• Journal of Veterinary Clinics
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• v.30 no.3
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• pp.178-185
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• 2013

This study evaluated the effects of milk yield on the postpartum health and reproductive performance of dairy cows. In total, data were collected from 1,060 cows on six dairy farms, including their milk production, body condition score (BCS), postpartum disorders, and reproductive performance. The lactation data were grouped based on the 305-day milk yield into control (< 10,000 kg, n = 445) and high milk yield (${\geq}$ 10,000 kg, n = 615) groups. The milk fat and protein, and BCS were lower during the first 5 months postpartum in the high milk yield group compared with the control group (p < 0.01). Ovarian cysts were more frequent (p < 0.0001) in the high milk yield group (28.6%) than in the control group (15.3%), whereas endometritis tended to be less frequent in the high milk yield group (29.6%) than in the control group (35.1%, p = 0.06). A higher proportion of cows tended to receive reproductive hormones (p = 0.06) in the high milk yield group (62.4%) than in the control group (56.6%). The probability of a pregnancy after first insemination tended to be lower (odds ratio = 0.78, p = 0.07) in the high milk yield group (30.2%) than in the control group (35.2%). Furthermore, the hazard of pregnancy by 210 days in milk was lower in the high milk yield group (hazard ratio = 0.84, p = 0.04) than in the control group, which resulted in a 20-day increase in the median interval to pregnancy. In conclusion, high milk yield was related to lower milk fat and protein, lower BCS, an increased incidence of ovarian cysts, and increased use of reproductive hormones, which resulted in decreased reproductive performance of dairy cows.

• Korean Journal of Animal Reproduction
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• v.11 no.1
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• pp.22-25
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• 1987

This study was carried out to investigate the effects of imported pellet frozen semen on sperm motility and NAR acrosomes after thawing, and the farrowing rates, litter sizes and preweaning body weights after artificial insemination. A total of 28 sows of Landrace, Large White and Duroc were inseminated at the Chungnam Provincial Animal Breeding Station. The results obtained are summarized as follows: 1. Landrace andLarge White had higher sperm motility than Duroc by about 20% and had higher NAR acrosomes by about 10%. 2. The farrowing rates of Landrace, Large White and Duroc were 63.6, 55.6 adn 50.0%, respectively. The number of pigs born alive per litter were larger in Landrace and Large White as compared with Duroc (p<.01). 3. Duroc had the highest mean pig weight at birth, followed by Landrace and Large White (p<.01). The mean pig weights at 21 days and 56 days had no significant differences between the breeds.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.07a
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• pp.130-135
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• 1999

젖소 농가에서 생산성을 높이려면 젖소의 번식성능을 최상으로 유지해야 한다. 성공적인 번식관리는 효율적이고 정확한 발정 감지 기술에 크게 의존한다. 발정감지에 실패하게 되면 공태기간이 길어져 유량은 물론 송아지 생산이 감소된다. 발정감지 실패로 인한 공태기간이 한 주기일 경우, 국내 연간 손실이 85억원(2400원/두/일 $\times$ 562,000 두 $\times$ 30% $\times$ 21일)에 이를 것으로 추정된다(Senger, 1994). 공태기간이 지나치게 길어진 저 능력소는 대개의 경우 도태시켜야 하므로 이에 따른 추가손실이 발생되며, 인공수정 횟수 증가에 따른 손실과 수의사 비용 등의 추가 비용은 전체 손실의 10%에 해당된다 (Ruiz et al., 1992, Britt, 1985). (중략)

• Journal of Embryo Transfer
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• v.9 no.1
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• pp.31-41
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• 1994

핵 이식 기술을 이용한 cloning 송아지 생산이 처음 보고(Prather et al., 1987) 된 후, 소 수정란 Cloning에 대한 많은 연구가 분자 생물학 등 여러 분야에서 꾸준히 계속되고 있다. 이 기술은 빈우의 번식 능력을 향상시켜 유전적 개량량을 증대할 수 있는 번식과 육종을 위한 도구로써 많은 잠재력을 지니고 있다. 최근 핵 이식 기술을 이용하여 유전적으로 우수한 빈우로부터 수천개의 수정란을 생산하여, 이들 수정란에게 생산된 송아지가 번식 축군으로 공시되어 있으므로, 그 결과가 주목되나 아직까지는 비용이 많이 들고 송아지 생산 효율이 저조하므로, 가까운 장래에 일반 양축가에 이용될 가능성이 낮다. 그러나 이 기술의 실용화를 위하여 선결되어야 할 많은 문제점들 중, 지난 몇 년 동안 많은 연구기관에서 수행된 활발한 연구의 결실로써, 난포란 제핵, cell fusion 과 oocyte activation의 방법등 주요 장애 요인들이 점차 극복되면서 실용화를 위한 접근이 예견되어지며, 구미의 일부 개량 기관에서는 이를 상업화 하기 위한 여건을 다지고 있다. 그러므로 이 Review에서는 fllicular dynamics, 난포란의 성숙, cell cycle, 난포란 제핵, cell fusion과 oocyte activation, 이식후 핵의 remodeling과 reprogramming에 대한 현재까지의 보고된 자료를 기초로 그 기본 원리를 재고하는데 초점을 맞추었다.

