Associations between polymorphism localised in the third exon of the prolactin gene (PRL-RsaI) and milk xproduction traits of Black-and-White and Jersey cattle were analysed. A total of 427 cows were included in the study. PCR-RFLP method was used. The frequencies of genotypes and alleles were as follows: 0.7107 – AA, 0.2851 – AB, 0.0042 – BB; 0.8533 – PRL^A and 0.1467 – PRL^B for Black-and-White cattle and 0.0919 – AA, 0.4324 – AB, 0.4757 – BB; 0.3081 – PRL^A and 0.6919 – PRL^B for Jersey cattle. Statistically significant differences between the breeds were observed in the frequencies of genotypes and alleles. Associations between PRL-RsaI polymorphism and milk production traits of Jersey cows and lack of associations with these traits in Black-and-White cows were observed.

Milk yield in goats was influenced by environmental conditions connected with the calendar year. Daily milk production was observed to decrease with progressing lactation, while an increase was observed in SCC, as well as percentage fat and protein contents, while the lactose content in milk...

Associations between polymorphism of the bovine growth hormone releasing hormone (GHRH) and pituitary transcription factor 1 (PIT1) genes and production traits of Limousine cattle were analysed. A total of 130 calves were included in the study. PCR-RFLP method was used for genotyping. The frequencies of genotypes and alleles of PIT1 and GHRH were as follows: 0.0692 – AA, 0.4077 – AB, 0.5231 – BB, and 0.2731 for PIT1^A, 0.7269 for PIT1^B; 0.0154 – AA, 0.1692 – AB, 0.8154 – BB, and 0.1 for GHRH^A, 0.9 for GHRH^B. Associations between polymorphism and production traits of Limousine calves were found. Statistically significant differences (P ≤ 0.01) between individuals of different GHRH genotypes were found in relation to height at sacrum (cm) and height at withers (cm) at 210th day of age. The calves with AA genotype of GHRH were shorter (−8,14 and −8,33 cm) than AB and BB individuals (P ≤ 0.01). The small number of calves with the AA genotype did not enable important conclusions.

Zlotnicka Spotted (ZS) is a native Polish pig breed. It is characterized by low reproduction and litter performance. This study aimed to determine the suitability of ZS pigs when crossed with Duroc and Polish Large White (PLW) according to reproduction and litter performance. Data concerning the number of piglets in the litter, litter weight, litter balance and piglet wastage were evaluated at birth, on the 7th and 21st days, and during weaning. ZS sows in purebred litters had 8.82 piglets at birth. However, the number of weaned piglets was of particular importance being only 7.33 heads in this study population. Wastage in purebred litters up to weaning was 17.34%. The highest number of piglets at birth (10.76 heads) and number of weaned piglets (8.98 heads) were estimated for D/ZS x ZS litters, although, at weaning, the heaviest piglets (9.61 kg) came from PLW x ZS litters. Results show that crossing ZS sows with Duroc, PLW boars, as well as crossing of D x ZS, improves reproduction and litter performance.

Analyses were conducted on pedigrees of 845 animals registered at the Hovawart Club in Poland (113 dogs and their ancestors). The degree of inbreeding was calculated for the whole population (0.0026) and separately for male dogs (0.0021) and bitches (0.0031), and the coefficient of mean relationship was calculated for the entire population (0.0064), among male dogs (0.0064), among females (0.0073) and between males and females (0.0061). The inbreeding and relationship coefficients obtained are lower than those estimated for Polish populations of other dog breeds. The calculated effective number of founders (268) and ancestors (233) may indicate rather low genetic diversity. Preferences of breeders concerning coat colour were discussed. Black and tan coat dogs dominated at first, followed by blond ones, and over the last five of the analysed years black coat dogs emerged.

The study attempted to estimate the lactation curves of primiparous dairy cows in relation to their feeding management. Therefore, the first aim of the study was to determine and compare the lactation curves of primiparous dairy cows using Wood’s model and to estimate the association between the lactation curves and feeding management. The second objective was to investigate the effect of the culling rate on improvement in the milk yield of primiparous dairy herds. The study was conducted on four commercial dairy farms of Polish Holstein–Friesian cows using different feeding systems (TMR—total mixed ration and PMR—partial mixed ration) and management (T1—one TMR throughout lactation; P1—one PMR throughout lactation; T2 and T3—three feed periods such as FRESH, TMR I and TMR II according to days in milk). The data used for the study were obtained from monthly milk performance evaluations of 1662 primiparous cows conducted by the Polish Federation of Cattle Breeding and Dairy Farmers throughout the year 2015. Wood’s lactation model was used to plot curves for milk yield, fat and protein content, lactose content, and milk urea contents. The highest milk yield for the whole lactation and in the peak lactation phase was recorded for cows in herd T1. This herd reached peak lactation on day 105 of milking, with an average milk yield of 42.1 kg, which was about 5 kg more milk than in the other herds. The study showed that the culling of primiparous cows in herd T1 after 30, 60 and 90 days of lactation prevented a significant reduction in milk yield in a 305-day lactation. It also increased average milk production by 1586.9 kg per primiparous dairy cow.