Preparation of Nanoemulsions of Vitamin A and C by Microfluidization: Efficacy on the Expression Pattern of Milk-Specific Proteins in MAC-T Cells.

In this study, we prepared stabilized vitamin A and C nanoemulsions, and investigated their efficacy on milk-specific proteins in bovine mammary epithelial cells (MAC-T). Emulsions of vitamin A (vit-A) and C (vit-C) were prepared using Lipoid S 75 and microfluidization. The particle size and polydispersity index (PDI) of nanoemulsified vit-A and vit-C were studied. The cytotoxic effect of nanoemulsion-free and nanoemulsified vit-A and vit-C was determined by an MTT assay. In addition, the efficacy of nanoemulsified vit-A and vit-C on the in vitro expression pattern of milk-specific proteins in MAC-T cells was investigated by quantitative RT-PCR. The results showed that the efficacies of stabilized nanoemulsions of vit-A and vit-C were 100% and 92.7%, respectively. The particle sizes were around 475.7 and 225.4 nm, and the zeta potentials were around -33.5 and -21.3 mV, respectively. The expression changes of αs2-, ß- and κ-casein were higher in the presence of a stabilized nanoemulsion of vit-A, compared with nanoemulsion-free vit-A. Furthermore, the expression changes of αs2- and ß-casein were lower and that of κ-casein was higher in the presence of a stabilized nanoemulsion of vit-C, compared with nanoemulsion-free vit-C. Thus, our findings demonstrate the efficacy of nanoemulsified vit-A and vit-C in changing the expression of milk-specific proteins in MAC-T cells.

The effect of nanoemulsified methionine and cysteine on the in vitro expression of casein in bovine mammary epithelial cells.

OBJECTIVE: Dairy cattle nutrient requirement systems acknowledge amino acid (AAs) requirements in aggregate as metabolizable protein (MP) and assume fixed efficiencies of MP used for milk protein. Regulation of mammary protein synthesis may be associated with AA input and milk protein output. The aim of this study was to evaluate the effect of nanoemulsified methionine and cysteine on the in-vitro expression of milk protein (casein) in bovine mammary epithelial cells (MAC-T cells). METHODS: Methionine and cysteine were nonionized using Lipoid S 75 by high-speed homogenizer. The nanoemulsified AA particle size and polydispersity index were determined by dynamic light scattering correlation spectroscopy using a high-performance particle sizer instrument. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to determine the cytotoxicity effect of AAs with and without nanoionization at various concentrations (100 to 500 µg/mL) in mammary epithelial cells. MAC-T cells were subjected to 100% of free AA and nanoemulsified AA concentration in Dulbecco's modified Eagle medium/nutrient mixture F-12 (DMEM/F12) for the analysis of milk protein (casein) expression by the quantitative reverse transcription polymerase chain reaction method. RESULTS: The AA-treated cells showed that cell viability tended to decrease (80%) in proportion to the concentration before nanogenesis, but cell viability increased as much as 90% after nanogenesis. The analysis of the expression of genetic markers related to milk protein indicated that; αs2-casein increased 2-fold, κ-casein increased 5-fold, and the amount of unchanged ß-casein expression was nearly doubled in the nanoemulsified methionine-treated group when compared with the free-nanoemulsified methionine-supplemented group. On the contrary, the non-emulsified cysteine-administered group showed higher expression of genetic markers related to milk protein αs2-casein, κ-casein, and ß-casein, but all the genetic markers related to milk protein decreased significantly after nanoemulsification. CONCLUSION: Detailed knowledge of factors, such nanogenesis of methionine, associated with increasing cysteine and decreasing production of genetic markers related to milk protein (casein) will help guide future recommendations to producers for maximizing milk yield with a high level of milk protein casein.

Effects of supplementing Barodon, Bacillus subtilis, and Ampbio on growth performance, biochemical metabolites, and hormone levels in Korean native heifers.

