• Journal of Embryo Transfer
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• v.23 no.3
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• pp.141-145
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• 2008

The objective of this study was to investigate the relationship between behavioral signs and duration of estrous in Hanwoo and Holstein cattle for the prediction of optical insemination. Fifty two of 58 and 71 of 89 in Hanwoo and Holstein cows or heifers showed estrous exhibition within 72 h after 2 days following $PGF_{2}\alpha$ administration, respectively. The number of mounting and standing heat were 54.2 and 57.6, 59.4 and 53.5, 42.0 and 30.8 and 16.2 and 10.7 times in Hanwoo cows, Hanwoo heifers, Holstein cows and Holstein heifers, respectively. Duration of mounting were no significantly difference for Hanwoo cows ($21.2\pm11.3$), Hanwoo heifers ($19.9\pm11.4$), Holstein cows ($8.7\pm4.4$) and Holstein heifers ($16.9\pm8.0$). Duration of standing heat were significantly (p<0.05) shorter for Holstein cows ($5.4\pm3.4$) than for Hanwoo cows ($17.1\pm9.6$), Hanwoo heifers ($16.5\pm6.3$) and Holstein heifers ($15.0\pm7.2$). Time until mounting after injection of $PGF_{2}\alpha$ were significantly (p<0.05) longer for Holstein cows ($56.3\pm11.45$) than for Hanwoo cows ($42.71\pm10.44$), Hanwoo heifers ($36.6\pm8.21$) and Holstein heifers ($40.70\pm6.15$). Time until standing heat after injection of $PGF_{2}\alpha$ were significantly (p<0.05) longer for Holstein cows ($61.6\pm8.92$) than for Hanwoo cows ($46.2\pm11.49$), Hanwoo heifers ($42.7\pm6.06$) and Holstein heifers ($44.1\pm6.72$). In the results of this study, duration of standing heat was the shortest in Holstein cows ($5.4\pm3.4$). The estimation of estrous with Holstein cows has more difficulty because to significantly shorter duration of standing heat than for Hanwoo cows, Hanwoo heifers and Holstein heifers. The standing heat can be a good predictor for time of ovulation but it is concluded that mounting behavior could be the best predictor for time of ovulation.

• Journal of Embryo Transfer
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• v.29 no.4
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• pp.327-331
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• 2014

The objective of this study was to investigate the interrelationship of weight and hormonal changes through the administration of vitamin A to first time pregnant heifers. A total of 28 Korean heifers was used for this study. The heifers were divided into two groups - with vitamin A (n=14) and without vitamin A (control) (n=14) in the feed. Body weight increased in vitamin A treated heifers starting 9 months until 15 months. After pregnancy, vitamin A treated heifers were found to maintain higher body weights than the control group. Pre-pregnancy and post pregnancy progesterone levels were not different between the two groups. Serum estradiol levels of heifers at different growth stages showed relatively higher E2 levels than the control. Also, the control during pregnancy may show higher serum E2 levels than the vitamin A treated heifers. The growth phase serum estradiol levels in heifers may be relatively higher than the control. During pregnancy it showed a similar trend. Serum levels of vitamin A treated heifers did not differ from pregnant heifers at 5 months of age. However, after 5 months from conception until 8 months of treatment it showed a high level. Serum cholesterol in pregnant cows was higher in the control group than the treatment from beginning until the end of pregnancy. This is considered to be related to fetus development during pregnancy, as well as the mother's health.

• Journal of Embryo Transfer
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• v.23 no.4
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• pp.257-261
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• 2008

