July 19, 2018

Interpretive Summary:Impact of health challenges on pig growth performance, carcass characteristics, and net returns under commercial conditions.

Interpretive Summary:Impact of health challenges on pig growth performance, carcass characteristics, and net returns under commercial conditions.

By: Dr. Caitlin Vonderohe

Modern hog production in the United States has largely geographically centered around the state of Iowa, with 63% of hog market sales originating in Iowa or the surrounding states. This has created a unique challenge because this increases the risk of disease transmission from farm to farm. The majority of swine disease research examines the effect of one pathogen on pig performance and physiology. However, multiple disease challenges, such as Porcine Reproductive and Respiratory Syndrome virus (PRRSv) and Influenza type-A virus, can combine to result in a more physiologically and economically significant problem. A recent study, “Impact of health challenges on pig growth performance, carcass characteristics, and net returns under commercial conditions” published in Translational Animal Science explores the effect of naturally occurring health challenges on swine facility productivity and net financial returns.

Three identical grow-finish barns, located on the same geographical site, were each filled with 936 crossbred pigs. Each facility was managed similarly by the same personnel, using the same ad libitum diets and phase feeding program. Pigs were observed daily; mortality, treatments and morbidity were recorded. The barns were characterized as low challenge, moderate challenge and high challenge based on naturally occurring disease processes. Oral fluids were collected three times throughout the study to monitor pathogen exposure. Personnel were restricted to only move from the low health challenge barn to the moderate and finally to the high health challenge barns to maintain biosecurity and disease status. Swine performance was measured, including feed disappearance and body weight. Pigs were marketed in three groups to achieve a target harvest weight.

Each barn experienced clinical signs related to PRRSv, but the high health challenge barn had the greatest level of PRRSv concentration in oral fluids for two of the three oral fluid samples. The authors also suspect that the high health challenge barn experienced a secondary infection with a different strain of PRRSv for the final test date. Oral fluid samples, coupled with observed clinical signs, also indicated that the moderate and high challenge barns were infected with Influenza type-A.

The increases in health challenges (from low to high) corresponded with increases in the number of injectable treatments administered. There was also an increase in mortality and a reduction in the number of pigs marketed as full value animals. High and moderate health challenges also resulted in significantly lower average daily gain and feed conversion compared to the low challenge barn. Days to market also increased with greater health challenges.

Based on the fixed-weight economic model, moderate health challenges resulted in losses of $21,454 and high health challenges resulted in losses of $46,199 compared to the low health challenge pigs. This was primarily a result of lower carcass weights and decreased numbers of full-value pigs marketed in the moderate and high health challenge barns. Overall, the authors calculated that financial losses due health challenges can range from $11.02 to $14.20 per pig marketed.

Diseases such as PRRSv and IAV-S can result in significant financial losses when alone but can result in much more significant losses when they co-infect a group of animals. Overall, the authors concluded health challenges can dramatically affect growth performance, number of injectable treatments administered, pre-harvest mortality and marketing strategies used in swine production.

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