The studies were carried out on 40 males and 40 females from A44 ancestral strain of ducks. Dissection analysis was conducted on 7, 8, and 9-week-old ducks for genetic potential manifestion. Duck carcases were measured for estimation of correlation coefficients between carcass measurements and tissue content. Trunk and chest measurements of ducks for slaughter were increased over rearing. Sexual dimorphism in trunk and chest width, and chest depth, and also in length, circumference and thickness of shank wasn’t noticeably observed in 7, 8, and 9-week-old birds. Male and female carcases were well-muscled. Weight and proportion of breast and leg muscles increased in males and females from 7 to 9 week of rearing, respectively from 560 to 669 g, and from 29.0 to 30.1%. Weight and proportion of skin with subcutaneous and abdominal fat also increased in the following terms of carcass evaluation, respectively from 602 to 756 g, and 31.1 to 34.0%. Trunk with neck length and breast bone length were found as a good indicators of breast and leg muscles weight in ducks aged 7, 8, and 9 weeks. It was showed that when proportion of breast and leg muscles was increased, thickness of skin with subcutaneous fat was decreased (respectively r = - 0.516 and r = - 0.442) in A44 ducks aged 7 and 9 weeks. Negative correlation coefficients between breast bone length and proportion of skin with subcutaneous fat in ducks aged 7 week (r = - 0.737), 8 week (r = - 0.660), and 9 week (r = -0.609) point that when the selection pressure for breast bone length was greater, carcass fatness should be lesser. Weel-muscled and lean carcases could obtain choosing to the slelection flock the A44 ducks which distinguished by measurements positively correlated with breast and leg muscles content (trunk with neck lenght, breast bone length, chest circumference), but negatively correlated with carcass fatness (chest width).

The aim of the study was to determine the concentration of Ca, P_ig and Mg in osseous tissue of the lambs of various breeds at age of 14 days. The studies were carried out on 217 lambs in various sheepfolds in Northwest Poland. The material for the studies comprised the osseous tissue ash of the 4th and 5th caudal vertebrae. The values of macroelement concentrations in osseous tissue were expressed in mmol l^-1 in 1 g of dry matter. The highest osseous tissue concentration of Ca was found in the lambs: Blackhead (19.74 mmol l^-1 ± 2.02) and Leine (15.94 mmol l^-1 ± 3.16). The lowest Ca was recorded in the lambs Romney Marsh (9.50 mmol l^-1 ± 1.80) and Merino (10.25mmol l^-1 ± 4,84) The lowest P_inorganic. concentration was found in the osseous tissue of the Polish Merino (11.43 mmol l^-1 ± 1.18). The concentration of Mg ranged between 0.82 mmol l^-1 ± 0.10 in the bone tissue of Merino lambs and 1.10 mmol l^-1 ± 0.21 in the bone tissue of the crossbreds Polish Merino x Suffolk lambs. The lowest Ca:P ratio was observed in the osseous tissue of the Romney Marsh lambs (0.50 ± 0.10), whereas the highest was found in the Blackhead lambs (1.17 ± 0.17). A wide range (p≤ 0.01) of the Ca:Mg ratio were recorded, from 11.40 ± 1.72 in Romney Marsh to 20.37 ± 2.09 in Blackheaded. The analysis of the results obtained from the studies of mineral composition of the lamb tail vertebrae osseous tissue demonstrated that the factor of the breed and the breed-related purpose type were the background of the differences between the lambs, and that the differences may have been associated to geochemical factors.

The aim of the studies was to compare the Ca, inorganic P and Mg in bone tissue in lambs born in different seasons. A higher (p≤ 0.01) concentration ash, Ca and Mg but a lower of inorganic P were found in the bone tissue of lambs born in autumn compared to the content of those elements in spring born lambs. It seems necessary to supplementationcalcium salts and magnessium in diet to eliminate those elements deficiency.

