I believe that shrink is a concept that isn’t fully understood by many people in the cattle industry. Simply put, shrink refers to weight loss during transport. However; how it occurs, what it does to cattle and the effect it has at the feedlot isn’t so simple.
There are two types of shrink. One is exudative which refers to the loss of urine and feces. The other is tissue loss which refers to loss of fluid from the cells. Tissue shrink isn’t regained very quickly. By the way, fat cattle shrink less than lean calves (more water in muscle than fat). So young calves that have a higher lean-to-fat ratio will shrink more than older, fed calves.
Cattle may lose as much as 75 percent of their rumen function since rumen protozoa and bacteria populations are sharply reduced during feed and water deprivation. It may take five or more days after feeding for rumen function to return to normal. During stress, calves excrete more potassium which also needs to be replaced in the receiving diet.
One estimate for shrink is 3 percent for the first 100 miles and 0.5 to 1.0 percent for each additional 100 miles. However, it is not necessarily distance that effects shrink as much as time in transit. The following table shows the effect time has on shrink and the resulting numbers of days required to regain payweight.
You can see that time on the trailer should be kept to a minimum – truckers should have eaten, showered, slept, etc. before loading the cattle. I have seen truckers load and then stop at the nearest truck stop – calves need to get where they are going and have feed and water as soon as possible.
Is there anything that we can do on this end of the production chain? Consider that calves are generally hauled to a stockyard in the morning, sold in the afternoon and, perhaps, loaded the next day and hauled to a western state. That’s a lot of time for shrink to occur. Although the payweight may have been taken at the salebarn, shrink started from the time they left the farm of origin.
The “sticking point” occurs where buyers want “good” (shrunk) weights and to pay for less pounds but more shrink means more days to recover payweight and an increased likelihood of sickness.
There’s a lot of disagreement on when or if calves should be fed during the marketing process. My personal opinion is that once calves are weighed, they should receive water and dry feed before being loaded. Dry feed should consist of some hay due to increased time it will spend in the rumen – giving the “bugs” something to feed on to keep them alive. Water is needed because dehydration in detrimental to body functions – second only to oxygen deprivation is its severity. If the calf knows how to eat from a bunk, some concentrate may be beneficial, too – think “carbo-loading” before running a marathon.
Anything that anyone can do to minimize the stresses associated with weaning, hauling, marketing, etc. is a win-win situation for everyone. Each party should realize that they have a stake in the marketing process. Let’s avoid those wrecks that reflect poorly on the reputation of our feeder calves.