ability to increase plant energy levels regardless of how they are measured is the ability to provide an environment that suits the plants we wish to grow and the provision of all nutrients as required by the plant.
Friable soils with excellent crumb structure provide the best medium for pasture plants. Excellent structure is achieved by ensuring biological activity is maximised and this is achieved by providing regular inputs of calcium as calcium availability drives beneficial soil biology. Dolomite contains both magnesium and calcium in the proportion beneficial to plant and stock health.
Well-drained friable soils are also able to hold more moisture. The root zone on monitored properties is often as deep as 0.8m. This ensures that growth throughout the drier months of January, February, and March is maximised. With strong pasture and animal production during this time a successful outcome to the season is largely guaranteed.