• 현장농수산연구지
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• 제20권2호
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• pp.49-56
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• 2018

최근 국내 낙농 현장에서는 육성우시기에 에너지가 높은 사료를 급여함으로써 초발정일을 단축시키고자 한다. 육성우 시기의 사양관리는 향후 유생산 및 번식능력과 밀접한 관련이 있으나 아직까지 관련 연구가 부족한 실정이다. 본 연구는 홀스타인 육성우시기에 에너지 급여 차이에 따른 번식능력을 분석하였다. 한국사양표준과 고에너지(한국사양표준의 110%) 사료 급여 시 체고 및 체중에는 차이가 없었으나 초발정일은 329.3일과 311일로 고에너지 급여 시 초발정일이 단축되는 결과를 보였다. 고에너지 급여에 따른 수태당 교배횟수 상승 및 분만 강도에는 차이가 없었으며 고에너지 급여 시 암송아지의 체중이 상승하였다. 또한 고에너지 급여에 따라 암송아지 생산 비율이 상승하였다. 연구 결과를 종합해 볼 때 현장에서는 한국 사양표준의 110% 에너지를 급여 했을 때 암소의 번식능력 상승이 기대된다. 본 연구 결과는 국내 낙농 현장에서 육성우 시기에 급여할 에너지양 및 이에 따른 번식능력의 상관관계를 제시함으로써 낙농 현장에 도움을 줄 것으로 사료된다.

• 한국동물생명공학회지
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• 제38권4호
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• pp.215-224
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• 2023

Background: Reproductive management practices play crucial roles to maximize the reproductive performance of cows, and thus contribute to farm profitability. We aimed to assess the reproductive management of cows currently practiced in the dairy farms in an urban farming system. Methods: A total of 62 dairy farms were randomly selected considering all size of farms such as small (1-5 cattle), medium (6-20 cattle) and large farms (> 20 cattle) from selected areas of Dhaka city in Bangladesh. The reproductive management-related parameters viz. estrus detection, breeding method, pregnancy diagnosis, dry cow and parturition management, vaccination and treatment of reproductive problems etc. were obtained in a pre-defined questionnaire during the farm visit. Results: The visual observation method was only used (100.0%; 62/62) for estrus detection irrespective of size of the farms; while farmers observed cows for estrus 4-5 times a day, but only for 20-60 seconds each time. Regardless of farm size, 89.0% (55/62) farms used artificial insemination (AI) for breeding the cows. Intriguingly, all farms (100.0%) routinely checked the cows for pregnancy at 35-40 days post-breeding using rectal palpation technique by registered veterinarian. However, only 6.5% (4/62) farms practiced dry cow management. Notably, all farms (100.0%) provided nutritional supplements (Vit D, Ca and P) during late gestation. However, proper hygiene and cleanliness during parturition was not practiced in 77.4% (48/62) farms; even though 96.7% (60/62) farms treated cows by registered veterinarian for parturition-related problems. Conclusions: While farmers used AI service for breeding and timely check their cows for pregnancy; however, they need to increase observation time (30 minutes/ observation, twice in a day: early morning and early night) for estrus detection, consider dry cow management and ensure hygienic parturition for maximizing production.

• Toxicological Research
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• 제16권3호
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• pp.229-238
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• 2000

The purpose of reproductive toxicity studies is to evaluate all effects resulting from paternal or maternal exposure that interfere with conception, development, birth, and maturation of offspring. In 1966, the US Food and Drug Administration (US FDA) published guidelines for a three-segment study for drug testing to examine adverse effects on fertility and pregnancy. Three segments were proposed: Segment I, Study of Fertility and General Reproductive Performance, to provide information on breeding, fertility, nidation, parturition, neonatal effects and lactation: Segment II, Teratological study, to provide information on embryo toxicity and teratogenicity: and Segment III. perinatal and Postnatal Study, to provide information on late fetal development, labour and delivery, neonatal viability, and growth and lactation. The classic guideline is still used to this day with only monor modification throughout the world. In the present review, the principles and methods of reproductive toxicity studies are discussed with special attention given to scientific issues.

