Macalister Demonstration Farm Update 480
(Week ending 27th September, 2018)
The next paddock on offer at the MDF has 1,200 kg DM available per hectare, is 38 days rested, and is at 2.4 leaves regrown, indicating a Leaf Appearance Rate of 16 days and with 32 kg DM grown per ha per day.
As it should be, the second leaf is very much bigger than first, showing that the growing conditions (especially soil moisture) were good while it was growing. Generally, soil moisture across the paddock is very good. Large clover leaves show that the P and K is OK, but the ryegrass leaves are not quite a dark enough green, indicating a shortage of Nitrogen. A reminder that the trace element Molybdenum (and Copper) should be applied every five years. The grass quality is very good, leafy, no rising seed heads yet, but some dead leaf tips. A frost will do that, especially if the plant is a bit stressed by slight lack of water and/or Nitrogen.
The paddock just grazed shows that the cows were a little hungry (they were bellowing at me) with grazing a fraction too hard for both the grass regrowth rate (it was left at 3 cm between the clumps) and for the cows (grazing hard up to the edge of the manure/urine clumps). The cows would eat more if it was available. Their manure is a bit sloppy, but acceptable, considering the transitioning cows, and the fibre level in the diet. Fat test is still a bit low, but it is hard to justify feeding a forage when it is so expensive and milk fat doesn’t command much money.
There is currently a very difficult decision to be made. Is very expensive concentrate at $500 per tonne DM worth feeding? The answer lies firstly in the physical response, then the financial response.
An indicator is in the Table under “average litres per Kg DM fed per cow”, that is, the physical response to feed. The cows are producing 25.7 litres. If we divide that by the 15.5 kg intake it gives an average response of 1.66 litres of milk per kg of intake. But this average is confounded by two main issues – firstly, some of the food (say 5.5kg) is used for cow maintenance so generates no milk, and secondly, a few litres (say 3) are coming from the cow’s back. So, we should recalculate: 22 litres divided by 10 kg intake that produces milk to give us the average response to food above maintenance of 2.2 litres per kg. Not for one minute am I suggesting that if a cow was fed one more kg, a marginal kg, it would definitely get a response of 2.2 litres, but that is the current average position of the MDF cows. With a milk price around 40 cents a litre, the price depending mostly on fat and protein content, and with concentrates at 50 cents per kg, any physical response above 1.25 litres provides a positive financial response. So even at $500 per tonne for concentrates the MDF is probably making money on the last kilo fed.MDF Fortnightly update 480 2018-09-27