• Journal of Veterinary Clinics
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• v.37 no.5
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• pp.235-241
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• 2020

We aimed to determine the effect of timed artificial insemination (TAI) protocols on the pregnancy rate per insemination and pregnancy loss compared with AI performed at detected estrus in dairy cows and Korean Hanwoo cattle under heat stress. In dairy cattle, 1,250 sets of data that underwent AI during heat stress (temperature-humidity index ≥ 72) were categorized according to their TAI protocols or as controls: 1) PGF_2α-36 h-estradiol benzoate (EB)-36 h-TAI (PG-EB group, n = 113); 2) GnRH-7 days-PGF_2α-56 h-GnRH-16 h-TAI (Ovsynch group, n = 455); or 3) GnRH-6 days-Ovsynch (G6G group, n = 136). The remaining cows underwent AI at detected estrus (AIDE group, n = 546). The probability of pregnancy per AI 45 days after AI was higher (P < 0.01) in the PG-EB (odds ratio [OR]: 1.68), Ovsynch (OR: 1.48), and G6G (OR: 1.79) groups than in the AIDE group. However, the prevalence of pregnancy loss between 30 and 45 days after AI did not differ among the groups. In Hanwoo cattle, 617 sets of data inseminated artificially under heat stress were categorized into AIDE (n = 281), PG-EB (n = 194), and combined Ovsynch or G6G (n = 142) groups. The probability of pregnancy per AI 45 days after AI and the prevalence of pregnancy loss between 30 and 45 days after AI did not differ among the groups. Thus, implementation of a TAI protocol (PG-EB, Ovsynch, or G6G) in dairy cows under heat stress improves the pregnancy rate per AI versus AIDE, whereas there is no beneficial effect of TAI on the pregnancy rate of Hanwoo cattle under heat stress.

• Journal of Embryo Transfer
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• v.27 no.2
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• pp.93-100
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• 2012

To investigate the biochemical nature of changes in vaginal physiology during estrus and pregnancy, we examined the cytology and viscosity, and monitored the protein expression profile in vaginal mucus during estrus and pregnancy. The viscosity progressively decreased from estrus to pregnancy. Cell type analysis revealed that white blood cells progressively increased from estrus to pregnancy, while red blood cells progressively decreased during pregnancy. The cornification index (CI) was higher in estrus than in pregnancy. Protein mass spectrumetry identified the presence of ribosome-binding protein 1, GRIP 1 (Glutamate receptor-interacting protein 1)-associated protein 1, DUF729 (Domain of unknown function729) domain-containing protein 1, prolactin precursor, dihydrofolatereductase, and MMP (Matrix metalloprotease)-9 in vaginal mucus. MMP-2 and MMP-9 proteins in the vaginal mucus were active throughout estrus and gestation, as measured by a gelatinase assay, but most abundant in the vaginal mucus on day 0 of estrus. Results from ELISA of MMP-2 and MMP-9 were in accordance with the gelatinase assay. In light of the crucial role of metalloproteinases in extracellular matrix remodeling, the level of MMP-9 in vaginal mucus might be useful as an indicator of estrus and pregnancy to increase the efficiency of reproduction.

• Journal of Embryo Transfer
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• v.31 no.2
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• pp.137-143
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• 2016

This study was conducted to evaluate a visual surveillance system. The advancement of recording technology and network service make it easy to record and transfer the videos. Moreover, progressed recognition technology help to make a distinction each other. Cows show distinguishing behaviors during their estrus period. The mounting is one of the behaviors. The result was different depending on the breed of the cows and the size of the farm. In the case of Korean native cattle, the estrus detection rate was 71.15%, however, dairy cows, the estrus detection rate was 39.38%. At the farms having below 6 modules, the estrus detection rate was 87.41%. On the other hand, at the farms having over 6 modules, the estrus detection rate was 77.78%. With the proper progress, the visual surveillance system can be used to detect heat detection.

