The objective of this study was to compare the feeding effects of imported timothy hay, domestic Italian ryegrass silage (IRGS) and IRG dried by hot-air dry system (IRGHDS) under basic total mixed ration (bTMR) on rumination activity, milk production, and milk composition in lactating dairy cows. Eighteen Holstein dairy cows were divided into three groups: control (bTMR + imported timothy hay), treatment 1 (bTMR + IRGS) and treatment 2 (TMR + IRGHDS) groups. The study was conducted over a total period of 24 days, including a 10 days adaptation period and a 14 days main experimental period. The results indicate body weight was not significantly different between the three groups (p>0.05), and rumination time was significantly higher in the treatment 1 group compared with the control group (p<0.001). Milk fat, protein, and lactose were not significantly different between the three groups (p>0.05), however, somatic cell counts were significantly lower in the treatment 1 group compared with the control group (p<0.001). As a result of the economic feasibility analysis, it is expected that feeding TMR using IRGS and IRGHDS will increase profit by 402.8 won/day and 331.4 won/day per cow compared to imported timothy hay. Therefore, IRGS and IRGHDS can be used as substitutes for imported timothy hay in feeding lactating dairy cows.

The objective of this study was to investigate the comparison of feeding a total mixed ration (TMR) containing imported alfalfa hay and TMR containing hot-air dried domestic alfalfa on rumination activity, milk production, and composition in lactating dairy cows. Ten Holstein dairy cows were divided into two groups: control (imported alfalfa hay + TMR) and treatment (hot-air dried domestic alfalfa + TMR) groups. The study was conducted over a total period of 18 days, including a 13-days adaptation period and a 5-days main experimental period. The results indicated no differences in total digestible nutrient and net energy intake between the imported and hot-air dried alfalfa. Body weight was not significantly different between the two groups (p>0.05), however, total feed intake and rumination time were significantly and tendentially higher in the treatment group compared with control group, respectively (p<0.001; p=0.075). Milk yield was not significantly different between the two groups (p>0.05), however, milk fat (kg) and lactose (%) concentration were significantly higher in the treatment group compared with control group (p=0.016; p=0.02). This study confirms that feeding TMR with hot-air dried domestic alfalfa results in no differences of feed intake, rumination activity, and milk productivity. Therefore, it is considered that hot-air dried domestic alfalfa can be used as a substitute for imported alfalfa on lactating dairy cows.

Accurate and rapid detection of antibiotics is critical for protecting human health and the environment. To this end, we report a novel electrochemical sensor for the simultaneous detection of Levofloxacin (LFX) and Tryptophan (TRP) in dairy samples. Outstanding electrocatalytic activity for the oxidation of LFX and TRP is exhibited by the Activated Nanodiamond (AND) and Ti3AlC2 max phase ( Ti3AlC2max) nanocomposite-modified glassy carbon electrode ( Ti3AlC2max AND/GCE) featured in our sensor. High selectivity and sensitivity are achieved by the sensor, with limits of detection (LOD) of 20.47 nM and 0.309 μM for LFX and TRP, respectively. Moreover, strong anti-parasite capacity is demonstrated by the developed sensor, making it an excellent candidate for the establishment of a reliable sensing platform for antibiotic detection. Findings suggest that this novel sensor could serve as a valuable tool for monitoring the content of LFX and TRP in dairy samples and enhancing the safety of these products.

This study divided the area capable of producing domestic forage into grazing pasture, hay production area, and silage crop area, calculated the required area according to the forage production volume, and examined whether self-sufficiency in forage leads to cost savings. When the self-sufficiency rate of forage for dairy cows and Hanwoo is 80%, the improvement in profitability per heaf ranges from 3% to 9%, typically around 5%, which is considered a significant benefit for both corporate and individual businesses. The average profit per ranch is expected to increase about KRW 50 million per year, and the country as a whole is expected to reduce forage costs by KRW 0.9 trillion per year. Recently, efforts are being made by the government and local authorities to cultivate summer forage at the rice fields for improving self-sufficiency in forage feed to stabilize rice supply and demand. Furthermore, it is also necessary to conduct research on reducing the cost of concentrated feed and TMR (Total mixed ration).

