A recent analysis of genetic trends in the Australian dairy herd shows that the rate of genetic gain has accelerated in the past decade.
DataGene's genetic evaluation manager Michelle Axford analysed the rate of genetic gain for Balanced Performance Index (BPI) based on the sires of cows (see Figure 1).
"When we look at the rate of genetic gain across five-year time blocks, it's very clear that the rate has sped up dramatically in the past decade," Mrs Axford said.
"The average rate of genetic gain since 2005 was about $15.80/year (green line in the graph), but the current rate is more than $20, which almost double that of in 2005-2009 ($10)," Mrs Axford said.
She said a number of initiatives had contributed to the acceleration in genetic gain, including the introduction of the Good Bulls Strategy in 2010, genomics in 2011 and dairy's three new indices in 2015.
"There's no doubt that genomics has increased the rate of genetic gain in dairy herds around the world," Mrs Axford said.
Genomics speeds up genetic gain by providing reliable predictions of genetic potential of animals from a very young age, long before performance data becomes available for traditional genetic evaluation methods.
"In Australian dairy herds, the rate of genetic gain has had the added boost from the Good Bulls Strategy and new breeding indices," she said.
Introduced in 2010, the Good Bulls strategy gives Australian dairyfarmers a simple tool to identify bulls that will contribute to increased herd profitability.
"Bulls that carry the Good Bulls logo meet the minimum criteria for Balanced Performance Index, availability and reliability," Mrs Axford said.
"There is a wide range of Good Bulls, giving farmers plenty of choice for Good Bulls that meet their priorities for specific traits, budget and company preferences."
The latest list of Good Bulls is published three times a year in the Good Bulls Guide and app, available from the DataGene website.
"Encouraging farmers to use a Good Bulls straw to breed every replacement is a collective effort," she said. "Bull companies, AI service providers, farmers, researchers and industry have all had an important role to play."
Mrs Axford said there had been rapid acceptance of the three dairy breeding indexes introduced in 2015.
The Balanced Performance Index (BPI) is an economic index that blends production, type and health traits for maximum profit. The Health Weighted index (HWI) gives greater emphasis to fertility, mastitis resistance and feed saved. The Type Weighted Index places more weighting on type traits.
"While the Health and Type-weighted indices have a following of farmers seeking to fast-track specific traits, the BPI rapidly became a widely-accepted tool for selecting bulls," she said. "The BPI is used by farmers, breeding advisers and in semen catalogues."
Within 18 months of the launch of the three new indices, 65 per cent of farmers surveyed were aware of the BPI, and almost 80 per cent of those said the BPI influenced their bull selection decisions.
Younger farmers were the most likely to be aware of the BPI as were large, extra-large and xx-large herds.
Mrs Axford said there were several reasons for the wide acceptance of the BPI. "The development of the three new indices was based on genuine and deep consultation with a broad range of dairyfarmers," she said.
"This meant the new indices were aligned to their breeding priorities. Having three indices recognised that not everyone has the same priorities.
"Extension activities have helped farmers more clearly define their breeding objectives, select their preferred index and use Good Bulls to build the herd they are looking for. The indices are backed by the strong science that is needed to have confidence in the results."D
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