Mortality Rate of Weaned and Feeder Pigs as Affected by Ground Transport Conditions

Abstract

Ground transport of pigs at early ages may result in profit-stripping incidences of mortality and compromised animal welfare due to stress stemming from unfavorable transport conditions. The objective of this study was to examine possible causative relationships of mortality rate of weaned and feeder pigs to ground transport conditions. A total of 7056 transportation records of weaned pigs (3174 records) and feeder pigs (3882 records) for the period from April 2012 to January 2014 were provided by a U.S. swine company. Effects of pig type (weaned vs. feeder pigs), ambient temperature (<15°C or cool/cold, 15°C to 25°C or mild, and >25°C or warm/hot), travel distance (<600 >km, 600 to 900 km, 900 to 1200 km, 1200 to 1500 km, and >1500 km), and the interactive effects on dead-on-arrival (DOA) rate (DOA per head loaded, %) were evaluated. The effects of the same variables on post-transport mortality of weaned pigs were also evaluated. Results show that DOA rate was affected by pig type, ambient temperature, and travel distance interactively. Weaned pig DOA rates (mean ±SE of 0.0333% ±0.0150%) tended to be higher than feeder pig DOA rates (0.0243% ±0.0110%) (p = 0.0004), and weaned pigs were more vulnerable to transport stress in warm/hot conditions. For weaned pigs, DOA rates were higher with >900 km travel distance (0.0543% ±0.0389%) than with <900 km travel distance>(0.0118% ±0.0078%) in cool/cold conditions, and DOA rates significantly increased as travel distance increased in warm/hot conditions. For feeder pigs, DOA rates were not affected by travel distance in cool/cold or mild conditions; however, higher mortality rates were found with >1200 km travel distance (0.2717% ±0.1326%) than with <1200 km travel distance>(0.0315% ±0.0151%) in warm/hot conditions. Statistical analysis showed that post-transport mortality rate of weaned pigs was affected by ambient temperature during transport and travel distance interactively for the first one or two weeks after transport. However, it should be noted that the relationship between post-transport mortality and transport conditions could have been confounded by other factors, such as management at the finishing farm. Outcomes of this study are expected to offer insight into improving the ground transport of pigs.

Evaluation of Conditions during Weaned Pig Transport

“…Only 28 pigs were DOA during the 78 trips used for analysis, which equals an overall mortality rate of 0.035%. Results are consistent with Zhao et al (2016) for weaned pig transport mortality with a rate of 0.0333% reported.…”

“…Hydration of early weaned pigs during transport appears to be a common concern among researchers. Zhao et al (2016) analyzed records from a swine production company that transports weaned piglets distances up to and beyond 1500 km and found that mortality averaged 0.0333+0.015% which was a function of weather and travel distance. Mortality was significantly greater for distances over 900 km compared to those under 900 km during ambient temperatures less than 15°C and increased significantly with increasing distance for ambient temperatures above 25°C.…”

Effects of dietary γ‐aminobutyric acid supplementation on antioxidant status, blood hormones and meat quality in growing‐finishing pigs undergoing transport stress

“…Transport is considered a major source of stress for farm animals; transport can have harmful effects on health, welfare, performance, ultimately and product quality (von Borell, 2001). Ground transportation is a great challenge to the mortality rate of early weaned pigs (Zhao, Xin, Harmon, & Baas, 2014). GABA exists in the mammalian central nervous system as a main inhibitory neurotransmitter.…”

A Review of Swine Transportation Research on Priority Welfare Issues: A Canadian Perspective

“…As ambient temperature increases, pigs modify their behavior to reduce heat production by reducing activity (75, 76) and also dissipate heat by accelerated breathing and increasing contact with cool or moist surfaces (20, 77, 78). However, at temperatures >30°C with relative humidity levels >88% these evaporative cooling mechanisms are significantly compromised (30, 31, 79). Under cold conditions, they will change posture and huddle together to maintain body temperature and limit heat loss (80).…”

“…Interactions can occur between journey duration, external temperature, and pig type (weaner or market weight pigs) that affect the risk of mortality during transport. Zhao et al (79) tried to examine the effects of the relationship between journey distance (<600 km; 600 to 900 km; 900 to 1,200 km; 1,200 to 1,500 km; and >1,500 km) and ambient temperature (<15°C or cool/cold; 15 to 25°C or mild; and >25°C or warm/hot) on mortality rate in weaned and slaughter pigs. To this end, a total of 7,056 transportation records of weaned pigs (3,174 records) and slaughter pigs (3,882 records) for the period from April 2012 to January 2014 were provided by a US swine company.…”