• 한국임상수의학회지
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• 제20권3호
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• pp.369-375
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• 2003

The ultrasonography was performed in 77,924 subestrous dairy cows from 680 dairy farms at 57 districts. The cows were examined for confirmation of resumption of ovaries and uterus after 30 days postpartum, for early pregnancy diagnosis after 30 days post-insemination, confirmation of pregnancy at 8 month post-insemination, and for diagnosis of reproductive dysfunctions, respectively. The results of reproductive examination by ultrasonography in 77,924 dairy cows were ovarian disorders 35,452 (46.8%), uterine disorders 10,721 (13.8%), pregnancy and pregnant failure 24,044 (30.8%), adhesion of reproductive tracts 167 (0.2%), freematins 13 (0.01%) and others 6,527 (8.4%) cows, respectively. The 13,732 (49.6%) cows out of 27,694 cows were treated for silent heat or error of estrus detection, 3,473 (12.5%) cows for follicular cysts, 815 (3.0%) cows for luteal cysts, 606 (2.2%) cows for inactive ovaries, 4 (0.01%) cows for granulosa cell tumors, and 6,455 (23.3%) cows for endometritis, respectively. The indices of reproductive efficiencies before (2001-08-10) and after (2003-07-20) periodical examination of reproductive status were as follows; the mean intercalving interval were shortened from 471 days to 383 days, the mean interval calving to conception were shortened from 187 days to 99 days, the mean interval calving to first service were shortened from 105 days to 67 days, the mean cows showing heat by 60 days postpartum were increased from 33% to 89%, the mean conception rate to first service were increased from 43% to 68%, and the mean service per conception were shortened from 2.6 times to 1.8 times, respectively. These results suggest that periodical examination of reproductive status would be useful for the improvement of the reproductive performance in dairy cows.

• 한국동물생명공학회지
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• 제37권4호
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• pp.266-275
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• 2022

The impact of heat stress (HS) on reproductive performance and its problems in cows remains to be investigated in Bangladesh. The study was, therefore, aimed to evaluate the effect of HS on fertility and reproductive health problems of dairy cows in a selected area of Bangladesh. A total of 1,095 cows from 500 farms were included in this study. The climate-related data were recorded daily basis for every month in a year and temperature-humidity index (THI) values were calculated to determine the level of HS. Concurrently, data on fertility parameters [number of services per conception (NSC), conception rate (CR) and calving to the first service interval (CFSI)], and reproductive problems were collected through a pre-defined questionnaire. The results show that crossbred [Native x Holstein-Friesian, (HF)] cows were more vulnerable (p < 0.05) to a magnitude of HS effects considering physiological parameters of cows [age, body condition score (BCS), parity and milk yield]. Regarding fertility, HS had no effect on NSC, CR and CFSI in both native and crossbred cows (p > 0.05). The findings on the reproductive problems indicate that HS had significant influence on the prevalence of anestrus (χ² = 21.814, p < 0.05) and retained placenta (χ² = 24.632, p < 0.05) in cows. Of note, the prevalence of repeat breeding syndrome was 2.5 folds higher in stress condition than in no stress condition. Abortion and dystocia were not influenced by HS. In conclusion, HS does not influence the fertility parameters of cows studied; however, anestrus and retained placenta are likely to occur under HS conditions in cows.

