Oral and Poster Abstracts

211 Endocrine Status of Holstein Dairy Cows With Different Milk
Production during late Pregnancy and early Lactation
D. Gvozdic 1 , H. Samanc 2 , B. Kovacevic 4 , D. Kirovski 3 , N. Fratric 3 ,
I. Vujanac 2 , B. Dimitrijevic 2
1
Faculty of Veterinary Medicine Belgrade, Department of
pathophysiology, Belgrade, Serbia
2
Faculty of Veterinary Medicine Belgrade, Large Animal Clinic,
Belgrade, Serbia
3
Faculty of Veterinary Medicine Belgrade, Department of
Physiology, Belgrade, Serbia
4
Veterinary station, Veterinary Department, Teslic, Bosnia and
Herzegovina
Aim of this work was to determine endocrine status of Holstein
dairy cows with different milk production in various stages of
reproductive cycle. Total number of 60 Holstein dairy cows has
been selected during late pregnancy on the basis of average milk
production during the last lactation and divided in two groups: 1)
high production group (HP) - cows with average milk production
exceeding 7500L (n=30), 2) low production group (LP) - cows with
average milk production lower than 6500L (n=30). Blood serum
thyroxine (T4), triiodothyronine (T3), and insulin (Ins)
concentrations were determined in blood samples obtained from v.
jugularis during the last week prior to partus, between 7-14 days
after partus, and two months after beginning of lactation.Blood
serum thyroid hormones concentration was similar in both groups of
cows during the late pregnancy, decreasing after partus and two
months after beginning of lactation. Blood serum T4 and T3
concentrations were significantly lower in HP cows after partus and
two months after beginning of lactation (33.41±6.48:27.77±5.22
and 32.76±4.44:25.19±5.36 nmol/L, p