Milk, an essential source of offspring nourishment, varies in it's composition and properties significantly across species. In human nutrition, fresh milk and dairy products are valuable sources of protein, fat and energy, and are an important part of daily meals. Most of the world's milk production (85 %) comes from cows followed by buffaloes, goats, ewes, mares and donkeys. However milk related food allergies in infants may be a reason for health problems and may cause a decrease in milk. The objective of this paper was to give an overview of the overall composition of milk and fat from different species in comparison to women milk. Regarding the overall milk composition remarkable differences in energy content, fat, lactose, protein and ash of the various milks were found, but also some similarities among milk from ruminants and non-ruminants were detected. The structures of fat globule membranes were similar among non-ruminants and women milk, while the milk fat globule structure in ruminants differed significantly. The size of fat globules was significantly different between species and highly correlated to the milk fat content, regardless of the specie. The amount of triacylglycerols was notably higher, while the amount of free fatty acids and phospholipids was notably lower in milk from ruminants and women compared to milk from mares and donkeys. The triacylglycerol structure in women and non-ruminantsˈ was similar. The percentage of saturated and monounsaturated fatty acids was lower, while the unsaturated fatty acid content was higher in milk from non-ruminants, with a remarkably higher percentage of C-18:2 and C-18:3. The cholesterol content was similar in women and ruminantsˈ milk, but lower in that of non-ruminants. This review indicates that milk from non-ruminants could be more suitable for human nourishment than milk from ruminants.

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Farm breeding of cattle is organized so that the animals are kept in a controlled environment (an closed corner, feeding time, milking time, workers), where daily animal encounter with familiar sounds, smells, movements and equipment. Any positive or negative change of environment causes certain physiological reactions of cattle on it. Negative stimuli (relocation, new technological activities, unidentified sounds and people) disrupt the homeostasis of the animals and lead them into a state of stress. During stress in cattle appears central inhibition of milk ejection from the alveoli of the udder, causing its incomplete emptying which could lead to pathological changes. In stressful situation, there is a connection between nervous (SA system), endocrine (HPA-axis) and the immune system. Stimuli from the outside were obtained through sight, hearing, smell and touch, leading to nerve impulses which then activate the endocrine system (increased levels of cortisol, β-endorphin, adrenaline, and reducing levels of oxytocin in the blood), whose actions over a long time lead to decline in immune response and susceptibility to disease. Many studies suggest an association between central inhibition of milk ejection and stressful situations (first milking of primiparious cattle, environment changes), but the very principle of inhibition is not fully understood. Some studies indicate an association between endogenous opioids (β-endorphin) and catecholamines (adrenalin) in the central inhibition of milk ejection, however, there is still no clear evidence and there is still plenty to do in this area.

The modern equipment introduction into cow milking created technical possibilities for studying the milk flow curve and for using the results in cattle selection. In preventing mastitis, besides curing, other parameters of the milk flow curve could be used preventively. Research showed that cows that had the milk flow curve with a short duration of increasing flow rate (dIFR≤0.40 min) and a larger quotient between the peak and down phase (QPD>1.20) had also the least somatic cell count in milk (LSCC = 3.47, and 3.30 respectively). Such relation is favourable because increasing the relation, the duration of quick and uniform milking extends, and the duration of peak flow rate shortens. That also show correlation coefficients which were between the logarithmic somatic cell count in milk (LSCC) on one hand and the peak flow rate (dPFR), that means the quotient of peak and down phase (QPD) on the other hand negative (r= -0.25** and -0.27**). Breeding-selective procedures could create bull fathers and mothers with the most desirable milk flow curve and the duration of certain milking phases, whereby the somatic cell count in milk would be the least. Therefore it would be necessary to define desirable proportions of the milk flow curve with a special attention to the cow's health udder.

