The study was conducted in a herd of Polish Holstein-Fresian (PHF) cows. Experiments involved primiparous cows. Protein, fat and lactose content as well as dry matter, fat free dry matter, pH, °SH, density and thermostability were determined in milk samples. RW-2 prints served to evaluate the performance of cows. Differences in the properties of milk depending on stage of lactation were analyzed. Milk yield in primiparous cows increased until 90 days of milking and decreased from the fourth month of lactation. The study showed the highest levels of fat, protein, dry matter and fat content in milk from cows in the eleventh month of lactation. In XIII month lactation milk, characterized by the highest dentysity of a pH close to the isoelectric point of casein. We conclude that in the period of lactation performance, composition and physic-chemical characteristics of mammary gland secretions of cows are subject to change, and milk with the most desirable technological properties producing cows in the XI and XIII month milking.

The aim of the study was an evaluation of selected biochemical parameters level in blood of cows of various performance and housed in different environmental conditions. Sixty clinically healthy animals were selected for the study, 20 from each farm of differentiated milk yield (farm A and B), and the same number from individual farms. The cows selected for the study were between 40^th and 60^th day of lactation. Blood serum analysis included: β-hydroxybutyric acid, free fatty acids (FFA), aspartate aminotransferase (AST), γ-glutamyltransferase (GGT), total bilirubin, total proteins and albumins. Cows yield on farm A in the examined period was twice higher compared to farm B. An intensified lipolysis, without an excessive ketogenesis, was noted in high-yielding cows in lactation peak. In low-yielding cows these changes were not significant. An increase in AST and GGT was observed in high-yielding cows in an initial lactation period. Protein level in all sites exceeded the proper values, while albumins level was considerably lowered. On farm A, despite high yield, the aberrances from proper values were small. Regular blood analysis in the herd allow early detection of subclinical states, as well as an assessment of nutrition correctness.

The study was performed on corpses of adult: 40 domestic shorthair cats (Felis silvestris f. catus), 50 American minks (Neovison vison) and 23 bank voles (Myodes glareolus) of both sexes and different age. The study material underwent an anatomical preparation and morphometric analysis of the hearts was performed. None of the hearts carried signs of macroscopic abnormalties or pathological changes. The following elements were determined: the body weight (BW), the heart weight (HW), the heart height (H) and the heart width (W). The data thus obtained were used to determined the percentage of the HW compared to the BW. The difference between the population of males and females for each of the parameters was determined by the Fisher’s LSD test (for cats and minks) and the U-Mann-Whitney test (for bank voles) and the significance level was P≤0.05. In the studied material the W of all specimens was greater than the H. The average HW amounted to: 19.08 g in domestic shorthair cat; 13.05 g in American mink; 0.13 g in bank vole. The average I1 amounted to: 0.59% in domestic shorthair cat; 0.66% in American mink; 0.70% in bank vole.