News & Advice

Lambing Percentage

Nov 2, 2018 | Dry stock, Sheep

Ali Cullum, Veterinarian, Anexa Vets Morrinsville

Want to make the most of your ewes?

How many lambs do you have? And what are you doing with them now? Key Performance Indicators (KPI’s) are important and enable you to benchmark your business against others, to set goals, and make performance improvements for the coming years.
Your docking (marking, tailing) is probably over; do you know what your lambing percentage for this year is?

To calculate this KPI, you need to know:

  • Number of ewes mated
  • Number of lambs docked or tailed
  • Divide 2/1 and multiply by 100 to get the answer

For example, we had 1500 ewes mated and we docked 2200 lambs
2200/1500 = 1.47 x 100 = 147%

What does this mean and what can be altered?

It means that every ewe has reared 1.47 lambs to tailing. Beef and Lamb have some great business tools, and you can use their Lambing Calculator, available on the B+LNZ website at to see how you compare (147% is just better than the national average). Theoretically, every ewe can rear two lambs, and this should be our aim to make the most of the ewe maintenance unit. There are many factors that alter our ability to achieve this. Some factors are controllable, some are limitations of the ewe, some are farm and management practices, and some may not be able to be altered. We need to think now about what factors are involved for our own farms and what we can control for the 2019 lambing season.

First the ewe – is she able to ovulate two eggs and have them both conceive a foetus? This is called ewe fecundity and it is affected by breed and nutrition, then she has to be effectively mated by a ram.
So, we have ewe breed, health, and nutrition, ram breed, health, numbers of ewes to ram.
Then are the conceived lambs able to be carried through to birth? Again, health and nutrition during pregnancy are important.

Then when the lambs are born, are they deposited into an environment in which they can survive? Weather can play a big role in this, but also shelter and ewe nutrition and milk production are important. If you would like help to tease out what factors affect your lambing percentage and how you can improve for next year, talk to your local Anexa Vet – we are here to help.

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