Progesterone concentration andenergy balance influence on dairy cows with different milk yield during puerperium

The goal of this research was to establish the influence of body condition and milk production status on return of ovarian cyclicity of dairy cows during puerperium. 29 cows of Holstein breed, ages between 2 and 5 years were included in this research. Cows were divided in 2 groups considering their milk production status. Cows in group 1 (n = 15) had production of 24 L, and those in group 2 (n = 14) had 37.75 L (P < 0.05). Blood samples were taken every 4 days starting 7 days before parturition till the 45th day of puerperium. Cows were also subjected to gynaecological and ultrasound examination. BHB, cholesterol, triglycerides, NEFA, creatine kinase, AST ALT AF and progesterone level were measured. Body condition score (BCS) of cows was evaluated numerically from 1 to 5. By comparison of progesterone concentration and biochemical indicators in the blood of cows, no difference was found between the groups during puerperium, where values of all examined indicators were within physiological values. In the period before parturition, there was no statistically significant difference in BCS between the cows of group 1 (3.77) and cows of group 2 (3.99). Also, during puerperium, BCS did not significantly differ between the groups (3.29 in group 1 compared to 3.37 in group 2), although the difference almost equalised compared to the period before parturition. BCS in both groups of cows was moderately above the optimum values in the transition period before the parturition. However, as bio-chemical indicators in pueperium did not show liver function disorder, there was no absence of normal ovarian cyclicity and reduced milk production. Considering that there were no differences in progesterone level during puerperium between the groups of significantly different milk production status, our conclusion is that the milk production status as an independent factor does not have crucial impact on return of ovarian cyclicity in puerperium.