• Reproductive and Developmental Biology
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• v.41 no.2
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• pp.25-31
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• 2017

Effective estrus detection and artificial insemination (AI) are necessary for profitable management of dairy herd. In current study, 45 crossbred lactating cows have been selected with the complaint of unobserved oestrus for more than sixty days postpartum. All cows had functional corpus luteum as examined by transrectal ultrasonography. Cows were treated with $PGF_2{\alpha}$ analogue and AI was performed with observed oestrus and then single dose of GnRH was administered. Similar synchronization protocol has been repeated after 14 days in cows that did not repose to first treatment. Remaining cows received additional $PGF_2{\alpha}$ after 14 days of second treatment and timed AI was performed following GnRH administration. Among 45 cows, 28.89% showed estrus after first treatment and 78.79% responded to second hormonal intervention. A higher conception rate (88.89% vs 26.66 and 72.72%) was observed in cows after triple administration of $PGF_2{\alpha}$ and timed AI. We noticed a significant differences in body condition score (BCS, 1~5 scale), postpartum period, and daily milk production between cows that either responded of non-responded following first and second hormonal treatment. In addition, there was a significant positive correlation between daily milk production and BCS, age and postpartum days, milk production and estrus/BCS, and milk production/BCS/estrus and conception rate. Depending upon the findings we conclude that hormonal intervention with $PGF_2{\alpha}$ and GnRH enhances postpartum ovarian cyclicity and help decreasing the days open of dairy herd. Therefore, this finding might provide an excellent guideline for target breeding system for profitable dairy herd management.

• Korean Journal of Agricultural Science
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• v.42 no.3
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• pp.245-251
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• 2015

Records of 490,767 cows collected from 1990 to 2012 by dairy herd milk test of National Agriculture Cooperative Federation The pedigree of dairy cattle were provided by Korea Animal Improvement Association. The data were used to analyze the longevity of dairy cows with the life traits such as days in milk, number of lactation, productive life, and life span. The data were also used to investigate genetic relationship of these longevity traits with profitability of dairy cows, including heritability and genetic correlation. The profitability was calculated with simulation of milk income and production costs for individual cows. Days in milk among the traits had -0.287, -0.572 and -0.536 of genetic correlation with number of lactations, productive life and lifespan, respectively. The heritabilities of life span, number of lactations, productive life, and days in milk were found to be 0.045, 0.047, 0.059 and 0.081, respectively. Genetic correlations of profit with productive life, number of lactations, and days in milk were identified as 0.072, 0.080, 0.098 and 0.101. These results suggested that days in milk was most desirable traits to represent longevity of Holstein dairy cattle. In general, since longevity and profitability were close genetic relationship each other, genetic improvement of longevity is necessary for better profitable cows.

• Journal of Animal Science and Technology
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• v.48 no.3
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• pp.479-486
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• 2006

The current study was conducted to examine the effect of feeding and management practices on milk quality and dairy farm productivity in Korea. Fifty dairy farms in Gyunggi (11), Gangwon (22), Chungnam (17) provinces were surveyed to collect data on the herd size, housing style, feeding management, waste disposal, milking practices and milk yield. Milk tank samples from all farms under study were also collected to enumerate its composition and quality parameters. Large dairy herds are equiped with better housing, milking and waste control facilities than medium and small dairy herds. Higher concentrate feeding to lactating cows was noticed in small dairy herds (47.51 %) than in medium (32.59 %) and large dairy herds (31.82 %). The decrease in concentrate feeding to lactating cows with increase in number of cows per farm resulted in a simultaneous increase in the use of imported forages. Bacterial count in milk was affected by housing and milking facilities at dairy farms. Higher bacterial counts (Coliform and E. coli) in milk were observed in cows housed in stanchion than those under free stall with saw dust bedding. The bacterial counts were higher with bucket milking system than with pipe-line and parlour systems. The increase in the number of dairy cows per farm and thus better management and milking facilities resulted in a reduction in somatic cell score. Milk yield (per cow) was higher in herds with less somatic cell score. Average milk protein concentration was between 2.89 to 2.98 % and milk urea nitrogen was between 21.81 to 23.31mg/ml on surveyed dairy farms. This study concluded that large herd size with better dairy cow management facilities is crucial to produce quality milk with better dairy farm income.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.11
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• pp.1523-1526
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• 2001

