• 한국동물위생학회지
• /
• 제31권3호
• /
• pp.397-414
• /
• 2008

In order to evaluate conception rate of Hanwoo in northwestern region of Gyeongsang-nam-do, we investigated conception rate and reduction of reproductive disorder rate after artificial insemination (AI) in 1,000 heads of breeding cows, This study showed that 80.9% of cows were classified as fertility after 1st and 2nd AI. For a accurate pregnancy diagnosis with practicing ovariectomy and histeotomy, we comparatively investigated each of 80 slaughtered cows, including 30 of non-pregnancy, and used enzyme-linked immunosorbent assay (ELISA) for estimation of plasma progesterone concentration and serum luteal hormone. The mean diameter of non-pregnant corpus luteum is $18.9{\pm}4.2{\times}15.6{\pm}3.6 mm$ and that of pregnant corpus luteum is $22.5{\pm}2.7{\times}18.7{\pm}2.9 mm$. This indicates that corpus luteum is more developed in the ovary of pregnant than non-pregnant cows (P<0.05). The diameter of pregnant corpus luteum according to the stage of pregnancy showed $21.3{\pm}2.4{\pm}18.4{\pm}2.6 mm$ in early stage (1-3 month), $23.4{\pm}2.8{\times}19.1{\pm}2.7 mm$ in middle stage (4-6 month) and $22.8{\pm}3.0{\times}18.8{\pm}2.4mm$, in last stage (7-9 month). This indicates that corpus luteum in middle and last stage is more significantly developed than that of early stage(P<0.05). The mean plasma progesterone concentration of cows showing size of non-pregnant corpus luteum was $4.58{\pm}0.92ng/ml$ and that of pregnant corpus luteum $8.26{\pm}0.98ng/ml$. Thus, it was more significantly increased in pregnant corpus luteum(P<0.02).. However, it was low to $0.58{\pm}0.39ng/ml$. in estrus (corpus albicans). The plasma progesterone concentration according to gestation period was high in proportion to the degree of development in corpus luteum and more significantly increased (P<0.05) and maintained in middle and last state than early state. The concentration was sharply decreased to $0.56{\pm}0.32ng/ml$ at parturition. As a consequence, we can practice the early pregnancy diagnosis by confirming non-pregnancy when the mean plasma progesterone concentration is below 1ng/ml 19 to 22 days after AI and this can be available to diagnose reproductive disorder.

• 한국수정란이식학회지
• /
• 제32권3호
• /
• pp.171-176
• /
• 2017

본 연구는 한우 송아지 생산효율 향상을 위한 농가 번식 실태를 조사하였다. 한우 사육 규모별, 지역별로 나누어 45개 농가의 가임암소를 대상으로 조사를 실시하여 다음과 같은 결과를 얻었다. 한우의 최초 분만월령은 평균 28.7개월령이었다. 수태당 인공수정 횟수는 $1.45{\pm}0.32$회였으며, 분만 후 인공수정 일수는 119.8일이었다. 수태율은 소규모 농가가 $75.2{\pm}16.93%$로 중규모($70.6{\pm}17.46%$) 및 대규모 농가($71.4{\pm}11.03%$)보다 높은 것으로 나타났다. 번식률 상위 농가의 사육 방식을 보면, '발정관찰 보조기구를 사용하는 농가'가 '그렇지 않은 농가'보다 송아지 생산율이 10.42% 높았다. 번식소에 대해 IBR과 BVDV 예방접종을 실시한 농가는 유사산 폐사율이 4.41% 감소한 것으로 나타났다. 또한 농가여건에 따라 방목과 운동을 한 경우, 수태율과 분만율이 각각 3.47%, 18.29% 향상되는 것으로 나타났다. 본 조사 결과를 통해 발정관찰, 예방접종, 방목이 한우농가에서 송아지 생산 효율을 높이는데 중요한 지표로 나타났다. 한우 사육 농가의 번식실태 조사를 통해 농가 현장의 번식률 향상을 위한 연구 자료로 활용이 가능할 것이다.