Since there is not enough data about milkability of the Jersey cows, the aim of this paper is to show basic milkability traits of this cattle breed depending on the parity and milk flow curve types. Cows had average daily production (DMY) of 22.23 kg, milk yield per milking (MYM) of 9.72 kg, and average and maximum milk flow about 1.66 and 2.49 kg/min, respectively. Statistical analysis showed that DMY and MYM of the cows in 4th parity was significantly (p<0.05) higher comparing to cows in 1st and 3th parity. The duration of entirely milking is similar regarding the paritiesand only the cows in 3th and 4th differ significantly (p<0.05). Regarding the effect of milk flow curve, the significant (p<0.05) difference between unspecified and rectangular milk flow curve has been found for the average milk flow (AMF) and descending phase of the milk flow curve (TD). Cows with unspecified milk flow curve, have significantly (p<0.05) lower AMF and longer TD compared to cows with rectangular curve. Cows with bimodal milk flow curve have significantly (p<0.05) longer duration of the ascending phase compering to: unspecified, descending and rectangular. The results of this study have shown that Jersey cows have lower production and milk flow compared to other dairy cattle breeds. Nonetheless, they have uniform milkability traits, and a large representation of desirable milk flow curves which are associated with a beneficial effect on the udder health.

With the aim of analysis the influence of temperature-humidity index (THI) on daily performance of dairy cows in Croatian Mediterranean region, 217,509 test-day records collected from January 2005 until April 2010 were extracted from HPA (Croatian Agricultural Agency) database. Milk recording in Croatia occurs according to the alternative milk recording method every four weeks, therefore, daily production of milk yields and components was projected using projection parameters estimated in authors' earlier research (Gantner, 2008). Logical control of data was performed according to ICAR standards (2003). The yields recorded after the 500 th lactation day was deleted from the dataset. According to the parity, cows were divided into three classes (heifers, cows in second lactation and cows in third and higher lactations) while, regarding the calving date, cows were divided in two calving season subgroups. According to the test date, four measuring season subgroups were created. Based on temperature and relative humidity recorded in stable at each milking control the daily temperature-humidity index (THI) values were calculated using the equation by Kibler (1964). For estimation of the influence of exceeded THI (above critical value-72) on daily production of dairy cows statistical model that take into account effects of lactation stage, breed, calving season, measuring season as well as effect of THI group (T1-THI under critical value; T2-THI above critical value) was used. The significance of differences between the means of the daily milk, fat, protein and lactose yield, as well as between the means of the daily fat, protein, and lactose content within the THI classes in regard to parity classes was tested with Scheffe test. For the statistical analysis and the figures drawing the SAS/STAT package was used (SAS Institute Inc., 2000). The exceeded THI significantly decrease daily milk, fat, protein and lactose yield in heifers and cows in third and higher lactations. In second lactation determined decrease was not significant. Highly significant decrease of daily fat and protein content was determined in all cows, regardless the parity. The daily lactose content was not significantly influenced by enhanced value of THI. Management strategies are needed to minimize heat stress and to attain optimal cows' production in climatic condition of Croatian Mediterranean region.

ABSTRACT:Biological investigations on ewes of Merinolandschaf breed (n = 10) were conducted by the 60 th lactation day during the summer on pasture. Ewe milk sampling was carried out on the 2 nd ; 10 th ; 30 th and 60 th lactationday. An electrothermal technique was used to determine Cd and Pb concentrations in food and milk whereas As and Hg concentrations in food and milk were determined by a hydrid technique on an atomic absorption spectrophotometer. The investigation results indicate that concentrations of selected toxic elements in ewe milk varied in dependence on lactation stage. In colostrum (2 nd lactation day) Cd and Pb (0.011 and 0.035 mg/kg) concentrations were significantly higher (P < 0.01) whereas As (0.011 mg/kg) concentrations were lower in comparison with milk on the 10 th (Cd: 0.004; Pb: 0.022; As: 0.025 mg/kg), 30 th (Cd: 0.005; Pb: 0.024; As: 0.028 mg/kg) and 60 th (Cd: 0.006; Pb: 0.026; As: 0.029 mg/kg) lactation day. However, no significant differences (P > 0.05) were found in milk Hg concentration in relation to lactation stage (from 0.021 to 0.026 mg/kg). The selected toxic elements appeared to be present in ewe milk in very low concentrations.