<abstract xmlns="http://www.w3.org/1999/xhtml"><p> The hormonal activity of the thyroid gland has an important role in ruminants for the modulation of metabolic variables. In this study changes in thyroid hormones and biochemical parameters in dairy cows around calving were evaluated and the critical thyroid hormones thresholds for predicting the risk of ketosis were estimated. Blood samples were collected from 82 dairy cows at 5±3 days pre-partum and 5±3 days postpartum. Serum values of triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), insulin, glucose, Ca, Cl, Mg, P, K, Na, aspartate transaminase (AST), alanine transaminase (ALT) and urea were evaluated. Signifi cant decrease in the levels of T3, T4 and TSH was found in the postpartum period. The values of T3 and T4 were negatively correlated with NEFA and BHB levels, and TSH values were negatively correlated with NEFA. A critical T3 threshold was found by means of ROC analysis for predicting the risk of ketosis. T3 values &lt; 1.23 nmol/L were associated with BHB > 1.10 mmol/L in postpartum, which represents the BHB threshold commonly used as the indicator of hyperketonaemia. The results confirm that the peripartum period is accompanied by marked changes in circulating thyroid hormone profile that is correlated with lipomobilization predictors.</p></abstract>

The hormonal activity of the thyroid gland has an important role in ruminants for the modulation of metabolic variables. In this study changes in thyroid hormones and biochemical parameters in dairy cows around calving were evaluated and the critical thyroid hormones thresholds for predicting the risk of ketosis were estimated. Blood samples were collected from 82 dairy cows at 5±3 days pre-partum and 5±3 days postpartum. Serum values of triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), insulin, glucose, Ca, Cl, Mg, P, K, Na, aspartate transaminase (AST), alanine transaminase (ALT) and urea were evaluated. Signifi cant decrease in the levels of T3, T4 and TSH was found in the postpartum period. The values of T3 and T4 were negatively correlated with NEFA and BHB levels, and TSH values were negatively correlated with NEFA. A critical T3 threshold was found by means of ROC analysis for predicting the risk of ketosis. T3 values < 1.23 nmol/L were associated with BHB > 1.10 mmol/L in postpartum, which represents the BHB threshold commonly used as the indicator of hyperketonaemia. The results confirm that the peripartum period is accompanied by marked changes in circulating thyroid hormone profile that is correlated with lipomobilization predictors.

Changes in Thyroid Hormones Levels and Metabolism in Dairy Cows around Calving

Acta Veterinaria

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

{"article-title":"Changes in Thyroid Hormones Levels and Metabolism in Dairy Cows around Calving"}

The hormonal activity of the thyroid gland has an important role in ruminants for the modulation of metabolic variables. In this study changes in thyroid hormones and biochemical parameters in dairy cows around calving were evaluated and the critical thyroid hormones thresholds for predicting the risk of ketosis were estimated. Blood samples were collected from 82 dairy cows at 5±3 days pre-partum and 5±3 days postpartum. Serum values of triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), insulin, glucose, Ca, Cl, Mg, P, K, Na, aspartate transaminase (AST), alanine transaminase (ALT) and urea were evaluated. Signifi cant decrease in the levels of T3, T4 and TSH was found in the postpartum period. The values of T3 and T4 were negatively correlated with NEFA and BHB levels, and TSH values were negatively correlated with NEFA. A critical T3 threshold was found by means of ROC analysis for predicting the risk of ketosis. T3 values  1.10 mmol/L in postpartum, which represents the BHB threshold commonly used as the indicator of hyperketonaemia. The results confirm that the peripartum period is accompanied by marked changes in circulating thyroid hormone profile that is correlated with lipomobilization predictors.

The hormonal activity of the thyroid gland has an important role in ruminants for the modulation of metabolic variables. In this study changes in thyroid...

Changes in Thyroid Hormones Levels and Metabolism in Dairy Cows around Calving

Published Online: Sep 23, 2017

Page range: 318 - 330

Received: Nov 22, 2016

Accepted: Apr 24, 2017

DOI: https://doi.org/10.1515/acve-2017-0026

Keywords
dairy cow, metabolism, thyroid hormone, transition period

© by Giuseppe Piccione

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Changes in Thyroid Hormones Levels and Metabolism in Dairy Cows around Calving

Published Online: Sep 23, 2017

Page range: 318 - 330

Received: Nov 22, 2016

Accepted: Apr 24, 2017

DOI: https://doi.org/10.1515/acve-2017-0026

Keywordsdairy cow, metabolism, thyroid hormone, transition period

© by Giuseppe Piccione

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
dairy cow, metabolism, thyroid hormone, transition period