Measuring heifer puberty is not something many producers do because it's difficult and time consuming.
But NSW Department of Primary Industries researchers have found unlocking genetic patterns in heifer puberty will improve overall herd fertility performance.
As part of the $7.3 million Southern Multi Breed project, post weaning each heifer is assessed every 28-35 days until they reach puberty.
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There are 521 heifers due to calve in 2022 as part of the project. Around 63 per cent of these have calved to date, but this changes every day.
While there is no release of data from this project yet as it's the first time that females born in the life of the project are having their own calves, researchers are about to kick off the post-partum ovarian scanning on these first-calf heifers.
This is a first for the project and adds to the intensive and precise recording program for fertility traits.
Traits measured within the project include weight, hip height, and rump fat measure, as well as conducting an ovarian scan using an ultrasound to determine if they've reached puberty since their last assessment.
NSW DPI technical officer Renee Rippo said the most exciting aspect of this process was finding the corpus luteum for the first time in a heifer.
"When a heifer reaches puberty, she'll ovulate and once that egg has ovulated from the ovary, a structure forms on the ovary which is called a corpus luteum," she said.
"This means we can then establish her age of puberty."
Ms Rippon said the team would then measure how many follicles are present on each of the heifer's ovaries and the size of the largest follicle. This helps assess the follicular waves patterns.
"As an estimate, a heifer might have between five and 20 follicles per ovary. From there, using the ultrasound index, we can measure the size of the biggest follicle which might range between 3mm and 15mm," Ms Rippon said.
"The bigger the follicle gets, the closer it is to ovulating and forming the corpus luteum, so it's all quite interesting information we're collecting."
With female reproductive rate being a main profit driver for the beef cattle industry, Ms Rippon said recording this data would positively impact producers in the longer term.
"Measuring heifer puberty is not something many producers do because it's difficult and time consuming, but it's these traits that will have huge outcomes for their profit margins," she said.
"Females with poor fertility impact profitability of beef producers because they're slower to reach puberty or return to oestrus post-calving.
"There is variation in these traits between females of a similar age and under the same environmental conditions. We want to find those genetics that perform so we can continue to breed from them."
In addition to age of puberty, in the coming months researchers will also commence scanning two-year-old heifers post-calving to determine differences in return to oestrus.
Ms Rippon said recording these traits would provide foundation data for the development of new estimated breeding value (EBVs), which would be considered for inclusion in Breedplan.
"Once we've done this for a few years and gathered enough data, we can look at the role genetics is playing when it comes to individual reproductive maturing timeframes for females, both across breeds and within breed," Ms Rippon said.
"It's definitely something that industry can take a lot from to boost their productivity in the longer term."
The $7.3m Southern Multi Breed project is co-funded by NSW DPI, UNE, MLA and the Australian government through the MLA Donor Company (MDC).
