Heat detectors not far away

01-08-2007 | Gerard Hall

Technology capable of accurately detecting oestrus in dairy cows may not be too far away for hopeful dairy farmers.

Oestrus detection is one of the most labour intensive and skilled tasks dairy farmers and their staff have to perform. Later calving leads to fewer days in milk and fewer heifers available for replacement purposes.

Getting it right is important as the cost of poor oestrus detection is high. Estimates of the costs to the New Zealand dairy industry of missed heats is put at $65m each year.

While it will be some time before the technology becomes readily available, Dexcel researcher Jacqueline McGowan's New Zealand Society of Animal Production presentation covered the use of technologies that can monitor behaviour of dairy cows.

The study used a detailed recording device, called IceTag, developed by IceRobotics in Scotland for objectively measuring behaviour in dairy cows. A key area of the study was an assessment of its potential for detecting oestrus.

McGowan says for a 315-cow property, improving the three-week submission rate from the national average of 80% to the targeted 90% is worth an additional $7000 income.

In terms of the on-farm use of the IceTag technology, at this stage it will not completely substitute for well structured and dedicated visual oestrus detection and the effective use of tail painting or heat-mount detectors.

However in large dairy herds, she believes it can assist in identifying
whether a cow is in oestrus or not.

IceTags are strapped on to the back leg of the cows and record at each second whether they are lying down, standing or moving, as well as counting how many steps they take.

McGowan says IceTags have potential as a research tool for objectively measuring behaviours, such as onset of oestrus, where more subjective human observers might otherwise have been used.

Several equations to detect oestrus were developed using the data. Two focused on behaviour between midnight and 5am, a period when cows are known to have consistently low activity. At this time any increase in activity or reduction in time spent lying down would be at its most obvious, and trigger an oestrus alert.

Change in activity was also examined, measuring changes hourly by comparing the 24-hour average to the same measurement from five or ten hours previous. A sudden increase in activity at any time would create an oestrus alert.

The number of heats the IceTags detected ranged from 50% to 93%, but the false positives ranged from 13% to 36%. This means for every 100 alerts given, 13 to 36 of them will be false alarms. One of the equations detected 93% of the oestrus events with only 18% false positives; the worst detected only 50% and had 36% false positives.

Although further development of the technology may increase the accuracy of oestrus detection, although this level of false positive alerts is comparable to other automatic oestrus detection methods.

The results also illustrate the need to consider multiple cues for accurately identifying cows in oestrus. Interestingly, all equations detected some heats that visual observation and tail paint did not.

McGowan believes oestrus detection is just one of the potential on-farm applications for IceTags and other similar technologies.

In the coming season, Dexcel is planning to examine how useful behaviour monitoring might be in alerting dairy farmers to the changes that occur prior to calving or when a cow becomes lame.

Ultimately a behaviour monitor could be a multi-purpose tool incorporating electronic ID and the capability to detect a variety of events including oestrus, lameness and calving.

They may also have applications in the deer and beef cattle industries.

The IceTags used in the Dexcel studies are a research version. IceRobotics are developing a wireless version for on-farm use capable of providing user-friendly summaries or alerts for detecting oestrus and cow lameness.

While the current $50 target price for the farm version might seem quite high, like all technologies it must be weighed up against the value it offers.

While other step counters are available, McGowan says the IceTag's key difference is the range of cow behaviours it can monitor. It also allows researchers to look for changes over shorter time periods.

While electronic monitoring devices for heat detection is relatively old technology, so far very few farmers have adopted this approach.

The devices are seen as expensive, especially in a seasonal breeding system where every cow would need to have one. Also, the dairying environment can be harsh, sometimes causing equipment failure.

Learning to operate hi-tech electronic technology can be a barrier to some farmers and maintaining hi-tech systems can take too much time, defeating the purpose of being a labour saving device.

McGowan also says satisfactory submission rates can be achieved by visually detecting oestrus, provided sufficient technique and effort is put in.

Highly sensitive when they are well tuned, high numbers of false positives have always been an issue with these sorts of technologies when they are tuned to be sensitive enough not to miss any heats. In time ongoing improvement of the technology may tip the balance towards much greater rates of adoption.

High detection rates using traditional methods require healthy cycling cows, staff skilled in detection, and methodical procedures in place that are well planned, executed and monitored.

Current best practice involves using heat detection aids such as tail paint or heat mounted detectors which are inspected at the shed morning and night by a well trained and highly skilled team member coupled with observing cow behaviour out in the paddock morning and night.

It is also important that performance is retrospectively checked by analysing return-intervals.

With a particular interest in animal behaviour and welfare, other Dexcel projects McGowan is involved with include the automatic milking system, application of walk-over weighing technology, the oestrus sniffer project and the IceTag project.

After completing a Bachelor of Science at Waikato University focusing on zoology, animal behaviour and physiology, McGowan spent six months on a 280-cow dairy property. She then joined Dexcel in 2002 as research technician on the LIC Friesian-Jersey crossbreed trial in Taranaki.

Eighteen months later McGowan returned to the Waikato to join the team based at Dexcel's Greenfield Project. This research focuses around labour, lifestyle and cost saving automated technologies.

McGowan's research technician role involves everything from animal ethics applications and hands-on work with the animals, to data analysis, writing up and presentation of results.

Committed to making a significant contribution to dairy research in New Zealand, since joining Dexcel McGowan has completed several dairy science papers towards a post-graduate qualification.

The IceTag project was funded by DairyInsight, Foundation for Research Science and Technology and Dexcel Innovation Fund.

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