• Feed Journal
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• v.1
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• pp.100-102
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• 2003

"PSY 및 복당 이유총체중"으로 표현되는 모돈의 능력은 유전력이 5~15% 밖에 되지 않아 어떤 수준의 관리를 하였는가에 의해 판가름난다. 여기서 관리를 위생 · 번식 · 영양 · 환경적 요인으로 구분할 수 있다. 우리나라는 4계절이 뚜렷하며, 곡물의 해외의존도가 높아 사료 품질이 불규칙하기 쉬우며, 종돈이 통일되지 않아 모돈의 개체 차이가 많기 때문에 효과적인 모돈 관리를 하는데 실로 어려움이 많다. 따라서 본고는 모돈 등지방 관리의 핵심을 이해시켜 모돈이 건강하고 능력 발휘를 잘 할 수 있도록 하는데 주안점을 두고 기술하고자 한다.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.483-492
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• 2019

During the breeding season, both adults and immature Eurasian Oystercatchers (Haematopus ostralegus osculans) were observed to feed on prey, such as gastropods (Umbonium thomasi) and bivalves, at the tide water line around Yubu island in Korea. To determine differences in the foraging efficiency between the adult and immature birds, we recorded the feeding behavior using digiscoping with a telescope and a smartphone. We compared the pace, the prey search rate, the proportion of prey search techniques, the feeding success rate, the handling time, and the heads-up rate between the adult and immature birds. There were significant differences in the proportion of prey search techniques when gastropods were consumed and in the prey search rate and heads-up rate when bivalves were consumed but there were no significant differences in feeding success rates. Therefore, although the immature birds on Yubu Island were inferior to adults during the breeding season and they lacked the proficiency to locate prey, their overall foraging efficiency was similar to adults. This was considered to be due to the continuous eating of bivalves during the wintering season, which requires a high level of foraging efficiency.

• Feed Journal
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• v.4 no.7 s.35
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• pp.108-115
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• 2006

우리나라는 사계절이 뚜렷한 기후적 환경으로 여름철 한낮의 외부온도가 35℃ 이상이 되는 날이 계속되고, 야간에도 25℃ 이상인 열대야가 지속되는 날이 많다. 이러한 조건하에서 양돈 생산성 향상을 위해서는 돼지의 사육환경과 성장단계별 적절한 사양기술을 투입하여야만 한다. 돼지는 생리적으로 추위에 의한 영향보다는 여름철 더위에 의한 영향을 쉬게 받으며, 이로 인해 자돈의 쇠약, 압사,수태율 저하, 번식장애 등으로 생산성 저하의 원인이 되며, 사육기간 중에 일시적인 고온스트레스가 돼지가 생존하는 동안 능력의 저하를 초래하게 된다. 특히 하절기 양돈장은 우기와 무더위로 인한 돈사내 온도의 급상승과 더불어 습도의 불균형에 의한 환경적 스트레스로 번식능력과 생산성에 크게 영향을 미칠 수 있으며,돼지에 일시적인 고온 스트레스 피해는 장기간 계속되며, 생존하는 동안 능력저하를 초래하기 때문에 농장별 사육여건에 따른 성장저해 요인을 제거하는 안목이 필요한 계절이다. 즉,5~9월 모돈에 고온스트레스가 가해지면 11~12월, 다음해 1월 모돈의 분만율은 최저가 되고 , 이 시기에 생산된 자돈은 추운겨울을 이겨내야 함으로 육성률도 낮아지며, 이로 인해 4~7월의 출하성적은 최저가 되는 것이다. 따라서 모돈 관리는 5~9월이 집중관리가 필요한 시기이기도 하다. 고온 다습한 환경 하에서 어미돼지는 영양불균형과 생체리듬의 파괴로 인하여 신생자돈의 폐사가 증가할 수도 있고,이유 후 1주일 이내 발정 재귀율이 약 30%정도 감소하고 무발정돈이 많이 발생되며, 수태가 되어도 조기 배아사멸 및 흡수로 인하여 수태율이 25%까지 감소될 수 있다. 현재 국내 양돈농가에는 예년과 같이 돼지 조모성질환의 발생이 늘어나고 있고, 어려움을 겪고 있는 농장이 많은 것으로 조사 보고되어지고 있는데, 이는 농장에 사육되는 돈군이 외부환경에 대한 적응능력과 질병에 저항력이 부족하여 쉽게 질병에 노출되어 발생함으로 농장에는 돼지가 스트레스를 받지 않게 외부 환경과 사양관리 측면에 심혈을 기울려 강건한 축군을 유지하려는 노력이 무엇보다 우선되어져야 한다고 생각된다. 따라서 본고에서는 여름철에 돼지 스트레스를 줄이고 생산성을 향상시키기 위해 돼지의 생리변화와 돈사 급수설비와 사료관리 및 사육관리에 대해 알아보고자 한다.

