• Journal of Animal Science and Technology
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• v.64 no.1
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• pp.110-122
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• 2022

The reduction of milk yield caused by heat stress in summer is the main condition restricting the economic benefits of dairy farms. To examine the impact of hyperthermia on bovine mammary epithelial (MAC-T) cells, we incubated the MAC-T cells at thermal-neutral (37℃, CON group) and hyperthermic (42℃, HS group) temperatures for 6 h. Subsequently, the cell viability and apoptotic rate of MAC-T cells, apoptosis-related genes expression, casein and amino acid transporter genes, and the expression of the apoptosis-related proteins were examined. Compared with the CON group, hyperthermia significantly decreased the cell viability (p < 0.05) and elevated the apoptotic rate (p < 0.05) of MAC-T cells. Moreover, the expression of heat shock protein (HSP)70, HSP90B1, Bcl-2-associated X protein (BAX), Caspase-9, and Caspase-3 genes was upregulated (p < 0.05). The expression of HSP70 and BAX (pro-apoptotic) proteins was upregulated (p < 0.05) while that of B-cell lymphoma (BCL)2 (antiapoptotic) protein was downregulated (p < 0.05) by hyperthermia. Decreased mRNA expression of mechanistic target of rapamycin (mTOR) signaling pathway-related genes, amino acid transporter genes (SLC7A5, SLC38A3, SLC38A2, and SLC38A9), and casein genes (CSNS1, CSN2, and CSN3) was found in the heat stress (HS) group (p < 0.05) in contrast with the CON group. These findings illustrated that hyperthermia promoted cell apoptosis and reduced the transport of amino acids into cells, which inhibited the milk proteins synthesis in MAC-T cells.

• Korean Journal of Veterinary Research
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• v.62 no.2
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• pp.18.1-18.8
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• 2022

This study investigated dexamethasone (DXM) residues in the milk from intramuscularly dosed dairy cows and established the withdrawal time (WT) of DXM in milk. Eighteen healthy Holstein cows were injected with 20 (DXM-1) or 40 mL (DXM-2) of a drug containing 1 mg/mL of DXM. After administering DXM, milk samples were collected from all cows at 12-hour intervals for five days. The DXM residue concentrations in milk were determined by liquid chromatography-tandem mass spectrometry. The correlation coefficient of the calibration curve was 0.9966, and the limits of detection and quantification (LOQ) were 0.03 and 0.1 ㎍/kg, respectively. The recoveries were 97.0% to 104.0%, and the coefficient of variations was less than 7.22%. After treatment, DXM in DXM-1 was detected above the LOQ in two milk samples at 36 hours and below the LOQ in all milk samples of DXM-2 at 48 hours. Using the WT calculation program WT 1.4, the withdrawal periods of DXM-1 and DXM-2 in milk were established to be two days. In conclusion, the developed analytical method is sensitive and reliable for detecting DXM in milk. The estimated WT of DXM in bovine milk is shorter than the current milk WT recommendation of three days for DXM in lactating dairy cows.

• Food Science of Animal Resources
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• v.43 no.3
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• pp.383-401
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• 2023

Camel milk has a significant and pivotal role in the diet of people residing in semi-arid and arid regions. Ever since ancient times, marketing of camel milk has remained insignificant due to nonexistence of processing amenities in the camel nurturing areas, hence the utilization of unprocessed camel milk has continuously remained limited at family level by the nomads. Due to the superior medicinal values and health promoting effects, incredible growth in the demand of camel milk and dairy products have been noticed all over the world during last two decades. Such emergence has led dairy industry to provide diversified camel dairy products to the consumers with superior nutritional and functional qualities. In contrast to bovine, very few food products derived from camel milk are available in the present market. With the advancements in food processing interventions, a wide range of dairy and non-dairy products could be obtained from camel milk, including milk powder, cheese, yogurt, ice cream, and even chocolate. In some regions, camel milk is used for traditional dishes such as fermented milk, camel milk tea, or as a base for soups and stews. Current review highlights the processing opportunities regarding the transformation of camel milk into various dairy products via decreasing the inherent functionality that could be achieved by optimization of processing conditions and alteration of chemical composition by using fortification method. Additionally, future research directions could be devised to improve the product quality.

• Journal of Veterinary Clinics
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• v.25 no.4
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• pp.231-235
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• 2008

Various kinds of antibiotic intramammary infusions are used for treatment of bovine mastitis. As antibiotic-resistant bacteria are increased, the therapeutic rate for bovine mastitis is decreased. The goal of this research is to detect significant synergic effects of combination of antibiotics with sulbactam, $\beta$-lactamase inhibitor, on methicilin-resistant Staphylococcus aureus (MRSA). We used 5 strains of MRSA isolated from bovine mastitis with clinical and subclinical signs. All of the bacteria isolated had resistance to oxacillin and showed multi-resistant patterns in the antimicrobial susceptibility tests. Minimal bactericidal concentrations of ampicillin, amoxicillin, cephalexin, ampicillin/sulbactam(2:1), amoxicillin/sulbactam (2:1), and cephalexin/sulbactam (1:1) were measured according to broth microdilution method suggested by National Committee for Clinical Laboratory Standards (NCCLS, M31-A2) to compare the synergic effects of sulbactam combination with each antibiotic alone. Ampicillin and amoxicillin showed synergic antibacterial activity to 4 and 3 respectively in 5 strains of MRSA in combination with sulbactam. This study demonstrates that ampicillin/sulbactam and amoxicillin/sulbactam can be therapeutic choices for mastitis associated with MRSA.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.759-767
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• 2017