Given the recent increases in feed cost, the demand for rice straw has been increasing on dairy farms because it is cheaper than expensive imported forages. Therefore, it is necessary to study the effect of rice straw feeding on the growth and productivity of dairy heifers. This study compared how feeding tall fescue and rice straw affects the growth, age at first calving, and feed cost of heifers. we compared the growth, age at first calving, and feed cost for each group during the breeding period. Body height was higher in the tall fescue-fed group than in the rice straw-fed group (p<0.05). The length of the growing stage was significantly shorter in the tall fescue group than in the rice straw group (p<0.001) and the age at calving also showed a significant reduction in the tall fescue group compared to the rice straw group (p<0.001). However, the feed cost was lower in the rice straw group because of the difference in the unit price of forage (p<0.001). Based on these results, during the growing period, the rice straw group had delays in growth and the age at first calving compared to the tall fescue group, but also had reduced feed costs in the short term.

Background: Reproductive management practices play crucial roles to maximize the reproductive performance of cows, and thus contribute to farm profitability. We aimed to assess the reproductive management of cows currently practiced in the dairy farms in an urban farming system. Methods: A total of 62 dairy farms were randomly selected considering all size of farms such as small (1-5 cattle), medium (6-20 cattle) and large farms (> 20 cattle) from selected areas of Dhaka city in Bangladesh. The reproductive managementrelated parameters viz. estrus detection, breeding method, pregnancy diagnosis, dry cow and parturition management, vaccination and treatment of reproductive problems etc. were obtained in a pre-defined questionnaire during the farm visit. Results: The visual observation method was only used (100.0%; 62/62) for estrus detection irrespective of size of the farms; while farmers observed cows for estrus 4-5 times a day, but only for 20-60 seconds each time. Regardless of farm size, 89.0% (55/62) farms used artificial insemination (AI) for breeding the cows. Intriguingly, all farms (100.0%) routinely checked the cows for pregnancy at 35-40 days post-breeding using rectal palpation technique by registered veterinarian. However, only 6.5% (4/62) farms practiced dry cow management. Notably, all farms (100.0%) provided nutritional supplements (Vit D, Ca and P) during late gestation. However, proper hygiene and cleanliness during parturition was not practiced in 77.4% (48/62) farms; even though 96.7% (60/62) farms treated cows by registered veterinarian for parturition-related problems. Conclusions: While farmers used AI service for breeding and timely check their cows for pregnancy; however, they need to increase observation time (30 minutes/ observation, twice in a day: early morning and early night) for estrus detection, consider dry cow management and ensure hygienic parturition for maximizing production.

This study was performed to investigate immune changes by comparing the proportion and function of immune cells in the blood under high-temperature period and convalescence temperature period in Holstein dairy cows. The experiment was conducted using Holstein dairy cows of five animals per group (60 ± 20 months old, 175 ± 78 non-day) from the National Institute of Animal Science at high-temperature period (THI: 76 ± 1.2) and convalescence temperature period (THI: 66 ± 1.3). Complete blood count results showed no change in the number of immune cells between groups. In the analysis using Flow Cytometry of PBMCs, no significant differences were observed among B cells, Helper T cells, cytotoxic T cells, and γδ T cells between groups. However, there was an increase in Th17 cells producing IL-17a, while Th1 cells decreased during the convalescence temperature period. The results of gene expression analysis using qRT-PCR in PBMCs revealed an increase in IL-10 during the convalescence temperature period, while a decrease in HSP70 and HSP90 was observed. In conclusion, the increased expression of IL-10 and the decrease in HSP expression suggest the possibility of a weak recovery from heat stress. However, the lack of observed changes in B cells, T cells, and other immune cells indicates incomplete recovery from heat stress during the convalescence temperature period.