The growth in young goats graded up breed according to the birth date was analyzed in this study. The study was carried out with 50 young goats which were born on February and 32 on April. Goat growth was characterized on the ground of body weight, daily body weight gain and zoometrical measurements form birth to 6 month life. Body weight daily body weight gain and zoometrical measurements of young goats were affected by the date of kidding over investigated period. Young goats which were born on February grew more intensively and also characterized by greater values of all body conformation traits than young goats in the same age, which were born in April.

Clinical studies and estimation of teat canal carried out on 3884 quarters of mammaries which also were taken sample of milk to bacteriological investigations. The effects of genotype, the cow age, lactation phase and somatic cells count on occurrence frequency particular types inflammations and mammary contagions, post inflammation changes and domages teats canals were analyzed, using the chi-square test. Somatic cells count in samples of quarter milk was the most factor which had influence on occurrence frequency of particular conditions diseases. Among of recognize mammary diseases was the most subclinical inflammations – bacteriological and non-bacteriological (suitable: 25.6 and 21.5%).

The concentration of lead, cadmium, zinc and copper in egg’s content of hens housing in free range system (18 farms), in copper industry region, between 1997 and 2003 was determined. In that time twice decrease, statistically significant, of lead concentration (to 0,0646 mg kg^-1 f.m.) and increase of copper concentration (to 0,66 mg kg^-1 f.m.) has been examined. The content of cadmium and zinc did not change significantly during the investigation. The concentration of cadmium and lead was over the permissible limit occasionally, however the concentration of copper and zinc was on average level or lower, comparing with data from literature. The last two elements are not limited (Cu from year 2000 and Zn from year 2003) in the polish legislation concerning food safety.

The aim of this study was to determine the effect of higher light intensity on whelping interval, percentage distribution of litter sizes, and seasoality in reproduction of Polish and imported chinchillas. The analisys covered reproduction of 230 Polish (group A) and 250 chinchillas imported from Denmark and Sweden (group B). In selected part of the farm, lamps of higher powe were installed. The interiors of chinchillas cages were measured for light intensity and the chinchillas were divided into two groups: control)I) and experimental (II). Increased light intensity resulted in shorter whelping interval in both genetic groups, by 30 days on average, as well as in increased share of litters with 2 and 5 young. Elevated level of light did not eliminate seasonality in reproduction, especially in Polish chinchilles. Imported chinchilles had evenly distributed births throughout a year.

The studies were conducted in the years 1995-2002. The experimental material were Jersey cows imported from Denmark, and their progeny born and raised in Poland. Two herds were evaluated – herd A in Jonkowo and herd B in Bogaczewo. The manyyears' opinion of chosen of usable coefficients was the aim of investigations. The parameters of reproduction and productivity were estimated imported from Danii of cattle of race Jersey in conditions of Warmia and Mazury (NE Poland) province. It was found that cow fertility was good; its decrease was noted only after five calvings. An increase in milk yield and yields of its major components was observed until the fifth lactation. In the first lactation the highest productivity was reported for herd B - 3715 kg milk, 215.61 kg milk fat (5.78%) and 139.54 kg milk protein (3.76%). In the fifth lactation the highest productivity was noted in herd A: 5275 kg, 331.59 kg (6.30%) and 214.38 kg (4.04%) respectively. The cows born and raised in Poland (generation P) were characterized by higher productivity than those imported from Denmark. The highest statistically significant difference (p ≤ 0,01), i.e. 468 kg milk, 47.99 kg milk fat and 25.57 kg milk protein, was found in the first lactation. Analysis of six successive lactations shows that Jersey cattle imported from Denmark easily adapted to the conditions of north-eastern Poland.

