414 Abstracts � Vol 29, No 5 (2009)

was not different. Changing the horses from group hous-ing to individual stalls, however, resulted in significant in-creases in pre-transport concentrations of those stress-related compounds.

Keywords: Transport; Cortisol; DHEA

REFERENCES

1. Council of the European Union. Council Regulation No. 1/2005: On

the protection of animals during transport and related operations. 2005.

2. Collins MN, Friend TH, Jousan FD, Chen. Effects of density on dis-placement, falls, injuries, and orientation during horse transportation.

Appl. Anim. Behav. Sci. 2002;67:169-179.

3. Gibbs AE, Friend TH. Horse preference for orientation during trans-

port and the effect of orientation on balancing ability. Appl. Anim. Be-hav. Sci. 1999;63:1-9.

4. Iacono C, Friend TH, Keen H, Martin T, Krawczel P. Effects of density

and water availability on the behavior, physiology, and weight lossof slaughter horses during transport. J. Equine Vet. Sci. 2007;27:

355-361.

5. Kusunose R, Torikai K. Behavior of untethered horses during vehicle

transport. J. Equine Vet Sci. 1996;7:21-26.6. Stull CL. Responses of horses to trailer design, duration and floor area

during commercial transportation to slaughter. J. Anim. Sci.

1999;77:2925-2933.

7. Toscano MJ, Friend TH. A note on the effects of forward and rear-fac-ing orientations on movement of horses during transport. Appl. Anim.

Behav. Sci. 2001;73:281-287.

8. Waran NK., Robertson V, Cuddeford D, Kokoszko A, Marlin DJ.Effects of transporting horses facing either forwards or backwards

on their behaviour and heart rate. Vet. Rec. 1996;139:7-11.

31656 Health Factors Associatedwith Microchip Insertion in HorsesM.I. Gerber,* A.M. Swinker, W.B. Staniar, J.R. Werner,E.A. Jedrzejewski, and A.L. Macrina, The PennsylvaniaState University, University Park, PA, USA

INTRODUCTIONInflammation and migration were two major health con-cerns of horse owners when weighing the advantages anddisadvantages of using microchips. The use of radiofre-quency devices as a permanent identification method inhorses is being evaluated as the standard method for theNational Animal Identification System. Animal identifica-tion is the 2nd part of a 3 part registration that also includespremise registration and animal movement tracing.1 Whenmicrochips are inserted, the skin damage from the needleimmediately initiates a local immune response to addressany introduction of bacteria or other disease-causing or-ganisms and to begin repair on the damaged tissues. Fur-ther, the chip doesn’t present antigens for the immunesystem response, but it does cause tissue irritation untila capsule of scar tissue begins to form around the chip.2

This scar capsule has also been determined to be importantin binding with the glass capsule to prevent movement ofthe microchip after insertion.3 The objective of this studywas to characterize the inflammatory response and migra-tion of microchips.

MATERIALS AND METHODSQuarter horse mares (n¼ 18) assigned randomly to 3groups with 7 in the micro-chipped group, 7 in the dryneedle group and 4 as control animals. All of the horsesthat were microchipped were implanted in the nuchal liga-ment. Skin temperature, swelling area, and algometer mea-surements were collected over a 2 week period. Thealgometer is used to quantify the pressure necessary to in-duce a pain threshold response.4 The skin temperaturemeasurements were analyzed with nested longitudinalmixed effects ANCOVA with the covariate of outdoor(ambient) temperature. The algometer readings were ana-lyzed with nested longitudinal mixed effects ANOVA. Toassess migration, the 7 horses that were microchippedhad lateral radiographs taken at 0,1,2,4 and 6 m. All imagesincluded a metal marker of known length (for scaling), themicrochip and vertebrae 2 and 3. Measurements were re-corded from the most cranial portion of the fourth verte-brae to the microchip and analyzed through linearregression.

RESULTSThe microchip insertion and dry needle did not cause a de-tectable increase in temperature throughout the 2 week in-terval. The microchipped horses were more sensitive to thealgometer than the dry needle group at 2 h, 1 and 3d postinsertion (p< 0.05). The swelling begins 2 h post insertionand resolves by 3d. There was not a detectable difference inswelling area between injected groups.

Measurements for migration found no difference be-tween each measurement for each horse over time withina 2 cm margin of error. The marker length was also usedto determine the error of measurements and to determinethat magnification did not occur.

DISCUSSIONThe characterization and comparison of inflammatory in-dicators with microchip insertion can be used to describeto horse owners what is expected during this process.The inflammatory reaction that occurs from the implanta-tion of the microchip is comparable to the dry needle injec-tion. As such, horse owners can expect slight swelling tooccur and localized heat at the injection site to increaseseveral degrees between 6 h and 3d post injection. Also,there may be increased sensitivity to that area up to threedays after insertion. No movement of the microchip wasdetected when implanted according to standard protocol.

