Optiweigh’s new Individual Animals report reveals significant 24-hour weight fluctuations in cattle, averaging 25kg (5%) between morning lows and afternoon peaks due to gut-fill. Despite these variations, the system’s frequent data collection ensures accurate mob averages and weight-gain tracking without disrupting normal paddock routines.
Last week we introduced this new Individual Animals report on the Optiweigh website (the same data has been there for years, but it was a bit hard to find, and not as easy to interpret as it is now).
This prompted a query from a customer about the amount of change in a particular animal from one day to the next.
To answer his query, we had a look at the underlying data and found this animal to be a really good example to illustrate both the accuracy of the measurements, and the amount of variation in animal weight over a 24-hour period.
1. The data that initiated the query:
This was the data (below) that was accessed from the individual animal report, just laid out a bit differently to make it clearer. As you can see there are some quite large weight changes from one day to the next.
2. Digging Deeper
When we dug a little deeper, the first thing we found was confirmation of accuracy based on both the number and quality of records.
For example, on the 30th of March we had records at 477.0 and 476.4 within an hour of each other, both for about 20 seconds and both very stable.
On the 31st of March we again had two good stable records, this time at 452.2 and 445.3kg.
On the 14th of April there were records of 492.4, 492.9 and 501.4 within a few hours.
Right across the highs and lows of the period in question, we had good quality and repeat records at both the upper and lower ends of the weight range. That gives us confidence that the readings were correct, and were reflecting changes in gut-fill in this animal.
3. Looking for a pattern
The next thing to do was look for a pattern to explain the changes. The obvious first place to look was time of day, and there it was. Those records from the 30th were at around 6pm, while the ones from the next day were at 9am.
So, we looked at differences across all the data for this animal and found that the results were very clear. Weights were lowest between 8am and 10am, rising to peak between 4pm and 6pm.
While this is hardly surprising, the extent of the variation was – about 25kg difference on average.
4. Looking across the whole mob
Just to make sure, we then looked at the whole mob, adjusted for weight gain across the period. The pattern was the same, about 5% variation during the day.
But importantly, the spread of weighings across the day still meant that we were getting a good mob average each day, and a very accurate measure of the rate of weight gain.
5. Why is this useful to know?
The first thing this should do is give you confidence in the quality of data coming out of the paddock.
But it should also be a reminder that animal weights fluctuate a lot based on gut-fill, and that if anything disrupts their normal eating pattern it is going to show up dramatically.
The best example I can think of here is putting animals in a holding paddock the night before bringing them in for weighing. Time and time again we have seen this impact yard weights by up to 5%.
Of course, there are plenty of other things such as changes in the weather and changes in feed or water quality that will do the same thing.
6. Further thoughts
If you’ve got this far with the details your mind will be running off in different directions like mine, thinking about how we can use this information more.
Things like: “What if we could access AM vs PM weights?”.
We’ll keep working on these sorts of things as we always do. But in doing so, we will always be looking to keep it practical (given the nature of the environments we are operating in).
The beauty about all the data in this example is that it shows that just taking the averages from whenever the animals chose to get weighed still gives us a very accurate picture of weights and rates of gain.