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.

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).

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.

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 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.

The objective of the present study was to determine the best model to describe and quantify the changes in live body weight, height at withers, height at rump, body length and chest girth of Holstein cows raised under Korean feeding conditions for 50 months. The five standard growth models namely polynomial linear regression models, regression of growth variables on the first and second-order of ages in days (model 1) and regression of growth variables on age covariates from first to the third-order (model 2) as well as non-linear models were fitted and evaluated for representing growth pattern of Holstein cows raised in Korean feeding circumstances. Nonlinear models fitted were three exponential growth curve models; Brody, Gompertz, and von Bertalanffy functional models. For this purpose, a total of 22 Holstein cows raised in Korea used in the period from April 2016 to May 2020. Each model fitted to monthly growth curve records of dairy cows by using PROC NLIN procedure in SAS program. On the basis of the results, nonlinear models showed the lower root mean square of error (RMSE) for live body weight, height at withers, height at rump, body length and chest girth (12.22, 1.95, 1.55, 4.04, 2.06) with higher correlation coefficiency (R2) values for live body weight, height at withers, height at rump, body length and chest girth (0.99, 0.99, 0.99, 1.00, 1.00). Overall, the evaluation of the different growth models indicated that the Gompertz model used in the study seemed to be the most appropriate one for standard growth of Holstein cows raised under Korean feeding system.

The present study was designed to determine the effect of barn or cycle of grazing on changes of biochemical metabolites in prepartum and changes of milk composition in postpartum of dairy cows. For this purpose, a total of sixteen 25 months old Holstein primiparous dairy cows were allocated in two groups (n=8) with an average body weight of 571.61 ± 35.30 kg (Barn) and 578.10 ± 39.20 kg (Grazing). The study was conducted from June 2018 to October 2018. Results revealed that barn raised dairy cows had a higher increase in their serum albumin and calcium level on day 14 prepartum. However, the level of palmitic acid, saturated fatty acid increased significantly, and the level of fat, oleic acid, γ-linoleic acid, arachidonic acid and unsaturated fatty acids decreased significantly in barn raised dairy cow’s milk on day 14 postpartum. There were no significant differences observed with respect to all other biochemical metabolites, fatty acids and minerals between barn raised and cycle grazing dairy cows during prepartum and postpartum. Our study results could serve to a better understanding of barn raised cow with respect to changes of biochemical metabolites in prepartum and changes of milk composition, fatty acids and minerals content in grazing dairy cows in postpartum for estimating their physiological status.

In this study, the effect of daily short-distance walking exercise on milk production and metabolic status of the lactating dairy cows was investigated. The experiment was conducted with 10 lactating dairy cows comprising 2 groups (5 dairy cows/group), which were walking activity and non-walking activity. The walking activity (WA) group lactating dairy cows walked outdoors for 1 km/d, and the non-walking activity (non-WA) lactating dairy cows were maintained within a cowshed from 18thApril to30th May. The activity volume of the neck was not significantly different between the groups, but the activity volume of the leg was higher in WA group compared with non-WA (p<0.05). The rectal temperature was higher in the WA group (38.6 ℃) compared with non-WA (38.2 ℃) (p<0.05). No significant differences in dietary NE intake, milk production and milk composition were found between the groups. The plasma cortisol concentration was higher in WA group (2.14 μg/dl) compared to non-WA (0.95 μg/dl) (p<0.05). However, plasma cortisol level of WA dairy cows was significantly decreased as compared with non-WA cows. On the contrary, the level of plasma melatonin was increased in WA cows than that of non-WA dairy cows. It may be interpreted as a change in physical fitness. From this study, we suggest that walking activity can be improved energy balance. Further investigation is needed to determine whether different combinations of distance, rate or doing in morning or afternoon will stimulate energy balance.

