Detection and Identification of Sarcocystis cruzi (Protozoa: Apicomplexa) by Molecular and Ultrastructural Studies in Naturally Infected Korean Cattle (Bos taurus coreanae) from Daejeon, Korea.

To survey the prevalence of Sarcocystis infections, 210 heart samples were collected from Korean native cattle (Bos taurus coreanae) at an abattoir in Daejeon Metropolitan City, Republic of Korea. Sarcocysts were detected form 31 specimens (14.8%) and identified as Sarcocystis cruzi via transmission electron microscopy. The wall of S. cruzi has flattened protrusions that did not contain fibrils or microfilaments. The protrusions arose irregularly from the base, contained a fine granular substance, lacked internal microfilaments, and measured approximately 0.21-1.25 µm in length and 0.05-0.07 µm in width. Sequence analysis revealed 99.5% homology to S. cruzi. This is the first report on the prevalence of S. cruzi in native cattle from the Republic of Korea.

Identification of hemolytic anemia in Korean indigenous cattle with a criteria value of reticulocyte count, indirect bilirubin, and L-lactate concentration.

Bovine hemolytic anemia has a negative impact on animal welfare and productivity due to its associated clinical symptoms. Hemolysis is generally known to cause reticulocytosis, increased indirect bilirubin, decreased concentration of haptoglobin, and increased lactate dehydrogenase. Additionally, tissue hypoperfusion due to concomitant anemia increases blood lactate concentration. However, few studies have reported the correlation between these indicators and hemolytic anemia in cattle. We expected that alterations in hematological and biochemical parameters could identify cattle with hemolytic anemia. Therefore, in addition to reporting differences in indicators according to hemolytic anemia, this study aimed to derive indicators and set criteria for identification of bovine hemolytic anemia. In cattle with hemolytic anemia, reticulocytosis, increased indirect bilirubin, and increased L-lactate were observed, and the correlation of these indicators with hematocrit (HCT) was confirmed. And since HCT alone has limitations in identifying hemolytic anemia, we suggest additional criteria to identify hemolytic anemia in cattle.

Evaluating feed value of native Jeju bamboo (Sasa quelpaertensis Nakai) for beef cattle.

OBJECTIVE: Recently, indigenous Korean grass Sasa quelpaertensis Nakai (SQ) has garnered much interest as a roughage source for livestock to mitigate its adverse effects on habitat diversity. Thus, the objective of the present study was to evaluate the ruminal fermentation, palatability, and nutrient digestibility of SQ for Korean native beef cattle (Hanwoo) using in vitro rumen fermentation, in situ rumen degradability, and in vivo feeding trials. METHODS: Using in vitro tests with rumen fluid as the inoculum for 48 h, ruminal fermentation of SQ was evaluated and compared with that of other roughage sources commonly used in Korea (i.e., rice straw, Timothy hay, and Italian ryegrass [IRG]). Additionally, an in situ trial 96 h was performed using three cannulated Hanwoo steers. Further, an in vivo trial was performed using eight Hanwoo steers to compare the palatability of SQ with rice straw in total mixed ration (TMR) and forage-concentrate separate feeding conditions. Finally, an in vivo digestibility trial of SQ fed as TMR of two particle sizes was performed with four Hanwoo steers. RESULTS: In vitro and in situ trials revealed that SQ was comparable or superior to rice straw in terms of the ruminal fermentation characteristics of pH, gas production, total volatile fatty acid content, and effective ruminal dry matter digestibility (DMD), although its fermentability was lower than that of Timothy hay and IRG. In the palatability test, steers showed a greater preference for SQ when given as TMR. The total tract DMD of SQ fed as TMR was 75.9%±1.37%, and it did not differ by particle size. CONCLUSION: The feed value of SQ as a roughage source for Hanwoo steers is comparable or superior to that of rice straw, particularly when provided as TMR.

Effect of oestrus synchronisation through ovulation delay by vaccination against foot-and-mouth disease in Hanwoo (Bos taurus coreanae) cows.

