Monday, 15 June 2020 11:52

Pitfalls of dropping feed, not herd size

Written by  Greg Jarratt, vet and director of Matamata Veterinary Services

Greg Jarratt, vet and director of Matamata Veterinary Services, on why farmers shouldn't reduce feed without also destocking.

The main goal of any dairy producer is to successfully convert low quality feeds to high-value dairy products.

Success in achieving this goal can be assessed by looking at a single metric known as ‘Feed Conversion Efficiency’ (FCE). 

FCE is a simple calculation that defines the amount of feed (grown and purchased) required to produce 1kgMS. 

Here in NZ there is a large range in this metric. Top operators successfully convert approximately 10kg DM to 1kgMS while at the other end of the spectrum some farmers struggle, needing twice the amount of feed for the same result. 

Because in many systems feed purchased is a significant cost, FCE is a very important driver of profitability, regardless of which farming system you run. 

This is where stocking rate becomes really important. Overstocked farms will have higher maintenance costs relative to the same farm with fewer cows. Because of this, FCE on overstocked farms will be lower as more feed is partitioned towards the greater maintenance cost required in overstocked farms, leaving less feed available for milk production.

Making things more challenging this season is the large moving target of milk payout. Farmers will need to be on their toes when making calls around farm operating expenses including feed. 

Who knows where this year may end up and there will certainly be winners and losers depending on the ‘gearing’ of farm systems in the current volatile environment. Many farmers will have to ask themselves throughout this coming season if additional feed purchases will make or break the budget.

The important point here is, if you are considering pulling back on inputs, make sure you keep a close eye on stocking rates. Failure to address cow numbers as inputs are reduced will inadvertently reduce FCE, which may well expose the business to greater risk.

Thankfully, there is a lot of very sound information available to farmers around stocking rates. 

The most relevant of this information is on the topic of Comparative Stocking Rate (CSR) which is measured in kg live weight per tonne feed supplied. 

Because of today’s large variation of farm systems CSR helps compare apples with apples.

Higher CSR’s indicate the farm is overstocked and a greater proportion of feed supplied to animals is partitioned towards maintenance of more animals, and therefore less partitioning towards production.

Lower CSR’s also pose an issue as there is a limit to the amount of feed any cow can ingest. 

Generally a CSR of approximately 85kg DM/tonne feed appears to be the sweet spot on most NZ farms.

So, the take home message is pretty simple – if you’re pulling feed, don’t forget to destock. Often we see farmers pull feed and think the cows are going to miraculously harvest the deficit from pastures. 

While hungry cows tend to harvest more, in just about all cases they cannot replace feed removed from diet leading to an increase in CSR and a decrease in FCE.

This coming season it will be important to have a few options at the ready. Now is the time to start putting these options together and talking these through with your farm advisor. Adaptability will be king!

• Greg Jarratt is a vet and director of Matamata Veterinary Services.

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