Is calving index important for higher yielding herds?

Published 1 October 09

Piers Badnell DairyCo south west technical extension officer looks at the financial and health and welfare facts behind the classic fertility benchmark.

The national average calving index is 420 days.  This has risen over the years along with yields, and there are some who believe that a higher calving index doesn't matter if yield remains high. This is largely because it is at calving when more problems occur with the cow, so fewer calves means fewer problems. 

However, I would suggest this is short sighted as problems around calving need to be addressed, not avoided, and the reason for this is demonstrated in the table below:

 

 

Calving Index

Yield

Annual  Milk Income

Herd A

150 cows 8000 litre lactation yield

420 days

1,200,000 litres in 420 days equals  1,042,857 litres in 365 days at 22.99p/l*

£239,752

Herd B

150 cows 8000 litre lactation yield

375 days

1,200,000 litres in 375 days equals 1,168,000 litres in 365 days at 22.99p/l*

£268,523

*(ave. farmgate milk price July)

That's a difference of £28,770 or £192 per cow, a huge amount of money, it almost pays for someone to be employed just to deal with fertility!  Milk sold per year is THE measure.  Milk sold per year is important and we need to maximise this to increase our incomes, herd A has the same costs as B but so much less income to supply profit.

But can an 8000+ litre herd achieve a 365 day calving index?  The answer is yes, and there are a good number of herds doing it and at higher yields, however, a good target is 375 days and below.

How do they do it? The key is attention to detail. It isn't one thing but lots of little things and doing everything right. The jigsaw below shows these "things."

 This can be broken down into three parts:

  • Preparation for service - this includes cow condition, transition, herd health, calving, and using your vet well to get a return on that investment.
  • Service and pregnancy - keep records, service, AI/natural, herd health and good use of the vet.
  • Maintenance of pregnancy - Herd health - IBR, Neospora, Leptospirosis and BVD.

What are the indices you need to achieve?

  • Calving to first service 65 days
  • Calving index <375 days
  • Culls barren <6%
  • <2% abortion, 2% embryo loss
  • First service conception rate >50%
  • Submission rate 50-70%

Serve cows at first opportunity after 50 days, and present problem cows and all cows not served by 70 days.  Heat detection is critical so use action lists to enable you to concentrate on the right cows and to identify problem cows.  It is easier to improve heat detection rates by 10% than pregnancy rates by 10% so go for the easier route.  Enable the cows to show signs of heat through good housing floors and space.  A cow must be served to get pregnant so once 50 days are there, serve her.  It is more economic to serve the cow earlier than it is to wait until later and get a 5% higher conception rate.  Use the following table to help your decisions:

Nutrition and energy are vital, and are covered alongside all of the above in DairyCo's pd+, the same topics can be covered in the discussion groups that Milklink and DairyCo jointly run, or through DairyCo and Milklink open meetings.

A good calving index of sub 375 days is achievable and there is money to be made from it.