The objective of this study was to determine and evaluate the effect of parity on the fatty acids groups’ proportion in Holstein cows’ milk during the first phase of lactations, with an emphasis on its potential importance for consumer health. A total of 25 Holstein cows, 9 primiparous, 9 in the 2nd, and 7 in the 3rd and subsequent parity, were observed and sampled at 7-day intervals through the first 17 weeks of lactation. The percentage proportion of saturated (hypercholesterolemic and volatile as its components) and unsaturated (monounsaturated and polyunsaturated as its components) fatty acids in the samples of milk fat (n=425) was determined. The effects of parity and negative energy balance, as well as regression, on the lactation week and the fat to protein ratio were evaluated using SAS 9.3. A significantly (P<0.01) lower proportion of unhealthy hypercholesterolemic fatty acids was detected in primiparous cows (-2.67 %) and those in the 3rd and subsequent lactation (-2.94 %) compared to the 2nd lactation, as well as a simultaneously higher proportion of healthy unsaturated fatty acids (+2.07, respectively +3.08 %). The determined relationships corresponded to organism stress evoked by the initiation of milk production and its maintenance in higher parities. Therefore, the generally required prolongation of dairy cows’ longevity can influence on the quality of raw milk, especially considering composition of fatty acids.Cilj ovog istraživanja bio je utvrditi i procijeniti utjecaj rednog broja laktacije na udio pojedinih skupina masnih kiselina, u mlijeku holstein krava tijekom prve faze laktacije, s naglaskom na njihovu potencijalnu važnost za zdravlje potrošača. Ukupno 25 holstein krava, devet prvotelkinja, devet u drugoj, i sedam u trećoj i naknadnim laktacijama, promatrane su i uzorkovane u sedmodnevnim intervalima tijekom prvih 17 tjedana laktacije. Utvrđivan je udio zasićenih (unutar te skupine hiperkolesterolemičnih i hlapivih masnih kiselina) te nezasićenih (unutar te skupine mononezasićenih i polinezasićenih) masnih kiselina u uzorcima mliječne masti (n=425). Utjecaj rednog broja laktacije i negativne energetske bilance, kao i regresija, na tjedne laktacije i omjer masti i proteina procijenjeni su pomoću SAS 9.3. Značajno (P<0,01) manji udio po zdravlje nepovoljnih hiperkolesterolemičnih masnih kiselina utvrđen je u prvotelkinja (-2,67 %) i onih u 3. i naknadnim laktacijama (-2,94 %) u odnosu na krave u drugoj laktaciji, kao i istodobno veći udio po zdravlje povoljnih nezasićenih masnih kiselina (2,07 %, odnosno 3,08 %). Utvrđena veza objašnjava se stresom organizma prouzrokovanim početkom proizvodnje mlijeka i održavanjem te proizvodnje tijekom kasnijih laktacija. Dakle, općenito dulji životni vijek mliječnih krava može utjecati na kvalitetu sirovog mlijeka, osobito s obzirom na sastav masnih kiselina
