Baltrėnaitė, Lina

The use of genomic information in genetic evaluation has brought about revolutionary change in dairy cattle selection. In a pilot study 200 dairy cows in Lithuania were selected for dairy genomic profiling, including determination of genomic breeding values for traits, such as productive life, fertility, dairy form, somatic cell count (SCS), milk yield, fat amount, fat %, protein amount, protein %. DNA was extracted from blood by chloroform salt method. Genotyping was performed by Igenity SNP panel with multiple markers. Cattle for genomic breeding values were rated in Igenity cattle reference group. High genomic prediction breeding values, varying from 8 to 10 points, in productive life got 23% of tested cows, in milk yield 13%, in fat kg 25.5%, in fat percent 17%, in protein kg 27%, in protein percent 41.5%. Low genomic values varying from 1 to 3, which are desirable in SCS, have been found in 13% of tested animals. Middle genomic values, 5 or 6 points in all traits have been found in 35% of all tested cattle. Average genomic value of dairy cattle bred in Lithuania did not differ from reference group cattle, which reflects genomic values of animals kept in different environments. In Lithuania there are dairy cattle with high genomic prediction breeding values for separate traits, suitable for elite animal selection. Igenity SNP markers identify genetic variations that helps regulate milk yield, protein and fat content, without decreasing fertility. The combined results provide a more complete picture of production potential of animals.

Aim of the study was to investigate polymorphism of bovine kappa casein gene in Lithuanian milk cattle population and to evaluate relation of certain genotypes with milk production traits expressed by genome scores. DNA samples were collected from 189 milk breed cattle reared in Lithuania. DNA was extracted from blood by salt method (Miller et al., 1998). Bovine kappa casein gene polymorphism study was performed by PCR-RFLP method (Soria et al., 2003). After PCR 935 bp fragment was recieved, which was digested with restriction enzymes HaeIII / HindIII and the fragments were separated in the 3% agarose gel, what allowed to identify the kappa casein A, B, E alleles. A allele with frequency 0,72, E allele with frequency 0.05. B allele, which can be used to carry out selection to improve milk processing properties was found 0.23 frequency. Six genotypes were identified: AA, AB, AE, BB, BE, EE at different frequencies. The most common was the AA genotype, which had 49.2 % of the tested animals. EE was least frequently occurring genotype, which had only 0.5% of the tested animals. The biggest influence on the milk processing properties having BB genotipe was found in 2.1% of the cows. Cows with kappa casein AA genotype had the highest genomic scores for milk yield (6.05), observing statistically significant difference between kappa casein AA and AB genotypes (P<0.05); the highest protein amount genomic values had kappa casein BB genotype cows (6.25), the highest protein percent genomic scores had BB and BE genotype cows. Dispersion analysis showed that 2.8 % of milk yield variation expressed by genomic scores, 0.2% of protein amount variation and 3.3 % of protein percent variation (P <0.05) are dependent from kappa casein gene genotype. These results create opportunities to improve the properties of milk processing in Lithuanian dairy cattle population.

Milk manufactoring properties important for cheese and curd yield and quality a lot depends on milk proteins variants that are inherited for individual cows. BB genotype of Kappa casein, Beta casein and Beta lactoglobulins preferred for cheese production, AB and BE genotypes intermediates, AA, AE and EE genotypes least favourable. We have identified A, B and E alleles of Kappa casein with frequencies (A-0,739, B-0,227, E-0,034), A and B alelles for Beta casein with frequencies (A-0,974, B-0,026), A and B alelles for Beta lactoglobulin with frequencies (A-0,439, B-0,561). 40% of tested cows had AB genotype of milk protein Kappa casein, 2.1% BB and 1% BE. 5.3% of cows had AB genotype of Beta casein. No animals had BB genotype of Beta casein. 53.1% had AB genotype and 29.7 % of BB genotype of Beta lactoglobulin. Important BB and AB genotypes and B allele of milk proteins - Kappa casein, Beta casein, Beta lactoglobulin - were found in Lithuanian dairy cattle what indicates possibility for special selection of animals for cheese and curd making.