• 한국수정란이식학회지
• /
• 제2권1호
• /
• pp.33-35
• /
• 1987

This study was carried out to investigate the seasonal effect on the recovery rate of embryos in donors and on the conception rate in recipients following embryo transfer. The results obtained from this experiment were summarized as follows: 1. The ovulation point in winter and summer was 28.6 and 28.6, respectively. There was no difference in ovulation point between two seasons. More embryos recovered in the winter (27,0) than the summer (20.9). 2. The number of CL, unruptured follicle, hemorrhagic follicle, young born and pregnancy rate in the winter were 6.0,4.8,1.5,1.8 and 75%, and those in the summer were 2.9,5.7, 3.8, 2.2 and 46.7%, respectively. The rate of synchronization of recipients in the winter showed better results than that in the summer.

• East Asian mathematical journal
• /
• 제33권4호
• /
• pp.431-451
• /
• 2017

This is a descriptive study with the intent of providing a rich characterization of teachers' perceptions of rate of change. The nature of teachers' perceptions and differences among teachers were examined by collecting data through a survey on teachers' conceptions of rate of change in terms of learning goals, prerequisites, and beliefs about teaching and learning of rate of change, and an interview individually assessing teachers' concept images and definitions. The participating 13 teachers were selected to provide a range of similar and contrasting levels of experiences based on the teachers' educational background and the number of years they had been teaching. Findings and implications of this study are discussed.

• Reproductive and Developmental Biology
• /
• 제35권3호
• /
• pp.395-398
• /
• 2011

The objective of this study was to compare the accuracy analysis and the effect of field application of a newly developed automatic heat detector in dairy cows. From 2009 to 2010, we used 48 Holstein cows (mounting cows : 38 heads, standing cows : 10 heads) raised in experimental barn of National Livestock Research Institute (RDA) for the accuracy analysis of automatic heat detector, and 14 Holstein cows raised in three commercial dairy farms of Cheonan and Pochun area for comparison of the effect of field application. The accuracy of response in cows attached with automatic heat detector was 86.8% (33/38) displayed on board when mounting activity observed, and 100% (10/10) when standing activity observed, and on average, 90.0% (43/48) displayed on board. The accuracy of automatic heat detector in on-farm test was 85.7% (12/14), and conception rate was 75.0% (9/12).

• Asian-Australasian Journal of Animal Sciences
• /
• 제18권4호
• /
• pp.470-474
• /
• 2005

The efficiency of a short-term treatment with an intravaginal device containing progesterone (CIDR) combined with pregnant mares' serum gonadotrophin (PMSG) and prostaglandin analogue ($PGF_{2\alpha}$) was evaluated for the induction of estrus, initiation of cyclic activity, and fertility in postpartum suckled yak cows. Seventy-five postpartum suckled yak cows were assigned to three treatments: (1) insertion of a CIDR intravaginal progesterone (1.9 g) (day 0), an administration of $PGF_{2\alpha}$ (0.2 mg i.m.) on day 6 and PMSG (1,000 IU i.m.) at the time of CIDR withdrawal on day 7 (CPP group, n=28); (2) an administration of $PGF_{2\alpha}$ (0.2 mg i.m.) on day 6 and PMSG (1,000 IU i.m.) on day 7 (PP group, n=21); (3) untreated animals served as the control (CG group, n=26). Seven yak bulls were placed in pastures with the cows for natural mating. Estrus rate in the CPP group (28/28) was higher (p<0.01) than in the PP group (6/21) and in the CG group (0/26) within 96 h after the end of treatment. The first service conception rate in the CPP group (21/28) was higher (p<0.01) compared with in the PP group (2/9) as judged by serum $P_4$ concentration $\geq$2.35 ng/ml on day 21 after breeding. It is concluded that a short-term progesterone treatment combined with PMSG and prostaglandin increased the proportion of yak cows that exhibited behavioral estrus with more synchronized estrus response and satisfactory conception rate in postpartum suckled yak cows.

