Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2009
Publication Date: 8/1/2008
Citation: Ritter, M.J., Ellis, M., Berry, N.L., Curtis, S.E., Anil, L., Benjamin, M., Butler, D., Dewey, C., Driessen, B., Dubois, P., Hill, J., Marchant Forde, J.N., Matzat, P., Mcglone, J.J., Mormede, P., Moyer, T., Pfalzgraf, K., Salak-Johnson, J., Sterle, J., Stull, C., Whiting, T., Wolter, B., Niekamp, S.R., Johnson, A.K. 2008. Transport losses in market weight pigs: I. A review of cefinitions, incidence and economic impact. Professional Animal Scientist. 25:404-414.
Interpretive Summary: The long distance transportation of livestock from the farm to the slaughter plant has become a common practice in U.S. animal agriculture. Within the swine industry, the effect of long distance transport on well-being has become increasingly important. Over recent years, the number of pigs either dying during transport or becoming non-ambulatory during transport has increased. We conducted a review and basic statistical analysis of recent experimental studies that, combined, examined the effects of transportation on over 6.5 million slaughter-age pigs. Total transport losses included over 16,000 pigs dead on arrival and a further 30,000 non-ambulatory – i.e. unable to walk off the truck. Extrapolated to the U.S. industry as a whole, these figures represent losses worth over $50 million annually. The majority of the non-ambulatory pigs do not have any visible injury but are displaying signs of acute stress associated with metabolic acidosis, and they will recover if given time to rest. We are continuing to investigate factors that contribute to the incidence of non-ambulatory pigs and identify methods to reduce losses, which will impact the welfare of pigs during transport, provide economic benefits to the producer and address the animal welfare concerns of the consumer.
Technical Abstract: Transport losses (dead and non-ambulatory pigs) present animal welfare, legal, and economic challenges to the U.S. swine industry. The objectives of this review are to explore: 1) the historical perspective of transport losses; 2) the incidence and economic implications of transport losses; 3) the symptoms and metabolic characteristics of fatigued pigs and 4) the pre disposing factors for transport losses. In 1933 and 1934, the incidence of dead and non ambulatory pigs was reportedly 0.08% and 0.16%, respectively. More recently, 23 commercial field trials (n = 6,660,569 pigs) were summarized and the frequency of dead pigs, non ambulatory pigs and total transport losses at the processing plant were 0.25%, 0.44% and 0.69% respectively. Non-ambulatory pigs were classified as fatigued (non-ambulatory, non-injured) or injured in 18 of these trials (n = 4,966,419 pigs), and the average percentages were 0.37% and 0.05%, respectively. In 2006, total economic losses associated with these transport losses were estimated to be over $57 million to the U.S. pork industry. Fatigued pigs display signs of acute stress (open-mouth breathing, skin discoloration, muscle tremors) and are in a metabolic state of acidosis characterized by low blood pH and high blood lactate concentrations. However, the majority of fatigued pigs will recover with rest. Transport losses are a multi-factorial problem consisting of people, pig, facility design, management, transportation, processing plant, and environmental factors. Because of these multiple factors, continued research efforts are needed to understand how each of the factors and the relationship among factors impact the pig’s wellbeing during the marketing process.