How to Calculate How Much a Cow Eats

Determining how much a cow eats will help when purchasing feed, to ensure there is sufficient supply available until more can be harvested or purchased. Not all cows will eat at the same rate. It depends on the breed, time of year and climate, as well as whether the cow is producing milk, pregnant or just a pet. To determine how much the cow eats, you must weigh the feed before and after making it available to the cow.

Things You'll Need

  • Weigh scale
  • Calculator
  • Truck
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Instructions

  1. Bales

    • 1

      Load the feed source -- such as a round bale of hay or green feed -- into a pick-up truck or onto a trailer. Take the bale to a truck scale, and weigh the loaded vehicle or trailer. After weighing, give the bale to the cow, and then reweigh the truck or trailer.

    • 2

      Subtract the second weight from the first weight to get the starting weight of the bale. If you purchased round bales by weight, you may want to use the average bale weight provided at purchase as your starting weight, if you believe it will be accurate.

    • 3

      Keep track of the number of days that it took the cow to finish the bale, since you cannot easily reload the round bale once it has been opened.

    • 4

      Divide the starting bale weight by the number of days it took for the cow to eat it, and this will give you the figure that represents how much the cow ate per day on average.

    Grains

    • 5

      Weigh approximately one day's worth of the cow's grain, if it is on a grain-based diet because it is being fattened for slaughter. If you're unsure of the amount, weigh slightly more than you think the cow eats in a day, to be safe.

    • 6

      Put the grain in the cow's trough, and give it access for the next 24 hours.

    • 7

      Remove whatever grain is left in the trough, and weigh it again.

    • 8

      Subtract the second number from the first, to determine how much grain the cow ate in that 24-hour period.