Kirk Kreger keeps a herd of about forty Holstein dairy cows, which he manages by means of rotational grazing. During the heat of summer Kirk’s animals seek shade under the few accessible trees, which causes a number of problems. The trees are manured so generously that they are eventually killed, while the rest of the pasture suffers from nutrient deficit. The ground under the trees is worn bare and because susceptible to erosion. Further, these bare patches come to harbor substantial populations of parasites. The cows get dirty when they lie down in the bare spots and their udders then have to be cleaned before they can be milked. Finally, the animals stop grazing when they congregate like this, which depresses milk production.
Kirk decided to build a mobile shade rack to alleviate the problems cited above. He built a 20 by 70 foot framework out of PVC pipe and mounted it to the mobile home frame. He stretched a shade cloth over it and welded on drop legs for additional stability. The rack can be dragged by tractor to wherever it is desired and set up in about ten minutes.
Kirk tried it out over the summer of 1999, which was very hot and dry in Pennsylvania. He kept track of daily milk production and on eight occasions he withheld the shade rack and observed the effect this had on milk yield.
Results: The rack was quite effective. It proved sturdy and successfully weathered several storms. The cows made use of it and thus the formation of bare spots were prevented and the pasture was more evenly grazed and manured. A small but consistent decline in milk production, averaging 1.8% was observed on each of the eight occasions when the shade rack was withheld, production rising again the following day when the rack was restored.
Kirk reports the rack cost $1200 to build. He intends to keep using it. He figures that, with a herd this size, the rack will pay for itself in two seasons in terms of milk production saved.