• Asian-Australasian Journal of Animal Sciences
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• 제33권5호
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• pp.722-731
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• 2020

Objective: Two experiments were conducted using 28 healthy multiparous sows to evaluate the oxidative stress status and reproductive performance of sows during gestation and lactation under different thermal environments. Methods: Fourteen multiparous sows were used in Exp. 1 under a high thermal environment, and the other 14 multiparous sows were used in Exp. 2 under a moderate thermal environment. In both experiments, reproductive performances of sows were recorded. Plasma samples were collected on d 35, 60, 90, and 109 of gestation, and d 1 and 18 of lactation for malondialdehyde, protein carbonyls, 8-hydroxy-deoxyguanosine, immunoglobulin g (IgG), and IgM analysis. Results: For sows in Exp. 1, plasma malondialdehyde concentration on d 109 of gestation tended to be greater (p<0.05) than it on d 18 of lactation. Plasma concentration of protein carbonyl on d 109 of gestation was the greatest (p<0.05) compared with all the other days. Plasma concentrations of 8-hydroxy-deoxyguanosine on d 109 of gestation was greater (p<0.05) than d 18 of lactation in Exp. 1. For sows in Exp. 2, there was no difference of malondialdehyde and protein carbonyl concentration during gestation and lactation. In both Exp. 1 and 2, litter size and litter weight were found to be negatively correlated with oxidative stress indicators. Conclusion: Sows under a high thermal environment had increased oxidative stress during late gestation indicating that increased oxidative damage to lipid, protein, and DNA could be one of the contributing factors for reduced reproductive performance of sows in this environment. This study indicates the importance of providing a moderate thermal environment to gestating and lactating sows to minimize the increase of oxidative stress during late gestation which can impair reproductive outcomes.

• 한국수정란이식학회지
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• 제27권2호
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• pp.87-92
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• 2012

A study on estrus synchronized dairy cows using progesterone intravaginal device was done to classify each cow's reproductive status from calving to synchronization and to evaluate the reproductive performance according to ovarian and uterine status, and calving season. From calving to estrus synchronization, silent heat or error of estrus detection among ovarian status and endometritis among uterine disorders were exposed in the most distribution (75.4% and 48.3%, respectively). The pregnancy rate of cows with inactive ovaries was lower than those in the follicular and luteal phase. And according to the uterine status before estrus synchronization, the pregnancy rate was similar in three groups; normal, endometritis, and pyometra (70.9, 69.1 and 100%, respectively). The interval from calving to conception was shorter (p<0.05) in cows calved during autumn than in cows calved during spring and winter.

• 농업과학연구
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• 제47권3호
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• pp.667-672
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• 2020

It is well known that intensive selection caused a decline in reproductive performance in dairy cattle. Interestingly, the reproductive performances including fertility and calving interval of Korean native beef cattle have declined in the last 20 years, suggesting that a breeding program focusing on carcass weight and intramuscular fat may affect the reproductive physiology in Korean native beef cattle, too. In this study, we analyzed the calving interval (CI) and selection index (SI) based on genome-wide association studies (GWAS) of Hanwoo cows for seven years (2013 - 2019). Multiparous cows (4.5 ± 0.11) were analyzed, which were bred by artificial insemination (AI). We first examined the distribution of the AIs and calving dates. About 40% of the AIs were carried out in May to June and October to December; subsequently, calving was observed from March to April and August to October, respectively, indicating the cows were seasonally bred. No correlation between CI and SI was found (y = 0.0459x - 17.64; R² = 0.0356), but the ratio of cows with a positive SI was higher in the longer CI group compared to the shorter group, suggesting that the selection for meat quality and quantity may affect the reproductive performances. In addition, the average value of SI was - 3.42 in the CI < 400 while + 5.79 in the CI > 400 although the values were not statistically significant. However, our results suggest that reproductive indices such as fertility and CI should be considered for sustainability in the Hanwoo breeding selection program.

