| dc.description.abstract | The aim of the examination was to reveal the occurrence of the nutrition and management related subclinical metabolic disorders that may impair the milk production and reproductive performance of the herd. The examination was performed on a Hungarian dairy herd of 260 Holstein-Fresian cows and their offspring. The herd had experienced poor reproductive performance for a long period of time. By analyzing the metabolic status of a selection of animals, we aimed to reveal the metabolic risk factors affecting their reproductive performance. Metabolic profile testing was performed on blood, urine and hair samples from clinically healthy cows in different stages of lactation, and herd data was collected according to the health, milk production and reproductive performance. A farm inspection was also performed focusing on environmental factors. In the background of the suboptimal reproductive performance, different metabolic risk factors were revealed. One of the major problems in the herd is the NEB in early lactation. As a result the animals suffer from increased fat mobilization, ketosis and liver damage. Abnormal urinary pH and NABE levels could indicate acidosis.Minimizing environmental stress, improvingnutrition and grouping management are key elements in preventing NEB. Preventive administration of gluconeogenic precursors and supplements of rumen-protected choline and methionine may aid in this as well. The other remarkable metabolic risk factor is increased plasma urea levels. Because urea is excreted into uterine fluid, it may be the cause of the suboptimal fertility and embryonic mortality experienced in the herd. The herd was also found to suffer from a beta-carotene deficiency, which could further explain the fertility problems. The deficiency should be corrected immediately, and the TMR analyzed for RDP:UDP levels. Finally the testing indicated an inadequate trace element supply. Blood trace element values were decreased, however pigmented hair samples fell within normal values, except from suboptimal manganese levels. This mineral that plays an important role in ovarian function, and this deficiency could therefore be part of the cause of the fertility problems. | en |
