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        검색결과 131

        1.
        2018.11 구독 인증기관·개인회원 무료
        본 연구는 암말의 비번식계절 기간 중 인공조명에 의한 발정 유기율을 분석하기 위해 시행하였다. 공시마는 국립축산과학원 난지축산연구소에서 사육・보유하고 있는 한라마(더러브렛×제주마) 18 두를 공시하였으며, 2018 년 1 월부터 2018 년 2 월까지 공시하였다. 암말의 생식기 및 난소초음파 검사는 주 2 회 오전 09:00∼12:00 사이에 실시하였으며, 초음파 진단기를 이용하여 난소내 난포 및 황체를 확인하였다. 호르몬 분석을 위해 한라마 18 두를 공시하여 일주일에 2 회 채혈하여 호르몬을 분석하였다. 채혈 방법은 오전 9 시∼11 시 사이 heparin 처리된 10ml vacutainer 를 사용하여 경정맥에서 약 10ml 를 채혈하여 곧바로 실험실로 운반하였고, 3 시간 이내에 3,000rpm에서 15 분간 원심분리 후 혈청을 분리하여 분석 시까지 냉동보존(-20℃)하였다. 혈중 P4 농도는 의료용면역흡광측정장치(Roche E-170, 스위스)를 이용하여 분석하였다. 인공조명 처리는 일몰 후부터 22 시까지 점등하였으며 밝기는 200 룩스(lux)에서 측정하였다. 적어도 2 번의 연속적인 채혈을 통해 혈액에서 P4 수준이 ≥ 1ng/ml 일 경우 황체활성을 가지고 있다고 간주하였으며, 배란은 P4 수준이 ≥ 1ng/ml 으로 증가되기 5 일전에 일어난 것으로 분류하였다(Shrestha 등, 2004a). 약 2 주의 황체기와 약 1 주의 난포기를 보여주는 개체에 대하여 정상적인 주기로 정의하였다. 암말의 비번식계절 동안 인공조명 처리시 발정유기율은 88.9%(16/18)였으며, 체중별 발정유기율에서는 380kg 이하 개체의 발정유기율은 100%(8/8) 였으며, 380kg 이상 개체의 발정유기율은 80%(8/10)였으며 유의적인 차이를 보이지는 않았다. 말의 경우 번식기에 임신이 되지 않으면 다음해까지 공태기간이 길어지는 것이 일반적이다. 비번식기 동안 인공조명을 실시하므로써 발정을 앞당길 수 있으며, 인공조명에 의한 공태마의 조기번식에 대하여는 더 많은 공시축을 이용한 연구가 이루어져야 할 것으로 사료된다.
        2.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The artificial insemination (AI) is one of the best assisted reproductive technologies for increasing reproductive capacity and facilitating the genetic improvement in farm animals. AI has been used in Uganda for over 60 years, but a small population of the total herd has been used. This study was conducted to investigate the efficacy of AI with estrus synchronization technique and to propose ways of improving the productivity of dairy farms through AI services in Uganda. In total, 78 cows from 11 dairy farms were selected for timed-AI. Synchronization was performed according to the ovsynch programs followed by AI using frozen semen from Korean Holstein (0.5 ml straws). Pregnancy rate was varying among farms (0-50%) and the overall pregnancy rate was 28.2%. Cows in luteal phase at the time of treatment was 40.0% whereas that in follicular phase was 20.8%. After treatment, cows that showed normal estrus signal were 45.5% (25/55). Abnormal estrus was categorized into pre-estrus (9.1%), cystic ovaries (21.8%), anestrus (18.2%) and delayed ovulation (5.5%), respectively. These results imply that an assured protocol for timed-AI should be developed to improve the productivity of dairy farms through AI services in Uganda.
