Effect of Calpastatin Gene Polymorphism on Lamb Growth and Muscling: The calpain-calpastatin system plays a key role in skeletal muscle growth and development processes. It is known that calpastatin activity correlates highly with muscle growth rate, which implies that skeletal muscle growth is likely to result from reduced protein degradation due to compromised activity of calpains or substantial increase of calpastatin activity. The objective of the present research was to identify polymorphic forms in intron 12 of the ovine calpastatin gene in sheep of synthetic lines BCP and SCP, followed by determination of the correlation between each polymorphic form of CAST gene and chosen traits characterizing lamb growth and muscling. The present study's results suggest that lambs carrying the "b" and "e" alleles and the "ae" genotype could be preferred when selecting for growth rate. The breeding efforts to obtain substantial increases in sheep muscle mass could focus on animals carrying the "ac" genotype. No statistically significant relationship was observed in any of the analysed cases between values of the traits and the CAST genotype. However, a highly significant effect of the study year on the analysed traits was found. The results should be regarded as preliminary. The research should be continued on a larger group of animals to ensure the adequate number of each genotype. The trends mentioned and discussed above may also serve as an indicator showing the future direction of further studies in this area.

The main objective of the study was to determine the genetic diversity in the Polish Konik (PK) population in the context of a currently conducted conservation program. A total of 94 horses of 16 PK dam lines currently distinguished by breeders were considered. Pedigree analyses were carried out for the whole population of PK registered in the studbook. Basic molecular parameters were estimated. The average group linkage clustering method was used based on the Euclidean similarity measurements between the lines. The allele frequency of 17 microsatellites was used to determine Euclidean distances. Inbreeding coefficients were extracted from the additive relationship matrix. Moreover, some pedigree parameters were estimated. The observed heterozygosity ranged from 0.48 to 0.76. The expected heterozygosity estimated for the dam lines was higher. PIC values were higher than 0.6 in all the lines. F_is ranged from –0.19 to 0.28, whereas F_it and F_st varied between 0.12 and 0.41 and 0.12 and 0.29, respectively. Minor dissimilarity distances existed for some dam lines. The inbreeding level was 9.3%. The average number of discrete generation equivalents reached 6.85. The majority of the dam lines are not genetically differentiated. Hence, a revision of the breeding strategy seems to be necessary.

The research objective was to assess the behavior patterns of the Polish Konik horse breed and the Uhruska variety of the Polish Lowland Sheep breed under a mixed-grazing system, and their relationship with climatic factors. The observation included 4 adult horses, 27 ewes with lambs and 10 primiparous ewes. The behavior of the animals and the weather conditions were recorded at 60-min intervals. Horses and sheep displayed similarities in both species-specific behavioral patterns and timing of grazing activity, and the duration of foraging sessions was mostly influenced by time of day, lower temperature and relative humidity. In addition, the two species showed more interest in the watering place in the afternoon, and drinking frequency was mainly dependent on air temperature. The animals that pastured together gradually began to mix, but at first, they remained within their species group. Both animal species can be used for environmental protection and landscape conservation making rational use of pastures within protected areas.

The objective of the present research was to assess the instrumental and sensory textural attributes of lamb meat depending on the cold storage ageing under vacuum. The research material included two skeletal muscles, i.e. semimembranosus (SM) and rectus femoris (RF) from carcasses of Uhruska lambs. The age of animals ranged from 120 to 135 days. The ageing and muscle influenced significantly shear force and shear energy. However, significantly lower shear force and higher score of tenderness were observed on 7 vs. 2 days of ageing only for SM. The evaluated factors (ageing and muscle) affected slightly and not significantly the parameters of texture profile analysis. The muscle samples after the 7-day ageing showed higher hardness and chewiness. Significant correlation of sensory tenderness with instrumental shear and energy force and springiness was confirmed. The obtained results indicated that vacuum-packed lamb meat during cold storage for 7 days following slaughter develops the sensory attributes, especially tenderness.

A well-functioning immune system is the basis for protection against infectious and metabolic diseases, and a smooth return to homeostasis. The periparturient period is considered critical because major changes in the endocrine, behavioural, digestive, and immune systems dysregulate immune function, leading to immunosuppression. With age, the immune system could become dysregulated. The purpose of the present investigation was to compare changes in plasma concentrations of acute phase proteins, cortisol, and haematological parameters in the peripheral blood of two age-related groups of healthy ewes to get a better understanding of changes around lambing. Two groups of ewes were enrolled in the study: 3-year-old (young; n = 9) and 7-year-old ewes (old; n = 9). All females were synchronised and inseminated. In blood plasma, serum amyloid A (SAA) and cortisol concentrations were measured using ELISA tests, a spectrophotometric method to determine haptoglobin (Hp), and a thrombin clottable estimation to determine the fibrinogen (Fb) concentration. The blood parameters were examined using an automated haematological analyser. In clinically healthy ewes, no significant effect of age was observed in SAA, Hp, Fb and cortisol concentration in most of analysed terms. SAA, Hp, Fb, and cortisol fluctuations typical for the periparturient period were observed. There were no age-associated differences in red or white blood cell parameters.