This study was carried out to compare farrowing rate and litter traits for European and American lines with boar sperm frozen in straws. Farrowing rate, litter size and mean pig weght at birth and 21 days were investigated. A total of 36 gilts Landrace, Large white and Duroc were investigated at the Chungnam Provincial Animal Breeding Station. We obtained higher farrowing rate and litter traits for European line boars compared to American line boars.

This study was carried out to produce monozygotic twin calves by transfer of bisected embryos. Four Korean native cattle donors were superovulated with FSH and flushed to collect embryos on day 6 or 7 of the estrus cycle. Morula and early blastocyst embryos showed 1 or 2 grade were bisected with microblade and each set of demi-embryos without zona pellucida were transferred nonsurgically to 10 recipients respectively. The results obtained were as follows; 1. Twenty four demi-embryos (92.3%) were separated from 13 original embryos and among them 20 demi-embryos (83.3%) had normal appearance without severe damage. 2. Four sets of fresh demi-embryos were transferred to 4 recipients and one recipient was twin pregnant 3. Six sets of frozen-thawed demi-embryos were transferred to 6 recipients. Two recipients were pregnant, one of them twin.

The objective of this study was to produce calves derived from in vitro fertilization of in vitro matured follicular oocytes. Oocytes aspirated from small antral folicles of ovaries obtained at a local slaughter house were matured and fertilized in vitro. At l8hrs after insemination with Korean native cattle semen, oocytes were co-cultured for 6~7 days by utilizing co-culture system with bovine oviduct epithelial cell. After co-culture, good or excellent quality late morulae or early blastocysts were selected by morphological criteria under stereo microscope. Selected embryos were transferred to recipients on day 6 or 7 (estrus = day 0). Recipients were monitored by observation for estrus and rectal palpation after 60 days from embryo transfer. One of them went to term with the birth of a calf. This case is the first production of calf derived from in vitro fertilization in Korea.

This study was carried out to propagate Korean native cattle using beef recipients by embryo transfer. Seven Korean native cattle donors were superovulated with FSH 32mg and Embryos collected from donors were frozen and preserved in National Animal Breeding Institute. Frozen-thawed embryos were transferred to synchronized 40 beef recipients nonsurgically in Daekwanryeong Branch of National Animal Breeding Institute. The results obtained were as follows : 1. Total ova and transferable embryos per donor were 11.4 and 11.1 from 7 donors, respectively. 2. Among 40 recipients transferred with frozen-thawed embryos, 20 were pregnant(50.0%). 3. The pregnancy rate according to time from embryo thawing to transfer was higher when transferred within 3 hours than after 3 hours(57.6% vs. 14.3%). 4. The cow recipients showed slightly higher pregnancy rate than the heifer(53.3% vs. 48.0%). 5. Two grade embryos showed higher pregnancy rate than 1 grade(66.7% vs. 45.2%).

Effects of caffeine, heparin and caffeine-heparin treatments for in vitro capacitation of Korean Native Cattle sperm on acrosorne reaction and viability were studied using the methods of Wells-Awa and Dual stain. The results were summerized as follows: 1. The acrosome reaction of sperm when treated with caffeine after 0 to 4 hrs of preincubation were 11.0~75.7% for Wells-Awa stain, and 14.3~75.55% for Dual stain. True acrosome reaction of sperm for Dual stain was 3.0~29.2%. The viability of sperm was 62. 2~27.2%. 2. The acrosome reaction of sperm when treated with heparin after 0 to 4 hrs of preincubation were 17.0~81.2% for Wells-Awa, and 14.3~75.5% for Dual Stain. True acrosome reaction of sperm for Dual stain was 1.5~26.6%. The viability of sperm was 58.6~35. 8%. 3. The acrosome reaction of sperm when treated with caffeine-heparin after 0 to 4 hrs of preincubation were 13.0~83.2% for Wells Awa, and 11.0~78.5% for Dual stain. True acrosome reaction of for Dual stain was 5.1~26.3%. The viability of sperm was 60.5~30.1%.

These studies were conducted to investigate the effect of repreated superovulation on embryo production, the effect of the frozen-thawed embryos transferred on the developmental stage and grade, and donor-recipient synchrony on pregnancy rate in Korean native cattle. The results obtained in these studies were as follows: 1. Repeated superovulations in Korean Native Catile were not affected on the number of corpus luteum (CL), embryos recovered and embryos cleaved (range: 4.8 4.21 to 9.5 6.50, 1.8 2.53 to 8.2 8.04 and 1.6 2.32 to 4.0 4.59, respectively). 2. Blastocyst embryos (38.5%) showed higher pregnancy rate than morula (31.6%). 3. The pregnancyrates of cattle transferred with good and fair embryos were 33.3% and 40.4%, respectively. 4. The pregnancy rate when the donors exhibited estrus 12 hours earlier than the recipients (62.5%) was higher than when the donors and recipients exhibited estrus at the same time (33.3%) or when the donors exhibited estrus 12 hours later than the recipients (20.0%).