        4,000원
        3.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tscherskia triton is widely distributed in Northern China, Korea, and the adjacent areas of Russia. Except its distribution, reproduction, and growth development related to life history, reproductive cycle and reproductive organs of T. triton are rarely studied in Korea. The purpose of this study was characterized the estrous cycle of T. triton captured in Jeju Island in order to provide information to a better information of captive breeding of the species when longday (16L : 8D) and short-day (8L : 16D) photoperiod. Then, histological study of the ovaries and uterus with five females in each photoperiod was performed. The duration of the estrus cycle was 4~5 days and it showed regular cycle pattern. Results of the vaginal cytology examination showed four characteristic phase of the estrous cycle in long-day photoperiod (16L : 8D): proestrus, estrus, metestrus and diestrus. However, in short-day photoperiod, the diestrus phage of the estrus cycle was maintained from the 6th to 12th day. In the long-day photoperiod, females had many Graafian follicles and corpus luteums in large ovaries, and developed uterine glands in the thick endometrium. But they had some primary, secondary and tertiary follicles, and undeveloped uterine glands in the thin endometrium during short-day photoperiod. These results were identified difference of the estrus cycle and histological characteristics of reproductive tracts according to the photoperiod. These results are very important clues to the reproductive biology of T. triton, and it will be widely used as date for maintaining biodiversity.
        4,000원
        4.
        2017.05 구독 인증기관·개인회원 무료
        국내외 암말 발정주기 양상 분석에 대한 연구는 전무한 상태이며, 말 인공수정을 위한 호르몬 설정에 관한 연구도 전 세계적으로 미흡한 실정이다. 암말에서 발정 유기를 위한 PGF, progesterone 등 호르몬 투여 시 난포의 발달을 억제하지 못하고 호르몬 처리 동안 배란이 일어나 황체의 생성 으로 발정 유기에 실패할 수 있으므로, 양 등(2004b)은 초음파 진단을 통하여 난포 크기를 측정하 는 것이 매우 중요하다고 했다. 암말의 발정주기는 개체마다 큰 차이를 보이고 있으며, 아직까지 정확한 원인 분석은 이루어지지 않은 실정이다. Wespi 등(2014)에 의하면 계절 전환기에서 암말의 발정 발견율이 높으나, 배란이나 배란 간격에는 영향을 미치지 않는 것으로 보고되고 있다. 본 연 구는 국립축산과학원 난지축산연구소에서 사육하고 있는 제주산마 16두를 공시하였으며, 주 1회 초음파진단 및 주 2회 채혈 후 생화학 및 호르몬 분석을 실시하였다. 생화학 분석은 Glu, BUN, AST, Hemolysis 등 17개 항목을 분석하였다. 생화학 수준이 암말의 발정주기에 어떠한 영향을 미 치는지 분석하기 위하여 16두의 공시축 중 정상적인 발정주기를 보이는 개체와, 비정상적인 발정 주기를 보이는 개체에 대해 분석하였으며, 두 그룹 간 유의적인 차이는 나타나지 않았다.
        5.
        2016.10 구독 인증기관·개인회원 무료
        말은 봄과 여름에 번식하는 동물로 우리나라는 3월 초순부터 7월 초순까지 종부하며 종부시기에 수태를 하지 못한 암말의 경우 다음 해 종부를 기다려야 하기 때문에 농가의 손실을 가져오게 된다. 암말은 처해진 환경에 따라 발정주기 개시가 유연한 특성이 있으 며, 계절 전환기에서 성숙한 수말에게 노출되었을 때 발정 발견율이 높으나, 배란이나 배 란 간격에는 영향을 미치지 않는 것으로 보고되고 있다(Wespi 등, 2014). 본 연구는 국립 축산과학원 난지축산연구소에서 사육하고 있는 제주산마 15두를 공시하였으며, 주 1회 초 음파진단 및 주 2회 채혈 후 호르몬 분석을 하였으며, 15두의 공시축 중 12주 이상 호르 몬 분석이 가능한 개체 8두에 대해서 발정주기를 분석하였다. 분석결과 정상적인 발정주 기를 갖는 개체가 50%였으며, 비정상적인 발정주기를 갖는 개체도 50%를 보였다. 비정상적인 발정주기를 보이는 개체 대부분에서 매주 좌, 우 번갈아가며 우세난포가 확 인되었다. 생화학 분석은 Glu, BUN, AST, Hemolysis 등 17개 항목을 분석하였으며, 정상적인 발정 주기를 보인개체 비정상적인 발정주기를 보인개체 모두에서 정상적인 수준을 보였으며, Hemolysis에서 양성 수치가 나온 것은 채혈 시 말의 보정과정에서 혈구의 손상이 있었던 것으로 판단됨.
        6.
