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HUNTIN' DAYLIGHT -- SHRINKING RETURNS

by: Wes Ishmael


Most everyone who develops a strategy for managing cattle shrink based upon economics rather than convenience has a formula—in some cases closely guarded—they believe preserves the most hard-won pounds.

Unfortunately, anyone who has ever moved cattle anywhere, taking weights on both ends of the haul, knows that there is no surefire way to minimize shrink because of the antagonisms that exist.

For instance, some folks ship as early in the day as possible to avoid the warmer temperatures which do contribute to more shrink.

In one Kansas State University (KSU) study (Table 1), during a 40-hour fast and transit cattle hauled at temperatures of 3-21° F. shrunk at 7.7 percent compared to 9.5 percent on cattle hauled when the thermometer read 64-93° F.

As the Table 1 indicates, cattle moved in warmer temperatures actually lost less shrink in the form of urine and fecal excretion than those hauled in cooler weather, meaning shrink during warmer temperatures comes more from respiratory loss, presumably at the expense of fluid from body tissue or tissue shrink. Consequently, shrink in hotter weather is considered to be more costly, especially to buyers receiving the cattle, than shrink that occurs in cooler weather.

The flip-side of that is that other research points out that waiting to ship cattle until later in the morning can be worth more pounds.

According to multi-year research at KSU, which looked at steers grazing smooth Bromegrass pastures, producers can pick up about 3 lb. per head per hour for every hour after daylight they're allowed to graze, until 9 a.m. or so. Quick math says that a 9 lb. difference per head between gathering cattle at 6 a.m. versus 9.

More specifically, steers gathered three hours after daybreak shrunk at a rate of 0.5 percent per hour compared to .69 percent per hour for steers gathered at daybreak. Steers shrunk 0.71 percent and 0.67 percent per hour when gathered at one or two hours after dawn, respectively.

In part, researchers say this reality has to do with the typical grazing pattern of cattle. Depending on factors such as forage type and environment, cattle will usually graze during 2-4 distinct periods throughout the day; the primary grazing period is often during the early morning. So, trapping cattle at first light robs them of their main meal of the day.

Plus, since cattle shrink the most during the first hours of food and water deprivation, the less time they're standing around waiting on the trucks, the fewer pounds they should shrink.

KSU researchers explain cattle shrink at approximately 1.0 percent per hour for the first three to four hours of food and water deprivation, then shrink declines to as little as 0.1 percent per hour up through 10 hours.

     

The Feed Factor

This antagonistic conundrum is before considering the fact that research examining pre-shipment nutrition is all over the board in terms of results.

The amount of shrink, relative to the makeup of roughage and concentrate in the ration, varied with the transportation time, as well as how and when the cattle were fed before fasting. That's according to another KSU trial evaluating pre-fast diets.

In one case, steers fed a 50 percent concentrate diet shrunk less than those fed only hay. In another, steers fed hay shrunk less than those fed a 55 percent concentrate ration. You get the idea. Bottom line based on this and other data researchers conclude that it is questionable whether or not feeding concentrate prior to shipment will reduce shrink.

Likewise, research serves up varying results concerning the impact that feed additives may have on shrink. In one study, suckling calves hauled 120 miles shrank 45 percent less when Lasalocid was included in creep feed prior to shipment, compared to calves fed creep without the additive. Stocker heifers receiving lasalocid shrank a total of 5.5 percent, compared to 5.9 percent for those receiving oxytetracycline and 6.0% for the heifers receiving mineral without an additive. All told, indications are that feeding an ionophore for extended periods before shipment may help reduce shrink.

     

Handling for Dollars

Certainly not last nor least is the impact cattle handling has on shrink.

In one example, KSU researchers were gathering eight different sets of stocker cattle from eight pastures to weigh them for a trial. Seven sets of cattle found the gate easily; their weight compared to one taken the day before was 12.0 lb. less. The other set of calves took approximately a half-hour to find the gate; their weight compared to the day prior was 48.2 lb. less. So, in this example, the cattle too stirred up to find the gate incurred four times as much shrink as those that remained calm.

With that in mind, be it inherent disposition or the environment from whence the cattle come, excitable cattle seem to shrink more and take longer to recover the pounds they lose. In another KSU trial, cattle came from two different sources: one set was calm and easy to handle; the other group was easy to excite and hard to handle. During an 11-day period following an overnight shrink, the calm cattle recovered more of their lost body weight.

As well, other research indicates cattle hauled directly to the feedlot from the ranch shrank 21 percent less than cattle hauled to the feedlot from an auction market and took longer to recover the lost weight.

In fact, while length of hauling time, miles covered and season impact transportation stress and shrink (Table 2), research indicates cattle age may be the primary factor when it comes to how cattle deal with transportation. In studies looking at the relationship of calf (six months old or less) morbidity and mortality to everything from time of feed deprivation, to climatic conditions during the haul, to stocking density on the trailer, typically the younger the cattle transported the higher the sickness rates and death loss.

So, one of the most effective strategies for reducing transportation stress seems to be separating that stress from others you know the calf will encounter. For example, gathering, processing and loading stockers at the same time creates more stress than if those cattle were processed ahead of gathering and shipping time.

The information here is just one example of the insights you can find at www.beefstockerusa. org. The site features all kinds of research from universities across the country, along with fact sheets by topic. As the name implies, it's geared toward stocker cattle operators, but plenty of the information, such as that about shrink, is applicable to cow-calf producers as well.

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