Not surprisingly, this had a severe inhibitory effect on pasture growth, which, in turn, resulted in some significant management rethinking and decisions at the demonstration farm. Regular readers of this column will recall that the trial here is a comparison between the traditional low-cost system, relying almost exclusively on pasture and homegrown pasture-derived supplements for feed, and an intensive system with a much higher stocking rate and an unrestricted allowance to buy in additional feed, primarily palm kernel and maize silage.
In March the rapid decline in pasture growth rate combined with the increasing browning-off of pastures obviously raised concerns. But these were largely confined to the traditional herd.
While the declining volume of available pasture was ertainly having an impact on the intensive farmlet, the problem was easily avoided by purchasing and feeding more palm kernel.
The high use of palm kernel has certainly changed the face of New Zealand dairy farming. If nothing else it gives farmers the confidence to stock up and sail closer to the wind, knowing that if things don’t go as planned and the season goes against them they can always bail out with extra palm kernel.
This can be done knowing that feeding the palm kernel will be profitable unless there were some very unusual circumstances.
The sums to show this are simple. An average cow will get through 4500-5000kg drymatter (DM)/ year, depending on liveweight and production. Let’s assume over that period she produces 320kg milksolids (MS). At $7/kg MS this would gross $2240. However at 35c/kg DM, 5000kg DM in palm kernel would cost $1750 giving a fair profit margin, and indicating it would be quite profitable to feed cows nothing but palm kernel and/or equivalently priced supplements and still show a reasonable profit.
As this ignores all the other costs of running a cow, such as animal health, breeding costs and dairy expense, the message must be, as the TV presenters say, ”Don’t try this at home”.
While the economics of this total feeding of bought-in feed are extremely dubious the same does not apply to making up a shortfall of feed at the end of the season. This is because we are looking at existing cow numbers, so most annual cow running expenses have already been met, notably animal health and breeding.
This means there’s little cost in continuing to milk. Extra dairy expenses and electricity are the most relevant costs but they’re very small.
Bearing this in mind, let’s look at the situation on a normal commercial farm where an autumn shortfall of feed is occurring. The option is to dry off the cows in order to reduce feed demand and balance the winter feed budget, or buy in palm kernel and keep milking.
Again the sums are simple. Given a feed quality of 11 MJME/kg DM, an average crossbred cow will take about 80 MJME to produce 1kg MS. Add another three to cover the energy required for the extra walking to the dairy.
Dividing this by the 11 MJME/kg DM feed value gives a drymatter requirement of 83kg DM ÷ 11kg MS = 7.5kg DM. If the bought-in feed is costing 35c per equivalent kg DM then the kg of MS produced will have cost 7.5 x 0.35 = $2.63. Even after allowing for a few marginal costs this will still give a fair bit of change from the $7-$8 generated.
So in a normal commercial environment, in the situation of limited autumn feed reserves it makes good economic sense to buy in palm kernel, or any other similarly priced supplement, to keep on milking.
Unfortunately this option is not available on the low-cost traditional farmlet as palm kernel fails to qualify as either low-cost or traditional. This meant there was only the one option available and that was to dry off the herd early.
A feed budget calculated in late March indicated this would need to be done before Easter to ensure cows could be adequately fed through winter and there would be sufficient feed on hand at calving time.
This was done, with all cows in the herd dry by April 16. A new revision of the feed budget then showed a deficit situation existed, and this remains the case in mid-May. Admittedly the deficit has lessened over the past month, due to some above-average pasture growth. It’s now equivalent to the feed calculated to get the cows to the desired condition at calving. Hopefully the good growth will continue and this small deficit will be eliminated.
If not, with cows currently at body condition score (BCS) 4.5 the priority will shift to ensuring there are adequate feed reserves at calving to ensure full feeding from then on, rather than feeding to ensure BCS 5 at calving. As a result of doing this a punitive feed shortage will be caused in September – what is known as choosing the lesser of two evils.
This illustrates a weak point in feed budgeting. With a normal winter feed budget, the critical growth rate data will be for April- September. In the average year these estimates will be close enough to the final results for reasonably accurate planning, on the basis that the small unders and overs will tend to balance each other out so the end result will be pretty much that predicted and planned on.
Not so in a very dry or drought year.
In this instance, with growth close to zero, it’s impossible to predict with any sort of reliability when adequate soil moisture levels will be restored and pasture growth begin again.
The longer the dry conditions continue the longer and more protracted will be the eventual recovery.
Dry but still viable pasture will recover quickly and well once soil moisture is restored – it will grow from the leaf. But completely brown and burnt-off pasture will have a much longer recovery, as it has to start growing again from the roots. The longer the dry period goes past that budgeted for recovery growth, the more the delays and slower growth of the recovery period will be exacerbated.
This was the situation for the low input farmlet and the choice was no choice. Drying off had to be done on a safety-first conservative basis. Even with this approach it would appear we got it a bit wrong.
For the high-input farm, and for the normal commercial farm, none of these dilemmas exist. The farmer can take risks and there will be no agonising choices of the lesser of two evils. Security and surety lie with the knowledge that even if things go horribly wrong disaster can easily and profitably be averted by buying in palm kernel.