BACKGROUND: In Korean cattle, after foot-and-mouth disease (FMD) vaccination, anovulation increases, acute immune response is stimulated. OBJECTIVE: Here, we aimed to improve the fertility rate by ovulation delay caused by the foot-and-mouth disease vaccine. METHODS: 160 cows (control, FMD, FMD+Gn250 and FMD+Gn500 groups, with 40 cows each) were used. We analysed the ovulation delay, ovulation rate, conception rate and acute-phase immune responses. RESULTS: In the group vaccinated only with FMD, the average follicle size was maintained at 12 mm and ovulation was delayed. The ovulation rate of the FMD+Gn500 group (500 µg gonadotropin-releasing hormone (GnRH) injections 3 days after the FMD vaccination) was the highest at 81.8%. The ovulation rate of the FMD+Gn250 group (250 µg GnRH injections 3 days after FMD vaccination) was 54.5%, and that of the control group (not FMD vaccinated) was 53.3%. The conception rate was 52.5% (19/40) in the control group, 37.5% (15/40) in the FMD+Gn250 group, and 67.5% (27/40) in the FMD+Gn500 group. Analysis of acute-phase immune response revealed that the plasma contents of haptoglobin and serum amyloid A increased up to 7 days after vaccination against FMD in all the experimental groups, except the control group. CONCLUSIONS: We concluded that ovulation delay can be employed to improve conception rate after FMD vaccination through a modified ovulation synchronisation method with GnRH.

Differences in hormone levels around parturition in Hanwoo cattle (Bos taurus coreanae) following artificial insemination and embryo transfer.

BACKGROUND: With unique genetic traits, Hanwoo cattle (Bos taurus coreanae) are well-adapted to the Korean environment. However, their perinatal mortality rate is 2%-3%, which imposes an economic burden. OBJECTIVE: Due to insufficient data on hormonal changes around parturition, the timing of parturition is often predicted subjectively; few studies have examined hormones in Hanwoo cattle. We measured the changes in various hormones around parturition, to seek an objective predictor of parturition time. METHODS: In 14 female Hanwoo cattle, we measured progesterone, prolactin and cortisol concentrations daily in jugular vein blood samples, beginning 6 days before parturition until 7 days after parturition. Conception was induced in five animals using artificial insemination. Nine animals received embryo transfer. RESULTS: During parturition, the concentration of progesterone decreased significantly in the embryo transfer group (n = 9) and in the total population (n = 14); it did not change significantly in the artificial insemination group (n = 5). Prolactin concentration increased on the day of parturition but did not differ significantly among the groups. Cortisol remained constant throughout the study course. CONCLUSION: We concluded that parturition time can be predicted in Hanwoo cattle using progesterone concentration. This knowledge can reduce perinatal mortality, which would help to improve farm income and animal welfare.

Metabolomics Comparison of Hanwoo (Bos taurus coreanae) Biofluids Using Proton Nuclear Magnetic Resonance Spectroscopy.

The aim of this study was to identify the metabolomic profiles of rumen fluid, serum, and urine from Hanwoo (Bos taurus coreanae), using proton nuclear magnetic resonance (1H-NMR) spectroscopy. In all, 189, 110, and 188 metabolites were identified in rumen fluid, serum, and urine, and 107, 49, and 99 were quantified, respectively. Organic acids, carbohydrates, and aliphatic acyclic compound metabolites were present at the highest concentrations in rumen fluid, serum, and urine, respectively. In addition, acetate, glucose, and urea were the most highly concentrated individual metabolites in rumen fluid, serum, and urine, respectively. In all, 77 metabolites were commonly identified, and 19 were quantified across three biofluids. Metabolic pathway analysis showed that the common quantified metabolites could provide relevant information about three main metabolic pathways, phenylalanine, tyrosine, and tryptophan biosynthesis; caffeine metabolism; and histidine metabolism. These results can be useful as reference values for future metabolomic research on Hanwoo biofluids in Korea.

