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The aim of the study was to evaluate the effect of the unprotected sunflower oil in the diet on the milk production and composition in cows from private breeding. Ten healthy multiparous Simmental cows in mid-lactation were assigned for 5 weeks feeding trial. The animals where fed one of the diet: WSO - the basal diet which consisted of the 26% corn silage, 33% perennial ryegrass haylage, and 41% concentrate in DM, and SO diet - in basal diet 200g/cow/day of unprotected sunflower oil was supplemented in concentrate mixture. The milk production and production of milk components did not change significantly during the trial, whereas milk fatty acid composition altered significantly. Short chain and medium chain fatty acids decreased for 0.94%, and 6.42%, respectively, and long chain fatty acid increased for 7.76% in SO diet. The rumenic (cis-9, trans-11 CLA), linoleic (cis-9, cis-12 C 18:2) and stearic acid increased significantly, and palmitic, myristic and partially lauric acid decreased significantly during the SO treatment. We could conclude that unprotected sunflower oil efficiently modified the fatty acid composition of Simmental cows’ milk with no adverse effect observed on the milk production, standard milk components and animals health.

The aim of our study was to improve the milk production at the small-holder dairy farms in order to enhance the quality of the milk produced and to keep the animals healthy. We have introduced the quality milk and blood profile testing for the assessment of nutritional and metabolic status of cows. The blood and milk samples were collected from mid-lactating cows (70-150 DIM) with average milk production of 5800 L per cow a year at fife consecutive periods (1- spring ; 2-summer ; 3-autumn ; 4 -winter 1 ; 5-winter 2) with minimum of 7 cows per group tested. Blood profile consisted of 11 parameters. Milk composition (protein, fat, solids non fat, lactose), somatic cell count with additional superoxide dismutase (SOD) and thiobarbituric acid reactive substances (TBARS) concentration were monthly controlled. Milk protein, solids non fat (SNF) and milk fat changed over the research periods with significantly lower values measured in summer (3, 19 %, p < 0, 01 ; 8, 69%, p < 0, 05) with average of 3, 86% of milk fat, and the highest values were observed in autumn (3, 78% for proteins and 9, 15% for SNF) with significantly higher milk fat content of 5, 57 % (p < 0, 05). The SOD activity in milk was the lowest in autumn (223, 63 U/g prot.) and the highest in summer (429, 9763 U/g prot.) period, and the TBARS concentration was the highest in spring (253, 05 nmol/g prot.) and the lowest in winter (112, 49 nmol/g prot.). The concentration of blood parameters also changed significantly at some stage of the research. In the winter periods significantly higher concentration of urea, total cholesterol, albumin, and minerals calcium and phosphorus were measured (5, 21 mmol/L ; 5, 85 mmol/L, 40, 7g/L ; 2, 47mmol/L ; 2, 05 mmol/L) with the average the lowest values detected in spring. The significantly higher activity of enzyme gluthathion peroxidase (GPx) was also noted in autumn and winter periods (10858, 70 and 24085, 22 U/L ; p< 0, 001). The concentration of betahydroxibutirate (BHB) was significantly higher in the summer (0, 88 mmol/L) with the concurrent significantly lower phosphorus and urea concentration in blood (1, 65 mmol/L and 2, 12 mmol/L). The assessment of blood and milk parameters pointed to seasonal variations of the milk protein and milk fat, and physiology variations of blood parameters for the particular breed of dairy cows. The reason for the significant seasonal difference between the blood and milk parameters was attributed to imbalanced diet, particularly in summer. The results of our study promoted the preparation of the balanced diet for the following productive period at the farm.

The aim of the study was to evaluate the effect of the unprotected sunflower oil in the diet on the milk production, and changes in milk composition. Ten multiparous Simmental cows in mid-lactation (78 ± ; ; ; 40 DIM) were assigned to change over feeding trial, over 5 weeks research period. Treatment was the basal diet (WSO) and diet supplemented with unprotected sunflower oil (SO). The basal diet consisted of the 26% corn silage, 33% perennial ryegrass haylage, and 41% concentrate in DM. In SO diet 200g/cow/day of unprotected sunflower oil was mixed in concentrate mixture. The milk production and production of milk components did not change significantly during the trial, whereas milk fatty acid composition altered significantly. Short chain and medium chain fatty acids decreased for 0.94%, and 6.42%, respectively, and long chain fatty acid increased for 7.76%. The rumenic (cis-9, trans-11 CLA), linoleic acid (cis-9, cis-12 C 18:2) and stearic acid increased significantly during the treatment, and palmitic, myristic and partially lauric acid significantly decreased over the course of study. We could conclude that unprotected sunflower oil efficiently modified the fatty acid composition of Simmental cows’ milk with no influence on the milk production and the majority of standardly analysed milk components.