Tyrimo tikslas – ištirti beta adrenerginio receptoriaus (ADBR₂) geno poveikį galvijų melžimo savybėms: vidutiniam pieno tekėjimo greičiui, aukščiausiai pieno tekėjimo srovei ir melžimo laikui. Šios savybės ypač svarbios sėkmingam automatiniam melžimo procesui. Selekcija pagal genetinius žymenis yra daug tikslesnis metodas nei tradicinė selekcija siekiant gerinti pieninių galvijų melžimo savybes. Yra atrasti keli genai kandidatai, veikiantys melžimo savybes, iš kurių vienas yra ADBR₂ genas. ADBR₂ genas, priklausomai, kokių audinių ląstelėse randamas, koduoja receptorius, atsakingus už raumenų augimą, riebalų atsidėjimą ir laktacijos savybes. Yra žinoma, kad pieno primilžis ir aukščiausia pieno tekėjimo srovė mažėja vykstant alfa adrenerginio receptoriaus stimuliavimui ir didėja vykstant beta adrenerginio receptoriaus stimuliavimui. Įvykus ADRB₂ geno C₁₁A mutacijai ir pasikeitus baltymo molekulėje amino rūgščiai, iš prolino į histidiną pasikeičia ir laktacinės savybės. Tyrimas atliktas 116 pieninių karvių grupėje. DNR išskirta iš periferinio kraujo druskiniu metodu. Genotipavimas atliktas tikro laiko PGR metodu naudojant Tag Man®. SNP pradmenis ir zondus. Tyrimo rezultatai parodė, kad Lietuvos pieniniai galvijai turi tris ADBR₂ geno genotipus – AA, CA ir CC. 2,6 proc. karvių turėjo AA genotipą, 12,8 proc. – CA ir 84,6 proc. – CC genotipą. Laukinio tipo C alelis rastas 0.91 dažniu, A alelis 0.09 dažniu. Melžimo savybės, tokios kaip vidutinis pieno tekėjimo greitis, aukščiausia pieno tekėjimo srovė ir melžimo laikas, buvo geresni karvių, turinčių ADBR₂ AA genotipą (p<0.05). Vidutinis primilžis per dieną taip pat buvo aukštesnis AA genotipą turinčių karvių. Rastas ADBR₂ geno polimorfizmas Lietuvos pieninių galvijų populiacijoje rodo selekcijos galimybes padidinti ADBR₂ geno pageidaujamo A alelio dažnį ir labai pagerinant karvių melžimo savybes.

The use of genomic information in genetic evaluation has brought about revolutionary change in dairy cattle selection. In a pilot study 200 dairy cows in Lithuania were selected for dairy genomic profiling including traits of productive life, fertility, dairy form, somatic cell count, milk yield, fat amount, fat %, protein amount, protein %, milk proteins kappa casein, beta casein, beta lactoglobulin. The IGENITY profile calculates scores for traits using multiple DNA markers. Combined results provide more complete picture of an animal’s production potential. Genotypes were rated in Igenity dairy cattle reference group. High genomic values varying from 7 to 10 points in productive life got 34 % of tested cows, in somatic cell count 42 %, in milk yield 48 %, in fat 34 %, in protein 68 %. There are several forms of kappa casein – A, B and E – that are associated with milk protein and quality. These variants are important for cheese production. The E variant has an adverse effect on cheese production. Like kappa casein, there are several different forms of beta casein. Higher milk yield is associated with the A variant while higher protein and casein yields are associated with the B variant. Beta lactoglobulin B variant has a significant effect on casein number and cheese yield. 38 % of tested cows had AB genotype of kappa casein, 2 % BB and 1% BE. 7 % of cows had AB genotype of beta casein, 29 % AB genotype of beta lactoglobulin and 19 % of BB genotype.

Milkability traits are very important for automatic milking of dairy cows. Marker asssited selection is a new and more accurate tool than traditional selection in dairy cattle breeding that can be used for improvement of milkability traits. There are few candidate genes for milkability traits being one of them beta-adrenergic receptor (β2-AR). β-AR are metabotropic G protein-coupled receptors that responsible for the muscle growth, fat deposition or lactation characteristics of domestic animals. It is reported that milk yield and peak flow rate decreased during α-AR stimulation and during the oxytocin receptor blockade and increased during β-adrenergic stimulation. So if nucleotide mutation take place in β-AR gene, the lactation performance of dairy cattle would be influenced. However, there is little information about polymorphisms of β-AR gene in cattle at present [1]. The aim of this study was to investigate influence of β2-AR gene on cattle milkability traits by real time PCR. The results revealed 3 genotypes with the frequencies of AA - 2.6 %, CA – 12.8 , CC – 84.6 % and 2 alleles C and A. The wild-type allele C was ascendancy with the frequency 0.91, A – 0.09. Milkability traits such as average flow rate and peak flow were significantly higher in cows with genotype AA comparing to CC genotype cows (p<0.05), while milking time lower in cows with AA genotype, indicating cows with AA geotype more suitable for automatic milking procedures. The average milk yield per day was also higher in cows with β-AR gene AA genotype.

In a pilot study 200 dairy cows in Lithuania were selected for dairy genomic profiling including traits of productive life, somatic cell count, milk yield, fat amount, fat %, protein amount, protein %, milk proteins kappa casein, beta casein, beta lactoglobulin. The IGENITY profile calculates scores for traits using multiple DNA markers. High genomic values varying from 8 to 10 points in productive life got 23% of tested cows, in milk yield 13%, in fat kg 25.5%, in fat. The use of genomic information in genetic evaluation has brought about revolutionary change in dairy cattle selection. In a pilot study 200 dairy cows in Lithuania were selected for dairy genomic profiling including traits of productive life, fertility, dairy form, somatic cell count, milk yield, fat amount, fat %, protein amount, protein %, milk proteins kappa casein, beta casein, beta lactoglobulin. The IGENITY profile calculates scores for traits using multiple DNA markers. Combined results provide more complete picture of an animal’s production potential. Genotypes were rated in Igenity dairy cattle reference group. High genomic values varying from 7 to 10 points in productive life got 34 % of tested cows, in somatic cell count 42 %, in milk yield 48 %, in fat 34 %, in protein 68 %. There are several forms of kappa casein – A, B and E – that are associated with milk protein and quality. These variants important for cheese production. The E variant has an adverse effect on cheese production. Like kappa casein, there are several different forms of beta casein. Higher milk yield is associated with the A variant while higher protein and casein yields are associated with the B variant. Beta lactoglobulin B variant has a significant effect on casein number and cheese yield. 38 % of tested cows had AB genotype of kappa casein, 2 % BB and 1% BE. 7 % of cows had AB genotype of beta casein, 29 % AB genotype of beta lactoglobulin and 19 % of BB genotype.