The purpose of the present study was to determine the elaborate characteristics of ovarian changes including follicles and corpus luteum, and hormonal patterns of gonadotropin surge mode secretions during the normal consecutive estrous cycle in three dairy cows. Non-lactating and multiparous Holstein cows (n=3) used as experimental animals. The cows were assigned to examine the relationship among ovarian changes (follicle, corpus luteum), ovarian steroids (estradiol, progesterone) and gonadotropin (LH, FSH) surge mode secretion during the successive estrous cycles by rectal palpation, ultrasonography and hormonal assay. The mean length of the estrous cycle for the three cows was 23.1 ± 1.44 days (± SEM), with a range of 20-28 days. In six estrous cycles, the number of two follicular waves, three follicular waves and four follicular waves was 2, 3 and 1, respectively. The sequential ultrasonographic monitoring showed that the corpus luteum with ≥ 10 mm in diameter detected from Day 2 (Day 0 is ovulation) in six estrous cycles of all cows. Preovulatory increases in estradiol concentration reached 10.36 ± 1.10 pg/ml on the 2 days before ovulation of the last dominant follicle. All cows exhibited a preovulatory rise in estradiol concentration followed by a typical preovulatory LH and FSH surge. The mean interval from the peak of LH/FSH surge to ovulation of the last dominant follicle was 31.3 ± 1.76 h (± SEM). In these results, each dairy cow showed that ovarian morphological changes and gonadotropin surge mode secretion will be regulated by various environmental factors including age, breeds, nutrition, breeding conditions, etc.

The main objective of this experiment was to investigate effects of two different feeding systems on body weight, milk yield, milk composition, and mineral and fatty acids content of Holstein dairy cows’ milk. Sixteen of 25 months-old Holstein dairy cows were assigned to two groups (n=8) to study effects of the feeding system for 150 days. Two feeding systems were compared for five months; Group 1 was housed indoors and mainly fed a concentrate diet, Group 2 was maintained outdoors for five-seven hours/day on various kinds grass in a pasture. The experiment was conducted June-October 2017. Results revealed the indoor-fed cows had higher body weight, that was significant compared with the outdoor-based feeding system of Holstein dairy cows (p<0.05). Indoor-raised milking cows had higher milk yield (32.45 kg) as compared with pasture-raised milk yield (26.44 kg). Cows fed indoors significantly increased milk yield, total protein content, lactose, citric acid level, and lowered level of total solid and free fatty acids relative to the pasture-fed milking cows (p>0.05). There were higher levels of mineral content and fatty acid content in the milk of indoor-fed dairy cows than the pasture-raised dairy cows (p>0.05). Our study results demonstrated the potential benefits of the indoor feeding system for increased body weight, milk yield, mineral and fatty acids content summer through autumn when low pasture growth rates and quality may otherwise limit production.

A diverse of recommendation has been made for the structure and management of dairy cows, despite demanding research, the relationship between lactation number and various factors is yet to be established. The present study was aimed to investigate the covariance among lactation number, growth performance, calving interval, and milk production was considered to increase an efficiency of selection schemes and to manage more efficiently Holstein dairy cows that have been raised on small-scale family farms in Republic of Korea. For that purpose, the data were observed from 850 Holstein dairy cows, which a total of 3929 milking, since April 2016 - January 2017. We measured the body weight, height, age, calving interval, and milk production of the each dairy cow. Also, information about the date of lactation, calving interval, and milk production was recorded using an automatic milking system(AMS) with identification numbers. Milk production was calculated per udder quarter in the AMS. Our study results showed the increased average body weight(p>0.05) in 1, 2, 3, and 4th lactating dairy cows and afterwards, we noticed the tendency on the average body weight(p<0.05) per lactation progressed. There was no significant difference noticed on height measurement of dairy cows. From the processing data of 850 Holstein dairy cows, the lactation number 1 and 7 had a greater calving interval with significantly lowered milk production, and the lactation number 2, 3, 4, 5, and 6 had significantly lowered the calving interval(p<0.05) with a greater milk production. From our study results, we evidenced that there is a significant relationship between the lactation number, growth performance, calving interval, and milk yield, and the maximum production of milk occurring in the 3rd and 4th lactation dairy cows. The achieved results from this study can be used by the small-scale farmers to encourage the structure and management of growth performance, calving interval, and milk yield in Holstein dairy cows in Korea.

