Understanding Sessions
Use this article as a guide to understanding Optiweigh sessions and how to use them
Introduction
Sessions are a collection of weight records for a particular mob of animals over a period of time. The data from a session is displayed in a way that is easy to understand, when set up correctly. To learn more about setting sessions up correctly, follow this link: Managing Sessions and Mobs
It is important that any time the composition of the mob changes, the mob is edited.
Understanding Sessions
A session allows producers to gather data on a single mob - similar to a traditional yard weight session, but running on a continuous basis. Effectively, they are a continuous weighing event, with the averages and ADGs evolving in real time.
It is fairly common knowledge that if you bring livestock over yard scales 20 minutes apart you'll get vastly different results, this is the beauty of an Optiweigh session, an animal can weigh multiple times giving you a realistic average of that animal. In a yard session, if they come over the scales full or empty, their weight will be skewed.
It is for this reason that when we get asked how Optiweigh data compares to yard data, we say that an Optiweigh is far more accurate!
New sessions
Start a new session any time the mob changes
Starting a new session whenever the mob changes will ensure your data is always accurate.
Changing Mob Composition
Whenever the composition of a mob changes, you can edit the number of animals in the mob, and ensure the "Effective from" date is correct. E.g. If you add in some lights to a mob.
If you don't change the mob composition, your session information will be skewed. E.g. When the heavy animals are taken out of a mob for sale, the weight chart will plummet!
This is critical - even if the rest of the animals in the mob are the same!
Restarting Sessions
You can't re-open a session or go back to a previous session for animals that have been on the Optiweigh before. You need to create a new session. The Optiweigh will remember these animals (by their EID) and the data for these animals will be carried over to the new session. No data is ever lost.
The weight chart becomes useful here, because you can tick only 'Include prior weights' and see how the animals were doing in previous sessions, compared to now.
Old sessions cannot be restarted. Open a new one - no data will be lost!
Switching Mobs
There is a spectrum of ways producers use Optiweigh units, from continuous monitoring, to mob-shifting, to a combination of both. Which way you decide to use the units should align with your goals for the unit, and can even be season dependent. There are many reasons for going one way or the other.
Continuous Monitoring - Leave the unit with the same mob continuously.
- Pros: Never miss a weight loss event, hawkeyed on a particular and important mob, discover weight gain/loss drivers in real time
- Cons: One unit for one mob, fewer animals getting data
- Uses: Monitoring important mob all year, ensuring they are getting maximal productivity
Mob-Shifting - Put the unit in with a mob, once there is a big enough sample size to get an accurate mob average, switch to the next mob, and so on.
- Pros: Uses one unit across many mobs, data for a larger number of animals
- Cons: Potentially miss out on weight loss events, harder to discover drivers of weight gain/loss, not real time on every mob
- Uses: Multiple mobs nearly at sale weight
Combination - Leave the unit with a mob for weeks to months at a time and switching between mobs depending on timing, season and importance.
- Pros: Best of both worlds, but to a lesser extent
- Cons: Same as both, but also to a lesser extent
- Uses: Most farmers will be in the middle and have the flexibility to what is needed depending on their management goals and timing of the season
Monitoring Several mobs
If you mob-shift frequently, there are a few things to keep in mind.
- New sessions
Each time you move the unit to a new mob, a new session must be started - even if moving into a mob the unit has been with previously.
- Sample size
Before moving to a new mob, a big enough sample size must be achieved to be confident that the mob average is accurate. Generally, this will take five days - unless the unit gets very high records. We don't recommend switching mobs less than 3 days apart in normal circumstances. Use this link to learn more about how many animals are needed across the Optiweigh for different mob sizes and weight ranges: Interpreting Data
- Number of mobs
There isn't technically an upper bound with how many mobs an Optiweigh can be used with but, depending on management goals, the time between weighing events might get out of hand when switching between too many.
E.g. Switching mobs every 5 days between 3 mobs will leave 10 days in between weighing events after the unit is taken out of each mob. However if we put that up to 6 mobs, we are now at 25 days which may be too long at a critical point in the season.
- ADGs
The second, third, fourth (and so on) times a unit is put in with a mob, ADGs should appear as soon as the animals start scanning. Some may not appear depending on how long since their last weigh, e.g. if there are 15 days the unit is away from the mob, no 'Last 14 day' ADG will appear. To learn more about ADG calculations follow this link: Interpreting Data
If you have any questions about understanding sessions, please don't hesitate to reach out to Optiweigh Support on 1300 678 493