        2016.10 구독 인증기관·개인회원 무료
        소에서 저수태 발생율은 5∼35%로 지역, 조사방법 및 연구자 등에 따라 다양하게 보고 되고 있다(Purohit, 2008). 저수태의 원인으로서는 비정상적인 번식기관, 자궁 내 감염, 호 르몬 이상, 사양관리 부적합, 복합적 요인 등이 관여하고 있는데(Singh 등, 2008), 이 중에 서도 자궁 내 감염의 요인이 2.4∼20.0%로 비교적 높게 보고되고 있다(Rao, 1981). 자궁질 환을 가진 대부분의 암소들은 황체단계가 연장됨에 따라 무발정형태로 나타나게 되므로 적극적인 대처가 요구된다는 점에서, 호르몬 투여방법을 포함하여 PGF2α나 estradiol의 투 여 그리고 항생물질이나 povidone-iodine(PVP-I)의 자궁 내 주입과 같은 많은 치료방법이 적용되고 있다. 그러나 호르몬 잔류, 항생제 내성균 및 처리 중단시기 등의 문제점들을 가 지고 있다. PVP-I는 처리 중단시기가 필요하지 않고, 과도한 투여의 경우를 제외하고는 우유로 전이되지 않으며, 구입이 쉽고, 저렴하며, 투여하기가 용이하다는 실용성을 가지고 있기 때문에 매우 고무적인 방법이라고 할 수 있다(Rayos 등, 2002). 또한 자궁내막의 환 경을 개선하고, 암소의 자궁수촉을 촉진시키기 때문에 PGF2α를 생산하는 역할이 빨리 회 복된다(Ahmed와 Elsheikh, 2014). 그러나 PVP-I는 농도가 중요한데, 농도가 너무 높으면 자궁벽을 자극할 수 있고 문제를 더 키울 수 있는 반면에, 농도가 너무 약하면 효과가 나 타나지 않거나, 어떤 유형의 미생물이 제거되는 대신에 다른 기회적 미생물이 점유하기에 적합한 환경을 제공할 수가 있다(Rayos 등, 2002). 자궁내막염을 가진 암소의 경우에는 자 궁 내에 존재하는 화농과 유기물의 잔재가 PVP-I 용액의 살균효과를 저해할 수 있다는 부정적인 견해도 있으나(Nakao 등, 1988), 대부분의 연구자들은 1% 및 2% PVP-I 용액이 번식효율을 향상시키는데 매우 효과적이라고 보고하였다(Mido 등, 2016; Ahmed와 Nour, 2015; Ahmed 등, 2013; Knutti 등, 2000; Edwell 등, 2000; Rayos 등, 2002; Koujanz 등, 1996). 본 연구에서는 2% PVP-I 용액을 저수태우의 자궁 내에 주입하여, 발정발현 및 수 태율에 미치는 영향을 구명하고자 수행하였다. 저수태우에 2% PVP-I 용액을 50mL 자궁 내에 주입하여 자연발정 비율, 유기발정(PGF2α)에 의한 발정발현율, 자연 및 유기발정에 의한 수태율, 황체중기 및 황체중기 이외의 단계에 따른 자연발정 발현율을 조사하였다. PVP-I 처리 후 자연발정 비율은 27.3%(3/11두)였고, 유기발정에 의한 발정발현율은 87.5%(7/8두)였으며, 자연 및 유기발정에 의한 수태율은 63.6%(7/11두)였다. 황체중기(발정 주기 5∼10일) PVP-I 처리에 따른 자연발정 발현율은 60%(3/5두)였고, 황체중기 이외에 PVP-I 용액을 처리한 경우의 자연발정 발현율은 0%(0/6두)였다.
        7.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to compare the appearance rate of vaginal cytology during estrous cycle in small pet bitches. A characteristic features of vaginal cytology during the estrous cycle were the high proportion of superficial cell in proestrus, anuclear cell in estrus, small intermediate cell in diestrus, and small intermediate cell in anestrus, respectively. There were no statistically significant differences of appearance rate of vaginal cytology among small pet bitches in the each phase of estrous cycle. These results indicated that the vaginal cytology was useful method for estimating estrous cycle and optimal breeding time in small pet bitches.