Lactophoricin (LPcin), which is a part of proteose peptone isolated from bovine milk, is a cationic amphipathic ${\alpha}-helical$ antimicrobial peptide. Its truncated variants and mutated analogs were designed and their antimicrobial activities were evaluated by using various assays, like broth dilution methods and disk diffusion methods as well as hemolysis assay. Three analogs, LPcin-C8 (LPcin-YK1), LPcin-T2&6W (LPcin-YK2), and LPcin-T2&6W-C8 (LPcin-YK3), which showed better antibiotic activities than LPcin, were selected. Their secondary structures were also characterized by using CD spectropolarimetry. These three analogs of LPcin could be used as an alternative source of powerful antibacterial agents.

• Journal of Dairy Science and Biotechnology
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• v.25 no.2
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• pp.17-20
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• 2007

Bovine lactoferricin(LFcin B) is a peptide of 25 amino acids that originated from the N terminus of bovine lactoferrin, and is characterized as having potent antimicrobial activity against bacteria, fungi, protozoa and viruses. But, direct expression of Lfcin B is lethal to Escherichia coli. For the efficient production of Lfcin B in microorganism, we developed an expression system in which the gene for cationic Lfcin B was fused to an anionic peptide gene, and successfully expressed the concatemeric fusion gene in E. coli. The purified recombinant Lfcin B was found to have antimicrobial activity, as chemically synthesized Lfcin B peptide does.

• 한국유가공학회:학술대회논문집
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• 2007.09a
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• pp.13-20
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• 2007

Bovine lactoferricin(LFcin B) is a peptide of 25 amino acids that originated from the N terminus of bovine lactoferrin, and is characterized as having potent antimicrobial activity against bacteria, fungi, protozoa and viruses. But, direct expression of Lfcin B is lethal to Escherichia coli. For the efficient production of Lfcin B in E. coli, we developed an expression system in which the gene for cationic Lfcin B was fused to an anionic peptide gene, and successfully expressed the concatemeric fusion gene in E. coli. The purified recombinant Lfcin B was found to have antimicrobial activity, as the native Lfcin B peptide does.

• The Korean Journal of Food And Nutrition
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• v.12 no.1
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• pp.7-12
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• 1999

Bovine mastitis was examined by use of the rolling ball viscosity test in Kwang-ju area. Antibiotic sus-ceptibility of isolated pathogens from raw milk was investigated by the disc method. Positive rate of so-matic cell counts (over 500,000 cells/ml) was decreased from 11.1% in 1991∼1993 to 8.0-% in 1995∼1997. Isolated mastitis-causing-pathogens were identified as Staphylococcus sp. (49.7%) Escherichia coki(23.2%) Streptococcus sp. (10.4%) and Bacillus sp(7.2%) Antibiotic susceptibility of isolated pathogens to almost antibiotics was decreased.

• Journal of the korean veterinary medical association
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• v.22 no.10
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• pp.633-637
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• 1986

A total of 1.252 quarters milk sample (998 from 267 cows of 37 herds and 254 of received from dairyfarms) in Chunbuk province were classified as clinical and subclinical group by CMT and RBU test. Of these positive sample, the mastitic agents were isolate

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.5
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• pp.627-631
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• 2006

The objective of this study was to evaluate the association of genetic differences in the bovine leptin gene and milk yield, reproduction, body condition score (BCS), and plasma glucose level in Iranian Holstein cows. In total, two hundred and thirty eight cows were used and genotyped for a restricted fragment length polymorphism at the leptin gene locus. Two genotypes, AA and AB, have been distinguished which have the frequencies of 0.89 and 0.11, respectively. The genotypes were distributed according to the Hardy - Weinberg equilibrium ($x^2$ = 0.733). During the first 12 wk of lactation, milk yield and composition, live weight, BCS and plasma glucose were measured in 50 cows. Data were analyzed based on a repeated measures ANOVA. During this period, milk yield and composition, live weight, BCS and plasma glucose level were similar among the genotypes. The first cumulative 60-d milk yield, 305-d milk yield, days to first breeding, days open and days from first breeding to conception using previous lactation records were also analyzed using Standard Least Square within mixed models. Fixed effects were year, season, parity and age at calving, and sire. For the reproductive traits the cumulative first 60-d milk yield was also added to the model. Animal was fitted as a random effect. A significant association was detected between the RFLP-AB genotype and 305-d milk yield (p<0.05). The first 60-d cumulative milk yield was similar for the two genotypes (p = 0.21) and tended to be higher in the heterozygous cows. The heterozygous genotypes at the above mentioned locus had a trend to better reproductive performance than the homozygous. The results demonstrate that the RFLP B-allele can yield a higher 305-d milk production with a trend to better reproductive performance.