In a pilot study 200 Holstein cows in Lithuania were selected for dairy genomic profiling (Igenity SNP panel) - productive life, fertility, dairy form, somatic cell count, milk, fat, fat %, protein, protein %. Markers for coat color, cheese important proteins – Kappa Casein, Beta Casein, Beta Lactoglobulin, and heritable diseases – BLAD, DUMPS and CVM were tested. Genotyping was performed by Igenity SNP panel. 19.5 % of tested cows had B allele of Kappa casein. 12 % of cows had BB genotype of Beta Lactoglobulin, 26.5 % AB genotype of Beta Lactoglobulin. No cows with DUMPS have been found, but 1 carrier of BLAD allele and 2 carriers of CVM were detected which gives us indication of having carriers of genetic diseases in cow population causing calf death. 15 to 11 % of tested cows had high genomic values in different traits rating in Igenity dairy cattle reference group. Genomic profiles have been rated by Igenity software giving different value for traits: 25 % for milk kg, 15 % for milk fat, 15% milk protein, 15% somatic cell count, 15 % for longevity, 15% dairy form. Economic effects have been calculated for rated genomic values for each cow.

Parodomojo bandymo genominei selekcijai diegti pieninės krypties ūkiuose vykdymo metu 200 pieninių galvijų nustatytas "pieninio galvijo genominis profilis" pagal pieningumo, pieno baltymingumo, riebumo, somatinių ląstelių kiekio, pieninės formos ir produktyvaus amžiaus genetinius žymenis. DNR profilis skaičiuoja pieningumo, pieno riebumo ir baltymingumo taškus naudojant daugybinius DNR žymenis. Žymenys atpažįsta tuos genetinius variantus, kurie nemažina vasingumo. Šie kombinuoti rezultati duoda geresnę informaciją apie gyvulio produktyvumo genetinį potencialą. Bandymo metu papildomai buvo ištirti kūno dangos spalvos, pieno baltymų, svarbių sūrių ir varškės produkcijai – Kap kazeino, Beta kazeino ir Beta laktoglobulino bei paveldimų recesyvinių ligų – BLAD, CVM ir DUMPS genetiniai žymenys. Genotipavimas atliktas lgenity SNP metodu. 19,5% tirtų karvių turėjo Kapa kazeino B alelį, 12% tirtų karvių BB ir 26,5% AB Beta laktoglobulino genotipą. Nei viena karvė nebuvo letalaus recesyvinio DUMPS geno nešiotoja, tačiau rasta viena karvė BLAD geno, sukeliančio letalų leukocitų sukibimo nepakankamumą, ir dvi karvės CVM geno, sukeliančio letalų fermento trūkumą, nešiotojos. [...].

Insulino augimo faktorius (IGF-1) yra susijęs su keliais ekonominiu požiūriu svarbiais ypatumais, būtent su galvijų augimu ir vystymusi. Šio darbo tikslas – ištirti insulino augimo faktoriaus geno polimorfizmą ir nustatyti jo įtaką galvijų augimo spartai. Insulino augimo faktoriaus geno polimorfizmas nustatytas PGR-RFIP metodu, naudojant Sna BI restrikcinį fermentą. Galvijų IGF-1 geno A alelis rastas 0,471 dažniu, o B alelis – 0,529 dažniu. A alelis didžiausiu dažniu (0,708) rastas Lietuvos juodmargių veislėje, o B alelis (0,711) – Limuzinų veislėje. Sugrupavus veisles į mėsinių ir pieninių galvijų veisles, nustatyta, kad IGF-1 geno A alelio dažnis kito nuo 0,368 mėsinių galvijų veislėse iki 0,676 pieninių galvijų veislėse. Tuo tarpu B alelio dažnis kito nuo 0,324 pieninių galvijų veislėse iki 0,632 mėsinių galvijų veislėse. Galvijų IGF-1 geno AA genotipas rastas 0,235 dažniu, AB genotipas – 0,471 dažniu, o BB genotipas – 0,294 dažniu. AA genotipas didžiausiu dažniu (0,500) rastas Lietuvos juodmargių veislėje, AB – Šarolė veislėje (0,533) ir BB – Limuzinų veislėje (0,474). Nustatyta, kad statistiškai reikšmingai IGF-1 geno BB genotipo mėsiniai galvijai pasižymėjo didžiausiu priesvoriu 122.7 g p < 0,05 per visą penėjimosi laikotarpį lyginant su pieninių veislių galvijais.