Daughters of bulls with higher Australian Breeding Values (ABVs) for daughter fertility achieve 13 per cent higher 6-week in calf rates compared to their lower ranked counterparts.
This was one of the factors to better dairy herd fertility identified by a study which analysed the records from 74 herds over a 10-year period.
The findings were recently presented by InCalf and the Australian Dairy Herd Improvement Scheme (ADHIS) at a series of service provider forums held by the Department of Primary Industries across five Victorian locations.
The study identified trends in dairy herd reproductive performance between 2000 and 2009 and identified the factors that influence fertility. Better herd fertility was strongly associated with:
The use of ABVs for daughter fertility.Higher milk protein concentration.Middle-ag ed cows (3-4 years).Longer intervals between calving and mating start date.Michelle Axford from ADHIS said the results demonstrated the value of considering ABVs for daughter fertility when selecting bulls.
She has three recommendations for improving dairy herd fertility.
“Firstly make sure you choose bulls from The Good Bulls Guide with an ABV for daughter fertility of more than 100. This is an indicator of the bull’s genetic potential to sire daughters with higher than average fertility,” Mrs Axford said.
“Secondly, check the semen fertility values of the bulls on your short list. Semen fertility is an indicator of the bull’s semen to get cows in calf,” she said
The ADHIS website lists semen fertility values for bulls with more than 400 matings. Most bulls have a value between plus and minus 2.5pc Avoid using bulls with lower semen fertility values.
The third recommendation is to use enough straws to cover the number of replacement heifers you need in the herd in three years time.
“We work on a rule of thumb that you need six straws for every replacement heifer.”
For more information contact Michelle Axford at ADHIS ph (03) 8621-4240 or email maxford@adhis.com.au
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