Replace grass per serving? ... nooooo
In dairy production systems with access to pasture, the whole time you supplement with concentrated generate a substitution of grass.
The issue is that the intake of dry matter grazing is defined by 3 factors:
1.- The net time of grazing
2.- Snacks per minute
3.- The bite size
Various studies have shown that adding concentrates to the diet of a cow in pasture, the animal keeps the size of bite and the amount of bites per minute, but reduces the total time of grazing daily. This time decreased grazing does so at a rate of 12 minutes per kg of concentrate. Hence, the concept of substitution.
It is important to know that as it increases the supply of grass for the cow, increases the rate of substitution and decreases the answer in litres of milk/kg of concentrate. In this time of year (winter) offers are scarce, but from August the pastures and verdeos begin to grow at a higher speed and in a short time, we will offer a higher volume of green/square meter and we will begin to generate substitution significant.
As we can see in the following graph, with a replacement rate of 50% (usual value in the spring), the positive response is reduced to 600 cc of milk/kg of concentrate, and 3$/lt of milk and 1.8 $/kg concentrate, the marginal revenue is zero (zero).
A simple way to monitor the level of substitution is, once aware of largest deals of grass in the gaza strip daily, to reduce gradually the supply of concentrates to the level "...that the cow doesn't notice it..." in the sense that it does not lower your production.
Don't sleep, this will mean a big savings for the dairy farm.
Marcos Snyder