PROJECT RESULTS

Transportation of Early Weaned Piglets: Seasonal Effects

Applicant: 

Dr. N. J. Lewis
Department of Animal Science
University of Manitoba

Winnipeg, Manitoba  R3T 2N2  Canada

Table of Contents:

• Background and Objectives
• Procedure and Project Activities
• Results and Discussion
• Conclusions

ARDI Project:

#00-364

Project Status:

Completed August, 2004

Background and Objectives:

Segregated early weaning (SEW) has become a standard practice in the swine industry in Canada.  Piglets are weaned at an early age (14 - 20 d) and transported to a separate site to reduce the risk of transmission of disease from the sow to piglets.  The relocation of early weaned piglets to a separate site necessarily involves transport.  These journeys vary in length but typically, in Canada, fall within the 4-20 hr range.  Initially, transport vehicles were heated in winter but the industry has moved to winter transport without heating.  There is little information on the preferred transport temperature ranges for piglets or on actual temperatures experienced by early weaned piglets under commercial transport.

The objectives of this research were to:

1. Collect information on vehicle temperature in commercial vehicles transporting early weaned piglets during journeys of varying lengths and in different seasons.

2. To determine the effect of season on the behaviour and production of early weaned piglets following transport.

3. To determine the effect of transport factors other than duration and temperature on the behaviour and production of early weaned piglets following transport.

4. To determine the effect of piglet weight at weaning on the behaviour and production of early weaned piglets following transport.

Procedure and Project Activities:

A data logger (Campbell Scientific CR10X) was placed in commercial vehicles to record temperature and humidity on journeys of varying length and during 3 seasons (summer, winter, spring / fall).  Two sensors were used to collect data, one positioned directly above the piglets near the center of the trailer and the other positioned near the shell of the vehicle. Temperature (^oC) and relative humidity (%) were recorded every minute from each sensor, averaged and stored for each 10 min period during transportation.  The information from the data logger was used to calculate average temperatures in each season.

Two separate experimental trials were conducted, 1 in summer and 1 in winter.  In each trial 96 piglets were weaned at 17 " 1 day of age and assigned to either real or simulated transport.  Piglets were weighed and assigned to groups of small medium or large pigs.  Within weight groups, piglets were randomly assigned, in groups of four, to four transport durations (0 h, 6 h, 12 h, and 24 h).  Control (0 h) piglets were placed directly into the housing pens.  Real transport occurred in a one-ton cube van at stocking densities comparable to commercial transport.  Simulated transport occurred in high sided, bedded, wooden boxes, in a temperature-controlled room.  The average temperature recorded above the piglets during the 0-6 h, 6-12 h and 12-24 h of real transport were used to determine the temperature regime for the simulated transport groups.  In winter these temperatures were 11.5°C, 7.5°C and 0.3°C respectively.  In summer the following temperatures were used: 24.5°C, 25.4°C and 16.5°C respectively.  Following transport, piglets were housed in pens containing one free flow pellet feeder and a water nipple.  Feed and water was available ad libitum.  Behavior was assessed using time lapse video recordings.  Scan sampling of the video recordings at 10 minute intervals allowed the assessment of mutually exclusive behaviors (feeding, drinking, resting, standing, fighting, oral/nasal manipulation and other behaviours).  Due to the importance of feeding and drinking behaviour as a reflection of welfare and production these behaviours were also studied using continuous observations for the first 3 days in two hour periods starting from the time of entry to the pens as follows 0-2 h, 6-8 h, 12-14 h, and 18-20 h.

Piglet weights were recorded at weaning, daily for 8 days then on day 10, 12 and 14.  Using this data, computer generated growth curves were calculated.  The following measures were derived:  the day at which the minimum weight was reached, the minimum weight, the day at which the piglet returned to its weaning weight (day of recovery) and the average daily gain, as a percentage of weaning weight, from day of recovery to 14 d post weaning.  Care of piglets in this research project was conducted under CCAC guidelines (Canadian Council on Animal Care, 1993) and followed the Recommended Code of Practice for the Care and Handling of Farm Animals: Pigs (Connor, 1993).

Results and Discussion:

Transporters typically use unheated, straw bedded trailers with minimal air throughput during the winter.  Temperature in the trailer averaged 7.4°C for journeys of 12-20 h and 6.1°C for 24 ±1 h journeys.  Records showed that ambient air temperature within the trailer could fall dramatically with average minimum temperatures falling to -6.7°C on journeys of moderate length and -5.2°C during longer journeys (Table 1).  These mean temperatures were considerably lower than the recommended minimum temperature of 24°C stated in the Recommended Code of Practice (Connor 1993).  Even the highest mean temperatures 12.2°C and 16.2°C were below recommended temperatures for early weaned piglets.  Typically the coldest conditions were seen during loading, temperatures then rose presumably due to the activity of the piglets.  Further into the journey however temperatures fall dramatically possibly as piglets become less active.

Table 1.  Maximum and minimum temperatures recorded during the winter on journeys of varying lengths in commercial vehicles transporting early weaned piglets.

