The research were carried out in the herd with average annual number of 185 dairy cows in 2008 with average annual milk yield 8.009 kg. The animals were kept in a loose barn with deep litter system and were fed in TMR system. Statistical analysis considered the influ ence of first calving age, next calving, calving season, milk yield in standard lactation length and dry period length on fertility indices. It was found that the level of fertility indices was influenced by all analyzed factors. It should be emphasized that this influence was, however, not the same. Insemination index, length of interpregnancy and intercalving period were most influenced by length of complete lactation and previous dry period length. Decreasing of fertility indices with an increase above 8.000 kg of milk yield in standard lactation were observed. It suggests, that an increase of milk yield to 8.000 kg would not significantly decrease reproduction efficiency.

Correlation between GH/HaeII polymorphism and fattening and slaughter performances of fatteners was analyzed. Genomic DNA was extracted from the whole blood of 369 fatteners that belong to five different breed groups: Landrace, Landrace x Duroc, Landrace x Yorkshire, (Landrace x Yorkshire) x Duroc, (Landrace x Yorkshire ) x (Duroc x Pietrain). The frequency of occurrence of GH/HaeII allele polymorphism amounted to: A – 0.168 and C – 0.832, respectively. By comparison of expected abundance in GH/HaeII genotype groups with theoretical calculated abundance according to the Hardy-Weinberg law statistically significant difference were not found. Statistically significant influence on examined fattening and slaughter performances, and statistically significant interaction between breed group and GH/HaeII polymorphism for rate of growth of fatteners were shown. The GH/HaeII polymorphism itself did not differ in statistically significant way any of analyzed traits of fattening and slaughter performances within examined group of fatteners

Eighty Pekin ducks from P44 and P55 flocks – 20 males and 20 females from each line were studied. Ducks were penned in a confined facility on deep litter and fed ad libitum commercial diets for waterfowl. Compared to P55 ducks, P44 ducks had greater body weight at 8 weeks of age (3396 vs. 3333 g) and significantly longer keel (14.4 vs. 13.8 cm). P44 ducks used less feed per kg body weight (2.46 kg) and were characterized by a higher European Production Index (241 points) compared to P55 ducks (2.58 kg and 225 points). Dressing percentage was high (67.8% in P44 and 67.5% in P55 ducks). Compared to P55 ducks, the carcasses of P44 ducks had a higher content of skin with subcutaneous fat (31.7% vs. 30.0%) and abdominal fat (1.7 vs. 1.4%), and a slightly lower content of the other carcass components, including breast muscles (13.2 vs. 13.7%) and leg muscles (12.2 vs. 12.6%).

The aim of the study was estimating the relationship between the parameters of reproductive maturation of the crossbred gilts before first service and their reproductive performance at first and second reproductive cycle. Significant relationship were found out between age the first service of gilts and the number of piglets at 21 days and the number of the weaned piglets (0.282*, 0.276*), between weight of body of the gilts at first service day and the number of born piglets, at 21st day, weaned and weight of litter at 1st and 21st day of life and also average weight of piglets in 21st day (respectively: 0.482**, 0.507**, 0.490**, 0.381**, 0.509** and 0.234*). Also significant coefficients of correlation were found out between backfat thickness on shoulder (P1a) at first day of service and number of all born piglets (0.311*) and at 21st day of life (0.272*) and at weaning day (0.265*). There were significant correlations between backfat thickness at point P2a and number of piglets born alive (0.314*), at 21st day (0.248*) and at day of weaning (0.237*). During the first service the backfat thickness should be monitored to improve the reproductive performance.

The aim of the study was to investigate the effect of somatic cell counts on urea content in the milk of Holstein-Friesian cows of Black-and-White (N = 390) and Red-White (N = 86) varieties kept on a farm in the Wielkopolska region. It was found that urea level in milk of the evaluated genotypes of cows was within the accepted standard, with higher values of this parameter in Red-and-White cows. In Polish Holstein-Friesian of Black-and-White variety a decrease in urea level was shown with an increase in somatic cell count in milk. Taking into consideration the daily yield of milk and fat corrected milk (4%-FCM) the most advantageous results were recorded for animals with the lowest somatic cell count in milk.

The aim of the study was to determine the relationship between diseases of the reproductive tract and intensity of culling, and lifetime productivity of cows. Investigations were conducted in a large herd of Polish Holstein-Friesian cows of Black-and-White strain. When analyzing the intensity and causes of culling of animals in terms of the SYMLEK system codes it was shown that the largest number of animals (40.67%) was removed from the group comprising infertility and diseases of the reproductive tract. The most frequent cause of culling in animals from this group was infertility (71.67%), followed by retention of placenta with complications (7.08%), damaged inguinal ligament (6.23%), milk fever (4.81%), intrauterine tumours and adhesions (3.40%) and metritis (2.83%). The other specific causes of culling cows from this group were of minor importance, accounting for 1.42 to 0.57%. Statistical analysis showed a significant effect of selected specific causes of culling from the group of infertility coupled with diseases of the reproductive tract on lifespan, length of productive life and milking period as well as traits of lifetime milking performance, except for fat yield per day of productive life and day of lactation.

Examinations were carried out in a breeding flock of 5-year-old rheas (Rhea americana). A total of 62 eggs, coming from around peak laying period, were subject to incubation. During hatching, there were instances of giving assistance to chicks. Based on the performed analysis of post-hatching refuse, three groups were separated: I – egg shells of chicks hatched unassisted, II – egg shells of chicks hatched with personnel’s assistance, III – embryos died during embryogenesis. The results were subject to one-way analysis of variance using applying a Duncan’s test. It was found that rhea chicks frequently required assistance during hatching, and their relative weight (nearly 60%) on the day of hatch reached a low level. The analysis of egg shell ultrastructure showed that largest mammillae occurred in the egg shells after chicks hatched without assistance. On the other hand, significantly smaller mammillae were observed in the egg shell groups where embryos died during embryogenesis or chicks needed assistance during hatch. Moreover, it was found that the largest number of mammillae per area unit is characteristic of the egg shells after chicks hatched without assistance. Therefore, one may think that the structure of this layer, in particular the density of mammillae, is related to hatching performance results.