An experiment was conducted to evaluate the effects of supplementing feed additives of Barodon®, effective microorganism® (Bacillus (B.) subtilis), and Ampbio® on the growth performance, blood metabolites, stress, and reproductive hormone levels of Korean native heifers. A total of 48 Korean native heifers were assigned to four groups with 6 heifers in each group. The groups were control, Barodon (0.2%), beneficial microorganism (1%), and Ampbio (1%). Animals in all groups were fed a basal diet composed of selected feed additives and water ad libitum for 99 days. Results showed that there are significant changes in body weight and daily gain in the Ampbio-supplemented group as compared with the control and other feed additives groups (p < 0.05). The increased level of feed intake (7.30 ± 0.03 kg) and feed requirements (10.81 ± 0.52 kg) was observed in the Ampbio-fed group followed by the effective microorganism (EM), Barodon, and control groups. There were no significant changes in albumin, glucose, glutamic oxaloacetic transaminase (SGOT), serum pyruvic transaminase (SGPT), and total protein level, but the decreased levels of total cholesterol and triglycerides and the increased level of blood urea nitrogen were noted in the Ampbio-fed group as compared with the control and other feed additive groups. The reduced level of cortisol (p < 0.05) and elevated levels of progesterone and estradiol (p > 0.05) were noted in the Ampbio-fed group as compared to the other feed additive groups. It is therefore concluded that incorporation of Barodon, EM (B. subtilis), and Ampbio in the recommended diet improved the growth and health performance of Korean native heifers.

Effect of sodium stearoyl-2-lactylate supplementation on lactation performance, blood-biochemical profile, and economic efficacy of mid-lactation Holstein cows.

OBJECTIVE: This study was done to evaluate the effect of sodium stearoyl-2-lactylate (SSL) supplementation in a total mixed ration (TMR) on the lactation performance, blood parameters, and economic efficacy of mid-lactation Holstein cows. METHODS: Twenty-four cows (body weight 647±11.7 kg) were randomly divided into 4 treatment groups, with six cows per group. The dietary treatments were as follows: basal diet (CON); CON+17.5 g of top dressed SSL (treatment [TRT] 0.05); CON+35 g of SSL (TRT 0.1); and CON+70 g of SSL (TRT 0.2) per 35 kg TMR. RESULTS: The highest level of SSL supplementation (TRT 0.2) significantly improved milk yield during the second period compared to the TRT 0.05 group (5 to 8 wks; 33.28 vs 31.09 kg/d), during the third period compared to both the CON and TRT 0.05 groups (p<0.05) (9 to 13 wks; 32.59 vs 30.64 and 30.01 kg/d) and during the overall experimental period compared to both the CON and TRT 0.05 groups (p<0.05) (1 to 13 wks; 33.43 vs 32.06 and 31.40 kg/d), respectively. No negative effects on hematological or biochemical parameters were observed due to SSL supplementation. Considering both the milk fat and protein content, the total milk price was set at 1,073.60 (TRT 0.05), 1,085.60 (TRT 0.1), 1,086.10 (TRT 0.2), and 1,064.20 (CON) won/L, with consequent total milk profits of -1.7%, 5.4%, and 3.5% for the TRT 0.05, TRT 0.1, and TRT 0.2 diet, respectively, compared to those in the CON diet. CONCLUSION: The milk sales revenue related to SSL supplementation of the TRT 0.1 diet was increased by up to 5.4% compared to the milk sales revenue of the CON diet. Therefore, 0.1% SSL supplementation might be effective and profitable during the mid-lactation period of cows, without producing adverse effects.

Effect of optimal sodium stearoyl-2-lactylate supplementation on growth performance and blood and carcass characteristics in Hanwoo steers during the early fattening period.

OBJECTIVE: This study was conducted to evaluate the effect of different levels of total digestible nutrients (TDN) and sodium stearoyl-2-lactylate (SSL) supplementation on growth performance and blood and carcass characteristics in Hanwoo steers during the early fattening period. METHODS: Sixty Hanwoo steers (average body weight, 333±36.4 kg) were randomly allotted to 3 treatments, with twenty steers per treatment, and ten steers per pen with a size of 80 m2. Dietary treatments were as follows: CON, basal diet; treatment (TRT) 0.5, 0.5% down-spec of TDN with 0.1% SSL; TRT 1.0, 1.0% down-spec of TDN with 0.1% SSL. RESULTS: The results demonstrated that average daily gain and feed efficiency increased with TRT 0.5 (0.85 kg and 11.68) vs CON (0.82 kg and 11.27) or TRT 1.0 (0.78 kg and 10.74), indicating that 0.1% SSL supplementation in the feed of early fattening steers may result in a saving of 0.5% TDN. No significant differences were observed amongst all treatments (p> 0.05) for blood metabolite concentration and blood corpuscle values, which were all within the normally accepted range for healthy steers. CONCLUSION: Our study suggests that a TDN 0.5% down spec with 0.1% SSL supplemented feed may be effective and profitable for the early fattening period of Hanwoo steers without causing adverse effects.