• Korean Journal of Veterinary Research
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• v.37 no.4
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• pp.917-924
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• 1997

Estrus cycle of cow, season and follicldar stimulating treatment, having an effect on the number of follicle, are investigated for the oocyte recovery rate in ovum pick-up(OPU). The number of follicle aspirated and oocyte collected on the different days of estrus cycle(D 4~5, D 9~10 and D 14~15) were not significantly different among the groups. The higher number of viable oocytes were produced on Jan-May(79.0%) than Jun-Aug(33.3%) by OPU in cow. The number of follicle and aspirated oocyte in cows treated FSH or PMSG combined with bovine somatotropin(bST) were 1.2~1.5 times higher than in cows treated alone follicular stimulating hormone(FSH) or pregnant mare serum gonadotropin(PMSG). In conclusion, OPU can be repeatedly practiced 2 or 3 times in an estrus cycle. In addition, the high environmental temperature is not good for ovarian function of cow and the bST co-treatment with FSH or PMSG is increasing the number of aspiratable follicle.

• Korean Journal of Agricultural Science
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• v.46 no.2
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• pp.395-404
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• 2019

This paper investigated the changes in Hanwoo breeding farms and herds according to their farm size and farm types based on traceability data in the Hanwoo industry. The major results are summarized as follows. First, the notion that small sized farms are breeding farms and middle or large sized farms are fattening farms is wrong. The results show that middle or large farms are not only fattening cattle but also breeding female cattle. Based on cattle data for over 6 months and under the criteria of a female cow ratio of 10 and 90% using the 2/4 quarter of 2018, the results show that the ratio of fattening only farms is 5.7%, that of breeding only farms is 59.0%, and that of fattening and breeding farms is 36.1%. The ratios of fattening, breeding, and both are 13.3, 13.5, and 73.2%, respectively, for a farm size with over 100 cattle. Second, this study found that the ratio of breeding farms over total farms has been increasing continuously over the last 5 years. This trend is apparent in the middle or large sized farms. However, the birth rate of cows is relatively lower in the middle and large sized farms than in the small sized farms. Hence, we can infer that the demand for a detection system for standing estrus in female cattle will increase. Additionally, the government should prepare relevant policies to stabilize the managerial conditions of middle or large sized farms.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.125-130
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• 2021

Implementation of livestock smart-farm can be done more effectively with IoT technology developing. An build of useful stock management system can be possibile if push messages of these judgement are notified on smart-phone after cattle's illness and estrus are judged using IoT technology. These judgement method of cattle's illness and estrus can be done with gathering living stock data using temperature sensor and 3 axis acceleration sensor and sending these data using IoT and internet network into server, and studying AI machine learning using these data. In this paper, to build this cattle management system based on IoT, effective system of the whole architecture is showed. Also an effective analysis and design method to develop this system software will be presented by showing user requirement analysis using object-oriented method, flowchart and screen design.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1093-1101
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• 2003

Reproductive data, such as numbers of days to the first estrus and A.I. service postpartum, number of days to conception, number of A.I. services required for conception, interval between the first estrus and first A.I. service and the average interval of A.I. service in Thai native-Friesian crossbred and pure Friesian dairy cows, were compiled in the National Dairy Training and Applied Research Institute in Chiang Mai, Thailand. The data were analyzed statistically and the effect of milk production on these reproductive traits was investigated. The reproductive efficiency of purebred cows was obviously inferior when compared with crossbred animals, in spite of special care being given to the purebred only in order to alleviate the effect of a tropical climate and provide better feeding. However, the regression analysis between reproductive and lactational parameters revealed a definite antagonistic effect of lactation on reproduction, especially in the purebred cows, which had a larger amount of milk production and longer lactation period. If these effects of lactation were eliminated, there would be no evident difference in reproductive efficiency between purebred and crossbred cows in the conditions of this study. Among the reproductive parameters examined, the number of days to the first estrus and interval between the first estrus and first A.I. service were less affected by breed difference and the magnitude of lactation than other reasons.