This study investigated the awareness and consumption behavior of 118 vegetarians and omnivores toward plant-based dairy alternatives. The preference and choice attribute questionnaires were compared. Significant differences were obtained between the two groups when considering the purchase experience, preference, and selection attributes of plant-based dairy alternatives. Vegetarians had more experience purchasing plant-based dairy alternative products. In both groups, environmental and animal protection were the major factors that influenced the highest response rate for purchasing plantbased dairy alternatives. The preference score of vegetarians for plant-based dairy alternative products was high, indicating that vegetarianism had a significant effect on their preference for plant-based dairy alternative products. Analysis of selection attributes revealed that price, product weight, appearance, and manufacturer were considered important by vegetarians, whereas nutritional components and labeling, manufacturing environment, composition of ingredients, and taste and texture were considered more important by the omnivores. Results of this study can be used as basic data for the future development of the fast-growing industry producing plant-based dairy alternative products.

This study examined the feasibility of exporting dairy products from Korea to Vietnam by identifying characteristics of its dairy product market based on results from the analysis of its dairy product market, and surveys on consumers, wholesalers, and retailers. The results from surveys provide characteristics of Vietnam’s dairy product market, the propensity to consume Korean dairy products, and the feasibility of the Korean dairy product exports market. As rapid economic growth and changes in preference result in an expansion of import market in Vietnam, Vietnam’s dairy product market is highly attractive to Korean dairy products. Vietnamese consumers have high confidence in Korean dairy products and are willing to pay a high price for them. Besides, over 200 thousand Koreans are living in Vietnam. This is favorable to Korean dairy products exports. But the success of the Korean dairy products in Vietnam’s dairy product market also depends upon systematic disease controls, the establishment of its brand image, effective quality and sanitation/safety management, and government support. Notably, the economic effects of Korean dairy products exports to Vietnam are 68.7 billion won for a production inducement effect and 297 persons for an employment inducement effect.

본 연구는 2019년부터 2021년 9월까지 수집된 홀스타인 젖소 19,930두의 자료를 수집하였으며, 3 SD (Standard Deviation, SD) 범위에서 벗어나는 이상치를 제외한, 8,675두를 분석에 이용하였다. 자료분석은 Statistical Analysis System (SAS) 9.4 software를 사용하였고, 뒷유방높이, 뒷유방너비, 유방깊이, 유두길이 및 유두둘레의 실측치를 사용하였다. 그리고 뒷유방높이, 뒷유방너비, 유방깊이, 유두길이 및 유두둘레의 실측치와 산차, 305일 유량, 비유단계 및 착유속도의 환경요인의 효과를 추정하였다. 산차와 유량이 증가함에 따라 뒷유방너비, 유두길이 및 유두둘레의 실측치는 유의적으로 증가하는 것으로 나타났으며(p < 0.0001), 비유단계에 따라서 뒷유방너비 및 유방깊이의 실측치는 비유단계가 증가할수록 유의적으로 감소하는 것으로 나타났다(p < 0.0001). 각 환경효과에 따른 유방형질 실측치의 표현형 상관의 결과에서는 뒷유방너비와 유방깊이 실측치가 산차 및 유량수준에 대해 높은 상관을 나타냈으며, 특히, 유방형질 중 유방깊이 실측치와 산차에 대해 -0.40 ~ -0.67로 높은 음(-)의 상관을 보였다. 본 연구 결과로 미루어 볼 때, 유방형질이 유생산에 밀접한 관련이 있는 만큼 중요한 형질로 취급되어야 하며, 이들의 기초연구와 함께 유전적 특성을 구명하는 등 더 많은 연구가 수행되어야 할 것으로 사료된다.

