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Scientific Abstract

Behavior and welfare of Intramuscular or Subcutaneous injection in finishing pigs and piglets

K. A. Guay*, J. J. McGlone
Texas Tech University, Lubbock, TX, USA.

Physical castration (PC), typically performed at approximately 5 d of age, can be stressful for pigs. One alternative to PC is to immunological castration (IC), but the stress of the handling associated with immunological castration (or other immunizations) has not been assessed. Our objectives were to determine if subcutaneous (SC) or intramuscular (IM) injections were more painful or stressful than PC for piglets as well as measure the pain and stress associated with receiving a SC or IM injection in finishing pigs. To do this, we ran two experiments in which litter served as blocks in this randomized complete block design. After farrowing, 3 to 5 d old male piglets were randomly assigned to nothing (NO), SHAM handling (SHAM), IM, SC or PC with no pain relief. Piglets were videotaped and behavior was sampled for 1 h prior and 1 h post treatment. Behavior monitored included standing, walking, lying, nursing, lying with sow contact and signs of pain (standing hunched over, shaking). Finishing pigs received SC, IM, SHAM or NO injection. Finishing pigs were also monitored for 1 h pre and post treatment, and monitored for eating, drinking, lying, standing, walking, vocalization, open mouth breathing, blotchy skin and signs of irritation (rubbing the injection site). Blood was collected from all pigs for cortisol analysis 60 min post treatments so that the handling of blood collection did not impact the pig behavior. Analysis was in SAS using General Linerar Models procedure. PC piglets showed less (P < 0.05) lying in contact with sows and more (P < 0.05) pain-like behaviors than IM, NO, or SHAM treatments, but SC did not differ from PC. SHAM finishing pigs spent more time lying than the pigs in other treatment groups (P < 0.05). Cortisol did not differ among treatments for neither piglets nor finishing pigs. In conclusion, IM injections do not change piglet behaviors relative to no handling or sham handling. SC injections caused a small change in piglet and finishing pig behaviors. PC caused measureable pain-like behaviors and general behavioral dysregulation.

Key Words:Castration, Injection, Pigs

Scientific Poster

Behavior and handling of physically- and immunologically-castrated market pigs at home and going to market

Kimberly Guay, Guilherme Salgado, Garrett Thompson, Brittany Davis, Avi Sapkota, Wirawat Chaya, and John J McGlone
Pork Industry Institute, Texas Tech University, Lubbock, TX.

Physical castration is a common management practice on commercial pork farms in the USA. Castration is performed primarily to reduce the rate of boar taint (an offensive odor in the meat of intact male post-pubertal males) and aggressive behavior. One alternative to physical castration (PC) is to immunologically castrate (IC) male pigs by blocking gonadotropin releasing factor (GnRF) thus, reducing levels of LH, FSH, Testosterone and Androstenone and Skatole. The objectives of this study were to evaluate the effects of immunological castration on pig behavior, human-pig interactions, and handling during and after transport. Behaviors of PC barrows and IC barrows were sampled at three time points after entering finishing at 9 wk of age: 7 wk (prior to first injection), and 16 wk (after immunization was complete) into finishing and one day before marketing (16 to 19 wk into finishing). Handling during loading and unloading of trailers going to market were also quantified. Prior to the first injection, intact males showed increased aggression (P = 0.014) and mounting (P = 0.048) while the PC barrows spent more time feeding (P = 0.003) than boars. The treatment by time interaction were significant for lying (P = 0.018), aggression (P = 0.0001) and standing (P = 0.009) behaviors. Few differences were observed in pig-human interactions between PC barrows and IC barrows. IC approached people in the same amount of time as PC barrows, but were more aggressive in their chewing and rubbing on the test person's pant leg and boots. When handling and loading for processing in the home barn, PC barrows are more vocal than IC barrows (P < 0.05). Fewer dead and down pigs were observed among IC (zero) compared with PC barrows (1.17%). Immunological castration may result in similar or improved animal welfare compared to physical castration without pain relief.


Laboratory of Animal Behavior, Physiology and Welfare