Key Performance Indicators (Age at first calving)

KPI – Age at 1st Calving


In this second article I want to look at the KPI for Age at 1st Calving. If we look at the 2010 KPI, the average Age at 1st calving for the Guernsey breed is currently 2½ years.




Compared to the Jersey KPI below



The average cost of rearing a replacement heifer to calve down at 2 years is approximately £1300. For every additional month look at adding a cost of between £30 – £45 a month.


By calving at 2 years of age the heifer is now contributing to the herd and starting to pay back on the money invested in her so far. If you assume that an average heifer will give 4,500 litres in her 1st lactation and that the average milk price is 27ppl then this animal will have reduced the money you have invested in her by £1,215 by the time she is 3 years old. By the time she has ended her 2nd lactation she could be free from debt and contributing to the farm profit.


The top 25% of Guernsey herds calve their heifers between 2 years and 2 years four months. Eight of the 33 recorded herds achieved this. Only three herds calve their heifers at the age of three years and above. The Guernsey breed average is two and a half years age at first calving.



Five years ago, the average Age at 1st calving for the Guernsey breed was 1,010 days, now the average Age for the breed at 1st calving is 977 days.This is an improvement of 33 days but is still behind some other breeds.


The graph below compares the Age at 1st calving trend of the Guernsey breed to Jerseys and Ayrshires




As you can see, the average Guernsey herd (the blue line) has improved the age at 1st calving over the last five years by 33 days. The Jerseys have reduced by 54 days and the Ayrshires roughly the same.





What are the benefits of calving heifers at two years of age?


For example : Assume an average milk price of 27ppl and you have 20 heifers entering the herd calving at 2 years 7 months, then an extra milk income of £14,140  could have been achieved if they had calved 7 months earlier.


Look at your farms Age at 1st calving, if you don’t know your farms figures then NMR users can look on the Herd Companion site for their information or the paper copy Annual Summary.


Work out how many heifers entered the herd in the last 12 months take their average lactation yield, divide it by 12 to get an average monthly milk yield for the heifers, multiply by your average milk price to get the monthly income then multiply by the number of heifers that entered the herd last year. The end figure is the amount you could potentially earn in additional milk income for every month you knock off the Age at first calving. The sooner they calve, the sooner you start recouping your investment in them.


Remember, statistics show that 16% of all heifers that calve will never go on to a have a second lactation. Recording information also shows that of these 16%, over half (64%) had been served before they ended up being culled. These heifers that were culled in their first lactation had only partly repaid the money invested in their rearing.

You may have valid reasons on your farm for calving heifers at 2½ years, perhaps you can’t achieve good growth rates or perhaps that’s how it’s always been done. But take a moment and look at your setup to see if perhaps you can knock a month or two off your average Age at 1st calving and reap the financial rewards..



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