Marketing pigs at the correct weight is critical to capture the most dollars from the packer. Estimating market weights visually is very difficult for even the most trained eye. Ideally, pigs would be weighed on a scale; however, scales aren’t available in all situations and are cumbersome to move from barn to barn.
In response, Kansas State University researchers developed a “Market Pig Weight Tape” to aid producers in determining the average weight of a group of pigs. The process involves a flank-to-flank measurement. Researchers do point out that the weight tape should not be used to determine individual weights, as there can be as much as a 20- to 30-lbs. error in the measurement of a single pig. However, if you measure 20 to 30 pigs flank-to-flank, the overall estimate becomes quite accurate in providing an average weight of a group, researchers say.
The best application for the tape is to either: 1) measure the flank measurement on the 20 heaviest pigs in the group to determine whether they are ready to market; or 2) measure the flank measurement on 30 randomly chosen pigs to determine the average weight of pigs in the barn before starting to market. If average pig weight is 220 lbs. or greater, 10 percent to 11 percent of the barn will be 30 lbs. heavier than the average weight and 4 percent to 5 percent will be 40 lbs. heavier than the average weight.
Here's an example, if a group of 600 pigs averages 245 lbs, approximately 66 pigs will weigh more than 275 lbs. and 30 of those pigs will weigh more than 285 lbs.
Procedures for using the flank tape are similar to those used with Kansas State's tape designed for use on gestating sows. The measurement taken is from the bottom of the flank on one side of the pig, it moves over the highest point of the animal's back, and back down to the bottom of the flank on the other side. Place the tape loosely over the animal's back -- do not pull down tightly.
You can order a tape by contacting Lois Schreiner at firstname.lastname@example.org or (785) 532-1267.
Source: Kansas State University