• 한국임상수의학회지
• /
• 제28권4호
• /
• pp.339-343
• /
• 2011

젖소에서 쌍태분만이 이후의 산후질병 발생, 도태, 번식능력에 대한 영향과 쌍태분만에 대한 위험요인을 조사하였다. 9개 목장 1,717 분만축의 번식, 위생 및 분만관련 상세 자료가 분석에 이용되었다. 쌍태 분만율은 3.4%였으며, 임신기간은 쌍태분만 시에 단태분만 시에 비해 9일 단축되었다($270.6{\pm}2.0$ vs. $279.5{\pm}0.2$일, P < 0.01). 쌍태분만 시가 후산정체(47.5 vs. 16.0%), 대사성질병(18.6 vs. 3.8%) 및 자궁내막염의 발생(62.7 vs. 28.2%)뿐만 아니라 도태율(32.2 vs. 16.5%)이 단태분만 시에 비해 현저하게 증가되었다(P < 0.01). 쌍태분만은 분만으로부터 임신까지의 간격에 유의적인 영향을 미치지 않았으나, 분만계절이 영향을 미쳤는데, 즉 봄에 분만 시가 겨울에 분만 시에 비해 임신율이 감소되었으며(AHR = 0.80; P = 0.01), 또한 자궁내막염의 발생이 임신율의 감소를 초래하였다(AHR = 0.46, P < 0.01). 로지스틱 분석은 산차의 증가(P < 0.01)와 수태 전 번식호르몬의 사용(OR = 1.84, P < 0.05)이 쌍태분만의 위험요인임을 나타내었다. 결론적으로, 젖소에서 쌍태분만은 산후질병 발생과 도태의 증가에 의한 심한 경제적 손실을 초래하므로, 쌍태분만에 대한 적절한 관리 및 고산차 소 및 번식호르몬 사용에 대한 적절한 통제를 통한 위험요인을 감소시키는 것이 요구된다.

• 한국과학교육학회지
• /
• 제15권4호
• /
• pp.379-393
• /
• 1995

In spite of school science learning, the students' conceptions have not been changed easily. Therefore, to make students overcome their non scientific conceptions has been an important issue in science education. The purpose of this study was to identify the conceptions of students and teachers on the motion of the earth and the moon. The instrument was developed for estimating students' understandings of the concepts related to the motion of the earth and the moon. The validity of the instrument was examined by the specialists in Science Educator and Astronomer. At the same time, the two field trials had been executed, and the items were modified. Also, it consists of 12 items including 9 two-tier multiple choice items and 3 multiple choice items. The population of this study consists of 250 eighth-, 299 tenth-, 292 eleventh-grade students, 134 science teachers in secondary school. SPSS/PC+ was adopted for the statistical analysis. The type of misconceptions possessed students were as follows: 1) At 12:00 noon, the sun is directly overhead. 2) First quarter moon is a half of overall surface of the moon. 3) Air don't rotate with the earth surface because it keeps apart from the earth surface. 4) Summer is warmer than winter, because the earth is nearer from the sun in summer. 5) Whenever season is changed, the direction of rotation axis of the earth is changed. 6) The moon is the brightest at the position of new moon, because the distance between the moon and the sun is the shortest and the moon is received strongest sunlight. 7) The moon is not seen at the position of real full moon, because it is covered with shadow of the earth. 8) When the moon is not seen in the earth, sunlight is not reached at the moon. The major findings were as follows : 1) The middle school students had more misconceptions than those of high school students. And female students had more misconceptions than those of male ones. 2) The rate of correct answer and the type of conception in the tenth grade students were very similar with eleventh grade students. 3) The higher cognitive level, the better development of scientific conception and the less misconception. Also, the correlation coefficient between scientific conception score and GALT score was 0.57. 4) The students in scientific part had higher the rate of correct answer than those of students in human part and the former had less misconception than the latter. 5) The rate of correct answer about model and figure items was lower than descriptive ones, because they did not understand about figures itselves. These types of misconceptions will be used for science instruction and studies of other conceptions need.

