The purpose of the research was to establish the effect of concentrates A (C-A) and B (C-B) on the quantity and composition of the produced milk of dairy cows. The research included cows of Holstein Friesian and Simmental breeds and crossbreeds with Simmental breed. The test took place in two periods. The first period with the C-A lasted from December 2004 to February 2005 and included 113 cows. During the second period the C-B was fed. The test endured from April to June 2005. The results of monthly controls of milk quantity and protein and fat contents were entered into the Excel programme and processed with the statistical programme SPSS for Windows 12.0. When the concentrate B was fed, the milk quantity amounted to 21.99 L/day and was statistically significantly (P<0.05) greater than the milk quantity in case of feeding the concentrate A, when the milk quantity was 19.12 L/day. No statistically significant differences (P<0.05) of the protein and fat content in the milk were established.Željeli smo utvrditi utjecaj koncentrata A i B na količinu i sastav namuzenog mlijeka krava muzara. U istraživanje smo uključili krave holštajnsko-frizijske i simentalske pasmine te križance sa simentalskom pasminom. Pokus smo proveli u dva razdoblja. Prvo razdoblje s koncentratom A trajalo je od prosinca 2004. do veljače 2005. sa 113 uključenih krava. U drugom razdoblju s koncentratom B pokus je realiziran od travnja do lipnja 2005. Dobivene rezultate za količinu mlijeka, sadržaj proteina i masti kod svake mjesečne kontrole stavili smo u Excel te ih statistički obradili pomoću SPSS for Windows 12.0. Količina mlijeka iznosila je uz hranidbu koncentrata B 21,99 L/dan i bila je statistički signifikantno (P<0,05) veća od količine mlijeka kod primjene koncentrata A, gdje je iznosila 19,12 L/dan. Kod sadržaja proteina i masti u mlijeku nismo utvrdili statistički signifikantnih razlika (P<0,05)
