For immediate release 21 September 2011 (300 words)
Selecting dairy bulls with mastitis resistance can help fine-tune mastitis management in the long term.
Dairy Australia’s Countdown project leader John Penry said that although most mastitis control is achieved through management practices and the environment, genetics does have a small influence on mastitis resistance.
“Genetic variation for cell count exists and some bulls have been found to produce daughters which are more resistant to mastitis than others,” Dr Penry said.
While the heritability of mastitis resistance is relatively low at 10 per cent, the benefits are permanent and accrue with each generation.
This means an estimated 10 per cent of the variation in the Australian dairy cow population is due to genetics and the other 90 per cent is due to the management environment of the cow.
“For little or no cost you can make a long term difference to the level of mastitis in your herd by selecting bulls from the mastitis resistance list in the Good Bulls Guide,” Dr Penry said.
Australian Breeding Values for mastitis resistance – cell count ABVs – are available for AI bulls, based on their daughters’ cell counts.
Improving mastitis resistance involves selecting bulls with a Cell Count ABV which is more than
100 – the higher the Cell Count ABV, the greater the mastitis resistance.
The difference between the best bull (Cell Count ABV of 171) and the worst bull (Cell Count ABV of 20) is estimated to be $100 net profit per cow per year. Most bulls have a Cell Count ABV between 78 and 122.
Cell Count ABVs are incorporated in the Australian Profit Ranking because mastitis lowers farm profitability.
“If mastitis is part of your breeding plan then look at a bull’s Cell Count ABV, or use the mastitis resistance list in the Good Bulls Guide,” Dr Penry said.
More information: Countdown Fact Sheet H: The impact of genetics on mastitis and cell counts: go to the Dairy Australia website at www.dairyaustralia.com.au/countdown and type 'genetics' in the search box or phone Countdown Downunder (03) 9620-7283.
ADHIS Good Bulls Guide www.adhis.com.au
.

Countdown is an example of your levy at work. For more information on this and other examples of your levy at work visit www.dairyaustralia.com.au
ENDS
Photo: To receive a high res file by automatic email click on this link: cntdowngeneticsMastitis@monkscom.com.au
Caption: Genetics isn’t a silver bullet for mastitis control but it is well worth considering when making breeding decisions.
Media enquiries
Lee-Ann Monks (Monks Communication) ph 07-5450 0946 or 0419 349 244 email: media_releases@monkscom.com.au
(note – we are in a poor reception area for mobiles. Try the landline first)
About Countdown
Countdown helps Australian dairy farmers manage mastitis in their herds. Managing mastitis in dairy herds involves reducing the number of clinical cases as well as reducing the bulk milk cell count
(BMCC). Dairy Australia is the main source of funding for Countdown activities. For more information phone ph (03) 9620-7283, email: info@harrisparkgroup.com.au
or www.dairyaustralia.com.au/countdown