How to Spot the Bulling Cow

Published 1 May 09

Chris Coxon, DairyCo Extension Team South West

How to spot the bulling cow
Chris Coxon, DairyCo extension officer

Spotting the signs of bulling is crucial if farmers want to improve fertility and cut culling rates.  DairyCo extension officer Chris Coxon sets out what to look for.

Figures on herd calving indicate the average length of time between calving is 410 days, suggesting cows are not getting in calf as quickly as they might.  Modern herds have shorter and less intense heat periods, and with cows out at grass, and herds growing in size this means it can be easy to miss the signs of bulling.  But improvements in heat detection rates by 10 per cent can provide a financial improvement of £50 per head through maintaining more productive cows in the herd and reducing costs through less culling, so knowing the correct signs of bulling is vital.

Simply spending more time observing cows will obviously help you spot the signs of bulling, but it can be difficult to find the recommended 20 minutes, three times a day.  Combining periods spent observing cows with heat detection aids and good freeze branding to ensure that everyone knows who is who in the herd will ensure the right cows are served.  Some easily understood records that all staff can use can also make a significant improvement to heat detection levels.

To make the best use of time, it is useful to involve all staff on the farm in heat detection.  However, a tractor driver feeding the cows for several hours in the morning may not instantly be sure of the signs of early heat.  DairyCo has produced a short, multi-language DVD that takes you through all the signs of bulling.  Even if staff aren't certain, if they make a note of signs they think they've noticed this can help your records hugely by giving you a target list to refer to.

The DVD will provide new information for some - maybe new employees - but can prove to be a useful refresher for others.  It highlights the subtle signs of bulling, for example being restless, head-butting, bellowing and licking other cows more.  The more obvious signs of sniffing at the vulva or urine of other cows or attracting more attention from others are also covered.

It can be difficult to be certain which cow is bulling, but the most valuable sign is if she stands to be mounted.  If she doesn't attempt to move off you can be certain she is bulling.  Even if you don't see her being mounted then look out for signs that she has been mounted, such as dirt on the flanks or rubbing of the tail head.

Herd nutrition is also vital and cows need a balanced ration and a positive energy balance in order to show signs of bulling.  Cows who are not fed a balanced diet, or whose ration is changed too quickly, especially in early lactation, may not show signs of bulling.

Weight loss in early lactation must be accepted, however research has shown this has a huge impact on fertility.  The difference between losing between 0.5 and 1.0 Body Condition Score up to 5 weeks post calving (between about 30kg and 60kg liveweight) can potentially have a healthy first service rate of 53%.  Compare this to a cow losing over 1.0 Body Condition Score (over 60kg) who can suffer from only 17% first service pregnancy rates and the potential impact on conception rates is clear.  

Working with your vet and nutritionist together is also advisable.  You will be able to look at fertility records and establish whether heat detection is actually the problem.  Having routine meetings that involve all relevant staff from the farm can produce a thorough plan that will ensure all aspects of fertility are covered. DairyCo's pd+, rated highly by many vets, will help to prioritise a way forward.     

Remember, a 10 per cent improvement in heat detection rate will give you more cows to serve and more chances to get them back in calf and may significantly reduce potential losses from your herd.  DairyCo's Spotting the bulling cow DVD, and pd+ programme are available free of charge to dairy farmers.   

Not all bulling cows stand to be mounted so you may need to spot a combination of other signs.  In increasing value these are:
•    Change of behaviour
•    Bulling string
•    Head butting and bellowing
•    Licking other cows
•    Sniffing at urine and vulva
•    Being mounted and moving away
•    Chin resting
•    Trying to mount other cows
•    Head mounting
•    Standing to be mounted.