This study was conducted to examine the effect of corn (Zea mays L.) - soybean (Glycine max L.) silage prepared by intercropping method on the nutritive value of the silage, in vitro rumen fermentation characteristics, dry matter degradability, as well as milk yield and milk composition of dairy cows. In a couple of experiments intercropped corn-soybean silage (CSBS) was compared with corn silage (CS) and/or Italian ryegrass hay (IRG). Numerically, CSBS had higher crude protein, ether extract, and lactic acid contents compared to CS. In vitro rumen fermentation analysis demonstrated that up to a 24-h incubation period, both CS and CSBS showed higher total gas production, ammonia N concentration, and dry matter degradability compared to IRG (p<0.05). The investigation on animals was conducted in a commercial dairy farm located in Gyeongju, South Korea, employing 42 Holstein cows that were divided into 2 group treatments: CS and CSBS in a completely randomized design. Although no significant difference was observed in milk yield, animals fed on CSBS showed significantly higher milk protein (p<0.05) and milk fat content (p<0.01), compared to animals fed on CS. Taken together, our findings indicate that corn-soybean silage that is cultivated, harvested, and prepared through intercropping can improve the protein content of the silage, and can also enhance in vitro rumen fermentation, dry matter degradability, and performance of dairy cattle.

This study investigated the synergistic effects of a combination of cephalexin and gentamicin (CCG) against Streptococcus spp. isolated from bovine milk. Minimum inhibitory concentrations (MICs) and fractional inhibitory concentration (FIC) index were determined for 12 bacteria isolated from 12 bovine farms in Gyeongnam province. The MIC ranges of cephalexin, gentamicin and CCG were 0.25-0.5, 0.5-2.0 and 0.06-0.125 μg/mL, respectively. In addition, the FIC index range of CCG against the isolates was 0.32-0.34, showing a synergistic effect in the checkboard assay. In conclusion, CCG has a high antibacterial activity against Streptococcus isolates and may be utilized in the treatment of bovine streptococcal mastitis.

This study determined diagnostic threshold of polymorphonuclear cells (PMN) for cytological endometritis (CEM) and its impacts on reproductive performance in dairy cows. Uterine cytology using 407 Holstein cows was performed at 4 weeks postpartum and proportion of endometrial cells and PMN was evaluated. A receiver operating characteristics curve was built to assess the cutoff level above which the PMN proportion affected the hazard of pregnancy by 200 days postpartum. The cutoff level for CEM was set at ≥14% PMN (sensitivity = 31.3%, specificity = 81.7%, P < 0.05). Cows with CEM had a lower probability of resumption of cyclicity (OR = 0.58 P < 0.05) and lower hazard of pregnancy by 200 days postpartum (hazard ratio = 0.58, P = 0.0001) than cows without CEM. Cows with CEM tended to have a lower probability of pregnancy to the first insemination (OR = 0.65, P < 0.1) and a greater number of insemination per conception (2.3 vs 2.2, P < 0.1) than cows without CEM. In conclusion, the threshold level of PMN was 14% to define CEM at 4 weeks postpartum and CEM decreased subsequent reproductive performance in dairy cow

This study aimed to investigate the effects of Dandelion (Taraxzcum coreanum) supplementation on milk yield, milk composition and blood characteristics in lactating dairy cows. Eight lactating dairy cows were divided into two groups (control: TMR supplementation, treatment: TMR with Dandelion supplementation). The milk yield, milk fat, lactose, solids not fat (SNF) and somatic cells counts (SCC) were not significantly different between the control group and the treatment group, whereas milk protein, milk urea nitrogen (MUN) and free fat acid (FFA) were significantly higher in the treatment group compared to the control (p<0.05). The blood components of the treatment group were compared with those of the control group and only aspartate aminotransferase (AST) appeared significantly high (p<0.05). The other blood components were not significantly different in the two groups. Blood corpuscle components in the groups were not significantly different. Especially, all blood corpuscle components in the treatment group were within the normal range. However, the white blood cells (WBC), lymphocytes (LYM) and hematocrits (HCT) in the control group exceeded the normal range. Based on the above results, the addition of Dandelion to feed increased milk protein, MUN and FFA, but did not significantly affect the composition of the blood and corpuscle in Holstein milking cows.