The objective of present study was to investigate the effect of seasons on reproductive performance of Hanwoo and Holstein heifers. Heat stress in summer or cold stress in winter stress to Hanwoo and Holstein heifers may bring reproduction failure, which would pose an important economic loss, even around Daegwallyeong region located in high mountainous area. Seasonal differences in the serum levels of LH, FSH and progesterone ($P_4$) in response to environmental factors (hot and cold) out of 20 pubertal Hanwoo heifers in Daegwallyeong, Gangwon Province and 20 non-lactating Holstein heifers in Chonan city of Republic of Korea at 2-3 years of age were compared. Blood samples for hormonal analysis were from jugular vein after detection of estrus repeatedly over four seasons within four-week intervals (Spring: May to June, Summer: July to August, Autumn: October to November and Winter: January to February). In Hanwoo heifer population, averages of LH and FSH concentration in spring and in summer were greater compared to those in winter (p<0.05). LH or FSH levels tended to be greater (p=0.06) in spring and less (p=0.09) in winter compared to the levels in autumn. Only in summer, cattle seemed to show lower LH or FSH secretion (p<0.05). Similar to the results in Hanwoo heifers, the serum concentrations of LH and FSH in Holstein heifers decreased further by heat stress in summer when P 4 levels were high during luteal phase. The results demonstrate significant effect of summer heat on reproduction of Hanwoo or Holstein heifers. Although parameters indicating the extent of heat stress were not measured in this study, we suggest that serum hormone levels could be considered as successful indicators of summer heat stress condition for Hanwoo and Holstein heifers even under rather cool summer climate.

• Korean Journal of Agricultural Science
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• v.43 no.5
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• pp.818-827
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• 2016

This study hypothesized that dietary feed additive containing probiotics alter either immune-related serum substances or serum metabolites in Hanwoo heifers. A probiotic treatment was given at 0.5% top-dressing of concentrate diet for 6 months. The change of immunological indicators in the blood was analyzed under LPS (Lipopolysaccharide) challenge. One day before administration of LPS, all heifers were fitted with an indwelling jugular vein catheter for serial blood collections. Both a serum tube and an EDTA-coated tube were collected at 30-min intervals from - 2 to 8 hours relative to the LPS challenge at time 0 ($1{\mu}g/kg$ of BW). Serum was used for analyzing albumin (ALB), glucose (GLU), total protein (TP), triglycerides (TG), phosphorus (IP), and non-esterified fatty acids (NEFA). Plasma was used for analyzing white blood cell (WBC), red blood cell (RBC), platelet (PLT) and inflammation-related factors (NE, LY, MO, EO, BA, Hb, HCT, MCV, MCH, MCHC, RDW, MPV). There were significant differences in ALB, GLU, TG, IP, and NEFA concentration with the passage of hours post challenge (p < 0.05). The level of ALB, GLU, TG, and IP showed significant difference (p < 0.05) between treatments. However, none of the data showed interaction between time and treatments (p > 0.05). The level of WBC, EO, LY, and MO were reduced after LPS challenge (p > 0.05). In conclusion, LPS challenge after dietary supplementation of probiotics changed the levels of both serum metabolites and inflammation-related factors. The increase of GLU and TG indicated a probiotics-positive response under LPS challenge (p < 0.05).

• Reproductive and Developmental Biology
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• v.33 no.3
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• pp.179-182
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• 2009

This study was carried out between November 2007 and October 2008 in the experimental farm of Chunnam National University to investigate the effect of feeding of whole crop barley silage on the reproductive performance of Hanwoo heifers and cows. Two diets, rice straw or whole crop barley silage separately from concentrate were fed 11 Hanwoo heifers and 26 Hanwoo cows. In control group (=CON), heifers (n=6) and cows (n=13) were fed 7 kg (/head) rice straw and 4 kg (/head) commercial diet. In whole crop barley silage group (=WBG), heifers (n=5) and cows (n=13) were fed 8 kg (/head) whole crop barley silage and 1 kg (/head) commercial diet. 1. Conception rates for first service in CON or WBG heifers were 66.7% (4/6) and 60.0% (3/5), respectively, and the services per conception cows were $1.5{\pm}0.2$ for CON and $1.4{\pm}0.2$ for WBG group. 2. Days to post-partum insemination were $106.6{\pm}26.3$ days for CON and $85.6{\pm}12.6$ days for WBG group, and days to post-partum conception in CON or WBG were $128.4{\pm}27.1$ and $96.8{\pm}16.8$ days, respectively. 3. Post-partum conception rates for first service in CON or WBG were 76.9% (10/13) and 84.6% (11/13), respectively, and caving interval was $418{\pm}50.7$ days for CON and $392.8{\pm}20.7$ days for WBG group.