To study the secretion of trace elements during early lactation, twelve lactating Murrah buffaloes were selected from the herd of the institute. The buffaloes were divided into two groups of six each. Buffaloes of group I were not injected and served as control. Buffaloes of group II received oxytocin injection (2.5 I.U.) intramuscularly for a period of five days for let down of milk. Milk samples were collected from both groups of buffaloes five days before, during and after the administration of oxytocin. Aliquots of milk samples from each buffalo were composited in proportion to their milk yield and used for analysis of trace elements in milk. In both the groups of buffaloes Cu, Mg, Fe, Zn and Mn contents did not vary significantly between animals. However, Ca levels varied significantly (p<0.01) between animals. Administration of oxytocin influenced (p<0.01) Cu, Mg, Zn, Fe and Mn secretion in milk. However, Ca secretion was not affected by oxytocin administration. Secretion of these elements also varied significantly during different days of the study. Zinc content of milk in the control group also varied significantly (p<0.01) during different days and periods of study indicating thereby no effect of oxytocin. The study indicated that administration of oxytocin increases Cu and Mn content and decreases Mg, Fe and Zn content without altering the Ca concentration of milk.

• Korean Journal of Veterinary Service
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• v.36 no.4
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• pp.243-248
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• 2013

Q fever is a rickettsial infection caused by Coxiella burnetii that is transmitted from animals to humans. Modes of transmission to humans include inhalation, tick bites and ingestion of unpasteurized milk or dairy products. This survey was aimed at monitoring the seroprevalence of C. burnetii in bulk-tank milk (BTM) in Gyeongbuk province. In addition, the seroprevalence of C. burnetii was investigated at the herd level of dairy cattle in eastern Gyeongbuk province in which many dairy cattle are reared. Among 324 BTM samples collected from 20 country areas, 175 (54%) BTM samples from 15 (75%) country areas were positive for C. burnetii by ELISA. By regions, the seroprevalence of BTM samples in eastern, central, western and northern areas of Gyeongbuk province were 62.7%, 48.4%, 45.1%, and 41.4%, respectively. When analyzed in the dairy cattle reared in the eastern area where high seroprevalence occurred in BTM samples, 119 (24.2%) out of 492 dairy cattle were positive for C. burnetii. Seroprevalence of C. burnetii in dairy cattle was increased with daily milk yield of farm (P<0.05) and age (P<0.001). Since seroprevalence of C. burnetii is relatively high in both BTM samples and dairy cattle reared in Gyeongbuk province, further studies on the high risk farms and herds are needed to evaluate infection status and appropriate control programs in this region.

• Korean Journal of Veterinary Service
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• v.22 no.2
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• pp.159-167
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• 1999

This survey was conducted for the serological confirmation on large outbreak of bovine brucellosis in two dairy farms. Serological tests were performed by the plate agglutination test, tube agglutination test, enzyme linked immunosorbent assay(ELISA), complement fixation, ,test(CFT) and rose bengal plate test(RBPT). Total 200 heads(134 heads in farm A and 66 heads in farm B) were tested. The primigravida and positive group have been raised separately in the farm A and both group have been raised together in the farm B.. The result were summarized as follows ; 1. Positive ratios in positive herds of farms by the tube agglutination test were 68.3% in farm A and 53.2% in farm B. 2. Seroconversion to brucella was observed in the primigravidas group in farm B, but was not observed in the primigravidas group in farm A. 3. All calves born in positive herd were serologically negative at time of test. 4. Positive ratio of ELISA in farm A was higher than that of tube agglutination test. 5. Number of positive reactors by the CFT, RBPT in farm A were equal to those of tube agglutination test.