The impact of heat stress (HS) on reproductive performance and its problems in cows remains to be investigated in Bangladesh. The study was, therefore, aimed to evaluate the effect of HS on fertility and reproductive health problems of dairy cows in a selected area of Bangladesh. A total of 1,095 cows from 500 farms were included in this study. The climate-related data were recorded daily basis for every month in a year and temperature-humidity index (THI) values were calculated to determine the level of HS. Concurrently, data on fertility parameters [number of services per conception (NSC), conception rate (CR) and calving to the first service interval (CFSI)], and reproductive problems were collected through a pre-defined questionnaire. The results show that crossbred [Native x Holstein-Friesian, (HF)] cows were more vulnerable (p < 0.05) to a magnitude of HS effects considering physiological parameters of cows [age, body condition score (BCS), parity and milk yield]. Regarding fertility, HS had no effect on NSC, CR and CFSI in both native and crossbred cows (p > 0.05). The findings on the reproductive problems indicate that HS had significant influence on the prevalence of anestrus (χ2 = 21.814, p < 0.05) and retained placenta (χ2 = 24.632, p < 0.05) in cows. Of note, the prevalence of repeat breeding syndrome was 2.5 folds higher in stress condition than in no stress condition. Abortion and dystocia were not influenced by HS. In conclusion, HS does not influence the fertility parameters of cows studied; however, anestrus and retained placenta are likely to occur under HS conditions in cows.

This study evaluated the odor mitigation effect of rice husk biochar addition to the bedded pack dairy barn floor using lab-scale reactors for five days. Rice husk biochar mixed with dairy manure and sawdust mixture at different ratios (5%-addition test unit: adding biochar by 5% of the total solid weight of the mixture, 10%-addition test unit: adding biochar by 10% of the total solid weight of the mixture). Cumulative NH3 and H2S emissions of 10%-addition test unit were reduced by 26% (p< 0.05) and 46% (p = 0.0655), respectively, compared with control. However, 5%-addition test unit did not show NH3 and H2S emission reduction. Further research is needed to determine the appropriate level of biochar addition between 5 and 10%, and to evaluate applicability in the field through economic analysis.

This study investigated changes of milk production in dairy cows intramuscularly injected with drugs containing dexamethasone (DXM). Three types of dexamethasone formulations (Bueunde® (DXM 0.5 mg/mL), Dexason INJ.® (DXM 1 mg/mL) and Dexolone-20 inj.® (DXM 1 mg/mL)) were intramuscularly injected into sixteen healthy dairy cows each. Bueunde® was intramuscularly injected into 8 dairy cows with 5 mg (BED-1) and 10 mg (BED-2) of DXM once a day for 3 consecutive days, respectively. Dexason INJ.® was intramuscularly administered once into dairy cows with 20 mg (DXS-1, n=8) and 40 mg (DXS-2, n=8) of DXM, respectively. Dexolone-20 inj.® was intramuscularly injected once into dairy cows with 20 mg (DXS-1, n=8) and 40 mg (DXS-2, n=8) of DXM, respectively. Milk production (MP) of BED-1 and BED-2 significantly decreased during the drug administration and up to 48-hour post-drug treatment. Compared with the MP before drug administration, the MP of DXS-1 and DXL-1 was meaningfully decreased by 36 and 24-hour post-drug administration, respectively, and that in both DXS-2 and DXL-2 significantly decreased until 48-hour post-drug treatment. In conclusion, it was confirmed that the MP temporarily decreased by 48 hours after administration of DXM to dairy cows.

This study investigated chlorpheniramine maleate (CPM) residues in milk of intramuscularly dosed dairy cows and established the withdrawal time (WT) of CPM in milk. Sixteen healthy Holstein cows were injected with 10 (CPM-1) and 20 mL (CPM-2) of the drug containing 4 mg/mL of CPM, respectively. After administration of CPM, milk samples were collected from all cows at 12 hour intervals for 5 days. CPM residue concentrations in milk were determined using LC-MS/MS. The correlation coefficient of the calibration curve was 0.9956, and the limits of detection and quantification (LOQ) were 0.6 and 1.0 μg/kg, respectively. Recoveries ranged between 98.5-115.0%, and coefficient of variations were less than 10.96%. After treatment, CPM in CPM-1 and CPM-2 was detected below the LOQ in all milk samples at 12 hours. According to the European Medicines Agency’s guideline on determination of withdrawal periods for milk, withdrawal periods of both CPM-1 and CPM-2 in milk were established to 12 hours. In conclusion, the developed analytical method is sensitive and reliable for detection of CPM in milk, and the estimated WT of CPM in bovine milk will contribute to ensuring the safety of milk.