Social relationships enhance the time spent eating and intake of a novel diet in pregnant Hanwoo (Bos taurus coreanae) heifers.

The objective of this study was to evaluate the effects of social relationships on the feed intake, eating behavior, and growth, upon exposure to a novel diet, in Hanwoo (Bos taurus coreanae) heifers during pregnancy. Twenty-four pregnant Hanwoo heifers, averaging 438 ± 27.8 kg in weight, 21 months in age, and 194 ± 8.5 days in pregnancy, were involved in a two-month (eight weeks) experiment. The heifers were randomly assigned to either the single housing group (SG; one individual per pen, n = 12), or the paired housing group (PG; two individuals per pen, n = 12). All pens were of the same size (5 × 5 m) and provided with one feed bin, which automatically recorded the individual feed intake and eating behavior. As the experiment began, the diet of the heifers was switched from a total mixed ration (TMR; 250 g/kg ryegrass straw and 750 g/kg concentrate mix) to a forage-only diet (mixed hay cubes composed of 500 g/kg alfalfa, 250 g/kg timothy, and 250 g/kg blue grass hay). The heifers were fed ad libitum twice a day. The individual feed intake and eating behavior were recorded daily throughout the experiment, and body weights (BWs) were measured every four weeks before the morning feeding. PG animals visited the feed bin 22% less often than SG. PG, however, stayed 39% longer in the feed bin and consumed 40% more feed per visit, compared with SG. Consequently, PG heifers spent 23% more time in eating and had 16% more daily dry matter intake than SG during the experiment. Average daily gain during the experimental period tended to be greater in PG than in SG. When pregnant Hanwoo heifers encountered a novel diet, social relationships (i.e., presence of a pen-mate) enhanced their time spent eating and feed intake. Social interactions, even with an unfamiliar individual, may be helpful for pregnant Hanwoo heifers cope with a diet challenge compared to solitary situation.

The complete mitochondrial genome of Bos taurus coreanae (Korean native cattle).

Korean native cattle is one of the famous native breeds in Korean. In the present work, we report the complete mitochondrial genome sequence of Korean native cattle for the first time. The total length of the mitogenome was 16,339 bp with the base composition of 33.4% for A, 27.2% for T, 26.0% for C, and 13.4% for G, and an A-T (60.6%)-rich feature was detected. It harbored 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and 1 non-coding control region (D-loop region). The arrangement of all genes was identical to the typical mitochondrial genomes of cattle. The complete mitochondrial genome sequence of Korean native cattle would serve as an important data set of the germplasm resources for further study.

Identification of nontuberculous mycobacteria isolated from Hanwoo (Bos taurus coreanae) in South Korea by sequencing analysis targeting hsp65, rpoB and 16S rRNA genes.

Combinatorial molecular taxonomic approaches targeting 3 genes, 16S rRNA (1.2-1.3kbp), hsp65 (603-bp), and rpoB genes (711-bp) were applied to 43 non-tuberculous mycobacteria (NTM) strains isolated from a Korean native cattle from bronchial lymph nodes and lung, Hanwoo (Bos taurus coreanae) in South Korea. Of 43 NTM isolates, Mycobacterium avium complex strains (MAC) were isolated with the highest frequency (31 strains, 72.1%). Contrary to other reports, M. intracellulare strains (23 strains, 53.5%) of MACs were more prevalent than M. avium strains (8 strains, 18.6%). Further separation of isolated M. intracellulare into genotype level by hsp65 analysis showed that isolates of the HG-1 genotype (60.9%, 14/23 isolates), known to be specific to Korean patients, was more prevalent than the HG-2 type (17.4%, 4/23 strains), which include the type strain, M. intracellulare ATCC 13950(T). Compared to NTM infections of Korean human patients, the pronounced difference found in this study is that no M. abscessus infections in Hanwoo were found. In conclusion, our data showed that the isolated species frequency of NTMs, particularly MACs from Hanwoo, was very comparable to that obtained from Korean human infection, suggesting that humans and Korean native cattle may share common environmental sources for NTM infections.