본(本) 연구(硏究)는 한우육용화(韓牛肉用化) 개량(改良)에 있어서 가장 중요한 경제형질(經濟形質)인 체중에 대(對)한 유전적개량량(遺傳的改良量)을 최대(最大)로 증대(增大)시킬 수 있는 적정규모(適正規模)를 산출(産出)하여 한우(韓牛)의 육용능력(肉用能力)을 조기(早期)에 효율적(效率的)으로 개량(改良)할 수 있는 방안(方案)을 제시(提示)하기 위하여 수행되었다. 체중에 대(對)한 유전적개량량(遺傳的改良量)과 세대별(世代別) 체중평균치의 변화(變化)를 추정(推定)하기 위하여 2재(才)이상의 암소잡균(雜菌)은 매세대(每世代) 675,000두(頭)가 유지(維持)되고 또한 암소는 매년(每年) 15%가 도태(淘汰)된다는 등(等) 몇가지 반정(飯定)아래서 다음과 같은 요인(要因)이 고려(考慮)되었다. 1) 암소 집단중(集團中) 인공수정(人工授精)되는 비율(比率); 30, 40, 50, 60, 70% 2) 종모우(種牡牛) 두당, 년간(年間) 정액(精液) 생산(生産) 수량(數量); 5,000, 7,000, 10,000, 15,000, 20,000두분(頭分) 3) 종모우(種牡牛)의 평균체중; 480, 520, 560, 600, 640, 680, 720kg/18개월령(個月齡)이다. 본연구(本硏究)에서 얻어진 결과(結果)를 요약(要約)하면 다음과 같다. 1) 체중의 유전적개량량(遺傳的改良量)은 이용(利用)되는 종모우(種牡牛)의 체중에 크게 영향(影響)을 받으며 매세대당유전적개량량은 28.66~36.31kg으로 추정(推定)되었다. 2) 유전적개량량(遺傳的改良量)의 80~90%는 종모우선발(種牡牛選拔)에 기인(起因)하는 것으로 나타났다. 3) 종모우(種牡牛)의 평균체중이 매세대(每世代)마다 40kg씩 증가(增加)되고 암소의 인공수정(人工授精)되는 비율(比率)이 50%이상으로 확대(擴大)되어지는 경우 5세대(世代)이후에서 수소 및 암소의 체중평균치는 인공수정집단(人工授精集團)에서는 600kg과 520kg, 그리고 전(全) 모집단(母集團)에 있어서는 560kg과 480kg에 도달될 것으로 추정(推定)되었다.

Telomeres at the end of the eukaryotic chromosomes consist of tandem repeats of (TTAGGG)n DNA sequence and shelter in protein complex. Telomeres have the essential functions in chromosome stability and genome integrity and are hence related to cell senescence and cancer. Stripped, Black and White Cattle (Endangered Korean Native Cattle) characterized by their coat color, live in the Korean peninsula. However, they are endangered, with very small populations remaining. To investigate the karyotypic pattern of chromosome and also to quantify the amount of telomeric DNA was carried out from the traditional Korean beef cattle species, HanWoo and endangered cattle bull. We quantified the amount of telomeric DNA by the Quantitative-Fluorescence in situ Hybridization (Q-FISH) technique using the telomeric DNA probe and chromosome analysis of lymphocytes was carried out using GTG-banding in 9 bull at age of 18 months. In results, we found that the normal (60, XY) male karyotype were detected in metaphase chromosomes from korean native cattle including Hanwoo, Stripped, Black and White cattle, respectively. In addition, there were no significant differences in the relative amount of telomeric DNA among the korean cattle bull. However, the relative amount of telomeric DNA of Hanwoo was slightly higher than that of White cattle. In conclusion, this study reported karytype and the amount of telomeric DNA which could serve as baseline information for comparison in conditions of physiological and health status of endangered Korean native cattle. Although we have no definitive explanations as to why this occurs, further investigations are needed to continue investigation of these animals throughout their life spans.

The objective of this study was to evaluate the effect of applying alum (aluminum sulfate) and aluminum chloride on pH and pathogen populations of Hanwoo manure. A total of 36 steers (8 months old and averaging 300 kg in weight) were used in this trial and allotted to 9 pens (3 replication pens per group with 4 steers per experimental unit, 5 x 8 m). Chemical additives were applied as a top dressing with garden rake to a depth of 1 cm of manure with wood shavings in each treatment. The chemical amendments were control (without chemical amendments), 50 g of alum and 50 g of aluminum chloride/kg of Hanwoo manure. The experiment was carried out for 4 weeks. Adding alum and aluminum chloride to Hanwoo manure reduced (P < 0.05) pH compared to untreated controls during the 4-wk period. Both levels of the alum and aluminum chloride treatments tested decreased (P < 0.05) Escherichia coli and Salmonella enterica populations in Hanwoo manure at 2 and 4 weeks. It appears that the reduction in pathogen populations was primarily associated with the lower manure pH. If more strict environmental regulations are put into effect regarding pathogen populations from Hanwoo facilities, treating Hanwoo manure with alum and aluminum chloride may be a good management practice.