Evaluation of segregated early weaning investigating performance, immunologic indicators (CD4, CD8), and herd health status
Thomas J. Fangman, DVM, MS; Roderick C. Tubbs, DVM, MS; B. Ann Becker, PhD; Gary L. Allee, PhD; Mike L. Misfeldt, PhD; Kelly Henningsen-Dyer, MBA
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Purpose: To evaluate the reported benefits of segregated early weaning (SEW) as determined by performance, by immunologic status as indicated by T-lymphocyte differentiation antigens, and by health status.
Methods: Experiment I was conducted at a commercial herd with pigs weaned at 11-18 days of age and blocked by age to include 11- to 14-day-old pigs and 14- to 18-day-old pigs. Pigs were randomly assigned to three management groups: 1) onsite, commingled; 2) onsite, sanitized, and 3) offsite, sanitized. Experiment II was conducted in environmentally controlled research chambers. Pigs were weaned at 12-15 days of age and randomly assigned to two management groups: 1) remained in non-sanitized farrowing crates and weaned by removing the sow; and 2) weaned and transferred to a sanitized chamber and crates with access severely restricted.
Results: Pigs from both herds used for experiments I and II were found to have Streptococcus suis in 77%-88% of the animals tested. Neither performance nor percentages of T-lymphocytes expressing CD2+, CD4+, or CD8+ differentiation antigens were significantly affected by the on- and offsite facility or sanitization, although pigs from the onsite commingled group gained slightly less (P<.05) than the on- and offsite sanitized groups. Weaning age also had a significant effect on performance with the later-weaned pigs (14-18 days) gaining significantly (P<.05) more than the earlier-weaned pigs (11-14 days).
Implications: Production systems practicing good sanitation and conscientious biosecurity measures to establish a minimum pathogen exposure may not demonstrate significant performance results in nursery pigs moved offsite at an early age (<14 days). Also, single T-lymphocyte differentiation antigens are not appropriate indicators of immune status in SEW pigs with minimum pathogen exposure.
Keywords: segregated early weaning (SEW), immunologic antigens, growth performance
Cite as: Fangman TJ, Tubbs RC, Becker BA, et al. Evaluation of segregated early weaning investigating performance, immunologic indicators (CD4, CD8), and herd health status. J Swine Health Prod 1996;4(5):217-222.
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