DairyNZ Farmers Forum with Sue Edmonds

Having written mainly about mostly grass dairy systems for years, I was astounded at the complexity of running a System 5 farm on my first visit to one recently, which was demonstrating how they’ve been making a profit by autumn calving and winter milking.

If a farm’s dairy platform is only 53ha, and 10ha of that is growing maize silage and annuals, what do they feed 240 cows on? Well, grass only partly comes into it.

The concrete feed pad can fit the whole herd, with long mangers down each side, filled with an obviously palatable mixture of molasses, corn, canola, Palm kernel Expeller, barley straw and hay, with the moisture provided by chopped potatoes. These come from a nearby spud farm as rejects at a very good tonnage price. There is also some in-shed feeding of pellets and corn-gluten pellets when needed. Fully fed is the mantra here.

There’s some carefully grown ryegrass for spring grazing, but no weeds allowed, and the oversown clover wasn’t making much of an appearance. And winter grazing is minimal. However, they haven’t used urea in 10 years, and fertiliser consists of lime and trace elements, with some sulphate of ammonia spread in winter. The cropping soil obviously gets turned over regularly, and no mention was made about the pasture soil, but the ryegrass is renewed when needed.

Autumn calving

The dry and pregnant cows, Friesian-crosses, looked beautiful and were obviously used to people, as some of us standing in their paddock were being licked over and over.

So, to date, autumn calving with a February 21 start and system 5 have worked well. But now one or two problems have arisen externally. Initially beef-only sires had been used to maximise the return on autumn-born calves. But to keep the system going at peak, there has been quite a bit of buying empty cows, fattening them up and, if not producing enough to mate, selling them as prime. But Mycoplasma bovis is putting a stop to being able to find ‘safe’ cows to buy. And the hotter summers, due to climate change, are making largely black cows more subject to heat stress hey are now experimenting with finding a breed that copes with heat when pregnant, milks well, and gets in-calf.

Heat stress

DairyNZ people are now getting clued up on heat stress in cows, and it was interesting to find the temperature differences between us and cows which causes stress. They feel it at lower temperatures than we do, and with streams fenced off, and often little in the way of shade plantings, hotter summers will probably mean lower milk yields, whenever calving is done. And they will drink a lot more too.

High fibre foods – such as poor pasture quality or silage quality, straw and hay – increase the heat in the rumen and the heat load on the cow. Humidity plays a part too, and Jersey cows may fare better than Holstein/Friesian and Kiwi Cross as the climate heats up, and the darker cows yield progressively less during summer.

So, it doesn’t seem to matter how you farm, and what you milk, life is going to get more complicated while farmers continue to strain for increased production, even if Fonterra moves to value rather than volume.