The aim of the research – is to study the qualitative composition of milk of cows of Ukrainian brown dairy breed in terms of households and in the context of genealogical descent.
 Method. Research conducted under the conditions of the State Enterprise "Pilot Farm of the Institute of Agriculture of Northern East of NAAS» in Sumy region, Enterprize of Additional Liability “Mayak” in Trostyanetc region, State Enterprise "Pilot Farm Agricultural Firm “Nadiya” of the Institute of Agriculture of Northern East of NAAS» in Romny region. Milk production was assessed by monthly milking control with sampling of milk. Quality indicators measured in the laboratory of the former Sumy State Breeding Center on the equipment of Bentley. We investigated the percentage of fat, percentage of protein, including casein, percentage of dry matter, skimmed residue, contents of somatic cells. Biometric processing of results was carried out by the conventional method (Plohynskoho M.O., 1969), using software Statistica 6.0.
 The results of the research. Studies have been conducted on the content of fat, protein, casein, lactose and somatic cell count in cow milk. Established difference of qualitative composition of milk of cows depending on the households and on the genealogical origin of the animals.
 Analysis of our studies indicate that the level of quality indicators of milk production of animals of Ukrainian brown dairy breeds in different farms is significantly different. All the main indicators of quality prevailed in animals of Enterprize of Additional Liability “Mayak”.
 For the fat content of milk cows of Distinkshna line 159523 were dominated. They though not significantly, but dominated the animals of Eleganta 148551 and Laddi 125640 lines for 0.16% and 0.19% respectively. The substantial significant difference of the content of lactose in the milk of cows of different lines is not set. Animals of Distinkshna line 159523 significantly superior cows of Eleganta 148551 and Laddi 125640 lines for the protein, for 0,24% (P < 0,05) and 0,32% (P < 0,05) respectively. For the casein content they were significantly superior then Laddi 125640 line cows – on 0,24% (P < 0,05). For the dry matter content and skimmed milk residue animals of Distinkshna line 159523 also have the advantage.
 Conclusions. As a result of studies found that the level of quality indicators of milk production in animals of Ukrainian brown dairy breed in different farms is significantly different. So fat content in milk varies 3,43–3,98%; protein content – 3,10–3,55%; casein content – 2,83–3,31%; dry matter content – 12,4–13,1%, fat-free dry milk residue – 8,95–9,13%.
 The dependence of milk quality indicators based on linear descent. For the main indices are preferred animals of Distinkshna line 159523.
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