The ability of exact determination of genotype of individual pigs in a chosen locus brings about a possibility of studying possible associations between determined genotype and expected production traits. Different stations in the world deal with this issue. In many cases genetic researches are aimed at detection of loci (position, a part of chromosome) that have a statistically significant effect on some of the parameters of efficiency (Dvořák, 1999). The results of their research are mentioned by Kahánková et al. (1996), Fiedler et al. (1999), Cieslak et al. (2000.In addition to relations to reproductive traits a lot of authors specialize in analyses of results of carcass value traits. Aspiration of scientific workstations is an exploitation of determined results in subsequent selection work in individual pig populations.Besides the most frequently studied gene RYR1 there is an effort to use other genes for determination of possible relation with carcass value of pigs. One of them is MYF4 gene, a member of MyoD family, which is responsible for differentiation of proliferous myoblasts and its genetic variability (which is probably related with the number of myofibrils) ranks it among candidate genes. Pietruzska et al. (2002) studied the relation of myogenin to meatiness. In a set of 118 tested pigs they identified 98 animals with AA genotype and 20 pigs with AB genotype. In the set no animal with BB genotype was detected. Meatiness of slaughter pigs with AA genotype reached 53% and it was by 2.3% higher in comparison with AB heterozygotes. Kaniak and Jasek (1999) reported significantly higher meatiness of AA homozygotes in comparison with AB heterozygotes and slight dominance of AA homozygotes over pigs with BB genotype. Kahánková and Dvořák (1998) stated that animals with recessive allele B showed lower meatiness in comparison with AA homozygotes. Kolaříková et al. (2002) studied the influence of myogenin gene polymorphism on meat efficiency in Czech Large White pigs. They found out no significant differences in muscle depth in pigs with BB genotype in comparison with pigs with AA and AB genotype. They did not determine any relation with backfat thickness. In this breed statistically significant differences (P ≤ 0.05) were detected between the genotypes AA and AB in these traits: MLLT area, percentage of main lean cuts and weight of main lean cuts in favour of genotype BB of MYF4 gene. We did not find any significant differences in the measured levels of carcass value traits between different genotypes of MYF4 gene in L breed.

In the present study called “An Ethological Study of Young Horses” we focused on the behaviour of foals from their birth to separation from their mother. We observed and analysed their behaviour and daily activities, and from the achieved results we drew conclusions for practical horse breeding. We studied the following forms of behaviour of the foals: feeding behaviour (sucking, drinking, eating roughage and concentrates, gleaning, coprophagia), defecation and micturition, comfortable behaviour and mutual comfort behaviour, manifestations of relaxation (resting posture, lying down), movement manifestations, playful behaviour, stereotype behaviour, other manifestations (acoustic, olfactory etc).As a result we recommended several changes in the technology, e.g. larger stables, salt-lick out of reach of the foals, more frequent exchange of bedding, shelter for horses grazing in the open.

The aim of the experiment was to analyse reproductive characters in hybrid pig combination (CLW x CL) x (D x Pn). These reproductive traits of sows were studied: number of all, live born and weaned piglets, loses from live born piglets till weaning. These influences with an impact on reproductive characters were monitored: order of litter, number of piglets in a litter, birth weight of piglets, influences of sex and litter order on birth weight of piglets. An average number of all born piglets per sow and litter it was 13.25 piglets. From this an average number of live born piglets it was 12.48 piglets per sow and litter and from each litter there was 11.40 of weaned piglets. The highest number of live born piglets was reached in sows on the fourth litter -14.50 piglets. On eighth and nineth litter fertility decreased to 11.60 and 11.00 piglets. Statistical conclusive difference (P ≤ 0.05) was found between fourth (14.50) and nineth (11.00) litter. Among birth weight in both sexes a statistical conclusive difference (P ≤ 0.05) was found. Higher birth weight (1.46 kg) was found in boars in comparison with gilts (1.40 kg). The highest birth weights in gilts were reached in litters of sows on the second and nineth litters -1.49 kg and 1.48 kg. Birth weight decreased on tenth litter with average weight of 1.28 kg. The highest birth weight in boars was detected on the seventh litter but on the seventh litter piglets of only one sow were weightened so the result 1.67 kg is not objective. The second highest average birth weight was reached on the third litters -1.53 kg. On the contrary the lowest average birth weight was on the fourth and tenth litters where boars reached weight of 1.28 and 1.25 kg. Statistical conclusive difference (P ≤ 0.05) was found between the second (1.53 kg) and tenth (1.25 kg) litter.

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In pure pig breeds used for creation of final carcass hybrids in the Czech Republic a content of intramuscular fat (responsible for marbling) decreased during the process of selection on high meatiness. Duroc breed is mentioned as less affected by this process. The study evaluated 28 animals of Duroc breed, 14 hogs and 14 gilts and chosen traits were compared between sexes. Animals were slaughtered in average weight 102.1 kg with an average lean meat percentage 57.73 (hogs reached 57.61, gilts 57.84%). An average pH1 was measured on a level of 6.11 (hogs 6.07, gilts 6.14 with a statistically conclusive difference among sexes, p ≤ 0.05). PH24 reached values of 5.80 (hogs 5.74, gilts 5.86 with a statistically conclusive difference among sexes, p ≤ 0.01). Determined level of intramuscular fat was 1.67% (hogs reached 1.92% of intramuscular fat, gilts 1.42%). Values of pH1 and pH24 were on a really good level and showed good meat quality without tendency to some meat defect. Level of lean meat percentage corresponds with other authors. Level of an intramuscular fat content was lower than values mentioned by other authors, but close to an optimal level, so it is possible to confirm good quality of actual population of Duroc pig breed in the Czech Republic and recommend this breed for production of final carcass pig hybrids.