Commercial journeys in summer typically occurred in well ventilated trailers with minimal bedding.  Temperature during summer travel averaged 22.9°C for short journeys of approximately 1 h and 25.8°C for longer journeys of up to 12 h.  Average temperatures ranged from 17.3°C to 28.3°C.  These journeys occurred during average summer days and do not reflect truck temperatures when the outside temperatures are above 30°C.  Humidity averaged 56.4 %, well within the comfort zone for piglets.

Temperatures were recorded for 3 commercial journeys in the fall with a duration of just over 12h.  The temperatures during the fall were typically low during the early morning (1.4°C) but rose rapidly during the day to highs of 31.2°C.  In fact some of the highest temperatures recorded were during fall journeys.  Transporters in this instance were likely restricting air flow into the trailer to negate morning chilling but the consequence of this was that the trailer heated up dramatically during the afternoon.

Duration of transport had a direct effect on drinking during the first day post transport.  As duration of transport lengthened, the percentage of time spent drinking increased (p<0.01) (0 h: 0.5 %, 6 h: 1.05 %, 12 h: 2.0 %. 24 h: 3.2 %).  This was a direct result of an increase (p<0.01) in the number of drinking bouts (0 h: 13.5, 6 h: 26.6, 12 h: 44.5, 24 h: 55.3 bouts / day).  After 24 h of transport, piglets also exhibited an increase (p<0.01) in the duration of drinking bouts (0 h: 10.8, 6 h: 11.7, 12 h: 12.9, 24 h: 17.0 sec.).  During day 1 in the summer, when we would expect to see an increase in thirst following transportation, the number of drinking bouts (32.1 bouts / day) was actually lower (p<0.05) compared to day 1 in winter (37.7 bouts / day).  However, the duration of drinking bouts increased (p<0.01) from summer (14.8 sec) to winter (11.4 sec.) lengthening the total time spent drinking in the summer (475 sec) over that in winter (429.8 sec).  Thirsty piglets appeared to drink longer at each bout, with the result that the number of bouts was reduced.  The percentage of time spent drinking returned to normal by day 2 indicating that the piglets were able to replace water deficits during the first day.  The most significant risk factor in dehydration appeared to be the length of the transport; however summer transport may also be a higher risk.

Feeding behaviour increased (p<0.01) each day in the weanling pens (day 1: 0.25 %, day 2: 2.0 %, day 3: 5.8 %).  Feeding was more frequent (p<0.01) as duration of transport increased (0 h: 1.48 %, 6 h: 2.62 %, 12 h: 2.82 %, 24 h: 3.71 %) due to an increased bout frequency (0 h: 7.1 bouts / day vs. transported: 6 h: 12.8, 12 h: 12.0, 24 h: 14.5 bouts / day) (p<0.01).  Piglet age, as well as transport effects were theorized to contribute to this difference.

The weaning weight of piglets in this trial averaged 6.28 ± 0.83 kg.  Piglets lost 6.4 % of body weight on average following weaning.  They reached the lowest weight at 2.2 d post weaning and recovered weaning weight at 3.5 d after weaning for a total growth check of 3.5 days.  Average daily gain from the end of the growth check until 14 d post weaning was 5.75 % of weaning weight.  The lowest weight reached by the piglets was affected by transport duration (p<0.01).  Piglets transported for 24 h (7.4 %) lost more weight than piglets transported for 6 h (5.64 %).  However, weight loss by non transported piglets (6.7 %) did not differ significantly from losses in transported piglets.  Average daily gain post recover was lower (p < 0.01) following winter transport (5.3 %) than following summer transport (6.2 %).  Other production measures were not affected by season of transport.  In this experiment winter transport was not shown to be substantially more detrimental for the piglets than summer transport.  However, lower average daily gains in the winter may be indicative of some longer lasting effects of winter transport.

Piglets in the real transport group exhibited significantly (p<0.01) higher percent weight loss (6.8 %) than piglets in the simulated transport group (6.1 %).  However day of recovery was not affected by transport type.  Average daily gain was higher (p<0.01) following real transport (6.0 %) than following simulated transport (5.5 %) although no reason for this was apparent.  Very few differences were seen when transport using trucks and transport in simulated conditions were compared indicating that the largest stressors for early weaned piglets were temperature and duration of transport.

Large piglets averaged 7.4 ± 1.1 kg, medium piglets averaged 6.2 ± 0.7 kg and small piglets averaged 5.3 ± 0.8 kg at weaning.  Larger piglets were more (p<0.01) likely to fight (3.2 %) on day 1 than medium and small piglets (1.8 %) even though they were housed separately.  This trend continued on day 2.  Large piglets took longer to reach their lowest weight (2.64 d) than small pigs (1.7 d) (p<0.05) with medium weight pigs intermediate (2.3 d).  Day of recovery was also longer (p<0.05) for large pigs (3.93 d) than for small pigs (3.06 d) with medium pigs in the center (3.61 d).  However the % weight loss (6.4 %) was the same in all groups of pigs.  ADG post recovery was higher (p<0.01) for small (6.14 %) and medium pigs (6.13 %) than for large pigs (4.98).  Clearly larger pigs did not do as well following early weaning.  This may have been due to less experience with creep feed in piglets suckling from high producing teats.

Conclusions:

ARDI Home - Contact ARDI