Comparing the dynamics of Toxoplasma gondii seroconversion in growing sheep kept on raised slatted floor cages or floor pens in Yucatan, Mexico

• Published in: Small ruminant research Vol. 121; no. 2-3; pp. 400 - 403
• Main Authors: Hernández-Cortazar, I.B., Jiménez-Coello, M., Acosta-Viana, K.Y., Guzmán-Marín, E., Torres-Acosta, J.F.J., Rodríguez-Buenfil, J.C., Ortega-Pacheco, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2014
• Subjects: Cummulative incidence; Feedlot system, Tropics; Indirect ELISA; Sheep; Toxoplasma gondii; Cummulative incidence; Sheep; Toxoplasma gondii; Feedlot system, Tropics; Indirect ELISA
• ISSN: 0921-4488; 1879-0941
• DOI: 10.1016/j.smallrumres.2014.06.011

•Lambs in fattening systems with raised floor cages have a lower risk of infection to T. gondii compared to lambs kept in floor cages.•Lambs raised in floor pens have 5.7 times more chances to seroconvert against T. gondii in comparison to the raised floor cages.•The contact of weaned lambs with infective oocysts may occur at an early stage of life.•Sheep meat from traditional floor cage fattening systems posses a high risk of infection with T. gondii for the human consumer. The objective of this study was to compare the dynamics of Toxoplasma gondii seroconversion in growing sheep kept on raised slatted floor cages (RFC) or floor pens (FP) in Yucatan, Mexico. A cohort study was performed in four sheep farms with a sample size of 104 newly weaned T. gondii seronegative lambs (60 days old). Blood samples were collected individually from all the lambs after weaning and every 15 days to determine the presence of IgG antibodies against T. gondii in the serum using an indirect ELISA test. The true incidence rate (TIR), cumulative incidence (CI) and relative risk (RR+/−95% confidence interval [95%CI]) were calculated. Difference in the dynamic of seroconversion was determined by means of a survival analysis. On day 30 of the study (3rd sampling) 1.92% of the sheep seroconverted in the RFC system, while 7.69% of the lambs were positive on the fifth sampling point. In the FP 26.92% of the sheep seroconverted at the second sampling point (15 days of the study), 9.61% at the third sampling point (30 days of the study) and 5.76% at the fourth sampling point (105 days old). The TIR was 0.019 and 0.113 for every 2 weeks at risk (15 days) for the RFC and FP respectively. The RR indicates that lambs kept in FP were 5.7 times more likely to seroconvert against T. gondii than lambs kept in the RFC (95%CI=2.45–13.62; P<0.05). The results indicated that the use of RFC reduce the speed of seroconversion against T. gondii, compared to lambs kept in the FP, despite of being in an environment with high circulation of the agent.