        4,000원
        8.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study is to evaluate the effects of vitamin or mineral supplements on the conception rates of dairy heifers when replacing the last injection of GnRH with hCG in ovsynch protocol (experiment 1) and also to investigate whether the estrus synchronization treatment in the heifer stage affects the conception rates after 1st parturition (experiment 2). In experiment 1, 50 heifers were randomly assigned into 3 groups: 20 heifers each in groups 1 and 2, and 10 in group 3. All three groups were treated with an intramuscular injection of GnRH on day 0 (day 0 = the day of program start), PGF2α on day 7 and hCG on day 9, and were inseminated on day 10, 12~16h after hCG injection. In group 1 (vitamin group), the heifers were treated with an intramuscular injection of 5 ml of vitamin-ADE 500Ⓡ, and group 2 (mineral group) was treated twice with an intramuscular injection of 30 ml of mineral supplement-LAPTOVETⓇ on a one-week interval beginning on the day of hormone treatment (day 0 and day 7 respectively). Group 3 (control) was treated only with hormones. Pregnancy diagnosis was performed by ultrasonography through a rectal probe. First service conception rates (FSCR) and average services per conception (ASPC) were recorded for all subjects. Of the total 50 heifers, 6 (2 in group 1, 3 in group 2, and 1 in group 3) heifers were eliminated due to accidents during experiment 1. FSCRs were 58.8% (10/17), 66.7% (12/18) and 44.4% (4/9) in groups 1, 2 and 3, respectively. ASPCs were 1.53±0.72, 1.27±0.59 and 1.63±0.74 in groups 1, 2 and 3, respectively. Although there were no significant difference between the groups, relatively good results (higher FSCR and lower ASPC) were obtained in both group 1 and 2. In experiment 2, 11 primiparous cows from group 2 of experiment 1 in heifer stage which had been treated both with the hormones for estrus synchronizing and mineral supplements (ES group), and 12 primiparous cows treated only with minerals (non-ES group) were compared to examine the effects of estrus synchronization program on conception rates after 1st parturition. Following the examination, postpartum ASPCs were 1.55±0.82 and 2.17±1.47 in ES group and non-ES group, respectively. The postpartum average days open (ADO) were 116±56 and 197±93 in ES group and non-ES group, respectively. Although there were no significant difference between the two groups, desirable results (lower ASPC and shorter ADO) were found in ES group after 1st parturiton. In conclusion, experiment 1 indicates that vitamin or mineral supplement with ovsynch protocol may have some positive effect on FSCR and ASPC of dairy heifers, and in experiment 2, ES program in heifer stage had a positive effect on ASPC and ADO following 1st parturition.
        4,000원
        9.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was to investigate effect of progesterone (P4) on prostaglandin (PG) synthases and plasminogen activators (PAs) system in bovine endometrium during estrous cycle. Endometrium tissues were collected from bovine uterus on follicular and luteal phase and were incubated with culture medium containing 0 (Control), 0.2, 2, 20 and 200 ng/ml P4 for 24 h. The PGF2α synthase (PGFS), PGE2 synthase (PGES), cyclooxygenase-2 (COX-2), urokinase PA (uPA), and PA inhibitors 1 (PAI-1) mRNA in bovine endometrium were analyzed using reverse transcription PCR and PA activity was measured using spectrophotometry. In results, COX-2 was higher at 2 ng/ml P4 group than control group in luteal phase (p<0.05), but, it did not change in follicular phase. Contrastively, PGES was significantly increased in 2 ng/ml P4 group compared to control group in follicular phase, but there were no significant differ among the treatments in luteal phase. uPA was no significant difference between P4 treatment groups and control group in both of different phase. PAI-1 was decreased in 20 ng/ml P4 group compared to control group in follicular phase (p<0.05). PA activity was decreased in 2 ng/ml P4 group compared to other groups in follicular and luteal phase (p<0.05). In conclusion, we suggest that P4 may influence to translation and post-translation process of PG production and PA activation in bovine endometrium.
