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Rest Feed Calculation

* As information can change over time, if you read this outside of 6 months from the original post date, please confirm with your WCR advisor that the information is still valid and accurate.*


There are quite a lot of different opinions about the feeding principle in Horizon, but how does it actually work?


First thing to know:

  • A cow has no 24 hour clock, but we create 24 hour overviews in Horizon.

  • Feed calculations are therefore ongoing.

  • Definition of rest feed in the milking robot: rest feed in the milking robot is the amount of concentrates that will not be fed to a cow anymore.

Feeding principle

The programmed amount of concentrates per day is the amount of the concentrates we want to feed our cows. This is based on the feed table (based on lactation days or milk yield) or on a set fixed amount. This is also the amount of build-up per 24 hours. Horizon works according to this 'build-up' principle.


Build up: the amount of concentrates that are added to the cow's credit every second.


Example:

  • 8 kg concentrates per day

  • Build up per hour: 8/24 = 333 g/hour

  • Build up per minute: 8/1,440 = 5.5g/minute

Credit: the amount of concentrates available to the cow.

Max. amount per visit: The maximum amount of concentrate a cow can get in one visit.


Take over maximum (50%):

  • A maximum of 50% of the daily credit can be taken over two (milk) visits.

    • This influences the maximum credit a cow can have.

    • If the percentage is 50% and the programmed amount of concentrate is 8 kg, the max credit will be 4 kg.

  • This 50% is used when retaining a visit frequency of twice a day (each 12 hours).

  • These are concentrates a cow is still able to eat/take in during the day.

Rest feed: if a cow does not visit the robot, the build up over this 50% is called the 'rest feed'. This is feed the cow will no longer be given.

  • Horizon does not allow the maximum feed take over % to be less than 50%.

  • This would mean 'rest feed' would already be created at a milking interval (milk visit) of less than 12 hours. This poses (too) great a risk that too little concentrate is eaten by the cow and that unnecessary rest feed is produced.

  • Horizon does allow the maximum feed take over % to be over 50%.

  • This is adjustable up to a maximum of 80%, however, in practice this setting is never or rarely set higher than 50%. Sometimes we see values above 50% at farms with outdoor grazing. This gives cows the opportunity to take in concentrates that they have built up during grazing hours.

How rest feed build up works

Example 1: The programmed amount is 8 kg and the take-over % is 50% (as default in Horizon); shown as a dotted line in the image below. The build-up speed is: 8 kg per day/24 hours = 0.33 kg/hour. (Officially the calculation is in seconds, but to keep things simple in this example we have shown the build-up in hours.

  • In this case, the cow has a credit of 3 kg at 00:00.

  • According to her build-up speed, she reached her maximum credit of 4 kg at 03:00 (in 3 hours – 3 hours x 0.33 kg = 1 kg).

  • This maximum credit is based on the take-over percentage (50% of 8 kg = 4 kg).

  • At 04:00, the cow visits the robot.

    • The time between the moment when the cow reached her max. credit (03:00) and the time the cow visits the robot (04:00) is the time during which rest feed was built up/created (0.33 kg).

  • At 04:00, the cow visits the robot and receives 3 kg of concentrate

    • This is maximised by the setting ‘Maximum amount per visit’; after this visit, her credit is still 1 kg.

From this point on, the cow starts to build up her credit again.

  • At 13:00, the cow reaches her max credit of 4 kg again

  • From this point, the rest feed starts to build up once more

  • At 20:00, the cow visits the robot and eats 3 kg in the robot

  • In the time between 13:00 and 20:00, the cow has created rest feed again

    • Time above max. credit is 7 hours: 7 x 0.33 kg = 2.33 kg

  • After the second visit, the cow has a credit of 1 kg

  • Until 00:00, she builds up her credit again

    • At 00:00, her credit is 2.33 kg

    • Her rest feed over the whole day is 2.66 kg (2.33kg + 0.33 kg)

  • She starts the next day with a credit of 2.33 kg


Example 2: The programmed amount is 8 kg; the take-over % is 50%. In this example, we have more visits during the day.

  • The cow starts the day with a credit of 3.66 kg from the previous day.

  • During the day she makes a total of 4 visits

    • At 14:00, we see that the cow only has a credit of 2.3 kg, so she can only get a maximum of 2.3 kg in that visit.

    • At 00:00, the cow ends the day with a credit of 0.66 kg.

  • In Horizon, this is displayed as:

    • Programmed: 8 kg, Intake: 11 kg, Rest feed: 0 kg.


Example 3: What happens if we increase the take-over percentage? Situation: programmed amount is 8 kg, take-over % is 75%.

  • The higher take-over % gives the cow a higher credit, in this case 6 kg (75% of 8 kg)

  • The cow starts the day with a credit of 5.66 kg

    • This might be, for example, because the cow had fewer visits the previous day

    • During the day, there was credit every visit

      • Because the cow stared with high credit

  • Based on her milk access table, she was able to visit the robot multiple times.

  • At 0:00, in Horizon this is displayed as:

    • Programmed: 8 kg, Intake: 13.6 kg, Rest feed: 0 kg


This last example shows the risk of changing the take over %. When the cow has high credit combined with multiple visits the next day, she can be overloaded with concentrates which can be potentially cause rumen acidosis. Because of this, in general we strongly advise using the default setting of 50%.


Adjusting settings for: min. visit amount, feed speed, max. visit amount, max. take over %, max. increase and decrease per day, feed speed based on milk speed, temporary increase per day.

Click manage - Feed - Feed Type - Find the Feedstuff and animal group you want to change the settings for - click preferred setting to change.


You can find this article under the Help section in Horizon.

  1. On the Horizon dashboard, click the '?' on the top right corner.

  2. Click on 'Your Guide/Help'

  3. A web page will open.

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