Method of sprinkling trailers during hot weather and effects on transport losses of market weight pigs

Abstract Text:

The objective was to determine the effects of 3 sprinkling methods on transport losses. A total of 53 trailers (n = 9,016 pigs) were used in a randomized design, over 3 wks in July 2012 in Iowa.  Treatment 1: pigs only (dry bedding and pigs being sprinkled for 6 to 8 min after loading completed); treatment 2: bedding only (bedding already damp or sprinkled for 4 to 6 before the start of loading); treatment 3: pigs + bedding (both pigs and bedding sprinkled as previously described). A non-wetting treatment was not included due to pig well-being concerns. At loading, ambient temperature (T) and relative humidity (RH) were collected. Temperature humidity index (THI; average 22.4 ± 1.6) was then calculated using the following equation: T – {[0.55 – (0.0055 * RH_decimal)](T – 14.5)}. Pigs/trailer and average weight of pigs on that trailer were used to calculate density of pigs on the trailer: (average 289.9 ± 22.1 kg/m²): [(pigs/trailer)(average weight)]/(m² floor space in trailer). The interval from the first pig stepping onto the trailer until the last pig stepped onto the trailer was defined as load time. Wait at the farm was defined as the end of loading to the trailer leaving the farm. Stress signs (open mouth breathing, red blotchy skin, and muscle tremors) were counted from a randomly selected group of 100 pigs/trailer during loading. At the plant, number of non-ambulatory (NA; sum of fatigued and injured) and dead (sum of dead on- and euthanized on arrival) were recorded. Total losses (TL) were summed from dead and NA pigs. Data were analyzed using PROC GLIMMIX of SAS where a Poisson distribution was noted; trailer of pigs was the experimental unit. Sprinkling treatment was the variable of interest and covariates were: THI, density, load time, wait time, and stress signs. Farm, transporter, and researcher at loading were used as random effects. Sprinkling methods used in this study in Iowa of July 2012 did not impact transport losses for market weight pigs.

	Sprinkling Treatment			P – value	R2
HOT weather, Transport losses, pigs/trailer	Pigs only n = 31	Bedding only n = 9	Pigs & bedding n = 13
NA	0.01 ± 0.01	0.00 ± 0.00	0.00 ± 0.01	0.47	0.37
Dead	0.35 ± 0.12	0.18 ± 0.11	0.20 ± 0.11	0.39	0.35
TL	0.38 ± 0.14	0.16 ± 0.10	0.22 ± 0.12	0.25	0.41

 Keywords: market-weight pig, sprinkling, transport losses