• Proceedings of the KSAR Conference
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• 2001.10a
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• pp.59-59
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• 2001

This study was designed to assess effect of MUN concentration on reproduction performance and monitoring of feeding and fertility management in commercial dairy herd. The mean of milk yield is 26.48±8.38㎏ per day, milk fat 3.80±0.58%, protein 3.13±0.3% MUN 16.68±5.87㎎/㎖ and somatic cell 392,000±77,060㎖. Milk yield has been shown that negative correlation with fat, protein and somatic cell(P〈0.01). The finding of this study was significant relationship between non-pregnant days and MUN concentration. (omitted)

• Korean Journal of Veterinary Research
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• v.61 no.4
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• pp.33.1-33.5
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• 2021

This study reports the detection and genotyping of the first clinical case of bovine anemia due to Theileria orientalis group (BATOG) in non-grazed dairy cow in upper South Korea. Blood and serum tests revealed anemia and hyperbilirubinemia from animal showing clinical symptoms, and later confirmed as piroplasmosis-positive. Follow-up surveillance on the herd revealed 2 asymptomatic cows with anemia. The three animals were confirmed theileriosis-positive and genotyping revealed the clinical and one of the asymptomatic cases have Chitose, while the other has Ikeda genotype. Clinical BATOG cases were rarely reported worldwide, and asymptomatic animals left untreated could serve as parasite reservoir.

• Korean Journal of Veterinary Research
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• v.41 no.3
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• pp.407-412
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• 2001

Milk data may be increasingly used as indicators of the protein-energy balance and actual farm feeding practices. It was related to milk production, nutritional and reproductive disorders. The purpose of this study was to investigate the relationship between level of fat, protein or milk urea nitrogen (MUN) from the first test within 35 days in milk and displaced abomasum (DA) in a large dairy herd with high yielding Holstein cows. Milk data from forty-five DA cases were compared to those from 90 healthy cows. Higher odds of DA diagnosis was found with higher 5.0% milk fat, lower 3.0% milk protein. Therefore, cows with a fat to protein ratio of>1.5 had higher risks for DA. Also, incidence rates of DA was higher in the cows which the level of MUN was lower than 12.0 mg/dl or higher than 25.0 mg/dl relative to healthy cows. These results indicate that cows diagnosed with DA were energy deficient prior to DA diagnosis. We conclude that level of fat, protein or MUN serve as a monitoring tool of protein and energy nutritional balance in early lactation cows and also as a significant predictor of risk for DA.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.2
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• pp.153-158
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• 2004

Data containing 14,188 lactation and reproductive records of Korean Holstein cows at first parity distributed across 3,734 herd-year-season groups were analyzed to get genetic (co)variance estimates for milk yield, fat yield, calving ease, and days open. Milk and Fat yields were adjusted to 305 d. Heritabilities and genetic correlations were estimated in two different animal models on which were included direct genetic effects (Model 1) and direct+maternal genetic effects (Model 2) using REML algorithms. Milk and fat yields were affected by age at first calving as linear and quadratic. Heritability estimates of direct effects were 0.25 for milk yield, 0.17 for fat yield, 0.03 for calving ease and 0.03 for days open in Model 2. These estimates for maternal effects were 0.05, 0.08, 0.04 and less than 0.01 for each corresponding trait. Milk productions at first lactation were to show genetically favorable correlation with calving ease and days open for direct genetic effects (-0.24 - -0.11). Moreover, calving ease was correlated with days open of 0.30 for direct genetic effects. Correlations between direct and maternal effects for each trait were negatively correlated (-0.63 - -0.32). This study suggested that maternal additive genetic variance would be not ignorable for genetic evaluation of milk production as well as reproductive traits such as calving ease and days open at first parity. Furthermore, difficult calving would genetically influence the next conception.