Evaluation of the nutritional value of locally produced forage in Korea using chemical analysis and in vitro ruminal fermentation.

OBJECTIVE: The use of locally produced forage (LPF) in cattle production has economic and environmental advantages over imported forage. The objective of this study was to characterize the nutritional value of LPF commonly used in Korea. Differences in ruminal fermentation characteristics were also examined for the LPF species commonly produced from two major production regions: Chungcheong and Jeolla. METHODS: Ten LPF (five from each of the two regions) and six of the most widely used imported forages originating from North America were obtained at least three times throughout a year. Each forage species was pooled and analyzed for nutrient content using detailed chemical analysis. Ruminal fermentation characteristics were also determined by in vitro anaerobic incubations using strained rumen fluid for 0, 3, 6, 12, 24, and 48 h. At each incubation time, total gas, pH, ammonia, volatile fatty acid (VFA) concentrations, and neutral detergent fiber digestibility were measured. By fitting an exponential model, gas production kinetics were obtained. RESULTS: Significant differences were found in the non-fiber carbohydrate (NFC) content among the forage species and the regions (p<0.01). No nutrient, other than NFC, showed significant differences among the regions. Crude protein, NFC, and acid detergent lignin significantly differed by forage species. The amount of acid detergent insoluble protein tended to differ among the forages. The forages produced in Chungcheong had a higher amount of NFC than that in Jeolla (p<0.05). There were differences in ruminal fermentation of LPF between the two regions and interactions between regions and forage species were also significant (p<0.05). The pH following a 48-h ruminal fermentation was lower in the forages from Chungcheong than from Jeolla (p<0.01), and total VFA concentration was higher in Chungcheong than in Jeolla (p = 0.05). This implies that fermentation was more active with the forages from Chungcheong than from Jeolla. Analysis of gas production profiles showed the rate of fermentation differed among forage species (p<0.05). CONCLUSION: The results of the present study showed that the nutritional values of some LPF (i.e., corn silage and Italian ryegrass) are comparable to those of imported forages widely used in Korea. This study also indicated that the nutritional value of LPF differs by origin, as well as by forage species. Detailed analyses of nutrient composition and digestion kinetics of LPF should be routinely employed to evaluate the correct nutritional value of LPF and to increase their use in the field.

Comparison of bacterial communities in leachate from decomposing bovine carcasses.

OBJECTIVE: Burial is associated with environmental effects such as the contamination of ground or surface water with biological materials generated during the decomposition process. Therefore, bacterial communities in leachates originating from the decomposing bovine carcasses were investigated. METHODS: To understand the process of bovine (Hanwoo) carcass decomposition, we simulated burial using a lab-scale reactor with a volume of 5.15 m3. Leachate samples from 3 carcasses were collected using a peristaltic pump once a month for a period of 5 months, and bacterial communities in samples were identified by pyrosequencing of the 16S rRNA gene. RESULTS: We obtained a total of 110,442 reads from the triplicate samples of various sampling time points (total of 15 samples), and found that the phylum Firmicutes was dominant at most sampling times. Differences in the bacterial communities at the various time points were observed among the triplicate samples. The bacterial communities sampled at 4 months showed the most different compositions. The genera Pseudomonas and Psychrobacter in the phylum Proteobacteria were dominant in all of the samples obtained after 3 months. Bacillaceae, Clostridium, and Clostridiales were found to be predominant after 4 months in the leachate from one carcass, whereas Planococcaceae was found to be a dominant in samples obtained at the first and second months from the other two carcasses. The results showed that potentially pathogenic microbes such as Clostridium derived from bovine leachate could dominate the soil environment of a burial site. CONCLUSION: Our results indicated that the composition of bacterial communities in leachates of a decomposing bovine shifted continuously during the experimental period, with significant changes detected after 4 months of burial.

The effect of lactation number, stage, length, and milking frequency on milk yield in Korean Holstein dairy cows using automatic milking system.

