LIC | The Importance of BCS


The Importance of BCS

With the variation in where the rain has been falling, comes a large variance in pasture covers.  I am also starting to see some large ranges in cow condition between farms and within herds.  In the following I will cover off what you should now be thinking about to ensure cow condition is protected through autumn.

Low Cow Condition

Cow condition and feed planning are two areas that currently require careful monitoring to ensure next season’s milk production and reproduction is not affected by the current climatic conditions.
As lactation carries on, we start to see who the real high producers are within a herd.  Often these high performance machines will keep milking well despite the limited levels of feed, and will lose weight in the process.  Other cows (often lower PW cows) will now start to partition energy toward BCS gain, and get fat in the process.  If we do not manage this well, then the herd average BCS may be okay, but the range of cows can be 3.0 to 6.0 by late autumn.

BCS Targets

A DairyNZ study has re-confirmed that the targets of 5.0 body condition score (BCS) for mixed age (MA) cows and 5.5 BCS at calving for first and second calvers to maximise profit. 

These are not just nice targets to achieve. They should be the aim of every farmer at calving because it will affect your milk production and reproduction potential.

The study showed that the gain in milk production by calving cows at 5.0 BCS instead of 4.5 was 5.2kgs of MS - worth about $30 per cow.  

Multiply that over your total cow numbers to see what you could be missing out on.  

Another study also showed that cows calving at BCS 4.0 compared with BCS 5.0 resulted in seven per cent less chance to be cycling at planned start of mating (PSM).  Cows that have not started cycling at PSM have a 16 per cent lower six-week in-calf rate and a higher empty rate of six per cent.

So what is the best way to manage your herd through autumn? 

Start with body condition scoring your herd to get a realistic understanding of condition as opposed to just thinking they are okay ‘apart from the odd light one’.

Dairy NZ’s ‘Body Condition Scoring Made Easy’ booklet will help to guide you in condition scoring. Aim to do at least 70 cows to get a good cross section of the herd. The DairyNZ booklet will explain how to work out an average from these cow’s scores. Or, get an accredited BCS assessor in to independently score your herd so you have impartial data to work from.  To find a local assessor, have a look on the DairyNZ website

Once you have worked out what percentage of your herd are in the 4.0 BCS or lower category, then you can decide what management changes you can make to achieve days in milk and hit BCS targets by June.

So what are the best options for protecting BCS right now?

  1. Work out what supplements are needed for winter and spring.  Ring fence these, and don’t be tempted to use them now.  What supplements are available for this autumn?  
  2. Pregnancy testing now and dropping stocking rate proactively (APC dependant) so that empty cows are not stealing valuable feed off your capital stock for next season will likely be a more profitable option.
  3. OAD for all or one herd is an effective way of reducing BCS loss.  SCC will need to be managed to ensure this is feasible.  If running two herds, then put the two and three year olds and any other in-calf MA cows that are 3.5 BCS onto OAD.  
  4. Run your supplement feeding options through the online feed calculator on DairyNZ’s website to aid decisions over what types and prices of supplementary feeds will actually be profitable.
  5. Once you know what options you have for feeding supplements or not, you can plan out what dates you will need to start drying off cows that are too light.  For example; a MA cow that is calving on the 20th July that is 3.5 BCS needs to be dried off on the 10th of April.  A R3 year old that is 3.5 BCS needs to be dried off by the 20th of March.

Be proactive in not letting BCS slip when you can alter management now provide options for days in milk at a lower cost structure.  

Written by Darren Sutton, FarmWise Consultant

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