Vertical mixer, feed pad gives flexibility to grass-fed system

Their philosophy is to look after their cows and get them back in calf. Their stocking rate is 3.3 cows/ha, and production 530kgMS/cow/annum.

A key part of the system is keeping animals well-fed by way of a total mixed ration (TMR) regime centred on the recent arrival of a new Keenan vertical mixer, the first delivered in New Zealand, and a significant departure from the better known paddle mixer sold by the company for 30 years.

The Hunters were already Keenan converts, having run the traditional machine for several years at a previous property; the change to a vertical format machine arose from a need to increase mixing capacity without the need for a larger tractor to cope with a steep site.

The vertical format allows this at a lower machine weight and greater capacity.

Feeding at a rate of 13kgDM, the mix typically comprises straw, soy hulls, DDG, tapioca, maize silage, PKE, whey product, molasses and urea. As grass growth comes on stream the ration is typically reduced to 7-8kgDM to make full use of the core product.

Pam Hunter says “the TMR produced by the Keenan is a means of complementing our grass-based system. Grass will always be our main source of feed for the cows, but the mixer and feed pad give us flexibility”.

“During heavy rain such as we have recently encountered we can keep cows off the paddocks. In periods of drought we have much more stability and consistency.”

Looking at the machine in more detail, the VA2-24S comprises a tub with two vertical augers, driven by Comer gearboxes to transfer PTO input into a reduced rotational speed.

A heavy-duty chassis carries three load cells for accurate weighing at about +/- 2%, with mixed material being delivered to a front mounted, bi-directional delivery conveyor. Additional chopping blades can be introduced hydraulically into the tub to create a finer mix when required.

Comparing the end-product to their experiences with the conventional Keenan, the couple see little difference in mix quality, except that very dry straw isn’t chopped quite so well and care needs to be taken with low volume ingredients such as magnesium flours to ensure they are incorporated thoroughly.

This is confirmed by Danny Nathan, the third member of the farm team, whom the couple describe as “the glue in the system”, getting things done in a calm and methodical way that belies his youth.

Nathan draws attention to the Keenan PACE system fitted to the machine, by which ration composition is input, then giving a visual display of the ingredient type and weight required during loading, based on the number of cows being catered for.

Any adjustment of the diet required by changing cow numbers or more reliance on grass is also easily accommodated.

Overnight, an integral SIM card transmits the day’s activities to a central database, which sends details of the loads mixed and amounts fed to the users. This can be used to compare daily milk collection data, so giving an early warning of developing trends.

Completing the package is 24/7 support from the Keenan distributor in nearby Morrinsville; operational and technical support are given by Padraig Meany and nutritional advice by regional consultant Seamus Callanan.