Date Full Report Received10/28/2014
Date Abstract Report Received10/28/2014
InvestigationInstitution: Texas Tech University
Primary Investigator: John McGlone
Co-Investigators: Anna Johnson
Funded ByNational Pork Board
Weaned pigs are transported on many USA farms. Some are transported short distances and others many hours. During transport pigs can be exposed to several stressors prior to and during transport including handling during loading, exposure to a novel environment, mixing with unfamiliar pigs, food and water deprivation and temperature fluctuations. Weaning is also a very sensitive stage in the life of a pig and a time at which welfare may be at risk. Therefore, the combined stress of transport and weaning has the potential to compromise wean pig welfare. However, little research has been conducted to understand the effect of transport duration on the well-being of weaned pigs and the associated effect of feed and water withdrawal. Therefore, the purpose of this study was to evaluate the effect of feed and water withdrawal on weaned pigs during transport of different durations based on behavior, performance and physiological measures of welfare.
The objective of this study was to evaluate the effect of feed and water withdrawal on weaned pigs during transport of different durations. At 18-22 days of age (the average weaning age of pigs on commercial swine farms in the US) pigs were randomly assigned to one of five treatment groups. Both gilts and barrows were evenly presented in each treatment group (10 pigs/treatment; 5 gilts and 5 barrows). The study involved 5 treatment groups:
1) Not weaned: pigs remained on the sow (CON)
2) Weaned, not transported, but had access to feed and water: pigs removed from the sow and moved into pens that had feed and water (WEAN+)
3) Weaned but had no access to feed and water: pigs were removed from the sow and moved into pens that did not have feed and water (WEAN-)
4) Weaned and transported with access to feed and water: pigs were removed from the sow and transport for up to 32 hours with access to feed and water (TRANS+)
5) Weaned and transported (as normally done) without access to feed and water: pigs were removed from the sow and transport for up to 32 hours without access to feed and water (TRANS-)
This study was replicated with 2 sexes X 5 treatments = 10 pigs X 9 replications = 90 pigs. The transport involve placing pigs in pens and transporting them in a goose-neck trailer. The pigs were transported along the same route for each replicate. The route involved a 32-hour trip. Each 8 hours, the truck/trailer would return to the New Deal farm, all the pigs were blood sampled, and weighed, then the truck/trailer continued for another phase (sampling at times 0, 8, 16, 24 and 32 hours). During sampling periods, (approximately 15-25 minutes) travel time would continue; thus, all sampling periods would take place at the time markers listed above. At the end of the trip, all pigs were placed in weaning pens at the farm of origin and followed at 24 hours and 7 and 14 days after weaning.
To assess pig welfare, measures of performance (weights, health, injury), behavior (on the truck or at the farm and after unloading), were measured.
Performance. Pigs were weighed before, immediately after and at 7, and 14 days after transport. Percetn weight change was calculated. Before and after shipping, each pig was examined for injuries, wounds, abscesses, and lameness.
Behaviors. Pig behavior was recorded during and after transportation. Behaviors of interest during transportation included standing, lying, sitting, drinking, and eating. After transportation pigs were penned with the same pen mate they had while being transported and video was taken for 24 hours post transport for all groups and quantified to examine potential treatment effects.
Physiology. Only 2 mL of blood were collected before transport and 2 mL every 8 hours after the start of the study. Blood was examined for baseline total white blood cell (WBC) counts and differential counts for the different white blood cell populations (neutrophil:lymphocyte ratio goes up with stress), plasma cortisol concentrations (an indicator of stress), glucose, creatine phosphokinase (indicator of stress and fatigue), total protein and hematocrit (indicators of dehydration).
There was a significant loss in percent body weight within treatments. Control pigs had a 6.5 ± 0.45% increase in body weight by the end of the transport study. Weaning caused a 5.9 ± 0.45% loss in body weight. Weaning without feed and water caused and 7.8 ± 0.45% loss in body weight. Transport with feed and water caused a 6.5 ± 0.45% loss in body weight in addition to weaning loss in body weight. Not providing any feed and water during transport caused a 9.1 ± 0.46 % loss in body weight. While control pigs continued to increase in weight, all other groups lost weight and were significantly different from the control group. There was no difference in percent weight loss in treatment groups until after 16 hours of transport. Transporting without feed and water has a greater impact on percent loss in body weight, and becomes apparent by 24 hours of transport.
Neutrophil to lymphocyte ratio (N:L) had a significant increase by 8 hours of transport. All treatment groups were had significantly higher N:L ratios compared to control pigs. At 16 hours of transport only Wean+ pigs has similar N:L ratios than the control pigs. After 16 hours N:L ratios began to normalize, possibly suggesting piglet adaptation to their environment.
Blood glucose levels for all treatment groups were all significantly lower than the control group by 8 hours of transport. Blood glucose levels continued to drop until the end of the transport study. Although pigs were provided with feed, they may not consume enough to maintain blood glucose levels.
Creatine Kinase (CK) was significantly higher for Trans+ females than males. Typically at weaning age there is no sex difference.
Total plasma protein (TP) was significantly higher in Trans- pigs by 16 hours of transport and remained higher than all other treatment groups until 24 hours of transport. By 32 hours of transport all treatment groups has increased TP, except control pigs. This possibly indicates that dehydration and stress were increased at this point in time.
Significant changes in behavior were observed during and after transportation. Behavioral changes can be indicative of stress. Significant changes in behavior were observed during and post- transport, with lying behaviors and standing behaviors being predominantly high in both phases. It has also been previously reported that high levels of resting after weaning are common and can affect the level of lying during transport. Lying can also be a sign that pigs have habituated to their environment. Sitting behavior was significantly higher in Tran+ and Trans- and Wean- pigs compared to Wean+ and control pigs. It has been reported that sitting is a behavior identified as a stress indicator. This indicated that transported pigs and pigs weaned and not provided with feed and water were possibly more stressed than pigs weaned and provided feed and water. There was not a difference in eating behaviors between Trans+ and Wean+ pigs. There was a difference in water consumption in Trans+ and Wean+ pigs during the transport phase, where Trans+ pigs consumed significantly more water than Wean+ pigs by 32 hours of transport.
Transportation has an additive effect on weight loss, especially if not provided with feed and water. Additionally, transportation impacts physiological and behavioral changes over time. In conclusion, there is limited research pertaining to transportation of weaned pigs and comparison of studies is sometimes difficult due to the variation in methodology, pig age/weight and densities studied (Lewis 2008). The transportation process is a stressful situation for pigs as they are exposed to long periods of transport, in many cases high stocking density, fasting, environmental factors, noise, mixing with conspecifics, injuries, and even death. Transportation death is painful and by no means an easy death, characterized by heart failure, and suffocation that may last from 10 minutes to 2 hours (Van Putten 1982). Thus, transportation is important in an animal welfare point of view and economically. Further research is needed to provide more insight on how to improve weaned pig welfare during transport.