| Popis: |
The relationship between cows' homeostasis in the early postpartum period and the effectiveness of fertilization during lactation was analyzed. There were found a decrease in vitamin E to 3.9 ± 0.16 μg/ml, an increase in urea to 6.4 ± 0.24 mmol/l, alkaline phosphatase to 120.7 ± 5.24 U/l, urea nitrogen to 12.3 ± 0.46 mg/ 100 ml and aspartate aminotransferase up to 137.8 ± 10.45 IU/l in cows that were culled or left infertile throughout the lactation period. These data may indicate an overload of the compensatory reactions of the enzymatic and oxidative systems of the liver in cows with defective rumen digestion. There was also persistent hyperproteinemia with compensated oxidative stress due to a decrease in zinc and vitamin E content in cows fertilized 60-120 days compared with those fertilized six months and later after calving. Key words: cows, postpartum period, homeostasis, fertilization, culling, time of fertilization, productivity |