• Animal Bioscience
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• v.35 no.3
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• pp.410-421
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• 2022

Objective: Two series of experiments were conducted to determine how the incremental levels of sodium metabisulfite (SMB)-treated fruit and vegetable discards (FVD) in diet of Hanwoo heifers and cows affect their performance and health. Methods: In Exp. 1, 36 Hanwoo heifers were stratified by age (13.3±0.83 mo) and initial body weight (305±19.7 kg), and divided randomly to one of three diets containing 0%, 10%, or 20% SMB-treated FVD (as-fed basis). The experiment lasted 110 d, including 20 d of adaptation. In Exp. 2, 24 multiparous Hanwoo cows were divided into three groups based on age (48.2±2.81 mo) and initial body condition score (2.64±0.33). Cows in each block were assigned randomly to one of three diets containing 0%, 11%, or 22% SMB-treated FVD (as-fed basis). The experiment lasted 80 d, including a 20-d adaptation period. In both experiments, SMB-treated FVD was used as a replacement for wet brewers grain in total mixed ration (TMR). Results: Growing heifers exhibited no differences in their daily feed intake (6.58±0.61 kg/d dry matter [DM]), average daily gain (0.60±0.07 kg/d), and body condition score when they consumed the incremental levels of SMB-treated FVD. Although most blood metabolites were unaffected by treatments, blood urea-N and β-hydroxybutyrate levels decreased linearly as the SMB-treated FVD level increased in TMR. Similar to Exp. 1, minor differences were found in daily feed intake (8.27±0.72 kg DM/d) and body condition score of Hanwoo cows. Most blood metabolites remained unaffected by treatments, but blood urea-N decreased as the SMB-treated FVD level in TMR increased. Conclusion: Our findings suggest that SMB-treated FVD could be safely incorporated into the diet of Hanwoo heifers and cows, potentially improving N-use efficiency in the body while not impairing performance or health.

• Journal of Animal Science and Technology
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• v.57 no.1
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• pp.3.1-3.6
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• 2015

This study investigated the effects of feeding by-product feed (BF)-based silage on the behavior of growing Hanwoo heifers. Twelve Hanwoo heifers (13.2 months-old, 315 kg body weight; four heifers per pen) were assigned to three diets: a rice straw (RS) diet (concentrate mix and free access to RS), a RS and BF-based silage (RSBFS) diet (concentrate mix and free access to RS and BF-based silage), and a BF-based silage (BFS) diet (concentrate mix and free access to BF-based silage). Behavior was recorded for 5 days using camcorders. Compared to the RS group, the BFS group showed 21.7% higher dry matter intake, shorter feeding, rumination, and chewing times, as well as longer resting time (p < 0.05). Although all groups exhibited similar drinking, urination, and defecation frequencies, the BFS group exhibited higher feeding rates, rumination efficiency, and chewing efficiency than the RS group (p < 0.05). Compared to the BFS group, the RSBFS group showed higher $peNDF_{8.0}$ intake (15.2% vs. 25.0% dry matter intake), longer feeding and sitting times, lower defecation frequency (p < 0.05), and similar rumination efficiency. In conclusion, complete replacement of conventional RS with BF-based silage reduced rumination and chewing activity in growing Hanwoo heifers, and BF-based silage feeding with large-particle straw is an effective approach in improving heifer behavior.

• Journal of Animal Science and Technology
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• v.65 no.5
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• pp.951-970
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• 2023

This study utilized Italian ryegrass silage (IRGS) - based total mixed ration (TMR) as feedstuff and evaluated its effects on rumen fermentation, growth performance, blood parameters, and bacterial community in growing Hanwoo heifers. Twenty-seven Hanwoo heifers (body weight [BW], 225.11 ± 10.57 kg) were randomly allocated to three experimental diets. Heifers were fed 1 of 3 treatments as follows: TMR with oat, timothy, and alfalfa hay (CON), TMR with 19% of IRGS (L-IRGS), and TMR with 36% of IRGS (H-IRGS). Feeding high levels of IRGS (H-IRGS) and CON TMR to heifers resulted in a greater molar proportion of propionate in the rumen. The impact of different TMR diets on the BW, average daily gain, dry matter intake, and feed conversion ratio of Hanwoo heifers during the growing period did not differ (p > 0.05). Furthermore, the blood metabolites, total protein, albumin, aspartate aminotransferase, glucose, and total cholesterol of the heifers were not affected by the different TMR diets (p > 0.05). In terms of rumen bacterial community composition, 264 operational taxonomic units (OTUs) were observed across the three TMR diets with 240, 239, and 220 OTUs in CON, L-IRGS, and H-IRGS, respectively. IRGS-based diets increased the relative abundances of genera belonging to phylum Bacteroidetes but decreased the abundances of genus belonging to phylum Firmicutes compared with the control. Data showed that Bacteroidetes was the most dominant phylum, while Prevotella ruminicola was the dominant species across the three TMR groups. The relative abundance of Ruminococcus bromii in the rumen increased in heifers fed with high inclusion of IRGS in the TMR (H-IRGS TMR). The relative abundance of R. bromii in the rumen significantly increased when heifers were fed H-IRGS TMR while P. ruminicola increased in both L-IRGS and H-IRGS TMR groups. Results from the current study demonstrate that the inclusion of IRGS in the TMR is comparable with the TMR containing high-quality forage (CON). Thus, a high level of IRGS can be used as a replacement forage ingredient in TMR feeding and had a beneficial effect of possibly modulating the rumen bacterial community toward mainly propionate-producing microorganisms.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.3
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• pp.232-237
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• 2015

