Some Australian herds have made big improvements in fertility over the past five to ten years.
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But nationally, Australia still trails New Zealand and Ireland. We also haven’t made the gains seen in the US.
The introduction of the daughter fertility Australian breeding value has improved the fertility of our cows but genetics alone will not fix the problem.
Day-to-day herd management still matters.
In seasonal and split-calving herds, the average 6-week in-calf rates are:
- Australia: 51per cent
- New Zealand: 70 per cent
- Ireland: 69 per cent (6-week calving rate)
Australian year-round herds perform at a similar level to US herds. However, US 21-day pregnancy rates have risen from 14 per cent to 21 per cent over the past 20 years while Australian year-round reproductive performance has barely changed.
What is holding us back?
Every herd is different. To identify the biggest opportunities, Dairy Australia and Dr John Morton analysed reproductive data from more than 1,200 Australian herds. The analysis identified four key areas for improvement:
- heat detection
- artificial insemination technique
- data recording practices
- heat stress
John’s other recent work also identified two priorities: growing replacement heifers well and using high-fertility sires.
Heat detection
Submission rates quickly show whether enough eligible cows are being mated. Herds not meeting the targets below should urgently review their heat detection practices:
- Seasonal and split-calving herds: at least 60 per cent of eligible cows mated in the first three weeks
- Year-round herds: at least 40 per cent of eligible cows mated by 80 days in milk
Good heat detection remains essential on most Australian dairy farms. Dairy Australia’s Heat Detection workshops help staff recognise heats and use detection aids correctly. During joining, an “all hands on deck” approach can also lift submission rates.
Many farmers are now investing in collars and other wearable heat detection technology. Several farmers I spoke to described the technology as game changing. It can take pressure off milking staff, especially where confidence using heat detection aids, such as scratchies is low.
Automated heat detection is most likely to lift reproductive performance where submission rates are poor. Herds that already detect heats well may save time and labour but may not get more cows in calf.
Fixed-time AI removes the need to detect heat before insemination. It is widely used in Wisconsin and is also being adopted by some Australian seasonal, split-calving and year-round herds. It must be carefully planned with your vet or reproductive adviser. Poorly managed programs can become expensive very quickly.
Artificial insemination technique
In some herds, conception rates varied between AI technicians. Herds using a professional AI technician should check that the technician is NHIA accredited. Farmers who inseminate their own cows should use Dairy Australia’s semen handling and insemination checklists to regularly review practices.
Data recording practices
The causes of poor reproductive performance are not always obvious. Good records help identify where the problem is occurring. Use submission-rate targets above and check progress regularly.
Useful records include:
- birth and calving dates
- health events
- bull ID
- semen type (e.g. frozen, fresh, sexed)
- AI technician
- synchrony and non-cycling cow treatments
These records can show whether problems are linked to particular cows, treatments, semen types, technicians or times of year.
More herd management programs now have phone apps. This makes it easier to record information in the paddock, dairy or yards.
Heat stress
Farmers in northern dairy regions already knew heat stress was hurting fertility and John’s analysis confirmed it.
Some year-round herds are reconsidering whether joining during the hottest months is worthwhile. Others are shifting more joining into cooler periods. Herds that continue joining through summer will need strong heat-stress prevention to protect fertility.
Replacement heifers
First-lactation milk production suggests heifers may not be reaching their growth potential on three-quarters of farms. Failure to get back in calf is also the main reason young cows leave the herd early.
Farmers are often caught out by unexpectedly poor growth rates. Because heifers are smaller, they cannot eat as much as mature cows. This makes good-quality feed especially important. Poor growth can be difficult to see.
Regular weighing is the best way to know whether heifers are on target.
Genetics
Farmers are using more high-fertility sires than they were 15 years ago. However, many replacement heifers are still bred from bulls with average or below-average daughter fertility.
Farmers should aim to use sires with a daughter fertility ABV of 105 or higher. High-fertility bulls are readily available.
A recent Good Bulls App search found 214 Holstein bulls and 49 Jersey bulls with a daughter fertility ABV of 105 or higher.
Next steps
Dairy Australia is using these findings to update its fertility tools, resources and training for farmers and advisers.
We thank Dr John Morton for his ongoing work with Dairy Australia, and the farmers and advisers who contributed data and expertise to the project.
By Dr Stephanie Bullen, National Animal Health and Welfare lead, Dairy Australia