• Journal of Veterinary Clinics
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• v.28 no.4
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• pp.339-343
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• 2011

This study determined the effects of twin birth on subsequent postpartum disorders, culling and reproductive performance, and its risk factors in dairy cows. Detailed data related to reproduction, health, and calving events, including dates of artificial insemination (AI) and calving, hormonal treatment prior to conception, cow parity, twin birth, retained placenta, metabolic disorders, and endometritis were collected from 1,717 individual calvings on 9 dairy farms. The incidence rate of twin birth was 3.4%. Gestation length was shorter in cows with twin birth ($270.6{\pm}2.0$ days) than cows giving birth to singletons ($279.5{\pm}0.2$ days, P < 0.01). The incidence of retained placenta (47.5 vs. 16.0%), metabolic disorders (18.6 vs. 3.8%) endometritis (62.7 vs. 28.2%), and culling rate (32.2 vs. 16.5%) was greater in cows with twin birth than in cows giving birth to singletons, respectively (P < 0.01). The hazard of pregnancy (adjusted hazard ratio, AHR) by 210 days in milk analyzed using Cox proportional hazards model was affected by calving season, in that the rate of pregnancy for cows calved during spring was less than for cows calved during winter (AHR = 0.80; P = 0.01); this was also true for endometritis (AHR = 0.46, P < 0.01). AHR was not affected by twin birth. Logistic analysis demonstrated that increasing the cow parity (P < 0.01) and hormonal treatment prior to conception (adjusted odds ratio, AOR = 1.84, P < 0.05) increased the risk of twin birth. These results demonstrate that twin births are responsible for severe economic losses through the increased occurrence of postpartum disorders and culling; thus, appropriate management for the deleterious impact of twin birth, and/or reducing the risk factors by herd control regarding cow parity and the use of reproductive hormones prior to conception might be necessary.

• Journal of Veterinary Clinics
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• v.25 no.4
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• pp.280-285
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• 2008

This study evaluated the correlation between the body condition score (BCS) during prepartum, calving and postpartum periods and the reproductive performance of Korean brown cattle. The BCSs of 33 cows who underwent 73 calvings over a two and a half period [the parities of the cows ranged from 1 to 4 ($mean{\pm}SD,\;2.0{\pm}0.9$)] were scored at months 2 and 1 prepartum, calving, and every month postpartum until month 7. A marked prepartum loss of BCS in the month preceding calving was noted. The correlations between the interval from calving to conception and the month 1 prepartum, calving and months 1 and 2 postpartum BCSs were analyzed by Pearson correlation analysis. The correlation between the interval from calving to conception and the prepartum body condition loss was also evaluated. The interval from calving to conception correlated positively with the month 1 prepartum BCS (r = 0.389, P = 0.0007) and the prepartum body condition loss (r = 0.488, P < 0.0001) but did not correlate significantly with the BCS at calving (r=-0.070, P=0.56) or months 1 (r=0.107, P=0.37) or 2 (r=0.102, P=0.39) postpartum. The prepartum body condition loss correlated positively with the month 1 prepartum BCS (r=0.587, P<0.0001). In conclusion, the month 1 prepartum BCS may be a good criterion for predicting subsequent reproductive performance. Moreover, the prevention of obesity and/or excessive prepartum body condition loss may result in higher fertility in Korean brown cattle.

• Korean Journal of Animal Reproduction
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• v.12 no.1
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• pp.15-19
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• 1988

This study was carried out to investigate the fertility and farrowing date in post-weaning sows using PG600 and inseminated with frozen semen. A total of 48 sows of Landrace, Large White and Duroc after 7-week lactation were used at the Chungnam Provincial Animal Breeding Station. The results obtained were summarized as follows: 1. Motility had no significant differences between the breeds, but NAR acrosome was highest in Landrace, followed by Duroc and Large White(p<.01). 2. Interval from weaning to estrus and length of estrus were, respectively, 3.7 days and 52.6hours of sows treated with PG600, and 6.5 days and 53.8 hours for control sows. The average interval from weaning to onset of estrus was significantly(p<.01) shorter by 2.8 days in PG600 treated sows compared to control sows. 3. In Landrace, Duroc and Large White, farrowing rate and number of pigs born alive per litter were 55.0%, 10.0; 43.8%, 8.1; and 16.7%, 3.5, respectively. Average pig weight at birth and survival rate at 56 days had no significant differences between the breeds. 4. Farrowing rate, number of pigs born alive per litter, average pig weight at birth and survival rate at 56 days were, respectivey, 45.8%, 101, 1.56kg and 94.5% for sows treated with PG600, and 37.5%, 7.0, 1.66kg and 93.8% for control sows. Sows treated with PG 600 had an average of 3.1 more pigs at farrowing compared to control sows.