Breeding stock are frequently shipped considerable distance from isolated high-level biosecurity facilities to farms across North America. Little scientific data exists on the reproductive or health effects of long-distance transportation on breeding stock. To address this lack of knowledge we shipped breeding-aged gilts at various space allowances for different lengths of time up to 30 hours.
During the first experiment we shipped pigs for 30 hours at TQA recommended space allowances plus an extra 20%, which is common practice when shipping breeding gilts. Every 6 hours we assessed health and well-being of the gilts by measuring weight loss, dehydration, stress levels, and blood chemistry parameters. During the second experiment we compared 2 space allowances, TQA recommended space allowance and TQA +20% recommended space allowance. In each study a group of gilts remained in their home pen to serve as controls. At the end of each study gilts were returned to the TTU herd as replacements and their reproductive performance was assessed.
In both studies a similar pattern in the physiological response to transport was observed in the gilts. An initial negative response to transport was followed by an adaption period, and then as the transport period increased a gradual increase in the number of physiological changes that differed from control gilt was observed. Space allowance (TQA and TQA +20%) did not affect any of the measured variables. After a 6 and 12 hour transport period there were significant changes in cortisol concentrations, neutrophil to lymphocyte ratio, and glucose concentrations. These changes suggest an acute stress response to transportation at 6 and 12 hours. After a 6 hour transport period total protein and weight loss were significantly different compared with control gilts, suggesting that transported pigs were experiencing dehydration. Changes in aspartate aminotransferase, creatine kinase, and blood urea nitrogen concentrations at transport durations longer than 6 hours indicate increasing fatigue as a response to physical activity and possibly tissue damage. Reproductive performance (measured as farrowing rate, total born, born alive, stillborn, mummies, weight at processing, number weaned, and weight at weaning) was not affected by transport or duration of transportation in either of the studies.
These data support the growing body of evidence showing that short duration transportation can be stressful to pigs but some degree of acclimation occurs as transport continues. However, after a 30 hour transport period some variables indicative of animal well-being appeared to decrease possibly due to dehydration and hunger. Even though physiological changes were observed in gilts in response to transport, these physiological effects appeared to be only transitory as there was no effect of transport or transport duration on the reproductive performance of these breeding gilts. When carefully managed, healthy gilts can travel long distances with little risk of long term effects on health, well-being, and reproductive performance.