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Comparison of Intramuscular or Subcutaneous Injections vs. Castration in Pigs-Impacts on Behavior and Welfare
John McGlone1, Kimberly Guay2, Arlene Garcia3,4
1Laboratory of Animal Behavior, Physiology and Welfare, Texas Tech University, Lubbock, TX 79409, USA. John.McGlone@ttu.edu.
Animals : an Open Access Journal From MDPI
|September 3, 2016
Summary
Physical castration (PC) causes significant pain and distress in piglets. However, immunological castration (IC) via subcutaneous (SQ) or intramuscular (IM) injections did not induce notable pain or behavioral changes in piglets or finishing pigs.
Area of Science:
- Animal Science
- Veterinary Medicine
- Animal Behavior
Background:
- Physical castration (PC) in piglets is a painful and stressful procedure.
- Immunological castration (IC) is a potential alternative, but the pain and stress associated with injections require assessment.
Purpose of the Study:
- To quantify the pain and distress caused by subcutaneous (SQ) and intramuscular (IM) injections compared to PC in piglets.
- To compare the effects of SQ versus IM injections in finishing pigs.
Main Methods:
- Piglets (3-5 days old) and finishing pigs were randomly assigned to treatments: no handling (NO), sham-handling (SHAM), IM injection, SQ injection, or PC.
- Behavioral monitoring (social, feeding, pain indicators) was conducted for 1 hour before and after treatments.
Main Results:
- Physical castration (PC) induced significantly higher pain-like behaviors and behavioral dysregulation compared to all other groups.
- Neither SQ nor IM injections caused significant behavioral or physiological alterations in piglets.
- SQ injections in finishing pigs led to a decrease in feeding behavior post-treatment (p = 0.02).
- SHAM-treated finishing pigs exhibited increased lying time compared to other groups.
Conclusions:
- Physical castration is demonstrably more painful and stressful than handling or injections in pigs.
- Subcutaneous (SQ) and intramuscular (IM) injections are not associated with significant pain or distress in piglets.
- While SQ injections caused a minor reduction in feeding behavior in finishing pigs, both injection methods appear to be viable alternatives to PC with minimal welfare impact.