The present study investigated the effects of Lysophospholipid (LPLs, LIPIDOL$^{TM}$) on the growth performance and nutrient digestibility of Hanwoo heifers. A feeding trial was performed for 120 days until slaughter using a herd of 24 Hanwoo heifers. Eight heifers were assigned to each of 3 experimental groups (control, 0.3% LIPIDOL$^{TM}$ and 0.5% LIPIDOL$^{TM}$). Growth performance, nutrient digestibility, and carcass characteristics were investigated. Significantly improved nutrient digestibility was found in the LIPIDOL$^{TM}$ treatment group compared to the control (p<0.05). No significant effect by LIPIDOL$^{TM}$ supplementation on growth performance was observed (p>0.05). However, interestingly, greater carcass weight was detected in the treatment of LIPIDOL$^{TM}$ where less daily gain was found. Although not a significant effect, greatly decreased back-fat thickness and increased loin area were detected in the treatment of LIPIDOL$^{TM}$. In meat characteristics, LIPIDOL$^{TM}$ increased intramuscular fat and tenderness. Therefore, the present study results suggest that the inclusion of LIPIDOL$^{TM}$ in the diet of Hanwoo heifers can improve carcass performance and meat quality by increasing the carcass index and the meat quality index. The results also suggest that a level of 0.3% might be more efficient than 0.5% with regard to economic effectiveness.

• Journal of Animal Science and Technology
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• v.64 no.5
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• pp.897-910
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• 2022

Bovine fecal microbiota is important for host health and its composition can be affected by various factors, such as diet, age, species, breed, regions, and environments. The objective of this study was to evaluate the impact of diet and gender on fecal microbiota in Korean native Hanwoo cattle. The 16S rRNA gene amplicon sequencing of fecal microbiota was conducted from 44 Hanwoo cattle divided into four groups: (1) 11 heifers fed an oat hay plus total mixed ration (TMR) diet for breeding (HOTB), (2) 11 heifers fed an early fattening TMR diet (HEFT), (3) 11 steers fed the early fattening TMR diet (SEFT), and (4) 11 steers fed the late fattening TMR diet (SLFT). Firmicutes and Bacteroidota were the first and second most dominant phyla in all the samples, respectively. The Firmicutes/Bacteroidota (F/B) ratio associated with feed efficiency was significantly greater in the SLFT group than in the other groups. At the genus level, Romboutsia, Paeniclostridium, and Turicibacter were the most abundant in the SLFT while Akkermansia, Bacteroides, and Monoglobus were the most abundant in the HOTB group. Although the same early fattening TMR diet was fed to Hanwoo heifers and steers, Marvinbryantia and Coprococcus were the most abundant in the HEFT group while Alistipes and Ruminococcus were the most abundant in the SEFT group. Shannon and Simpson diversity indices were significantly lower in the SLFT group than in the other groups. Distribution of fecal microbiota and functional genetic profiles were significantly different among the four treatment groups. The present study demonstrates that different diets and genders can affect fecal microbiota and the F/B ratio may be associated with feed efficiency in Hanwoo cattle. Our results may help develop strategies to improve gut health and productivity through manipulation of fecal microbiota using the appropriate diet considering Hanwoo cattle gender.