What is the Return Interval Analysis graph?
The Return Interval Analysis graph evaluates heat detection accuracy by analysing the distribution of short, normal, and long returns. It calculates the percentage of returns based on Eligible Cows (or the selected group). The goal is to have less than 13% short returns and less than 18% long returns. If rates are exceeded, the colour of the graph will change from blue to red.
How do I read the Return Interval Analysis graph?
The Return Interval Analysis graph shows return rates on the left and intervals along the bottom. It uses the total number of returns and days between matings to first categorise your returns as either short, normal and long. Next it calculates the portion of returns (as a percentage) for each category. Return rates are broken down into the following:
Short - return occurred between 1 to 17 days after the previous mating
Normal - return occurred between 18 to 24 days after the previous mating
Long - return occurred more than 25 days after the previous mating
If you click on the graph, you'll see details of the interval, how many returns occurred and the target for that interval. The table below also provides the same information with the corresponding colour.
Tip: Use the Summary of Matings report and sort by Days Gap to see which cows have returned and the interval.
Short or Long Returns exceeding targets
Short or Long Returns below target
Return Interval Analysis breakdown
Return rates are first categorised into short, normal and long using:
Total number of returns (if AB Only is selected, it will only use AB mating returns)
Number of days between a cows matings (return interval)
Once categorised, returns in each category are divided by the total number of returns to give your actual percentage.
Return rates
Return interval
The table gives a breakdown of the intervals, targets and what your actual returns were for each return rate.
Select All Matings to include recorded natural matings on the graph.
Things to note
The Return Interval Analysis graph is best used after day 28-35 of the mating period. Why? If you look at this graph prior to day 28, you'll see mostly short returns as there wouldn't have been enough time for normal or long returns to occur.
For the graph to provide accurate results, we recommend having at least 50 returns recorded. If you have less, you'll see the message "The information in this graph could be misleading as there are less than 50 returns recorded or less than 24 days of mating have passed."
If you're having issues loading the graph, double check that your calvings have been recorded correctly i.e. were not recorded as bulk with the same date.