        4,000원
        10.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To describe the macroscopic anatomy and ovarian-physiological difference of the genital organs of the female Korean water deer, organs from captured animals in a wild area of Korea were dissected. The ovary of estrus group was about 1.10 ± 0.02 mm long and weighed about 0.50 ± 0.02 g. And pregnant group was about 1.3 ± 0.10 mm long and weighed about 0.40 ± 0.05 g. And the crowns of corpora lutea were found in the estrus group, but we couldn't find crowns at the pregnant group. Especially, the estrus ovaries tended (p=0.04) to be heavier than the ovaries during pregnancy. The MMP-9 activity was higher at the Graafian follicles of pregnant group than that in estrus group. However, with regard to follicles of estrus group, MMP-2 level was higher than that in pregnant group. Furthermore, apoptosis detection marker (Casp-3) was highly expressed in Graafian follicle of the pregnant group and the corpora lutea of estrus group. Thus, the differential expression of MMPs observed in this study suggests that the reflected the mechanisms underlying of monovulatory in estrus and/or pregnancy. Our results may be very useful as it provides with information that may be considered for the development of reproductive biotechnologies in endangered animals.
        4,000원
        11.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is generally accepted that chronic stress impairs female reproduction. It negatively affects ovarian function and the number of ovulated oocytes. Chronic stress lowers the number of retrieved oocytes. Ovarian follicular development is regulated by both pituitary-derived gonadotropins and intraovarian regulatory factors. The main corticosteroids are cortisol, cortisone, 11-deoxycortisol and corticosterone, cortisol being one of the most commonly used welfare and stress physiological indicator. In this study, we investigated the effect of cortisol level on progesterone patterns and ovulation in the dog. Cortisol and progesterone level of serum were analyzed by radioimmunoassay. The day of ovulation was considered as the day when serum progesterone concentration was 6.0∼8.0 ng/ml. In vivo dog oocytes were collected by flushing oviducts of mixed-breed bitches at three days after ovulation. We classified dogs as having group 1 (cortisol level, 0 ≤ or < 2 μg/dl), group 2 (corisol level, 2 ≤ or < 4 μg/dl), group 3 (cortisol level, 4 ≤ or < 6 μg/dl) and group 4 (cortisol level, 6 μg/dL ≤). The patterns of progesterone were not different in four cortisol groups. The average numbers of retrieved oocytes was not different in four cortisol groups. These results suggest that different cortisol levels on estrus dogs do not affect ovulation, number of ovulated oocytes and progesterone changes.
        4,000원
        12.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to analyze the accuracy of estrus detection of heat detector and analysis of estrus behavior (mounting and mounted), and the evaluation of conditions required for improving reproductive efficiency in Holstein dairy cows fitted with a estrous detector. The heat detection system consists of estrous detector based on wireless sensor and an electric bulletin board displayed estrus behavior data. When cow mounting other cows, the accuracy of estrus behavior displayed an electric bulletin board were 87.5% (mounting other cows only), 100% (mounting other cows but not standing), 80.0% (mounting other cows with standing for 1∼4 seconds), 90.0% (mounting other cows but not standing for 1∼4 seconds), 80% (mounting other cows with standing for more than 5 seconds) and 90.0% (mounting other cows but not standing for more than 5 seconds). When cow mounted other cows, the accuracy of estrus behavior displayed an electric bulletin board were 100% (mounted other cows but not standing), 100% (mounted other cows with standing for 1∼4 seconds), 100% (mounted other cows but not standing for 1∼4 seconds) and 100% (mounted other cows with standing for more than 5 seconds). Circadian distribution of first observed in estrus were 59.1% (am 8∼pm 6) and 40.9% (pm 6∼am 8). Distribution for the number of estrus behavior were 40.9% (less than 3 times), 36.4% (4∼6 times) and 22.7% (more than 4 times). The conception rates relative to interval from first estrus behavior to insemination for estrus periods were 23.1% (less than 11 hours) and 55.6% (12∼20 hours).
        4,000원
        13.
        2013.09 구독 인증기관 무료, 개인회원 유료
        An uterus is female reproductive tract organ that affected estrus cycle. During a various changes occur at uterus in estrus cycle, one of them is body fluids secretion be called uterine fluid. Therefore, the objective of this study was to investigate the changes of protein patterns using two-dimensional gel electrophoresis in uterus fluids during the follicular and luteal phases in estrus cycle of pigs. In changes of protein spots were confirmed during the follicular and luteal phases. The 136 spots were expressed in follicular phase, the 57 spots of them showed reproducibility. On the other hand, the 140 spots were expressed in luteal phase, the 73 spots of them showed reproducibility. Also, spots expressed in follicular phase were number 69 and 94 spots and spots expressed in luteal phase only were number 156, 157, 184~187, 190 and 191 spots. The spots which of higher expression levels in the luteal phase than in follicular phase were number 76 and 79 spots. In conclusion, the spots expressed in follicular and luteal phases were confirmed with difference levels and these differences are function of RNA resolving, protein synthesis and cytoskeletal architecture.
