Genomic and conventional breeding values for clinical mastitis

Conventional and genomic breeding values for clinical mastitis were estimated,based on a dataset of 15,905 cows (36,250 lactations) from 10 farms, calving years from 1996 to 2014. The number of genotyped bulls was 2647 and 799 of them had offspring among the surveyed cows. Pedigree consisted of 64,306 individuals. Analyzed trait was defined as the number of incidence of clinical mastitis per standard lactation. Parity was limited from 1 to 7. The highest proportion of mastitis disease was observed in early lactation and decreased with month of lactation, while there was an upswing of diseases with parity. Genetic trend for cows showed a deteriorating tendency for clinical mastitis. From 1992 to 2010 there was a rise in the relative values of breeding values from 88% to 112% (worsening). Relative breeding values of these bulls were on average above 100%. The correlations between classical genomic breeding values and the values were high: 93% for the whole sample, 81% to 48 young genomic bulls without daughters born in years 2011 and 2012

THE INFLUENCE OF MARKERS CSN3 AND ETH10 ON MILK PRODUCTION PARAMETERS IN CZECH PIED CATTLE

V této práci byly sledovány parametry mléčné užitkovosti u 5506 dcer po 37 plemenících českého strakatého skotu. U plemeníků byly zjišťovány genotypy markerů CSN3 a ETH10. Cílem práce bylo zjistit vztah genetických markerů CSN3 a ETH10 ke sledovaným parametrům mléčné užitkovosti. Statisticky významný vztah byl zaznamenán mezi markerem CSN3 a parametry mléčné užitkovosti. Genotyp CSN3 AA byl spojen s vyšší produkcí mléka, bílkovin a tuku a naopak genotyp BB byl spojen s vyšším obsahem bílkovin a tuku v mléce. Zjištěné četnosti alely B a genotypu BB u českého strakatého skotu odpovídají četnostem u plemen simentálského původu a jsou zároveň vyšší, než četnosti uváděné u mléčných plemen, zejména u plemene holštýn. Uvedené výsledky jsou v souladu s poznatky jiných autorů a po ověření na širší populaci plemeníků v rámci granddaughter design je možné tyto poznatky využít ve šlechtění českého strakatého skotu. Dále byl zjištěn statisticky významný vztah mezi mikrosatelitním lokusem ETH10 a obsahem tuku v mléce dcer. Toto zjištění bude vhodné ověřit na rozsáhlejším souboru plemeníků a jejich otců s vyšší variabilitou plemenných hodnot před jeho doporučením k využití ve šlechtitelském procesu. Tato práce vznikla za fi nanční podpory projektů MSM 122200002, MSM 432100001, NAZV QD 0176 a NAZV QF 3020.There were observed milk production parameters in 5506 daughters of 37 Czech Pied cattle sires in our study. Sires were genotyped for markers CSN3 and ETH10. The aim was to fi nd relation between genetic markers CSN3, ETH10 and observed milk performance parameters. The relation between CSN3 genotype and milk production parameters was found to be signifi cant. The effect of CSN3 genotype AA on milk, protein and fat yield and effect of genotype BB on protein and fat percentage was proved. Frequency of allele B and genotype BB in Czech Pied cattle was similar to other Simmental breeds and was also higher than allele frequencies found in Holsteins. These fi ndings also conform with fi ndings in other studies and after verifi cation on larger populations using granddaughter design population structure can be used in breeding programme of Czech Pied cattle. Signifi cant relation was also found between microsatellite marker ETH10 and milk fat content. Further study is needed to prove this fi nding in larger populations of sires and their grandsires with higher genetic variability of their breeding values before considering to implement markers into breeding process. This research was supported by projects MSM 122200002, MSM 432100001, NAZV QD 0176 and NAZV QF 3020