OBJECTIVE: The aim of the current study was to describe the relationship between milk yield and lactation number, stage, length and milking frequency in Korean Holstein dairy cows using an automatic milking system (AMS). METHODS: The original data set consisted of observations from April to October 2016 of 780 Holstein cows, with a total of 10,751 milkings. Each time a cow was milked by an AMS during the 24 h, the AMS management system recorded identification numbers of the AMS unit, the cow being milking, date and time of the milking, and milk yield (kg) as measured by the milk meters installed on each AMS unit, date and time of the lactation, lactation stage, milking frequency (NoM). Lactation stage is defined as the number of days milking per cows per lactation. Milk yield was calculated per udder quarter in the AMS and was added to 1 record per cow and trait for each milking. Milking frequency was measured the number of milkings per cow per 24 hour. RESULTS: From the study results, a significant relationship was found between the milk yield and lactation number (p<0.001), with the maximum milk yield occurring in the third lactation cows. We recorded the highest milk yield, in a greater lactation length period of early stage (55 to 90 days) at a 4× milking frequency/d, and the lowest milk yield was observed in the later stage (>201 days) of cows. Also, milking frequency had a significant influence on milk yield (p<0.001) in Korean Holstein cows using AMS. CONCLUSION: Detailed knowledge of these factors such as lactation number, stage, length, and milking frequency associated with increasing milk yield using AMS will help guide future recommendations to producers for maximizing milk yield in Korean Dairy industries.

The In vitro Effects of Nano-encapsulated Conjugated Linoleic Acid on Stability of Conjugated Linoleic Acid and Fermentation Profiles in the Rumen.

This study was aimed to evaluate the stability of conjugated linoleic acids (CLAs) by nano-encapsulation against in vitro ruminal biohydrogenation by microbial enzymatic conversion. CLAs (free fatty acid form of CLA [CLA-FFA], nano-encapsulated CLA-FFA, triglyceride form of CLA [CLA-TG], and nano-encapsulated CLA-TG) were used in the in vitro fermentation experiments. When Butyrivibrio fibrisolvens (B. fibrisolvens) was incubated with CLA-FFAs, the concentrations of cis-9, trans-11 CLA and vaccenic acid (VA) slightly was decreased and increased by nano-encapsulation, respectively. When B. fibrisolvens was incubated with CLA-TG, the concentrations of cis-9, trans-11 CLA and VA decreased, but these were increased when B. fibrisolvens was incubated with nano-encapsulated CLA-TG. The nano-encapsulation was more effective against the in vitro biohydrogenation activity of B.fibrisolvens incubated with CLA-FFA than with CLA-TG. In the in vitro ruminal incubation test, the total gas production and concentration of total volatile fatty acids incubated with nano-encapsulated CLA-FFA and CLA-TG were increased significantly after 24 h incubation (p<0.05). Nano-encapsulated CLA-FFA might, thus, improve the ruminal fermentation characteristics without adverse effects on the incubation process. In addition, nano-encapsulated CLA-FFA increased the population of Fibrobacter succinogenes and decreased the population of B. fibrisolvens population. These results indicate that nano-encapsulation could be applied to enhance CLA levels in ruminants by increasing the stability of CLA without causing adverse effects on ruminal fermentation.

Effects of dry period length on milk production and physiological responses of heat-stressed dairy cows during the transition period.

The objective of this study was to investigate the effects of a traditional dry period (60 d) versus a no dry period (0 d) on the milk production, physiological response, and metabolic status of dairy cows exposed to heat stress during the transition period. Holstein dairy cows (n = 15) with similar expected calving dates were randomly assigned to two different dry period lengths: (1) no dry period (n = 7) and (2) a traditional dry period of 60 days (n = 8). All cows were studied from 8 weeks before expected calving to 10 weeks after calving and experienced heat stress during the transition period. The results showed that cows with no dry period decreased their milk yield in subsequent lactation, but compensated for the loss of milk yield accounted for by additional milk yield before calving. The energy balance at postpartum was improved in cows with no dry period compared to cows with a traditional dry period. There were no significant differences in the physiological response and blood metabolites at postpartum between the dry period lengths of dairy cows exposed to heat stress during the transition period. Taken together, our results showed that omitting the dry period improved the milk production and metabolic status of dairy cows exposed to heat stress during the transition period.

Effects of photoperiod and light intensity on milk production and milk composition of dairy cows in automatic milking system.