• 한국가축번식학회지
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• 제26권3호
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• pp.291-298
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• 2002

본 연구는 경상북도 영주지역의 한우 사육농가를 대상으로 사육규모와 형태, 사양관리 방법 등 번식우의 사양관리 형태와 번식우의 번식장애 발생률을 조사하였으며, 번식장애우에 대하여 proge-sterone제재인 control internal drug releasing for cattle(CIDR)를 처리하여 치료효과를 구명하기 위하여 수행하였다 번식장애우에 대한 CIDR 처리는 7일간 질내에 삽입하였으며, 제거 하루 전에 PGF$_2$$\alpha$를 투여하여 황체를 퇴행 발정을 유기하고 발정 확인 후 10시간 간격으로 인공수정을 실시 임신의 유무로 치료 판정한 결과는 다음과 같다. 1. 경북 영주지방의 127호의 한우 사육농가에서 사육하는 총 1,061두의 번식우의 번식상황을 조사한 결과 번식장애우는 209두로서 발생률은 19.7%이었다. 사육규모별 번식장애 발생율은 10두 이하, 10~20두 및 20두 이상 농가에서 각각 37.5, 14.7 및 13.6%로서 사육규모가 커질수록 발생률이 유의적으로(P<0.05) 낮아지는 경 향이 었다. 2. 번식우의 농가 사육형태별 번식장애 발생률은 계류사육이 30.4%로서 군사의 14.7%보다 유의 적으로(P<0.05) 발생률이 높았으며, 군사의 경우 두당 사육면적이 넓을수록 번식장애 발생률이 낮아지는 경향이었다. 3. 번식장애우의 산차별 분포를 보면 미경산우가 50.7%로 가장 많았으며 산차가 증가할수록 번식장애우에서 차지하는 비율이 감소하는 경향이었다. 4. 번식장애우의 요인별 분포는 무발정이 65.1%, 미약발정 29.2%, 난소낭종 4.3% 그리고 기타1.4%의 순으로 많이 분포되었다. 5. 209두의 번식장애우에 CIDR를 처리하고 인공 수정한 결과 157두가 임신되어 75.1%의 치료효과를 얻었다. 번식장애우의 신체충실 지수별 치료효과는 신체충실 지수가 1, 2 및 3인 경우 수태 율이 각각 85.7, 84.9 및 86.8%로서 유의 적으로(P<0.05) 높았으며, 전체적으로 다소 야윈 경우가 과비된 경우에 비하여 치료 효과가 좋았다. 본 연구결과를 종합하면, 한우 사육농가의 번식장애 발생률은 19.7%로서 사육규모가 커서 농가의 관심도가 높을수록 또한 계류보다는 넓은 면적에서 군사하는 경우가 번식장애 발생률이 낮았으며, 요인별로는 발정과 관련된 장애가 많았다. 이러한 번식장애우도 농가에서 손쉽게 이용할 수 있는 progesterone 제재인 CIDR를 처리함으로서 75.1%를 치료할 수 있으며 치료 효과를 높이기 위해서는 신체충실지수를 1, 2 및 3으로 유지하기 위한 적정 사양관리가 필요하다고 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권7호
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• pp.932-936
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• 2014

Breeding records of 57 Arabian and 66 Thoroughbred mares were analysed to assess their reproductive performance under the subtropical conditions of Pakistan. The Arabian mares showed significantly higher conception rates (p<0.05) in second mated oestrus and foal heat mated oestrus compared to Thoroughbred mares. However, conception rates for first lifetime mated oestrus were similar in both breeds of mares. Age at first mating ($1,301{\pm}40$ vs $1,500{\pm}32$ days) was significantly (p<0.05) less in Arabian compared to Thoroughbred mares. Both breeds of mares showed significantly (p<0.05) higher frequencies of oestrous cycles and conception rates during the winter (October to March) compared to summer (June to August) months. Age of mares affected the conception rates, as mares at ages 3 to 7 and 8 to 12 years of ages had significantly higher conception rates (p<0.05) than those ${\geq}18$ years old in both breeds. This study demonstrates that i) reproductive performance in Arabians is better than Thoroughbred mares under the subtropical conditions of Pakistan, ii) mares remain cyclic throughout the year and iii) conception rates were higher in mares bred during winter compared to summer months.