Methodology for the quantification of tibial dyschondroplasia in gallus gallus domesticus (aves : Phasianidae).

Abstract

Objective: To compare the efficacy of the score technique of the tibial dyschondroplasia lesions with a quantification technique in broiler chickens, in search of a better objectivity and reliability of the diagnosis. Materials and methods: 384 male one-day-old chickens were raised until day 36. A total of 192 chickens were sampled, 96 at day 21 and 96 at day 36; the tibial dyschondroplasia disorder was evaluated by comparing two techniques: 1. Qualitative evaluation of the score of tibial dyschondroplasia and, 2. Quantitative measurement of the percentage of area with tibial dyschondroplasia as an alternative test. Results: the Score test of TD lesions had a sensitivity of 83% and 100% with a specificity of 55% and 54% for day 21 and day 36 respectively, and a positive predictive value of 60% for day 21 and of 66% for day 36, while the negative predictive value was 80% and 100% for days 21 and 36. Conclusions: The evaluated alternative test proved to be an effective and efficient method of quantification of tibial dyschondroplasia in broiler chickens, offering more objectivity than the traditional macroscopic test.