The mRNA from distal ileum of Indian goat was cloned and characterized after purification. cDNA was synthesized using goat ileal epithelial RNA, omniscript and sensiscript reverse transcriptase and amplified by Hotstart Taq DNA polymerase with primers designed by taking conserved regions of cattle enteric _Ò-defensin, cattle lingual antimicrobial peptide(LAP) and goat _Ò-defensin-2 sequences. The amplified cDNA of 253bp was, ligated to linearised TA cloning vector and transformed into XLblue strain of E.coli which was grown overnight at 37oC in a LB plate containing ampicillin, IPTG and X-Gal. The recombinant plasmid was isolated and digested with NcoI. The white colonies showed a release of 253bp insert. The sequence analysis showed 26, 16 and 5-nucleotide substitution having 85.6%, 91.3%, 97.4% homology with reported cattle EBD, buffalo EBD and goat BD2 mRNA respectively. The deduced amino acid sequence encodes for a 64 amino acid precursor peptide showing 12,18 and 4 amino acid substitution having 80%, 70.8%, 93.8% homology with buffalo EBD, cattle EBD and goat BD2 peptide respectively. Both nucleotide and amino acid sequence homology showed that the cloned sequence was closer to goat BD2.

In the conditions of the Republic of Belarus there were analyzed indices of impregnating ability and efficiency of stud bull mothers of various genotypes on a kappa-casein gene (CSN3). As a result of genotyping of kappa-casein gene by DNA-diagnostics method it is revealed three genotypes - CSN3АА, CSN3AB, CSN3BB. Frequency of occurrence of homozygous genotype CSN3AA at stud bulls - 87,3%; heterozygotic CSN3AB - 20,5%; homozygous CSN3BB - 1,2%. Statistically authentic difference between these indices depending on a genotype it is not established. Thus, authentic connection between indices of impregnating ability and efficiency of stud bull mothers and their genotype on a locus of a kappa-casein gene that specifies in absence of influence of the last on the given indices is not established and gives the chance to conduct selection on gene CSN3 without decrease in breeding value of stud bulls on reproductive qualities.

In the conditions of the Republic of Belarus there was determined the genetic structure of population of breeding boars, sows, replacement and crossbred stores in accordance with RYR1 gene which was connected with stress resistance. Also, there was analyzed the influence of genetic polymorphism of this gene on meat productivity. In course of the study there was presented a genetic structure of breeds according to gene loci RYR1. There was analyzed the frequency of occurrence of alleles and genotypes in accodance with gene loci RYR1 of breeding boars and replacement stores of different lines. There were showed the indexes of meat productivity and acid capacity of purebred and crossbred stores with different RYR1 gene genotypes. As a result of study there was revealed a rather high level of presence of allele RYR**n in all sex and age specific groups of Belarusian meaty breed (21%) and crossbred stores of Large white x Belarusian meaty breeds (40%). But in the experimental group of three-breed cross breeds (Large white x Belarusian meaty) x Duroc there was not stated the presence of allele of malignant hyperthermia. High level of RYR**n allele presence in populations of meaty breeds and their crossbreeds proved the necessity of obligatory genetic control of pedigree as well as imported animals by means of DNA diagnostic.

In the conditions of Vitebsk region of the Republic of Belarus there was realized a programme on creation of breed type of Hereford cattle. In course of the study there were realized experiments on increasing the number of livestock of beef cattle breeding by means of accumulation cross breeding of black-and-white cattle with Hereford producer bulls as well as by means of pedigree breeding of Hereford cows and calves imported from Russia and Hungary for the production of marbled beef. Breeding background of obtained purebred calves was determined by DNA-testing method in accordance with the international standard of certification. Into the breeding group of created meat type of Hereford cattle in the analyzed cattle breeding enterprise there were selected 1183 heads, including 24,2% of purebred animals and 17,2% hybrids of the third and fourth generations. The breeding estimation thoroughbred Hereford cattle showed that all producer bulls belonged to the class elite-record. The percentage of cows and heifers of the elite-record class was 89,3% in the conditions of growing number of a thoroughbred livestock on 98 heads. Purebred young stock in number of 45 heads and their mother passed the estimation of their origin by DNA method-testing.