Abstracts � Vol 29, No 5 (2009) 415

Therefore, this research indicates that when performed ac-cording to standard protocol, microchip insertion is notdetrimental to the health of the horse.

Keywords: Equine; NAIS; Microchip; Inflammation

REFERENCES

1. http://animalid.aphis.usda.gov/nais/

2. Spire M, Drouillard J, Galland J, Sargeant J. Use of infrared thermo-

graphy to detect inflammation caused by contaminated growth pro-motant ear implants. J Am Vet Med Assoc 1999;215;1320-1324.

3. Jansen J, van der Waerden J, Gwalter R., van Roy S. Biological and

migrational characteristics of transponders implanted into beagle

dogs. The Veterinary Record 1999;145:329-333.4. Stafford K, Mellor D. The assessment of pain in cattle: a review. CAB

Reviews: Perspectives in Agriculture, Veterinary Science, Nutriton and

Natural Resources 2006;1-10.

ACKNOWLEDGEMENTS

PSU Horse Barns

31849 Sodium PentobarbitalResidues in Compost Piles ContainingCarcasses of Euthanized Equines

L.M. Cottle,* L.A. Baker, J.L. Pipkin, and D. Parker,West Texas A&M University, Canyon, TX, USA

INTRODUCTIONDue to the closing of slaughter plants in the United States,equine carcass disposal has been a recent consideration inthe horse industry. Composting is a disposal method thathas been successfully implemented in a variety of environ-ments and situations. No data currently exists, however,with regard to any drug residues in compost piles used todispose of euthanized equines. Researchers observed thateagles have died from eating the carcass remains of eutha-nized animals left uncovered at a landfill1 . The objective ofthis study was to determine if the euthanasia drug, sodiumpentobarbital, remained in compost material after equinecarcasses were composted for 6 mo.

MATERIAL AND METHODSA licensed practicing veterinarian euthanized each equinewith a pentobarbital solution (Beuthanasia-D: Schering-Plough Animal Health) according to AAEP Guidelines.All horses used in the trial were euthanized at local veteri-nary clinics. Immediately after euthanasia, a 5 to 10 cmliver sample was taken. Carcasses were then immediatelytransported to composting site. Base layer of compost pileswere constructed with 45 to 50 cm of waste hay and 5 to10 cm of horse stall cleanings. The carcass was then placed

on the base layer, legs removed directly above the knee andhock and placed beside the carcass in the pile. The carcasswas then covered with 90 to 100 cm of horse stallcleanings.

Compost piles containing a euthanized equine carcasswere replicated eight times. Total length of trial was 334d. Individual compost piles were mechanically aerated at90-d intervals. Internal pile grab samples were collectedat d 0, 10, 14, 90 and 180. Compost pile temperatureswere recorded every hour until 180 d using two continu-ous HOBO units (Onset Computer Corporation) placednext to the carcass during pile construction.

Pile grab samples and liver samples were sent to State ofIllinois Department of Agriculture Animal Disease Labora-tory (Centralia, IL) for a detection and quantitation of pen-tobarbital. Composite samples for each pile were obtainedat d 10, 14, 90, and 180, making a total of 32 pile grabsamples and 8 liver samples. Samples were analyzed usinggas chromatography and mass spectrometry [GC/MSDHewlett Packard 6890 GC with a split/splitless injectorand a series 5973 Mass Selective Detector (MSD) and a se-ries 7683 autosampler or equivalent] to determine pento-barbital concentrations in compost and liver samples. Inaddition, a control sample of shavings material used tobuild piles containing no pentobarbital was sent to the lab-oratory to be used as a test blank. Control material was for-tified (spiked) by adding the appropriate amount of sodiumpentobarbital according to SOP recommendations for de-tection and quantification of pentobarbital ((Standard Op-erating Procedure SOP, C.TOX.241.49.1). Analyzedsample pentobarbital concentrations were considered ac-ceptable if amounts were within 30 \%of the fortified testblank concentration.

RESULTS AND DISCUSSIONDetermination of differences between mean pentobarbitolconcentrations at different sampling times was conductedusing one-way ANOVA test with a significance level ofa¼ 0.10. There was no significant difference between pen-tobarbitol concentrations and sampling date (P¼ 0.686).Quantitative pentobarbital concentrations at d 10, 14, 90and 180 as well as liver concentrations can be observed inTable 1. Three composite pile samples at d 10 and foursamples at d 14 had non-detect values (<0.005 ppm) forpentobarbitol. For data analysis purposes, all non-detectvalues were assigned the lower detection limit of0.005 ppm. Due to sampling technique and compostinglimitations, a homogeneous sample was unattainable atd 10 and 14. At these two sampling times the carcass stillremained in the middle of the pile, therefore each samplewas taken at different locations around the carcass. Atd 90 and 180 the compost piles were aerated and mixedthoroughly allowing for a more homogenized sample.Composite samples from all piles had pentobarbital