This study was conducted to identify and assess key parameters affecting greenhouse gas emissions and odor intensity at a naturally ventilated dairy farm. Measurement data of greenhouse gases (CO2, CH4, N2O), odorants (NH3 and H2S), and meteorological data (wind speed, temperature, relative humidity, and solar radiation) were posited as the parameters influencing those emissions. Carbon dioxide and methane emissions correlated well to CO2-equivalent emissions and the contribution of carbon dioxide emissions (R2=0.9181) was greater than that of methane emissions (R2=0.8854). Hydrogen sulfide emissions were highly correlated with odor intensity (R2=0.9989), but the contribution of ammonia emissions to odor intensity was not significant (R2=0.0081). No correlation among CO2-equivalent and odor intensity emissions and meteorological parameters was observed. In this study, the relationship between emissions of greenhouse gases and odor intensity in a naturally ventilated dairy barn mainly depended upon carbon dioxide and hydrogen sulfide emissions. The results in this study will be helpful in the mitigation planning of greenhouse gases and odor in animal feeding operations (CFOs).

This study attempted to determine the characteristic features of postpartum dairy cows during their return to estrus. Moreover, it investigated the effects of abnormal ovarian cycles (AOC) on subsequent reproductive performance and the relationship between normal ovarian cycles (NOC) and the blood urea nitrogen (BUN) level postpartum. Incidentally, 56.3% of the Holstein cows and 66.7% of the Jersey cows had NOC, whereas the 43.7% and 33.3% of the Holstein and Jersey, respectively, had AOC. Within 100 days of calving, the cows with AOC had significantly lower rates of artificial insemination (AI) submission as well as pregnancy and a significantly longer interval to first AI, as compared to that in the cows with NOC. Additionally, the cows with NOC had a significantly higher first AI conception rate than that in the cows with AOC. In this study, of the 32 Holstein cows, 8 resumed their ovarian cycle within 20 days of calving, 10 resumed the cycle with 21-40 days of calving, 8 within 41-60 days of calving, while the remaining 6 did not resume their ovarian cycles until 60 days postpartum. Furthermore, the likelihood ratios of incidence of NOC are 0.93, 1.94, and 0.38, respectively, in the groups with BUN levels ＜ 15, 15-19.9, and ≥ 20 mg/ dl. In conclusion, AOC postpartum adversely affects reproductive performance such as AI submission rate, pregnancy rate, interval to first AI and first AI conception rate; moreover, an increase or decrease in the BUN levels beyond 15-19.9 mg/dL leads to the AOC postpartum.

In this study the effect of vitamin C administration on pregnancy rates during summer heat stress in dairy cows was examined. A total of 80 Holstein-Friesian cows were divided into control and treatment groups (n = 40 each). Control group animals were given 10 mL isotonic normal saline, and treatment group, Vitamin C (4 mg/kg) on artificial insemination day (day 0) and 4th, 8th and 12th day post insemination. Pregnancy diagnosis was performed on 30th day post insemination by ultrasonography. Blood samples were randomly taken from 11 animals from each group. Serum P4, GSH, MDA and plasma 8-OHdG levels were determined by using ELISA method. Results showed that 8-OHdG levels were lower in treatment group on day 4, 8 and 12 (p < 0.05) compared with the control group. Similarly, pregnancy rate was higher in treatment group (32.5%) than control (22.5%), respectively. However, MDA, P4 and GSH levels were similar in both groups at 4th, 8th and 12th day. A gradual increase in P4, and MDA levels, and a strong positive correlation between 0, 4th (r = 0.54), 4, 8th (r = 0.59) and 8, 12th (r = 0.51) day was found. Similarly, GSH levels also showed positive correlation at days 0, 4th (r = 0.47) and 4, 8th (r = 0.56). However, a strong negative correlation (r = -0.56) between MDA day 0, and GSH day 8 was found. In conclusion, vitamin C application during insemination period in postpartum cows increases pregnancy rate, and reduces oxidative stress metabolite 8-OHdG levels.

