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Cheese production is a complex process that is influenced by many factors: protein:fat ratio, acidity, and type of rennet. An option for improving the profitability of the cheese industry is the genetic selection of dairy cows to produce milk with good rennet protein coagulation. The object of the study is the technology of cheeses made from milk from cows with different β-casein genotypes (А1А1, А1А2, А2А2). The subject of the study is the physical-chemical parameters of milk from cows with different genotypes for β-casein; yield of cheese from this milk and its quality indicators. Samples of Gouda cheese were produced according to traditional technology. The research established that the quality indicators of milk samples are typical for fresh cow's milk. The content of fat, protein, and dry matter in the milk of cows with the β-casein genotype A2A2 were slightly higher compared to A1A1 and A1A2. The study of the quality indicators of the cheese samples showed that the type of β-casein did not affect the organoleptic properties of the cheese. However, according to the content of the main chemical components, cheeses made from A1A2 milk had a higher content of dry matter and protein (61,6 % and 19,2 % on average, respectively) and a lower fat content (37.2 %). The amino acid profile of cheese from milk of cows with β-casein A1A2 and A2A2 genotypes showed a higher total content of amino acids – 14.89 mg/g and 13.84 mg/g, respectively. Calculations of cheese yield showed that cheese yield from milk of cows with β-casein genotype A1A2 was higher (mean value 13.1 %) than with A1A1 and A2A2. The obtained results are of practical importance, as it is possible to take into account how changes in the β-casein genotype in milk can affect the yield of cheese, and therefore, the profitability of production. [ABSTRACT FROM AUTHOR]

The study of polymorphism of beta-casein genes CSN2 and kappa-casein CSN3 in cows of Brown cattle, Simmental breed, Black and White cattle has been carried out with the use of polymerase chain reaction in real time. It is shown that the frequency distribution of CSN2 / CSN3 composite genotypes differs significantly in different breeds: Brown cattle - 22.0 А1А2/AB, 22.7% А2А2/AB and 22.0% А2А2/BB; Simmental - 26.8% А1А2/AB; А2А2/AF, 22.0%, А2А2/AB 19.5%; Black and White cattle - 26.9% А1А2/AA; А1А1/AB, 23.1%, А2А2/AA 23.1%. The obtained results indicate the prospects of breeding work concerning the formation of herds (micropopulations) by the A2A2/BB composite genotype, which is only possible among Brown breeds. This makes it possible to increase the effectiveness of measures to preserve the population of Brown cattle by improving the quality of their milk. [ABSTRACT FROM AUTHOR]

The authors investigated the possibility of using modern biotechnological methods for obtaining in vitro embryos from females of the local breed with the desired complex genotype by the A2A2/BB beta- and kappa-casein, cryopreservation and long-term storage in the system of preserving the gene pool. During the first stage of work, 27 oocytes-cumulus complexes (OCCs) were obtained from the ovaries of heifers, of which 66.7% were selected as suitable for in vitro cultivation, and from the ovaries of cows - 69.2% of oocytes-cumulus complexes (45 of the 65 obtained oocytes-cumulus complexes) were suitable for further cultivation. Our cytogenetic analysis of heifer egg cells showed that 33.3% (9 out of 27 cultured oocytes-cumulus complexes) of cells were at the metaphase II stage of meiosis, and 66.7% had chromosomal disorders. The second stage involved the fertilization of egg cells matured outside the body. During this stage, it was found that the level of zygote formation on average reached 23.8%, and further cultivation also provided in vitro fragmentation of embryos at the level of 22.2% (10 embryos from 63 inseminated eggs). It was found that the overall level of embryo formation after fertilization of egg cells of cows matured outside the body was 33.3%. For the conservation and rational use of breeding (genetic) resources of cattle at the cellular level, it is necessary to create cryobanks of gametes for long-term storage in order to further sell them for reproduction. [ABSTRACT FROM AUTHOR]

Genotyping of 47 stud bulls of Brown breeds was carried out by the gene CSN3. The results of scientific studies indicate that both Brown purebred and cross-breed cattle bred in Ukraine are characterized by a significant difference in the frequency of genotypes by this trait. The genetic equilibrium established by us corresponds to the global trends of breed populations. The creation of the desired micro-populations with the desired homozygous BB genotype by kappa-casein makes it possible to improve the quality of milk as a raw material for milk processing enterprises specialized in cheese making. Therefore, the increased frequency of the BB genotype by kappa-casein may contribute to the preservation and distribution of Brown cattle in Ukrainian farms. [ABSTRACT FROM AUTHOR]

In order to study the effect of sex and pre-slaughter weight on the performance of Irish Landrace pig carcasses, 400 pigs with equal number of barrows and gilts were selected and fattened. After fattening, the pigs were divided into two groups according to sex. Then, 20 gilts were selected using weighing into 4 groups with a pre-slaughter weight 90 kg, 100 kg, 110 kg and 120 kg. Similarly, 20 barrows were divided for 4 groups with same pre-slaughter weight 90 kg, 100 kg, 110 kg and 120 kg. All gilts and barrows from eight experimental groups were slaughtered and their carcasses were measured and then sampled to determine slaughter parameters. It was found that in general, gilts had higher carcass weight at pre-slaughter weight 90, 110 and 120 kg, higher chilled carcass weight at preslaughter weight 120 kg, higher carcass length and length of bacon halves at pre-slaughter weight 120 kg, higher thickness of longest back muscle and meat content at pre-slaughter weight 100 kg. Barrows had a higher fat thickness above the 6-7 thoracic vertebrae, the fat thickness in the buttocks, the fat thickness in the withers at preslaughter weight 100 kg. [ABSTRACT FROM AUTHOR]