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Precision condition scoring boosts fertility (Nov/Dec 23)

Body condition scoring could be the next management task to be automated using technology, offering greater accuracy and potentially big benefits for fertility.


TEXT PHIL EADES



Technology is playing a significant role in increasing cow-management precision, improving efficiencies and driving productivity. And the benefits of 3D imaging technology, capable of measuring a range of criteria to help improve cow productivity and welfare, are beginning to emerge.


These 3D camera systems were initially developed to improve the frequency and accuracy of mobility scoring to reduce the losses and welfare issues associated with lameness. But, according to HerdVision’s Stuart Adams, there are many other measurements the camera can take with a high degree of precision, making it possible to develop new algorithms to assess other key management parameters.


“We are seeing significant benefits from using the system to improve the accuracy of body condition scoring (BCS), with a large-scale farm study showing a reduction in calving-to-conception interval where BCS is more closely monitored,” he says.


Cows need to be in optimum condition at drying off, maintain this condition while dry and then avoid condition loss in early lactation. “On many units the challenge has been condition scoring cows often enough, as well as with a high enough degree of precision and consistency. Both can be overcome with technology.”


Considerable range


Typically cows are body condition scored to the nearest half or quarter score, with the aim of cows being at between body condition score 2.5 and 3.5 at drying off and calving. But this is a considerable range. Many cows within this range could be in sub-optimal condition and changes in BCS may be difficult to pick up, storing up potential fertility problems.


Mr Adams says that automated condition scoring using 3D cameras has the capability to significantly improve the accuracy of BCS recording and has been shown to offer significant management and economic benefits.


“The camera takes a 3D picture every time the cow walks under the system. This means we are able to measure depth to an accuracy of less than 1mm,” he explains. “Because the camera uses infra-red light it is accurate in daylight and during the night and, therefore, can be used throughout the year.


“This means we can measure BCS changes with far greater precision that can be achieved using manual methods, ascribing a more accurate score for a cow and detecting smaller movements in BCS, whether up or down.”



Automated system: camera picks up changes down to 0.01 of a BCS


Assess changes


The camera system measures changes down to 0.01 of a score, compared to manual scoring which measures, at best, 0.25 of a score change. As the system measures cows every time they walk under the camera, it is possible to build up a better picture of BCS and assess changes more closely. The system reports BCS on a seven-day rolling average rather than an individual day result.


“This greater precision means it is possible to identify changes in condition sooner, allowing management to be altered as required,” says Mr Adams. “It also means it has been possible to more accurately define the optimum condition for cows at drying off and calving.” A study carried out during a 15-month period on four UK dairy units, comprising a total of 4,000 cows, demonstrated the impact of sub-optimal condition on subsequent reproductive performance on different dairy farming systems.


“Analysing the data, it was possible to assess the consequences of cows calving at different BCS on calving-to-conception interval. As expected, fatter and thinner cows had extended calving-to-conception intervals. But what we were able to do was more precisely pinpoint the optimum BCS for future reproduction, which is a level that would not be discernible by manual BCS recording.”


The data show that at calving cows should be a condition score of greater than 2.85. Cows with a score of less than 2.85 had a calving-to-conception interval of 103 days, while cows with a BCS equal to or greater than 2.85 had an eight-day-shorter interval at 95 days. “Around 20% of the cows in the trial were calving below the threshold and suffering poorer fertility in the next lactation,” says Mr Adams. “As the camera records cows after every milking, these cows would have been spotted sooner with the system.


This allows action to be taken to more closely manage condition in the run-up to drying off, so they go dry at the correct score and to manage them for a stable BCS during the dry period.


“At £5 per day of extended calving interval, the cost of these cows being under condition was £40 per cow, which means there is a good potential return on investment on managing BCS.”


Visually imperceptible


The trial also assessed BCS change during the dry period and found that in many cases there were small and visually imperceptible changes in condition. But these changes were also significantly affecting reproductive performance.


The threshold was set at a 0.14 condition score change during the dry period. Cows that did not lose BCS, or lost less than 0.14 BCS units, averaged a calving-to-conception interval of 93 days with 34% achieving conception to first service and 58% to second service. Cows that lost more than 0.14 of a score had a 17-daylonger calving-to-conception interval at 110 days, with poorer service success rates – just 23% to first service and 47% to second service.


“These data demonstrate the significant consequences of cows losing condition while dry, even at these extremely low levels,” says Mr Adams. “By using 3D imagery it would be possible to keep a closer eye on how cows are managed while dry, providing an early indication of whether the dry-cow ration is supporting cows’ nutritional needs.


“If early signs of BCS loss can be identified it will be possible to refine dry-cow management, housing and diet to address the problem. It is also important to remember that cows losing even small amounts of condition when dry are already in negative-energy balance and at greater risk of continued problems when they calve.


“Being able to use 3D technology to monitor both mobility and BCS more frequently, requiring less labour and without disturbing typical cow behaviours, can open the door to increasing herd efficiency and welfare,” adds Mr Adams. “And it helps herds maintain productivity while reducing their carbon footprint.”

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