Our study was conducted to determine the effect of production factors (breed, sex) and aging time on the textural properties of beef using instrumental measurement of tenderness. Meat was obtained from Galloway, Simmental, Charolais, Czech Fleckvieh breeds and their crossbreeds. Meat was either unaged or aged for 14, 28 or 42 days. The tenderness was characterized by Warner-Bratzler test and compression test using Tira-test device. The cooking loss of meat juice was also evaluated. Analysis of variance at 5% significance level showed that tenderness was influenced by all tested factors (breed, sex, aging time). The shear force decreased with aging of meat. The correlation between shear force and compression test was 0.257 (p ≤ 0.001). The differences in tenderness were found among breeds. The highest initial shear force was measured in Simmental (151.98 N). Compression test showed better tenderness in Czech Fleckvieh and Galloway than in Simmental, Charolais and crossbreeds. Meat from bulls was significantly (p ≤ 0.001) less tender than from heifers. There was a significant (p ≤ 0.001) increase of cooking loss of meat juice during aging from 25.3% after slaughter to 34.0% after aging period. The research results could be useful for determination whether specific cattle breeds can produce tender meat with good aging patterns. According to findings of the current study it is especially necessary to emphasize that factor of aging time exceeded the influence of breed and sex on tenderness. The study also suggests extending of aging period to 6 week to assure tenderness of beef.

The aim of this study was to evaluate the polymorphic effects of two single nucleotide polymorphisms (SNPs) of fatty acid binding protein (FABP4) and stearoyl-CoA desaturase (SCD) genes on intramuscular fatty acid profiles in the longissimus muscle in two cattle breeds. Two previously reported SNPs of bovine FABP4 (7516G>C) and SCD (878C>T) were in turn assessed for their associations with intramuscular fatty acid profiles from the upper sirloin cuts of Aberdeen Angus and Blonde d'Aquitaine cattle. In total, 33 animals were genotyped using PCR-RFLP. Intramuscular fatty acid composition was evaluated using two complementary statistical approaches: a classical univariate regression model and a multivariate approach using a combination of Principal Component Analysis and Random Forests. Significant effect of FABP4

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The effects of inbreeding level on service period (SP) and pregnancy length (PL) were monitored in Holstein and Czech Fleckvieh after the first calving. The levels of inbreeding (F X ) ranged from 1.25 to 25 %. SP and PL of inbred cows were compared with their outbred equals -half-sisters, sharing the same sire (n = 1824) and their first calving happened in the same farm and at the same time (± 3 month). Database with the number of 631 810 animals (year of calving 1985-2004) was used for analyses. Inbred cows were grouped according to F x coefficient (1.5-2.3 %; 3.0-5.0 %; 8.0-12.5 %; 25 %). The GLM with fixed effects (the breed, breeding value of the sire and monitored individual for milk production, year of calving, age at first calving) was applied to all data. The effect of inbreeding depression on SP was more pronounced at higher levels of inbreeding (+2.81; +3.35; +4.53; +8.23 d, respectively according to above mentioned F x groups) but non-significant. Differences in PL (+0.3; +0.32; -0.08 and 1.68 d) were not significant either. Average value of PL for inbred animals was 0.43 d higher. The correlation coefficient was +0.023 for SP and +0.0658 for PL. The F x coefficient increasing by 1 % extends the SP by 0.22 day and PL by 0.063 day. There was a higher variability of SP and PL in inbred cows. The length of calving interval between the first and second lactation is affected more by SP than PL.

Genetic variability of four polymorphisms (CAPN1, CAST, SCD, and FASN) was evaluated and the relationships between them and the beef quality traits (tenderness and fatty acid composition) in Czech crossbred cattle population were assessed. Totally 331 animals were genotyped using multiplex PCR-RFLP. For the CAST NM174003.2:c.155C>T the CC genotype was associated with higher Warner-Bratzler shear force (CC > CT, P < 0.001; CC > TT, P < 0.05) and our results (CC > TT > CT) suggest a possible effect of overdominance. The CAPN1 AF252504.2:c.947G>C did not significantly influence the beef tenderness (strongly influenced by misbalance between the genotype frequencies) suggesting the breed specific effect of this marker. Our association study of the SCD AB075020:c.878T>C polymorphism revealed a positive effect of allele C on myristoleic acid content (CC > CT > TT, P < 0.01). The significant influence of FASN AF285607:g.17924A>G on fatty acid profile was confirmed in the content of myristoleic acid (AG > GG, P < 0.05), palmitoleic acid (AA > AG > GG, P < 0.05, P < 0.001), stearic acid (AA > GG, P < 0.05), myristic acid (AG > GG, P < 0.05), and palmitic acid (AG > GG, P < 0.05). Thus in our population the SNPs of FASN and SCD appeared to be useful markers for selection of animals according to the fatty acid profile as well as SNP of CAST for beef tenderness.