• Korean Journal of Animal Reproduction
• /
• v.15 no.1
• /
• pp.41-47
• /
• 1991

The ability of fertilization in vitro and subsequent development of superovulated oocytes was assessed in a controlled environment using an in vitro fertilization technique. The in vitro fertilization percentage of oocytes with cumulus mass declined significantly(P<0.05) with increased doses from 4~10 to 16~40IU of PMSG for superovulation. However, the porportion of polyspermic penetration varied from 2.3 to 9.7% and there was no significant difference between treatments in incidence of polyspermy. When morphologically normal ova with cumulus mass were cultured for 66~72h in a plastic mini-straw to undergo fertilization in vitro, the mean percentage of embryos developed to 2-16 and 4-16cell stage was 61.8 and 17.6%; it was slightly(P<0.05) superior to the corresponding results from petri dish. A total of 52 two-cell embryos fertilized in a mini-straw were transferred to seven pseudopregnant rat. Among these recipients, two normal young were born from one recipient which received a total of six embryos. These results suggest that superovulated oocytes are proportionately less competent than normally ovulated oocytes to undergo fertilization in a controlled environment using an in vitro fertilization technique. Also, a plastic mini-straw designed was slightly superior to petri dish as a culture vessel for fertilization and embryo development in vitro.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.6
• /
• pp.514-520
• /
• 2019

The reduction in performance due to inbreeding (i.e. inbreeding depression) has long been documented in plant and animal populations. The population of Korean native pigs are small and this breed is valuable in Korea.. This study was aimed to investigate effects of inbreeding depression on total number of piglets born (TNB) and number of piglets born alive (NBA) in Korean native pigs. We used 2,806 pedigree and 303 sows's data with 483 phenotypic records. After estimating genetic parameters for each traits, inbreeding depression was estimated using a mixed model in which the inbreeding coefficient was included as a covariate. Korean native pigs had high heritability for each traits. Inbreeding coefficient constantly increased from 1998 to 2017~2018 but there is no reduction for each traits in 2017~2018 in compared with those in 1998. Significant inbreeding depression was detected for TNB (p=0.03) but not for NBA (p=0.41). In addition there are significantly positive interactions between inbreeding coefficient and breeding value for both traits (p<0.05). These results suggest that Korean native pigs are still having genetic variation for TNB and NBA, which could overcome reproductive risks from inbreeding coefficient increase.

• Korean Journal of Ichthyology
• /
• v.36 no.3
• /
• pp.209-219
• /
• 2024

A survey was conducted in 2011 to investigate the reproductive ecology and spawning behavior of the natural monumental and endangered species, Cobitis choii. C. choii exhibits sexual dimorphism with the development of lamina circularis on the second pectoral fin ray in males at one year old, facilitating easy differentiation between males and females. A total of 1,288 females and 881 males were collected from January to December, resulting in a sex ratio of 1 : 0.68. The spawning season was estimated to be from late June to early July (spawning peak from late June, with water temperatures ranging from 22 to 25℃), coinciding with a sharp decrease in the condition index. Gonadal maturity was observed with maturity indices of 17.5±2.11% for females and 2.9±0.46% for males, with fecundity of 2,444±838 eggs and egg size of 0.75±0.05 mm. Spawning behavior was induced by hormone injection (Human Chorionic Gonadotropin, HCG) in laboratory conditions. Experimental results revealed that males and females paired in a 1 : 1 ratio before spawning. Males pressed the abdomen of females using their lamina circularis to induce spawning, followed by immediate fertilization. Spawning behavior was repeated 15 to 25 (average 20) times per pair of males and females, and 80 to 120 eggs were spawned per time, and the total amount of spawned eggs were 2,500±250 on average.