• Asian-Australasian Journal of Animal Sciences
• /
• 제5권2호
• /
• pp.261-266
• /
• 1992

Yearling replacement heifers were used in a two-year study at the Fort Stanton Experimental Ranch near Capitan, New Mexico, USA to compare frequency (once versus three times weekly) of feeding a cottonseed cake supplement. The study involved periods of 130 days (January 4 through May 14) in 1985, and 146 days (December 4 through April 29) in 1986. In each year, supplemental periods were just before the breeding season (natural breeding in multiple-sire groups) that lasted for 75 days during first year and 60 days during second year. During the first year, all (83) heifers (Angus $\times$ Hereford) were supplemented at a level equivalent to 45 kg/head daily and during second year, all (69) heifers (Angus $\times$ Hereford, Hereford) were fed at a level equivalent to .68 kg/head daily. In the first year, heifers were sorted by initial weight into two replications, i.e., those weighing under 223 kg were placed in replicate 1 and those weighing over 223 kg were placed in replicate 2. During the second year, heifers were sorted by breed into two replications, i.e., Angus $\times$ Hereford heifers were placed in replicate 1 and Hereford heifers in replicate 2. Each year, half of the heifers in each replication were supplemented once weekly and the other half three time weekly. Weight gains of heifers were similar for the two treatments over both years of study. During the first year, weight gains for heifers supplemented once or thrice weekly (.23 vs .21 kg daily, respectively) did not differ (p>.05) and the same trend for the second year (.15 vs .16 kg daily, respectively) was observed. Similarly, breeding performance was consistent with weight gains and no difference (p>.05) between treatments was observed either year. Lower conception rates during the second tear of study (92 vs 72% for years 1 and 2, respectively) were due mainly to involvement of Hereford heifers that had an average weight of 232 kg at the start of breeding season and conception rate of 54% (averaged across both supplemental treatments). Based on the combined results of both trials, frequency of supplementation did not affect growth rate of yearling heifers nor did it influence their subsequent conception rate.

• 한국수정란이식학회지
• /
• 제30권3호
• /
• pp.161-170
• /
• 2015

These studies were conducted to establish the practical Hanwoo (Korean native cattle) improvement system through the combining of embryo transfer technology and confirming individual Hanwoo oocyte culture system and to investigate that correlation of Hanwoo carcass classification (intramuscular marbling) and oocyte donor for blastocyst production in vitro. In case of Hanwoo, the carcass meat quality grades were divided to grade $1^{{+}{+}}$, $1^{+}$, 1, 2, and 3 depends on fat distribution of longest muscle cross-sectional surface. As results, the numbers of follicular oocytes collected from individual fundamentally-registered Hanwoo yielded $1^{{+}{+}}$, $1^{+}$, 1, 2 and 3 meat quality were 9.5, 9.4, 8.5, 8.8 and 8.8 per ovary, respectively. The numbers of retrieval oocyte from follicles were significantly higher in the cattle yield $1^{{+}{+}}$, $1^{+}$ meat quality than in the cattle yield 1, 2 and 3 meat quality (p<0.05). The rates of blastocyst formation were 18.2, 21.3, 29.4, 30.9, and 31.5% in the cattle yield $1^{{+}{+}}$, $1^{+}$, 1, 2 and 3 meat quality of after in vitro maturation, respectively. It was significantly lower in the cattle yield $^{{+}{+}}$ and $1^{+}$ meat quality than in the cattle yield 1, 2 and 3 meat quality (p<0.05). In order to evaluate embryos quality, TUNNEL assay was conducted for each meat quality grade using blastocyst stage embryo on day 8. The results showed that apoptosis cell number was higher tendency in the cattle yield $1^{{+}{+}}$and $1^{+}$ meat quality (81 and 79, respectively) than in the cattle yield 1, 2 and 3 meat quality (51, 48 and 50, respectively) but there was no statistical significance in each group. After embryo transfer, the conception rate of recipient was 53.5 (23 out of 43), 52.1 (38 out of 73) and 58.0% (58 out of 100) in the meat quality of 1, $1^{+}$ and $1^{{+}{+}}$, respectively. These results showed that the conception rate was significantly higher in the cattle yield 1 meat quality than in the cattle yield $1^{{+}{+}}$, $1^{+}$, 2, and 3 meat quality (p<0.05). In summary, these results indicate that the application of confirming Hanwoo individual oocyte culture system and embryo transfer technology can make good use of the genetic resources conservation and improvement of Hanwoo. Relevance of the meat quality grade and reproductive ability of carcasses of Hanwoo will be considered to be one of the effective means for the associated research with obesity and reproduction.