January 21, 2009

Cattle farm husbandry – feed budgets

Cattle, farming, husbandry, feeding, feed budgeting, how to do a budget, managing a feed deficit and feed surplus.

By Dr Clive Dalton

Feed budgets
Doing a feed budget is the best way to see if you have enough feed for the stock on the farm. Here are some basic things you need to know before starting:
  • There are two sides to the budget – the IN side – i.e. the DM in the feed you have, and the OUT side or DM needed by the stock.
  • Do the budget calculations on a “per hectare” basis for the farm. Always think per hectare.
  • You can do the feed budget using ME values too which is more accurate, but here we will stick to DM to keep things simple.
  • Get an experienced farmer or consultant to help you with the first feed budget, and then once set up, you can put in the values for subsequent budgets.
  • Doing a budget gives you the confidence that at least you know what’s going on – and if you have a feed deficit coming up, you can see it in good time and are not caught out like so many people seem to be.
  • Once upon a time, the long-hand arithmetic of a feed budget nearly drove us mad, but a consultant will show you all sorts of simple and smart ways to do this now on a computer spread sheet or commercial package.

When to do a budget?
In a grazing situation, start a regular monthly feed budget in autumn from the date when the animal feed needs exceed pasture growth on your farm. Stop when your feed supply exceeds the animal needs in spring. In winter as the feed gets tight, then do a weekly budget to keep you on track.

How to do a budget?

Step 1: Measure the feed on the farm
  • Walk the entire farm and estimate the DM on each ha. Use a pasture meter or learn to estimate it by eye from other farmers or at discussion groups. Any dairy farmer will show you.
  • You will need an accurate farm map with the area of each paddock on it. Make copies and take this map around the farm with you to write on. Laminate a copy so you can write on it and wipe it clean again.
  • Calculate how much DM is stored as hay. You can easily weigh small hay bales or you can accept the description of big bales of hay e.g. 12 bale equivalents. It’s better to get them weighed somewhere if you can.
A conventional square bale weighs around 30kg and is about 20kg DM

  • For silage stacks calculate the volume (volume = length x width x height) and use the density figures in the Table below to get a weight. Note they are very general values so use scales to weigh a bale where possible.
  • With crops it’s more difficult and you’ll have to weigh a few random square metre sample areas of crop, then get the DM from a sub sample and then calculate DM per hectare.
It's hard to estimate the DM from a turnip crop
as you have both tops and bulbs to sample

  • Now comes a tricky bit. You’ll have to estimate how much feed will grow over the coming period of the budget and include this.
  • You can use average figures for the district or your own values collected over time. Table 19 below shows pasture growth for the Ruakura Research Centre in the North Island of New Zealand where it has been measured for over 40 years. It grows about 15 tonnes of DM/year.

Step 2: Estimate the stock’s feeding needs
  • Calculate the DM feed needs for every animal on the farm. Typical figures that you’ll need are shown in tables 5 and 6.
  • You’ll need to add to this what is called “feed carried forward”. This is feed you need at the end of the budget period as it’s no good getting to the end of the period and have eaten all the feed on the farm. It’s “carry-over” feed and plan to have at least 1950 kg DM/ha for this.

Does it balance?
Now you’ll be able to see from the difference between Step 1 and 2 if things balance or you may find you have a feed deficit or a feed surplus. Here are some suggestions on how to mange each:
Managing a feed deficit
With a deficit there are three things you can do - some good ideas and some not so good! Remember you have to consider the farm, your management and work load, and your bank manager: Bank managers don’t like surprises! Consider these:

1. Reduce feed demand
  • Sell all culls and surplus stock.
  • Draft stock on the basis of their condition score and give the low CS animals the best feed.
  • Dry off some or all lactating cows, and wean calves from suckling cows.

2. Increase feed supply
  • Apply some nitrogen fertiliser if the 10cm ground temperature is above 6°C and the soil is moist. This should boost feed, provided all other soil nutrients are at adequate levels.
  • Buy in some supplements such as hay, silage, surplus crops or concentrate meal.
  • Graze animals off the farm. Check the Tb status of the farm they are going to before you move them.
  • Slow down the rotation to give the pastures time to grow. But you will have to feed supplements during this time to make up the difference.

3. Reduce production targets
  • Delay the date of making silage.
  • If you have paddocks closed for silage or hay, open the gates and feed your stock.
  • Accept that you will have thin stock and this will affect their performance. This is not a good decision!

Managing a feed surplus
Grazing a hay crop! A big waste of pasture

If you have a feed surplus, first check that you have you done the sums correctly? Is the surplus real or a misplaced decimal point? Don’t tell anyone till you have double-checked the figures.
  • If it’s a true surplus, then rejoice and enjoy the peace of mind.
  • But then start to worry about it going to waste.
  • Feed your stock more and let them convert it into body condition, and enjoy looking at them!
  • Sell some surplus as silage or hay.
  • Take on grazing stock from farmers who are overstocked.
  • Delay weaning calves off cows.
  • Buy in some stock as grazers.

This material is provided in good faith for information purposes only, and the author does not accept any liability to any person for actions taken as a result of the information or advice (or the use of such information or advice) provided in these pages.

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