The purpose of this study was to determine the effects of photoperiod and light intensity on milk production, milk composition, hormones levels and blood metabolites indices of Korean Holstein dairy cows in automatic milking system (AMS). A total of 24 Holstein dairy cows were selected and used to four subsequent treatments for the experimental periods of 60 days. The light programs consisted of (1) Control: the natural photoperiod with 14.2 h of the light period and 9.4 h of the dark period (below 10 Lux); (2) T1: 16 h of the long day photoperiod (LDPP) with 50 Lux of light; (3) T2: 16 h of LDPP with 100 Lux of light; and (4) T3: 16 h of LDPP with 200 Lux of light, respectively. Importantly, there was a significant difference in the thurl activity of dairy cows between the different light intensity programs (p < 0.05). Milk yield was higher in T1 and T2 (40.80 ± 1.71 and 39.90 ± 2.02 kg/d, respectively) than those of Control and T3 (32.18 ± 1.51 and 35.76 ± 2.80 kg/d, respectively) (p < 0.05), but DMI was lower in T1, T2, and T3 compared to Control (p < 0.05). Also, milk fat percentage, the contents of milk fat and total solids were higher in T2 than those in the others (p < 0.05). The average daily melatonin level in milk was high to T3 (28.20 ± 0.43 pg/mL), T2 (24.62 ± 0.32 pg/mL), T1 (19.78 ± 0.35 pg/mL), and Control (19.36 ± 0.45 pg/mL) in order (p < 0.05). Also, the cortisol levels in milk and blood were lower in treatment groups than in Control (p < 0.05). The results of this study showed that it will be effective to improve the milk yield and milk composition, and to reduce the stress of dairy cows when the light conditions regulate to extend the photoperiod to 16 h at a light emitting diode (LED) intensity of 100 Lux under the AMS in dairy farm.

The effect of seasonal thermal stress on milk production and milk compositions of Korean Holstein and Jersey cows.

OBJECTIVE: In this study we investigated the effect of seasonal thermal stress on milk production and milk compositions between Holstein and Jersey dairy cows under the temperateclimate in Korea. METHODS: A total of 9 Holstein lactating dairy cows (2.0±0.11 parity) which had a daily milk yield of 29.77±0.45 kg, and days in milk of 111.2±10.29 were selected similarly at the beginning of the experiments in each season. Also, a total of 9 Jersey lactating dairy cows (1.7±0.12 parity) which had a daily milk yield of 20.01±0.43 kg, and days in milk of 114.0±9.74 were selected similarly at the beginning of the experiments. RESULTS: Results showed that the average ambient temperature (°C) and temperature-humidity index (THI) were higher in summer, and were lower in winter (p<0.05). The average relative humidity (RH, %) was higher in autumn than that of other seasons (p<0.05). Milk production was significantly decreased (Holstein 29.02 kg/d and Jersey 19.75 kg/d) in autumn than in other seasons (Holstein 30.14 kg/d and Jersey 20.96 kg/d). However, the milk production was negatively correlated in Holstein cows, and positively correlated in Jersey cows with THI values increased from 16 to 80. In addition, milk yield was increased by 15% in Holstein cows and decreased by 11% in Jersey cows with the THI values increased from 16 to 20. The fat and protein content percentage was significantly higher in Jersey milk than in Holstein milk, furthermore the fat and protein content yield was higher in Jersey cow milk than that of Holstein cow's milk with all THIs. CONCLUSION: From the study results, we concluded that Jersey cows might be less adaptable to low temperature of the winter, and this would have a negative impact on dairy farmer income since Korea's milk price estimation system places a higher value on milk yield than on milk compositions or sanitary grades.

Evaluation of heat stress responses in Holstein and Jersey cows by analyzing physiological characteristics and milk production in Korea.

We evaluated the effects of heat stress on physiological responses and milk production in Holstein and Jersey cows reared in Korea. The mean average temperature-humidity index (THI) increased significantly from May to August and then decreased until October. The mean average rectal temperature (RT) was increased in Holstein cows compared with Jersey cows, as the THI values increased from 61 to 85. The average respiratory rate (RR) was increased in Jersey cows compared with Holstein cows when the THI value increased from 61 to 85. The average surface temperature of the rumen and udder was higher in Jersey cows than in Holstein cows when the THI value increased from 61 to 85. No significant difference was noted with respect to relative serum volumes between the breeds and THI ranges, but we measured significant changes in serum pH in Holstein and Jersey cows when the THI value increased from 61 to 85. Milk production was not significantly changed in Holstein cows when the THI increased from 61 to 85, but milk production and milk protein content were significantly altered in Jersey cows when the THI increased from 61 to 85. Current study suggests that Holstein cows still have an advantage in terms of the economic returns of dairy farms in Korea. Therefore, further research is required regarding the heat tolerance of Jersey cows in Korean climatic conditions.