• Reproductive and Developmental Biology
• /
• v.30 no.3
• /
• pp.219-224
• /
• 2006

The objective of this study was to investigate the toxic effects of Bisphenol A(BPA) and di-2 ethyhexyl phthalate (DEHP) as endocrine disrupters on sperm motility, viability, membrane integrity and abnormality during in vitro incubation of boar semen. Semen were randomly divide into 24 groups and healed with different concentrations of BPA md DEHP($1{\sim}100{\mu}M$) for 3, 6 and 9 hrs, respectively. The percentages of sperm motility and viability decreased by treatment time with both BPA and DEHP, and obiously differ from the controls. The percentages of sperm motility and viability significantly decreased by incubation with both $100{\mu}M$ of BPA and DEHP compared to control and other treatment groups(p<0.05). Sperm membrane integrity was significantly reduced by incubation with 10 and $100{\mu}M$ of BPA and DEHP, respectively(p<0.05), but sperm abnormality were not significantly affect both BPA and DEHP. These results indicate that high concentration of BPA and DEHP($>10{\mu}M$ can affect noxiously the sperm characteristics.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.44 no.2
• /
• pp.83-91
• /
• 2024

We compared the reproductive performance, non-productive performance, and milk composition performance of two groups of lactating cows that were either rice straw or tall fescue. We also compared and analyzed these parameters after the first parturition during the breeding period. The calving interval, artificial insemination, and duration from calving to conception were longer in the rice straw group than in the tall fescue group. The 305-day and peak milk yields were significantly higher in the tall fescue group than in the rice straw group (p<0.01). Milk fat content was significantly higher in the tall fescue group than in the rice straw group (p<0.001), but milk protein content was the same between the feeding groups. The difference in raw milk sales income between rice straw and tall fescue groups tended to increase as the number of lactations increased, but there was no effect of reduced feed costs. Analysis of the milk production and raw milk sales income of the surveyed farms revealed that the average milk production per head was significantly (p<0.05) higher in the tall fescue group than in the rice straw group, and raw milk sales income showed a similar tendency. Overall, these results provide important details to be considered when selecting feed as a way to reduce milk production and heifer raising costs. However, there remains a need for future follow-up studies exploring the relationship between feed choice and the management of heifers.

• Journal of Animal Science and Technology
• /
• v.48 no.2
• /
• pp.255-268
• /
• 2006

Twenty four Hanwoo cull cows were assigned to 2 groups, control and melengerol acetate(MGA)+selenium supplement containing vitamin E(SeE), based on the parity(6.5±1.7 birth) and body weight (493.17±55.61kg), and the experiment was conducted to establish the reasonable fattening method of cull cows for 240 days. Average daily body gains during 240 days were 0.51kg and 0.63kg in control and MGA+SeE, respectively(P<0.10). DDMI/ADG of MGA+SeE group improved compared to control group(P<0.05). Therefore, supplementation of MGA+SeE in concentrates may accelerate both of the growth rate and feed efficiency in Hanwoo cull cows. MQI from MGA+SeE was more developed based on the larger rib-eye area and thinner backfat thickness in carcass than that from control. Marbling score for MGA+SeE tended to increase compared to control. Dietary Se supplementation significantly affected muscle Se concentration in longissimus dorsi meat of MGA+SeE group(P<0.05). Similar results to Se were obtained from α-Tocoperol concentration. During 7 days of simulated retail display, accumulations of thiobarbituric acid reactive substances(TBARS) concentration in beef was greater(P<0.05) in control than in supplemented cows. These results supported the hypothesis that supplementation of MGA+SeE improve the growth performance and carcass grade both by the growth stimulating effect of MGA+SeE and by preventing the oxidation of the longissimus dorsi muscle in Hanwoo cull cows.

• Korean Journal of Agricultural Science
• /
• v.4 no.1
• /
• pp.84-87
• /
• 1977

The distribution of number of ovulation between right and left ovary in superovulated mice were examined. 50 adult female mice of CF#1 strain were used in this study. Superovulation was induced by the subcutaneous injection of 5 IU PMS and followed 48 hours later by the subcutaneous injection of 5 IU HCG. Females a were killed at 24 hours after injection of HCG, and ova in the oviducts were counted under a microscope. The number of ova ovulated from the left and the right ovary were 603 and 594. The number of ova in both sides were found equal frequency by $X^2$ test method. Ovulation occurred more frequently in the left ovary than in the right in 24 females and with equal frequency in both ovaries in 3 females, while more frequently in the right ovary than in the left in 23 females. The possitive correlation was found between right and left ovary.

