<abstract xmlns="http://www.w3.org/1999/xhtml">This study investigated the changes in: thyroid hormones, amount of subcutaneous fat, and selected indices of blood biochemistry in dairy cows in relation to the reproduction/production cycle. The blood samples were collected both <italic>ante</italic>- and <italic>post-partum</italic> every two weeks. When evaluating the mean values of the investigated indices, the major changes were recorded in dairy cows 3 to 14 days after calving. During this period, we observed a significant decrease in the mean serum levels of T3 (P &lt; 0.05), T4 (P &lt; 0.01), and triglycerides (P &lt; 0.01). An opposite trend was observed with a significant increase after calving in the: mean serum levels of β-hydroxybutyrate (P &lt; 0.05), urea (P &lt; 0.01), and mean AST activities (P &lt; 0.05). A significant increase over the normal range was recorded in the average levels of non-esterified fatty acids (P &lt; 0.01) and total bilirubin (P &lt; 0.01). From the next sampling (28 days after calving) onwards we recorded a significant increase in the blood serum levels of cholesterol (P &lt; 0.01), total lipids (P &lt; 0.01), total protein (P &lt; 0.01), as well as a significant decrease in the insulin levels (P &lt; 0.05) and a reduced layer of subcutaneous fat (P &lt; 0.01). The blood serum iodine concentration showed only slight significant changes (P &lt; 0.05) during the observation. Blood serum levels of glucose did not show any significant changes during the whole observation period. Within the whole observation period we found a negative correlation between T3 levels and the layer of subcutaneous fat (r = −0.2606; P &lt; 0.05). This correlation was much more marked in cows 3 to 14 days after calving (r = −0.5077; P &lt; 0.05), which may indicate a possible relationships between the thyroid status, body condition, and <italic>post partum</italic> negative energy balance.</abstract>

This study investigated the changes in: thyroid hormones, amount of subcutaneous fat, and selected indices of blood biochemistry in dairy cows in relation to the reproduction/production cycle. The blood samples were collected both ante- and post-partum every two weeks. When evaluating the mean values of the investigated indices, the major changes were recorded in dairy cows 3 to 14 days after calving. During this period, we observed a significant decrease in the mean serum levels of T3 (P < 0.05), T4 (P < 0.01), and triglycerides (P < 0.01). An opposite trend was observed with a significant increase after calving in the: mean serum levels of β-hydroxybutyrate (P < 0.05), urea (P < 0.01), and mean AST activities (P < 0.05). A significant increase over the normal range was recorded in the average levels of non-esterified fatty acids (P < 0.01) and total bilirubin (P < 0.01). From the next sampling (28 days after calving) onwards we recorded a significant increase in the blood serum levels of cholesterol (P < 0.01), total lipids (P < 0.01), total protein (P < 0.01), as well as a significant decrease in the insulin levels (P < 0.05) and a reduced layer of subcutaneous fat (P < 0.01). The blood serum iodine concentration showed only slight significant changes (P < 0.05) during the observation. Blood serum levels of glucose did not show any significant changes during the whole observation period. Within the whole observation period we found a negative correlation between T3 levels and the layer of subcutaneous fat (r = −0.2606; P < 0.05). This correlation was much more marked in cows 3 to 14 days after calving (r = −0.5077; P < 0.05), which may indicate a possible relationships between the thyroid status, body condition, and post partum negative energy balance.

Thyroid Hormones, Insulin, Body Fat, and Blood Biochemistry Indices in Dairy Cows During the Reproduction/Production Cycle

Clinic for Ruminants, University of Veterinary Medicine and Pharmacy, Košice,

Clinic for Swine, University of Veterinary Medicine and Pharmacy, Košice,

Folia Veterinaria

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

This study investigated the changes in: thyroid hormones, amount of subcutaneous fat, and selected indices of blood biochemistry in dairy cows in relation to...

Thyroid Hormones, Insulin, Body Fat, and Blood Biochemistry Indices in Dairy Cows During the Reproduction/Production Cycle

Published Online: Apr 04, 2017

Page range: 43 - 53

Received: Nov 09, 2016

Accepted: Jan 16, 2016

DOI: https://doi.org/10.1515/fv-2017-0007

Keywords
body fat volume, dairy cows, insulin, negative energy balance, thyroid

© 2017 Paulíková I. et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Thyroid Hormones, Insulin, Body Fat, and Blood Biochemistry Indices in Dairy Cows During the Reproduction/Production Cycle

Published Online: Apr 04, 2017

Page range: 43 - 53

Received: Nov 09, 2016

Accepted: Jan 16, 2016

DOI: https://doi.org/10.1515/fv-2017-0007

Keywordsbody fat volume, dairy cows, insulin, negative energy balance, thyroid

© 2017 Paulíková I. et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
body fat volume, dairy cows, insulin, negative energy balance, thyroid