Herd Inventory and Growth

Excel Formulas › Agriculture & Farming

All versions

Track a herd through the year — opening count plus births and purchases, minus deaths and sales, equals the closing count. It’s a simple flow balance that must always reconcile.


Quick formula: closing herd from the flows:
=opening + births + purchases - deaths - sales
Start with opening head, add births and purchases, subtract deaths and sales for the closing count.

The example

200 + 60 + 10 − 5 − 40.

AB
1ItemValue
2In − out+25
3Closing→ 225

The formula

The formula:

=opening + births + purchases - deaths - sales // opening + ins − outs

How it works

How it works:

  1. Start with the opening count for the period.
  2. Add the ins — births and purchases.
  3. Subtract the outs — deaths and sales.
  4. The result is the closing count, which becomes next period’s opening.

A herd is just a running balance. Each closing count rolls forward as the next opening, so a column of months reconciles automatically — and any month where the math does not match a physical count flags a missed birth, death, or unrecorded sale. The same opening-plus-ins-minus-outs pattern tracks any inventory: hay bales, breeding stock, or culls.

Try it: interactive demo

Live demo

Opening, births, purchases, deaths, sales.

Closing:

Variations

Net change

Ins − outs:

=(births+purchases) - (deaths+sales)

Death loss %

Mortality:

=deaths / opening

Calving / birth rate

Per breeding female:

=births / breeding_females

Pitfalls & errors

Roll forward. Closing becomes next period’s opening — chain the months.

Reconcile to a count. A physical headcount should match the formula.

Separate ins and outs. Births/purchases add; deaths/sales subtract.

Practice workbook

📊
Download the free Herd Inventory and Growth practice workbook
A herd-inventory sheet with the net-change, death-loss, and birth-rate variants, plus 4 challenges with answers. No sign-up required.

Frequently asked questions

How do I track herd inventory in Excel?
Balance the flows: =opening + births + purchases - deaths - sales gives the closing count.
How do I calculate death loss?
Divide deaths by the opening count: =deaths / opening for the mortality rate.
How does the herd roll across months?
Each month's closing count becomes the next month's opening, so the column reconciles automatically.

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