Dairy farmer Matt Kerr, of Berwick, speaking at a DairyNZ field day on Maungatua Dairies, said his cows were in their third season wearing Allflex collars.
He runs nearly 900 cows in two herds.
The collars had made the mating season easier including detecting the cows on heat.
"It was pretty daunting not putting tail paint on that first season."
Before using the collars, about half of his cows were in-calf within the first three weeks of the mating season.
The three-week in-calf rate was 58% last year.
There had been a 10% rise in the six-week in-calf rate to about 78%.
Before using the collars, he could use up to 170 Controlled Internal Drug Release devices, which get inserted into a cow’s vagina to release a hormone to bring it into heat.
Nearly 70 devices were used this year.
Other benefits of using the collars include detecting mastitis earlier.
The collars did not remove a need for farmers to get out on farm rather than relying on the technology to do the work.
"No amount of collars is going to make you a better farmer."
Dairy farmer Duncan Wells, of Outram, said he had invested in Smaxtec boluses, a battery-powered device which lies in the rumen of a cow and transmits data.
Fifty cows were fed a bolus about a year ago as part of a trial.
Another 600 cows were given a bolus in May this year.
A smart device which was a tag or a collar had never appealed.
"I struggle to keep two tags in cows so I didn’t want another thing hanging on them."
An appeal of a boluses was it produced accurate animal health and reproduction data, which reduced his workload.
"We have found it much easier to identify cows which haven’t cycled. In the past we would have done that with tail paint — it was quite a job keeping up to date with premating heats but all that pressure is gone."
The process of inseminating cows early in the mating period and getting them in calf quickly was now considerably easier, he said.
Before putting on the collars, he was happy with the mating performance of his herd including a six-week in-calf rate of up to 75%.
Consequently, it would be difficult to quantify a return on investment of the boluses for mating performance.
Benefits of the boluses included its mastitis report being very accurate, he said.
The boluses, which have a 5-year warranty, were put in cows at age 2.
If a signal was lost from a bolus, a cow was given another one. Each cow had capacity to fit three boluses if needed.
The boluses cost $50 per cow with an ongoing fee of $5 per cow, per month. The set up cost included a $5500 base station and two solar stations, costing $7200 each.
They also leased a fourth station.
The best dairy farmer was one who milked 100 cows and knew each one by name but those days were gone so smart technology assisted running a bigger herd, he said.
Dairy farmer Ian Frampton, of Henley, was attending the event and questioned if farmers were losing control by introducing technology which relied on wi-fi networks and call centres.
Maungatua Dairies co-owner Andrew Miller, of Woodside, was also at the field day and expressed a concern of dairy companies withholding farmers’ data they collected which, if available, could be used in the technology farmers use to increase farm productivity.
Industry stakeholders needed to work together to gain greater integration between available technologies.
"Get in the sandpit and play," Mr Miller said.
