Search

Up-to-date artificial insemination (AI) using frozen sperm consider as the most widely using technology for improvement of Korean Native Cow (Hanwoo) embryo production. However, it is time consuming, required at least 15~20 years to make more than 6 generations, and their offspring number is limited. To overcome such limitations, superovulation and in vitro fertilization have been developed. For superovulation, the number of produced embryos are not enough for commercialization and donor cows need rest period. This led to use of slaughterhouse ovary for in vitro fertilization, but it is impossible to repeat the collection from the same individual and it only can improve the genetic merits of offspring for one generation. Production of embryos using Ovum Pick-Up (OPU) technique, where oocytes can be repeatedly collected from living elite donor, might overcome these limitations. In this study, we investigated the possibility of using OPU technique from donors at different age and different session periods for mass-embryo-production. Oocytes were collected from 26 donor cows twice per week, 3 - 4 months per year, between 2013 and 2016. Results showed that, the average number of embryo produced in first year used donor was significantly higher than that in second year used donor (3.89 ± 2.85 vs 3.29 ± 2.70), however, there was no significant difference between third year used donor (3.51 ± 3.32) and other groups. Taken together, our data showed that repeated using of donor up to three years is possible for in vitro embryo mass-production. Moreover, OPU can be used as suitable embryo producing technique for livestock breed improvement.

The objective of this study was to investigate the effect of age and number of parities on the potential of the Korean native cow (Hanwoo breed) as oocyte donor in ovum pick-up and subsequent in vitro embryo production. All animals were divided into two different groups based on age (3–6 and 7–9 years) and parity (2–3 and 4–7). Ovum pick-up (OPU) was performed to ten Korean native cows over a 4-months period at intervals of 3–4 d (twice weekly). The population of follicles (≥3 mm diameter) present in both ovaries and the grades of all cumulus-oocyte complexes (COCs) retrieved were recorded. All COCs were matured, fertilized and allowed to develop in vitro and the morphological quality of embryos was evaluated before transfer to recipients. There were 18.4±5.7 (mean ± SEM) follicles available for aspiration throughout the experiments; the population of follicles decreased from 19.1±6.3 in the first month to 16.9±4.2 in the last month ( p ≤0.05). However, with advancement in age and parity of animals, there was an increase in number of ovarian follicles. Furthermore, the average number of COCs retrieved was 12.5±5.6 in the first month and this number was reduced in the fourth month (10.4±5.4). The total number of recovered COCs was increased in old cows with increased number of parities. Consequently, embryo production decreased from 4.8±3.1 to 4.2±2.8 on the first and last months, while, it was increased in old cows than young ones ( p ≤0.05). Furthermore, animals with high number of antral follicular count produced more COCs and embryos. Therefore, we concluded that repeated OPU of Korean native cows resulted in significant decrease in the in vitro production of embryos in young compared with old cows; this has negatively impacted embryo survival after transfer. [ABSTRACT FROM AUTHOR]

Histopathological findings of eosinophilic myositis in the carcass of a slaughtered Korean native cow are presented. Lesions contained massive fibrous septae with vacuolar changes in some lesions, and the hypercontraction and rupturing of muscle bundles, with replacement by eosinophils. Necrosis and severe eosinophil infiltration were observed. Sarcoplasmic fragmentation and atrophy developed. Typical of granuloma, calcified myofibers were focally surrounded by macrophages and numerous inflammatory cells, and multinucleated giant cell formation was evident. [ABSTRACT FROM AUTHOR]