        4,000원
        14.
        2013.03 구독 인증기관 무료, 개인회원 유료
        The objective of this work was to analyze the concentrations of progesterone (P4) and estrogen (E2) hormones changed during estrus synchronization in dairy heifers. Estrus synchronization was carried out with CIDRⓇ (Controlled Intravaginal Drug Release) devices. Corpus luteum (CL) was classified into three grades based on its size and palpable characteristics. The concentrations of P4 and E2 were measured by enzyme-amplified chemiluminescence. Serum P4 concentration was markedly low at the estrus stage (36 hrs after removal of CIDR) compared to other stages, while E2 concentration was kept high during estrus stage. The serum P4 concentration was highest in the CL classified into gradeⅠ. These results indicate that P4 concentration could be used as a criteria for determining recipients for artificial insemination or embryo transfer in dairy cattle.
        4,000원
        19.
        2012.09 구독 인증기관 무료, 개인회원 유료
        The present study was performed to identify the relationship between plasminogen activator (PA) and Heat Shock Protein-90 (HSP-90) in porcine uterus tissues during the estrous cycle. Porcine uterus tissues were obtained from preovulatory (Pre-Ov), post-ovulatory (Post-Ov) and early to mid-luteal (Early-mid L) stages. The protein was extracted from uterus tissue by using M-PER Mammalian Protein Extraction Reagent. Proteins were refined by RIPA Buffer and quantified by BCA methods. As results, t-PA expression was significantly (p<0.05) higher from pre-ovulatory(Epithelium tissue: 29,067 μg/μl, Myometrium tissue: 30,797 μg/μl) compared to the post-ovulatory stage(Epithelium tissue: 54,357 μg/μl, Myometrium tissue: 53,270 μg/μl) and early to mid-luteal stage(Epithelium tissue: 42,380 μg/μl, Myometrium tissue: 43,139 μg/μl). On the other hand, the uPA expression indicated higher from early to mid-luteal stage (Epithelium tissue: 0.02198 μg/μl, Myometrium tissue: 0.02412 μg/μl) than pre-ovulatory stage (Epithelium tissue: 0.01577 μg/μl, Myometrium tissue: 0.01531 μg/μl) and post-ovulatory stage(Epithelium tissue: 0.01414 μg/μl, Myometrium tissue: 0.01429 μg/μl). However, expression of u-PA did not differ from each estrous cycle in the epithelium tissue and myometrium tissue(p<0.05). Expression of HSP-90 was differ t-PA and u-PA from pre-ovulatory in Epithelium tissue(25,423 μg/μl) and early to mid-luteal stage in epithelium tissue(177,922 μg/μl) and myometrium tissue(26,664 μg/μl). These results suggest that HSP-90 and u-PA were related with change of uterus cycle according to the reformation of the tissues in porcine uterus.
        4,000원
        20.
        2012.09 구독 인증기관 무료, 개인회원 유료
        The decreased fertility is frequently thought to be problem of cattle production. However, studies figure out that number of these problems is related to bull factors especially in artificial insemination setting. Therefore, this study was designed to investigate the fertility status of bull by their estimated relative conception rate of cows that were inseminated by frozen semen from Korean proven bulls. Here we use the non-return rate (NRR) to access the bull fertility whereas, the NRR was define as the proportion of bulls that semen were used to inseminate cows and the number of cows that did not return for another service within 60 days. The data from 54,388 artificial inseminations (AI) were analyzed from 88 KPN semen. The NRRs of highest and lowest fertile bull were 83.81 and 51.33%, respectively. And mean NRR was 68.27%. In comparison to previously reported study, our data shows 17.38% higher NRR and the absolute value of difference in 50%>NRR and 50%<NRR group was 22.17 and 10.51, respectively (p< 0.001). In conclusion, the decreased fertility might consider as key aspect in achieving considerable conception of cows in existing integrated farming system at Korea.
        4,000원
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