Under today’s stressful economic conditions, it's wise to sharpen your focus on production efficiencies. There are a variety of areas where improvements can change your economic outlook.

One such area involves losses due to injured, fatigued and dead market hogs. These issues occur during the loading and transporting process, as well as during the holding period at packing plants. If you or your packer has a relatively high incidence of mortalities or fatigued animals, you both need to work to identify causes and solutions to reduce the incidence.

Many environmental and management factors such as weather and transportation influence the incidence of dead and fatigued pigs, which can be classified as whole-pig defects. Mortalities that occur during loading, transport or lairage are especially costly because you have incurred the full production costs for a market-weight animal. Processors also incur costs associated with increased labor and, in the case of dead pigs, removing them from trailers and disposal.

To investigate factors contributing to injured pigs, market-hog mortalities and fatigued pigs throughout the transport and lairage processes, we analyzed data from an integrated production facility. Because pig mortalities as well as injured and fatigued pigs all contribute to inefficiencies throughout the pork production process, they were identified as “total defects,” which were counted per trailer load (totaling 11,451 loads). Date, farm, trailer type, driver, normal or split load, trailer loading crew, number of hogs in the load, average live weight and the pull from barn were recorded for each trailer load and evaluated to determine the total number of defects.

Weather data were collected from a mobile weather station at the harvest facility. Wind direction, speed and gust were used as fixed effects. Temperature (°C) and relative humidity were used to calculate a temperature/humidity index. Density was calculated by multiplying the average live weight by the number of pigs per load. Density, minutes of rest in the pens at the plant, load time per pig and the temperature/humidity index were included as co-variants in the analyses.

In all, 14 variables were identified as significant factors contributing to the percentage of defects per trailer. Density accounted for the largest percentage of variation.

Figure 1 shows the scenarios of defects per trailer load based on different average market-hog weights and the number of pigs per trailer. To reduce the impact of density per trailer load, estimate the average live weight per animal and reduce the number of animals per load accordingly — especially when market hogs are heavy.

The effect of the temperature/humidity index is shown in Figure 2. Defects increase during extremes of the temperature/humidity index; however, defects also increase in either hot or humid conditions.

As you might guess, as shown in Figure 3, the percentage of defects per trailer fluctuates through the year. It seems logical to think that the highest incidence occurs during the hottest season. Not true. Winter months present the greatest challenges.

Load crew personnel must address environmental issues during winter months to prevent pigs and people from injuring themselves. Use proper bedding inside trailers to keep animals from getting too cold. Drivers must keep an eye on hogs when trailers are boarded up during cold periods. Temperature variations during winter, as well as in late fall and early spring, with trailers boarded up can cause inside temperatures to exceed the thermal-neutral zone and pigs become overheated.

Individual variables — trailer environment, load crew, temperature/humidity index and such — have a relatively small impact on mortalities, fatigued and injured pigs. That said, when a combination of variables or events occurs, the total loss of the animal or partial losses due to carcass trimming or condemnation can add up.

It’s worth noting that the integrated system providing data for this analysis is well below the industry average for defects per load occurring at any stage of the loading, transport and harvest process.

To identify factors that contribute to these related defects work with your trucker, processor and local swine educator to develop evaluations similar to those described within this article.

The authors want to acknowledge Neil Matthews and Collette Schultz Kaster of Farmland Foods for providing the data used in this study.

Editor's note: In the April Smart Thinking column, the author's affiliation was listed incorrectly. Don Levis, PhD., is a swine specialist at the University of Nebraska.

(Figure 1) Lighten the Load

In this study, the defects per trailer increased as density in relation to trailer space (approximately 790 sq. ft.) increased. For example, you could incur a greater percentage of defects per load as the number of pigs per load and/or the average weight of those pigs increased.

Shown here are five levels of average percent defects (injured and fatigued pigs, and mortalities) per trailer load. You can see that at the greatest pig density, the incidence of defects per load rose to 1 percent.

(Figure 2) It’s the Heat and the Humidity

Shown here is the effect of the temperature/humidity index on the percentage of defects per trailer. The THI equation from NOAA was calculated using temperature and relative humidity data. Values of THI represent “feel like” temperature conditions.

The THI proved to be a significant source of variation. The lowest percentage of defects occurred between -11º C and -6° C, or 12º F to 21° F.

(Figure 3) Winter is the Harshest

Illustrated here are the seasonal effects on injured, fatigued and dead market hogs per trailer, with the average percentage per month. The secondary vertical axis represents average live weight of pigs per trailer load.

As you can see, the greatest defects occurred during November through January, with the lowest frequency from May through August.