Body condition score and age do not affect the physiological responses, thyroid hormones, hematological or serum biochemical parameters for tropical ewes

ABSTRACT

Tropical ewes of the Morada Nova breed were used to evaluate concordance on the effects of body condition score (BCS) and age classification using canonical discriminant analysis (CDA) as the classification method. The dependent variables in this study were: physiological responses, thyroid hormones, hematological and biochemical parameters. The hypothesis of this study was that the effect of BCS and age classification of the ewes might explain changes in physiological responses, thyroid hormones, hematological and serum biochemical parameters; however, very little effect was observed. Only the physiological responses and the thyroid hormones presented a subtle change using the BCS classification effect. An elevated error rate with both effects was observed, especially for age. However, the lowest total error rate was detected when all variables for BCS and for the thyroid hormones according to chronological age were used in the analyses. Therefore, the results do not support the recommendation of using BCS and age as classification effects, and therefore other effects should be used to improve reference ranges.

KEYWORDS:

• Adaptation
• blood parameters
• locally breed
• multivariate analysis
• semi-arid
• tropical climate

Authorship statement

The idea for this paper was conceived by J.B. Ferreira and D. Façanha. Access to farms and support for study funding through EMBRAPA was O. Facó. The experiments were designed by J. Ferreira and D. Façanha. The experiments were conducted by D. Façanha, J. Leite, D. Chaves, W. Costa and A.M. do Vale. The data were analyzed by J. Ferreira, M. Guilhermino and R. Silveira. The paper was written by J. Ferreira.

Declaration of Animal Rights

All procedures used in this work are in accordance with the ethical standards and have been approved by the Ethics Committee on Animal Use the Federal Rural University of the Semi-arid Region (No 23091003895/2014-71).