Assessment of the effect of energy intake on the establishment of the ovaryan cycle in high-yielding dairy cows after calving

Uspostavljanje spolnog ciklusa kod visokomliječnih krava nakon teljenja je veliki problem na farmama koje imaju intenzivnu proizvodnju mlijeka. Iako visoka proizvodnja sama po sebi donosi puno problema oni se još povećavaju s lošim menedžmentom kao što je nedovoljno kvalitetna hrana i nepravilno izbalansiran obrok za visokomliječna goveda pa dolazi do metaboličkih i reproduktivnih problema tijekom laktacije. U radu je napravljena analiza razine opskrbljenosti goveda s energijom i njen utjecaj na uspostavu spolnog ciklusa nakon teljenja i reproduktivne pokazatelje kod visokomliječnih krava na farmi mliječnih krava „V.v. Farma“ na području Međimurske županije temeljem sadržaja proteina i uree u mlijeku. Na temelju odnosa mliječne masti i bjelančevina te sadržaja bjelančevina i uree u mlijeku može se zaključiti da 17,5% uzoraka mlijeka potječe od krava nedovoljno opskrbljenih energijom. Razdoblje rane laktacije (prvih 60 dana) je najosjetljivije razdoblje s obzirom na dostatnu opskrbu energijom i proteinima kod krava na što ukazuje činjenica da 45% uzoraka mlijeka analiziranih u ovom razdoblju ukazuje na deficit unosa energije, a u 16,5% uzoraka utvrđen je IMB >1,5 što sugerira opsežnu mobilizaciju masti iz tjelesnih rezervi i pojavu metaboličkih poremećaja. Uspostava spolnog ciklusa izražena kao razdoblje do prvog osjemenjivanja u većine krava bila je unutar 90 dana nakon teljenja (74%) dok u svega 9% krava to razdoblje je bilo dulje od 120 dana. Unatoč tome u čak 32% krava gravidnost je nastupila iza 120. dana laktacije što ukazuje na izostanak ovulacije i/ili postojanja nepovoljnih uvjeta za preživljavanje embrija (rana embrionalna smrtnost). Povezanost između pojedinih sastojaka mlijeka i reproduktivnih pokazatelja nije utvrđena.Establishing a ovarian cycle in high-yielding dairy cows after calving is a major problem for farms that have intensive milk production. Although high production itself brings a lot of problems, they are still growing with poor management such as inadequate quality food and improperly balanced meal for high-production cows, and therefore metabolic and reproductive problems occur during lactation. The paper analyzes the energy supply level and its impact on the establishment of ovarian cycle after calving and reproductive indexes in high-production dairy cows using the urea and protein content in milk. Investigation was caaried out on dairy cows farm "V.v. Farma"in the area of Međimurje County. Based on the ratio of milk fat and protein as well as urea content in milk samples, it can be concluded that 17.5% of milk samples come from cows that are not sufficiently supplied with energy. The period of early lactation (the first 60 days) is the most sensitive period in view of the sufficient supply of energy and proteins in cows. 45% of the milk samples analyzed in this period indicate a deficit of energy intake and 16.5% of the samples determined IMB> 1.5 suggesting extensive fat mobilization from body reserves and the occurrence of metabolic disorders. The establishment of the ovarian cycle, expressed as the period until the first mating, was within 90 days after calving (74%), while in only 9% of cows this period was more than 120 days. Nevertheless, even 32% of cow gravity appeared after the 120th day of lactation, indicating the absence of ovulation and / or the existence of unfavorable conditions for the survival of embryos (early embryonic mortality). The association between milk parameters and reproductive indicators was not detected