Evaluation of the equation for predicting dry matter intake of lactating dairy cows in the Korean feeding standards for dairy cattle.

OBJECTIVE: This study aimed to validate and evaluate the dry matter (DM) intake prediction model of the Korean feeding standards for dairy cattle (KFSD). METHODS: The KFSD DM intake (DMI) model was developed using a database containing the data from the Journal of Dairy Science from 2006 to 2011 (1,065 observations 287 studies). The development (458 observations from 103 studies) and evaluation databases (168 observations from 74 studies) were constructed from the database. The body weight (kg; BW), metabolic BW (BW0.75, MBW), 4% fat-corrected milk (FCM), forage as a percentage of dietary DM, and the dietary content of nutrients (% DM) were chosen as possible explanatory variables. A random coefficient model with the study as a random variable and a linear model without the random effect was used to select model variables and estimate parameters, respectively, during the model development. The best-fit equation was compared to published equations, and sensitivity analysis of the prediction equation was conducted. The KFSD model was also evaluated using in vivo feeding trial data. RESULTS: The KFSD DMI equation is 4.103 (±2.994)+0.112 (±0.022)×MBW+0.284 (±0.020) ×FCM-0.119 (±0.028)×neutral detergent fiber (NDF), explaining 47% of the variation in the evaluation dataset with no mean nor slope bias (p>0.05). The root mean square prediction error was 2.70 kg/d, best among the tested equations. The sensitivity analysis showed that the model is the most sensitive to FCM, followed by MBW and NDF. With the in vivo data, the KFSD equation showed slightly higher precision (R2 = 0.39) than the NRC equation (R2 = 0.37), with a mean bias of 1.19 kg and no slope bias (p>0.05). CONCLUSION: The KFSD DMI model is suitable for predicting the DMI of lactating dairy cows in practical situations in Korea.

Changes in milk production and blood metabolism of lactating dairy cows fed Saccharomyces cerevisiae culture fluid under heat stress.

In this study, Saccharomyces cerevisiae culture fluid (SCCF) has been added to a diet of lactating dairy cows to attempt to improve the ruminal fermentation and potentially increase the dry matter intake (DMI) and milk yield. This study was conducted to investigate the effects of SCCF on the milk yield and blood biochemistry in lactating cows during the summer. Twenty-four Holstein dairy cows were randomly assigned to one of four treatments: (1) total mixed ration (TMR-1) (Control); (2) TMR-1 supplemented with SCCF (T1); (3) TMR-2 (containing alfalfa hay) (T2); and (4) TMR-2 supplemented with SCCF (T3). SCCF (5 ml/head, 2.0×107 CFU/mL) was mixed with TMRs daily before feeding to dairy cows. The mean daily temperature-humidity index (THI) during this trial was 76.92 ± 0.51 on average and ranged from 73.04 to 81.19. For particle size distribution, TMR-2 had a lower >19 mm fraction and a higher 8-19 mm fraction than TMR-1 (p < 0.05). The type of TMR did not influence the DMI, body weight (BW), milk yield and composition, or blood metabolites. The milk yield and composition were not affected by the SCCF supplementation, but somatic cell counts were reduced by feeding SCCF (p < 0.05). Feeding SCCF significantly increased the DMI but did not affect the milk yield of dairy cows. The NEFA concentration was slightly decreased compared to that in the control and T2 groups without SCCF. Feeding a yeast culture of S. cerevisiae may improve the feed intake, milk quality and energy balance of dairy cows under heat stress.

A comparative study on milk composition of Jersey and Holstein dairy cows during the early lactation.

