REVIEW: Basic Principles and Economics of Transportation Shrink in Beef Cattle

Abstract

Shrink is a normal occurrence in cattle that affects both the seller and buyer; a few hours to over 30 d are required to replenish this lost BW. The primary factor affecting shrink is the length of time of feed and water withdrawal; rate of shrink averages ca. 1%/h during the initial 3 to 4 h, but decreases to as low as 0.1%/h after 10 h or more. Shrink is not only loss of gut fill but actual tissue loss, which can exceed 60% of the total BW loss. This amount is greater when ambient temperatures are high. Many other factors also affect the amount of shrink cattle incur. Shrink may be increased by up to 2 percentage units when environmental conditions are stressful, such as during periods of high ambient temperature, transport (compared with holding in a drylot), or during extra or rough handling. Preconditioning calves or feeding specific types of diets prior to shrink have not affected shrink conclusively. Allowing calves to consume feed or forage immediately before deprivation reduced the amount of shrink by up to 2.9 percentage units, and feeding ionophores reduced shrink by 0.2 to 1.5 percentage units. Electrolyte supplementation may also reduce shrink, but much more research is needed to determine which electrolyte or combination of electrolytes is needed, at what levels they are needed, and when is the optimal time to supplement with higher levels of electrolytes to have the greatest impact on reduction of shrink and stress.