THE INFLUENCE OF MARKERS CSN3 AND ETH10 ON MILK PRODUCTION PARAMETERS IN CZECH PIED CATTLE

V této práci byly sledovány parametry mléčné užitkovosti u 5506 dcer po 37 plemenících českého strakatého skotu. U plemeníků byly zjišťovány genotypy markerů CSN3 a ETH10. Cílem práce bylo zjistit vztah genetických markerů CSN3 a ETH10 ke sledovaným parametrům mléčné užitkovosti. Statisticky významný vztah byl zaznamenán mezi markerem CSN3 a parametry mléčné užitkovosti. Genotyp CSN3 AA byl spojen s vyšší produkcí mléka, bílkovin a tuku a naopak genotyp BB byl spojen s vyšším obsahem bílkovin a tuku v mléce. Zjištěné četnosti alely B a genotypu BB u českého strakatého skotu odpovídají četnostem u plemen simentálského původu a jsou zároveň vyšší, než četnosti uváděné u mléčných plemen, zejména u plemene holštýn. Uvedené výsledky jsou v souladu s poznatky jiných autorů a po ověření na širší populaci plemeníků v rámci granddaughter design je možné tyto poznatky využít ve šlechtění českého strakatého skotu. Dále byl zjištěn statisticky významný vztah mezi mikrosatelitním lokusem ETH10 a obsahem tuku v mléce dcer. Toto zjištění bude vhodné ověřit na rozsáhlejším souboru plemeníků a jejich otců s vyšší variabilitou plemenných hodnot před jeho doporučením k využití ve šlechtitelském procesu. Tato práce vznikla za fi nanční podpory projektů MSM 122200002, MSM 432100001, NAZV QD 0176 a NAZV QF 3020.There were observed milk production parameters in 5506 daughters of 37 Czech Pied cattle sires in our study. Sires were genotyped for markers CSN3 and ETH10. The aim was to fi nd relation between genetic markers CSN3, ETH10 and observed milk performance parameters. The relation between CSN3 genotype and milk production parameters was found to be signifi cant. The effect of CSN3 genotype AA on milk, protein and fat yield and effect of genotype BB on protein and fat percentage was proved. Frequency of allele B and genotype BB in Czech Pied cattle was similar to other Simmental breeds and was also higher than allele frequencies found in Holsteins. These fi ndings also conform with fi ndings in other studies and after verifi cation on larger populations using granddaughter design population structure can be used in breeding programme of Czech Pied cattle. Signifi cant relation was also found between microsatellite marker ETH10 and milk fat content. Further study is needed to prove this fi nding in larger populations of sires and their grandsires with higher genetic variability of their breeding values before considering to implement markers into breeding process. This research was supported by projects MSM 122200002, MSM 432100001, NAZV QD 0176 and NAZV QF 3020

Physiochemical characteristics and fermentation ability of milk from Czech Fleckvieh cows are related to genetic polymorphisms of -casein, -casein, and -lactoglobulin

Objective The aim of the study was to find a possible association between the β- and κ-casein and β-lactoglobulin genotypes and important milk physiochemical and technological characteristics such as acidity, alcohol stability, the contents of some minerals and the parameters of acid fermentation ability (FEA) in Czech Fleckvieh Cattle. Methods Milk and blood samples were collected from 338 primiparous Czech Fleckvieh cows at the same stage of lactation. The genotypes of individual cows for κ-casein (alleles A, B, and E) and β-lactoglobulin (alleles A and B) were ascertained by polymerase chain reaction-restriction fragment length polymorphism, while their β-casein (alleles A1, A2, A3, and B) genotype was determined using melting curve genotyping analysis. The data collected were i) milk traits including active acidity (pH), titratable acidity (TA), alcohol stability (AS); calcium (Ca), phosphorus (P), sodium (Na), magnesium (Mg), and potassium (K) contents; and ii) yoghurt traits including active acidity (Y-pH), titratable acidity (Y-TA), and the counts of both Lactobacilli and Streptococci in 1 mL of yoghurt. A linear model was assumed with fixed effects of herd, year, and season of calving, an effect of the age of the cow at first calving and effects of the casein and lactoglobulin genotypes of β-CN (β-casein, CSN2), κ-CN (κ-casein, CSN3), and β-LG (β-lactoglobulin, LGB), or the three-way interaction between those genes. Results The genetic polymorphisms were related to the milk TA, AS, content of P and Ca, Y-pH and Lactobacilli number in the fresh yoghurt. The CSN3 genotype was significantly associated with milk AS (p<0.05). The effect of the composite CSN2-CSN3-LGB genotype on the investigated traits mostly reflected the effects of the individual genes. It significantly influenced TA (p<0.01), Y-pH (p<0.05) and the log of the Lactobacilli count (p<0.05). Conclusion Our findings indicate that the yoghurt fermentation test together with milk proteins genotyping could contribute to milk quality control and highlight new perspectives in dairy cattle selection