Recently, Jersey cattle was introduced and produced by embryo transfer to Korea. This study was conducted to investigate the differences of milk compositions between Jersey and Holstein cows and the relationship between days in milk (DIM) and milk compositions during early lactation. Data were collected from twelve lactating cows from Department of Animal Resources Development at National Institute of Animal Science. Cows in parity 1 were used, and calved at spring from April to March of 2017. All cows were housed in two sections within a free-stall barn, which divided into six from each breed, and received a basal total mixed ration. Milk samples of each cow were collected at 3 DIM and 30 DIM for analyzing the milk compositions, including fatty acids (FA), amino acids and minerals. Total solids, citrate, and milk urea nitrogen level were differed between the breeds (p < 0.05). As DIM went from 3 to 30, milk protein, total solids, and somatic cell count decreased (p < 0.05), but lactose increased in all breed milk (p < 0.05). Citrate and free fatty acid (FFA) elevated in Jersey milk (p < 0.05), whereas reduced in Holstein milk (p < 0.05). Proportions of some individual FA varied from the breeds. Myristic (C14:0), palmitic (C16:0), and arachidonic acid (C20:4) in milk from all cows were higher at 3 DIM than at 30 DIM (p < 0.05). Also, stearic (C18:0) and oleic acid (C18:1) were lower at 3 DIM than at 30 DIM (p < 0.05), and the C18:1 to C18:0 ratio was significantly differed in DIM × breed interactions (p < 0.05). The contents of the individual amino acids did not differ from the breeds. Calcium, phosphorous, magnesium, and zinc (Zn) contents was significantly increased in Holstein milk than Jersey milk at 3 DIM. Also, K and Zn concentrations were higher in Holstein milk than in Jersey milk at 30 DIM (p < 0.05). It was concluded that Jersey cows would produce more effective milk in processing dairy products and more proper energy status compared with Holstein cows in early lactation under the same environmental and nutritional conditions.

Novel Acinetobacter parvus HANDI 309 microbial biomass for the production of N-acetyl-ß-d-glucosamine (GlcNAc) using swollen chitin substrate in submerged fermentation.

BACKGROUND: N-acetyl-ß-d-glucosamine (GlcNAc)6 is extensively used as an important bio-agent and a functional food additive. The traditional chemical process for GlcNAc production has some problems such as high production cost, low yield, and acidic pollution. Therefore, to discover a novel chitinase that is suitable for bioconversion of chitin to GlcNAc would be of great value. RESULTS: Here, we describe the complete isolation and functional characterization of a novel exo-chitinase from Acinetobacter parvus HANDI 309 for the conversion of chitin. The identified exo-chitinase mainly produced N-acetyl-d-glucosamine, using chitin as a substrate by submerged fermentation. The A. parvus HANDI 309 biofuels producing exo-chitinase were characterized by TLC, and was further validated and quantified by HPLC. Furthermore, the optimal temperature and pH for the exo-chitinase activity was obtained in the culture conditions of 30 °C and 7.0, respectively. The maximum growth of the stationary phase was reached in 24 h after incubation. These results suggest that A. parvus HANDI 309 biofuels producing exo-chitinases may have great potential in chitin to N-acetyl-d-glucosamine conversion. CONCLUSIONS: The excellent thermostability and hydrolytic properties may give the exo-chitinase great potential in chitin to GlcNAc conversion in industry. This is the first report that A. parvus HANDI 309 is a novel bacterial strain that has the ability to produce an enormous amount of exo-chitinase-producing bio-agents in a short time on an industrial scale without any pretreatment, as well as being potentially valuable in the food and pharmaceutical industries.

Meta-analysis of factors affecting milk component yields in dairy cattle.

The objectives of this study were thus to identify most significant factors that determine milk component yield (MCY) using a meta-analysis and, if possible, to develop equations to predict MCY using variables that can be easily measured in the field. A literature database was constructed based on the research articles published in the Journal of Dairy Science from Oct., 2007 till May, 2010. The database consisted of a total of 442 observed means for MCY from 118 studies. The candidate factors that determine MCY were those which can be routinely measured in the field (e.g. DMI, BW, dietary forage content, chemical composition of diets). Using a simple linear regression, the best equations for predicting milk fat yield(MFY) and milk protein yield (MPY) were MFY = 0.351 (±0.068) + 0.038 (±0.003) DMI (R(2) = 0.27), and MPY = 0.552 (±0.071) + 0.031 (±0.002) DMI - 0.004 (±0.001) FpDM (%, forage as a percentage of dietary DM) (R(2) = 0.38), respectively. The best equation for predicting milk fat content (%) explained only 12% of variations in milk fat content, and none of a single variable can explain more than 5% of variations in milk protein content. We concluded that among the tested variables, DMI was the only significant factor that affects MFY and both DMI and FpDM significantly affect MPY. However, predictability of linear equations was relatively low. Further studies are needed to identify other variables that can predict milk component yield more accurately.