A pregnancy diagnosis is an important standard for control of livestock’s reproduction in paricular dairy cattle. High reproductive performance in dairy animals is a essential condition to realize of high life-time production. Pregnancy diagnosis is crucial to shortening the calving interval by enabling the farmer to identify open animals so as to treat or re-breed them at the earliest opportunity. MicroRNAs are short RNA molecules which are critically involved in regulating gene expression during both health and disease. This study is sought to establish the feasible of circulating miRNAs as biomarkers of early pregnancy in cattle. We applied Illumina small-RNA sequencing to profile miRNAs in plasma samples collected from 12 non-pregnant cows (“open” cows: samples were collected before insemination (non-pregnant state) and after pregnancy check at the indicated time points) on weeks 0, 4, 8, 12 and 16. Using small RNA sequencing we identified a total of 115 miRNAs that were differentially expressed weeks 16 relative to non-pregnancy (“open” cows). Weeks 8, 12 and 16 of pregnancy commonly showed a distinct increase in circulating levels of miR-221 and miR-320a. Through genome-wide analyses we have successfully profiled plasma miRNA populations associated with pregnancy in cattle. Their application in the field of reproductive biology has opened up opportunities for research communities to look for pregnancy biomarker molecules in dairy cattle.

1. 말레이시아는 젖소 유전자원 개선을 위해 다수의 가축 사육 프로젝트를 지원해오고 있다. 그러나 소비자의 유제품 수요가 빠르게 늘어나는 상황에서 이를 충족시키기 위해 유전자 원과 유제품을 수입에 의존하고 있는 상황이다. 2. 이는 낙농산업 분야에서의 낮은 젖소 번식능력과 개체 수, 비구조화된 번식체계, 수입의존 유전자원, 수익성 있는 낙농산업 모델 부재, 현대적인 유전육종기술 한계에 기인한다고 볼 수 있다. 3. 말레이시아는 향후 정책지원을 통해 낙농산업의 효율성 향상을 진행할 것으로 전망되며, 이러한 상황 속에서 우리나라의 우수한 낙농 유전자원 수출을 위해서는 현지 낙농산업 현황과 검역절차에 대한 이해가 필요하다. 4. 말레이시아 젖소정액 검역 통관을 위해서는 포괄적인 검역조건 대응으로 협의를 통한 검역조건 간소화가 필요하며, 수출 지속성 제고를 위해 국제협력사업과의 연계, 현지 에이전트 발굴을 통한 적극적인 참여 유도, 한류 등을 활용한 현지 홍보활동 방안이 있다.

Escherichia coli (E. coli) can easily contaminate the bovine mammary gland; hence, monitoring of bulk tank milk (BTM) samples helps detect mastitis. In this study, we investigated the characteristics of E. coli from BTM of a dairy company. A total of 58 BTM batches were collected from 29 dairy farms of a dairy company, and 40 E. coli were tested in this study. E. coli showed the highest resistance to cephalothin (52.4%), followed by colistin (28.6%), ampicillin (19.0%) and tetracycline (19.0%). However, E. coli showed low resistance from 0% to 9.5% against other 14 antimicrobials. In the distribution of antimicrobial resistant gene, β-lactamases genes blaOXA and tetracyclines-resistant gene tetB were detected in 15 (37.5%) and 2 (5.0) isolates, respectively, and blaTEM, aac (6')-Ib, aac (3)-II, tetA, sul1 and sul2 genes were only detected once in each (2.5%) isolate. The O127 (22.5%) serogroup was the most predominant, but all E. coli isolates were divided into 20 serogroups. The occurrence of antimicrobial-resistant bacterial infection can be problematic as it not only deteriorates the milk quality but also limits the therapeutic choices of antimicrobials in humans. Therefore, continuous monitoring is recommended to track antimicrobial-resistant E. coli in BTM and raw milk.