• Journal of Embryo Transfer
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• v.1 no.1
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• pp.35-49
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• 1986

Recipients are an integral part of embryo transfer and they are expensive to maintain as a good recipient. Recipient management is one of the most important components in a successful embryo transfer program. Management includes selection and subsequent care of the animals. A good recipient is basically on "open" cows or heffers whose reproductive tract is capable of receiving one or two embryos and incubating it to term. Potential recipients should be always be healthy and cycling normally ranging from 18 to 23 days. A thorough veterinary examination is recommended for candidate of recipients and cattle for questionable health should be eliminated from the recipient herd. Age and size of recipients are particularly important considerations when heifers are used, because of most embryos available for transfer are from large dams and sires. Body condition can influence a recipient's production, reproduction and health. Obese and underconditioned cattle should be avoided for use. Transfer of fresh embryos especially requires precise synchronization of donors and recipients. For estrus synchronization, PGF$_2$$\alpha$ is injected twice 10 to 12 days apart and short4erm progestagen treatment is applied to potential recipient cattle by coil into vagina (PRID) or ear implant (Synchro-Mate-B). The highest pregnancy results are achieved in recipients at exact synchrony with donors or 12 to 24 hr earlier than donors. Estrus detection is a major factor in breeding efficiency. High accuracy can be achieved by use of heat mount detection alds or by obserbing cattle for 30-minute peroids 3 times daily. Assay progesterone in milk can be used to discrIminate between pregnant and nonprenant recipients. Rectal palpation on day 35 to 70 after is an accurate and safe method of pregnancy diagnosis. Embryonic mortality in recipients may be associated with factors such as high environmental temperature and nutritional or lactational stress in early lactation period. Achievement of short calving interval requires concentrated management activity during the first 90 days following calving. Acceptable candidate for a recipient should be routinely vaccinated for infectious diseases. Proper nutritional programs according to NRC requirements and body condition scoring system for recipient cattles are vital to the ultimate success of an embryo transfer program.r program.

• Journal of Embryo Transfer
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• v.12 no.1
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• pp.75-90
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• 1997

This study was carried out to establish the techniques for producing the calves of genetically superior Korean Native cattle by transfer of frozen-thawed embryos. The effects of some factors related to embryo recovery following superovulation and pregnancy rate following transfer of frozen-thawed embryos were evaluated. Also calving state was investigated. The results obtained were as follows ; The mean number of total and transferrable embryos recovered per superovulated cow was 8.72 and 4.90, respectively, from a total of 72 superovulations using 34 donor cows. There were no significant differences in the number of total or transferrable embryos recovered per superovulated cow between products of follicle stimulating hormone (FSH), years, seasons, and collection numbers. The pregnancy rate was found 44.44% following transfer of frozen-thawed embryos of Korean Native cattle to a total of 180 recipient cows including 82 Angus, 27 Charolais, 62 Hereford and 9 Korean Native cows. The pregnancy rate was significantly (P<0.05) higher in the transfer of excellent (42.99) and good embryos (40.17%), compared with fair (5.90%) grade embryos. And the pregnancy rate was significantly (P<0.05) higher in the transfer of embryos of morula stage (43.86%) than blastocyst stage (15.51%). But there were no significant differences in pregnancy rates between natural and induced estrus estrus asynchrony of 1 days, breeds, and parities of recipient cows. The normal calving rate of 80 pregnant cows following transfer of frozen4hawed em-bryos was 87.5% and the other 10 pregnant cows showed abortion during the period from pregnancy diagnosis at 50~60 days to calving. The average gestation length of normally delivered recipients was 288.50 days and the average birth weight of 70 calves born was 24.22 kg. The gestation length was significantly (P<0.05) shorter in the recipients delivering female calves (286.70 days) than males (289.39 days). But there were no significant differences in gestation tength and birth weight of calves born between the recipient breeds.

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.3
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• pp.153-156
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• 1988

Bovine blastocysts were obtained by in-vitro culture of embryos derived from in-vitro fertilization of oocytes matured in-vitro. These blastocysts and blastocysts from inseminated donors were bisected by a simple method (without a holding pipette) using a microblade operated by a micromanipulator. A pair of demi-embryos was transferred nonsurgically into each uterine horn of a recipient cow 6 or 8 days after estrus. Pregnancy resulted from the third transfer. Ultrasound examination done 52 days after estrus (46 days after transfer) confirmed the presence of at least one fetus in the each uterine horn. This is the first report to show the viability of bisected bovine blastocysts obtained from in-vitro culture of embryos derived from in-vitro fertilization of oocytes matured in-vitro. In addition, a simple method to bisect bovine embryos is described.