The experiment was carried out on 32 Polish Landrace x Large Polish White sows, mated Pietrain boar, over pregnancy and lactation (28 days) divided into 4 groups, 8 animals each. The animals received the same, cereal-soybean meal based full-feed mixture but deficient in P and Ca. The treatments differed in feed additive: C – control (without any additive), MP – microbial phytase (500 PU kg^-1 mixture), Ca – citric acid (20 g kg^-1 mixture) ang MP+CA treatment – both phytase and citric acid additives. The apparent total tract digestibility (Cr₂O₃) was determined on weeks 8 and 14 of pregnancy and week 3 of lactation and, after accomplishing 28-day lactation – the apparent ileal digestibility of organic matter, protein and amino acids. The additive of microbial phytase increased (p≤ 0.05) the apparent total tract and ileal digestibility coefficients of organic matter, crude protein and some amino acids. The best results were noted when phytase was supplemented together with citric acid, although the increase, in comparison with phytase added solely, was not significant. Citric acid only sightly, statistically in significantly, elevated the investigated coefficients.

The analysis of the hundred days test of stallions was carried out on the basis of the results obtained in years 2001-2002. It has been proved that stallions originated from the Western Europe had large sport capability (especially for jumping competitions) special abilities showed mainly: KWPN, Holstein breed, Oldenburg breed and Hannover breed. As native breeds are concerned the best jumping results showed Małopolska breed.

The carried out analysis concerned skin quality of silver foxes (2560 individuals) and Blue Frost foxes (621 individuals) which were sold on the auction in Helsinki in season 2000/2001.As a result of the research we can draw conclusions that more merchants from abroad are interested in this sort of skins, particularly crossings. The price of crossings (102.52)€ was 12% higher than the price of silver foxes (91.46)€. In case of the domestic skins the difference was 9,41% higher than the mean auction price obtained for the silver fox skins (87.54)€. It has been proved that in relation to size and color, Polish skins of silver foxes and blue foxes had slightly lower prices than the mean auction price of skins. They had worse purity and quality. It has been visible especially in the silver fox lots which in majority (60%) had brown shades of skins.

The experiment examined whether the use of outdoor areas by broilers housed on an intensive farm had any consequences for production traits (body weight and feed intake, elements of carcass cut and dressing percentage, carcass tissue composition, weight of breast muscles and their percentage). The production results of birds of each sex reared together and separately were also compared. Free access to runs for broiler chickens shows no distinct effect on their performance. The birds probably were well adapted to intensive conditions of rearing during the years of selection. Chickens with access to runs were only characterized by higher body, liver and bone weights, and a lower dressing percentage in comparison with birds without access to runs. Feed intake and conversion appeared to be similar in both groups. Keeping sexes separately during the rearing period is not advisable.

The development of European bison herds founded by small group of animals was analyzed. Four variants of founding group with different numbers, age and sex structure were chosen. In computer simulation used only demographic parameters like reproduction and mortality rates. In period of 60 years some parameter like cumulative probability of extinction, the size of herd and the level of heterozygosity were compared. The size of founding group influenced mainly the level of genetic variability within the herd. Estimated value of cumulative probability of extinction in the worst scenario (only three young animals in the founding group) slightly exceeds 30% value. This allows conclude that European bison herds after serious founding bottleneck have great chance to survive.

The aim of the study was to analyzed the basic chemical composition and marbling of meat (m. longissimus dorsi) from 174 young crossbreed bulls (beef bulls x Black-and-White cows), slaughtered at body weights of ca. 550 kg. The experiment was performed on the progeny (8 to 12 young bulls) of Limousine, Charolaise, Piemontese, Aberdeen Angus, Red Angus, Hereford, Salers and Simental bulls. It was found that meat from young bulls by sires of various beef breeds differed significantly in the contents of the chemical components analyzed. The meat from young bulls by Piemontese and Salers sires contained the most protein, whereas the meat from young bulls by Aberdeen Angus and Red Angus ones– – the most dry matter. The meat from young bulls by Aberdeen Angus bulls was also characterized by the highest fat content and marbling. A relatively high variability concerning the fat content of meat from the young experimental bulls suggests that mating Black-and-White cows with bulls of the same beef breed may result in producing crossbreeds with different concentrations of this component.