• Korean journal of applied entomology
• /
• v.50 no.4
• /
• pp.383-393
• /
• 2011

Because communication facilitates behaviors that are critical for survival and reproduction, it is central to the study of behavior and evolution. One of the most important and difficult issues with respect to communication has been the definition of communication itself. Broadly, it can be defined as an exchange of information from a signaler to a receiver. However, evolution of a signal is likely possible only under conditions in which both the signaler and receiver increase fitness from the exchange of information, often referred to as "true communication." The three primary sensory channels of communication used by animals are chemical, visual, and acoustic. Chemical signals are the oldest and most widespread method of communication. Visual and acoustic signals convey a great deal of information due to ease of modulation, flexibility of signal production, and fast transmission. The most widespread contexts in which animals communicate are sexual interaction and conflict resolution. Signals used for sexual interaction typically contain information about species identity and sexual attractiveness, whereas signals used for conflict resolution may contain information about resource holding potential. Other contexts under which animals communicate include territorial defense, parent-offspring interactions, social integration, sharing of environmental information, and auto-communication.

• Korean Journal of Animal Reproduction
• /
• v.27 no.1
• /
• pp.69-75
• /
• 2003

The objective of this study is to improve the efficiency of embryo transfer in generation of transgenic mice using inbred mouse (C57BL/6J) embryos. The embryos of C57BL/6J and BCF1 mice were superovulated by the standard protocol. One-cell stage of embryos were microinjected and the resulted one-or two-cell were transferred into one-or two-side oviducts of foster mother, respectively. When one-cell stage of embryos were transferred into one-side oviduct of 0.75 d.p.c. foster mother, the results were not ideal because of showing pregnancy ratios of 68.8$\pm$7.83% for C57BL/6J and 48.3$\pm$14.22% for BCF1, and development ratios of pups vs transferred embryos of 11.9$\pm$5.51% for C57BL/6J and 10.5$\pm$8.03% fur BCF1 . However, when two-cell stage of embryos were transferred into two-side oviducts of 0.5 d.p.c. foster mother, we got better results of 94.4$\pm$9.64% and 100$\pm$0% pregnancy ratio, and 22.1$\pm$0.4% and 21.8$\pm$0.38% development ratio for C57BL/6J and BCF1, respectively. Therefore, transferring two-cell stage of C57BL/6J embryos into two-side oviducts of 0.5 d.p.c. foster mother may be competitive to the result in BCF1 embryos. Even if there are a lot of other factors affecting these results, we conclude from these experiments that transfer of two-cell embryos into two-side oviducts of 0.5 d.p.c. foster mother is a more efficient and safe method than others in generating transgenic mice using inbred mice embryos.

• Journal of Embryo Transfer
• /
• v.22 no.3
• /
• pp.195-198
• /
• 2007

This study was carried out to investigate the effects of hormones treated (progesterone, and combination of progesterone and estradiol) on the reproductive performance of dairy cattle. The intravaginal CIDR was inserted in the vagina of cow on day 14 (P-7, PE-7), 16 (P-5, PE-5) and 18 (P-3, PE-3) post-insemination to stimulate progesterone secretion with (PE) and without estradiol(P). The CIDR was removed on 7 (P-7, PE-7), 5 (P-5, PE-5) and 3 (P-3, PE-3) days after. The cows for control group were not treated with CIDR or hormones. Conception rate, the duration needed for conception after AI and the number of AI services needed for conception were measured. Conception rate in control, CIDR without estradiol (P-7, P-5 and P-3) and CIDR treated (PE-7, PE-5 and PE-3) cows were 15.8%, 40.0%, 31.5%, 28.6%, 62.5%, 50.0% and 0%, respectively. The days needed for conception after AI in control, P-7, P-5, p-3, PE-7, PE-5 and PE-3 were 64.9, 63.0, 59.1, 8.0, 0.0, 18.9 and 83.3 days, respectively. The days needed for conception in cows treated with CIDR (PE-7) has shown longer than control and PE-3 (p<0.05). The number of AI services needed for conception in control, CIDR (PE-7, PE-5 and PE-3) and CIDR without estradiol treated cows (P-7, P-5 and P-3) were 27, 2.3, 1.9, 1.3, 1.0, 1.7 and 2.8 times, respectively. The number of AI services needed for conception have shown significantly lower in PE-7 compared to control and PE-3.