The main objective of our research was to determine an effect of unrifined and unprotected sunflower oil on the fatty acid composition and blood lipid profile in Simmental cows. Ten Simmental cows in mid-lactation were appointed for changeover feeding trial over the 35-d period. Cows were allocated to basal diet (BD) ; 41% concentrate, 33% perennial ryegrass haylage, 26% corn silage in dry matter, or basal diet supplemented with 200g of unprotected sunflower oil (SO) per cow daily. The total blood cholesterol concentration increased significantly in SO diet (5.58 mmol/L vs. 4.58 mmol/L) and triacilglycerol concentration did not change between the treatments. The SO diet significantly and rapidly elevate ratio of cis-9, trans-11 CLA (1.25% vs. 0.80%) and linoleic acid (3.56% vs. 2.75%) in milk, and simultaneously significantly decrease palmitic acid ratio (25.14% vs. 29.99%). High individual variations in blood cholesterol concentration and milk CLA proportions were determined, especially after the introduction of sunflower oil in the diet. Highly positive correlation between the linoleic acid and CLA proportions were determined (r = 0.80), and negative correlation between the total blood cholesterol concentration and milk fat content, during the SO treatment, were observed. In conclusion, relative small quantity of unprotected high linoleic sunflower oil in the diet significantly modified the fatty acid composition of Simmental cows’ milk, with the individual differences in the response to the diet changes.

The fat supplements are often incorporated into the diet of dairy cattle to increase the feed energy of ration and to improve the fatty acid composition in milk fat, but also to enhance the overall animal productive conditions. The objective of this study was to determine an effect of unprotected sunflower oil to the total blood cholesterol, palmitic (C16:0) and stearic (C18:0) fatty acid level in milk fat of Simmental cows. Ten Simmental multiparous cows in mid lactation were used in change over design. Treatment was a basal diet (WSO) and basal diet supplemented with 2 % of high linoleic sunflower oil (SO) during the five week experimental period. The basal diet contained 26% of corn silage, 33% of perennial ryegrass haylage, and 41% of concentrate in DM. During the first experimental week the same basal diet was applied to all animals, with no significant difference in total blood cholesterol and C16:0 content in milk, but the average body condition score and C18:0 content in milk was statistically lower in the second group (3, 24 vs. 3, 07, and 9, 5 vs. 8, 88). In the second experimental week the body condition score and the C18:0 content in milk increased in SO group, with no detectable difference between group. The statistically higher total blood cholesterol was determined (6, 71 vs. 5, 00 in the fourth, and 6, 33 vs. 5, 07 in the fifth experimental week). The average body condition score decreased in WSO group in the fourth period and was significantly lower comparing to the SO group. The total blood cholesterol positively correlated with C18:0 in milk and C16:0 turn from positive to negative at the 5, 00 mmol/L of blood cholesterol. The results analysed with PROC MIXED procedure of SAS revealed significant increase of total blood cholesterol (4, 58 vs. 5, 58 mmol/L) with the sunflower oil treatment, while the body condition score did not change significantly. Unfavourable palmitic fatty acid content in milk was significantly reduced by the treatment (25, 14 vs. 29, 99%), and neutral stearic acid content was higher in SO comparing to WSO diet (15, 77 vs. 11, 49 %) but did not reach a significant level. We may conclude that sterol synthesis was increased by the sunflower treatment, indicating better energy level and at the same time decreasing critical level of palmitic fatty acid in milk, but probably higher dosage of oil might have caused a significant increase of stearic fatty acid and consequently oleic acid in milk.

For many years the various systems for evaluation of herd health status have been developed.In recent years, the great value of milk constituents as a useful tool for the nutritional monitoring but also as indicators of sub- clinical disease and impaired fertility have been introduced. Therefore, nutritional and health status were studied in cows using the method based on the measurement of protein, fat and urea content in milk. The research was carried out in 14 farms located in the northwestern part of Croatia during the winter period. The mean number of cows per farm was 11. The farms were chosen randomly from the herd book register. The individual milk samples were obtained from 94 Simmental cows between 3rd and 7th week postpartum. The average milk production was 19.6 +- 4.3L with annual milk yield 3966 per lactation. Low milk protein (lower than 3.19%) and low milk urea (lower than 2.9 mmol/L) were recorded in 44%, and high milk fat (higher than 4.0) in 50% of animals. The evaluation of dietary status in terms of milk component conteents revealed a greater shortage of energy and protein ratio. The nutritional status based the body condition scoring of animals showed to be adequate in all but one farms. The most important problems were periodical fertility in most animals. The inadequate supply of energy was posibly related to reproductive efficiency, although other elements should also be considered such as determination of biochemical parameters in milk proof, drawing more attention to meet dietary requirements for each production group and the obvious need for higher professional involvement in order to improve farm menagement.

In the present work the application of the method for the urea analysis in milk but initially devised for the urea determination in the blood, is presented. In order to prepare milk, the suitable medium for this analysis the deproteinization and fat removing in the milk sample was made ready. The analysis was always performed 24 hours after the sample collection. It is concluded that the method is accurate, simple and convenient for the analysis of the urea in milk. It is simplicity makes its application suitable for determining milk urea variations under practical conditions in relation to production and the detection of nutritional and metabolic disturbances in dairy cows.