4.6 Drawing Lactation Curves

A Python-language program, bestpred_curves.py, is included in the BESTPRED archive. If you have Python (http://python.org/) and the appropriate extensions (matplotlib, numpy) installed you can use bestpred_curves.py to draw lactation curves that are written to files in Portable Network Graphics format (PNG; http://en.wikipedia.org/wiki/PNG). To run bestpred_curves.py you must provide a trait (1 = milk, 2 = fat, 3 = protein, 4 = SCS, 5 = all). and you may provide an input file name. If you do not provide a file name then all files matching the pattern "cowcurve.*" are processed:

[jcole@aipl366 bestpred]$ python bestpred_curves.py
[ERROR]: You must provide a trait: 1 = milk, 2 = fat, 3 = protein, 4 = SCS, 5 = all
[jcole@aipl366 bestpred]$ python bestpred_curves.py 1
Processing cowcurve.ST.20070921
Writing file curve_AYUSA000000960899_Milk_1.png
Writing file curve_AYUSA000000960899_Milk_2.png
[jcole@aipl366 bestpred]$

One file is written per cow-trait combination in the input file. File names are of the form "curve_<cowid>_<trait>_<parity>.png". An example figure is provided in Figure 4.1.

**Figure 4.1:** Lactation curve for milk yield (pounds) of a second parity Holstein cow

The blue line in Figure 4.1 is the standard curve, the green line is the daily best prediction curve, and the green points are test day yields. The values in the top right-hand corner are the 305-d actual (green) and standard curve (blue) yields, respectively. All values in the figure are actual daily values, not mature equivalent values.

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