본 연구는 부모의 혈통정보를 모두 아는 혈통 및 고등등록우로 등록된 한우 암소 25,516두의 선형 및 외모심사형질에 대해 유전모수를 추정하였다. 각 심사형질에 영향을 주는 것으로 판단되는 주요인을 선 정하여 다형질 개체모형에 적용하여 EM-REML 알고리즘 분석방법을 통해 각 형질에 대한 유전력과 유 전상관과 표현형상관을 추정하였다. 한우 암소의 17개 선형심사형질 및 10개 외모심사형질(종합점수 포 함)의 유전력 추정치의 범위는 0.03(유두배열)에서 0.42(체장)까지로 추정되었다. 체고, 체장, 강건성, 체심, 윤곽성, 정강이두께, 피모의 색, 엉덩이기울기, 고장, 좌골폭, 넓적다리의 두께, 유방용적, 유두길 이, 유두배열, 발굽기울기, 뒷다리 비절기울기, 뒤에서 본 뒷다리자세, 체적․균형, 자질․품위, 머리․목, 전구, 중구, 엉덩이, 넓적다리, 유기, 지제보양 및 종합점수의 유전력은 각각 0.4, 0.42, 0.27, 0.25, 0.06, 0.14, 0.22, 0.31, 0.19, 0.17, 0.29, 0.04, 0.07, 0.02, 0.11, 0.03, 0.16, 0.27, 0.08, 0.15, 0.14, 0.14, 0.19, 0.16, 0.05, 0.08 및 0.3으로 추정되었다. 한편, 다형질개체모형에 의해 추정된 17개 선형심사형질과 종합점수에 대한 유전상관추정 결과는 다음과 같다. 고장과 좌골폭간에 0.96의 가장 강 한 양(+)의 유전적 관계를 나타내었다. 반면 발굽기울기와 뒷다리 비절기울기간에는 -0.57의 가장 큰 음(-)의 유전상관을 보였다. 전체외모 형질인 체고, 체장, 간겅성 및 체심은 각 형질간에, 그리고 기타 형 질들과 강한 양(+)의 유전상관관계를 나타내었다. 특히 체고 및 체심과 고장 및 좌골폭간에 높은 양(+)의 상관관계를 나타내었으며, 체고와 엉덩이기울기간에는 0.32의 양(+)의 상관을 나타내었다.

Assays for detecting pregnancy-associated glycoproteins (PAGs) levels in the blood of pregnant cattle have been developed and commercialized to determine pregnancy status. This study was conducted to determine the accuracy of a PAG-based ELISA test for pregnancy detection in Hanwoo. The anticoagulated treated whole blood was sampled from 595 Hanwoo that were 28-71 d (mean 49) and 85-128 d (mean 106) after artificial insemination. At the 2nd blood collection time, a transrectal palpation test was used as the standard for pregnancy diagnosis. For PAGs and the transrectal palpation test (n=595), the sensitivity was 98.4% (pregnancy, 481/489), the specificity was 100% (open, 106/106), and the accuracy was 98.7% (pregnancy+open, 587/595). In conclusion, the rapid PAG-based ELISA pregnancy test was highly sensitive and specific for pregnancy detection in Hanwoo.

This study was conducted to investigate the breeding status of farms to improve the production efficiency of Hanwoo calf. The study was conducted on 45 farms divided into two groups. This study was conducted to investigate the breeding size and breeding area of Hanwoo cows. The average age at first delivery of Hanwoo was 28.7 months. The number of artificial insemination per pregnancy was 1.45±0.32, and the number of artificial insemination days after birth was 119.8 days. Conception rates were 75.2±16.93% for small farms and 70.6±17.46% for medium sized farms and 71.4±11.03% for large farms. When we looked at farming methods, ‘the farmers using estrus observation aids’ had 10.42% higher calf production rate than the ‘unused farmers’. The farms vaccinated with IBR and BVDV for breeding cattle showed a 4.41% decrease in abortion, stillbirth and mortality. According to farming conditions, conception rate and delivery rate improved by 3.47% and 18.29%, respectively, when grazing and exercising were performed. Observation, immunization and grazing were found to be important indicators for improving calf production efficiency in Hanwoo farm. This study can be used as a research data to improve the reproductive rate of farmhouse sites through the survey on the breeding status of Hanwoo farmers.

This study was conducted to investigate the optimal artificial insemination (AI) time with diagnostic kit at ovulation time. We already applied the patent about the protein in the cow heat mucose in external reproductive tract. And we would examine the accuracy for detection of cow heat by the kit produced with the protein. Evaluation of optimal heat detection was tried two time at 12 hrs and 24 hrs after the heat. And then, AI service also performed two times with no relation to the results of heat diagnosis by heat detection kit and pregnancy rates were checked with rectal palpation on 60th day after AI. Heat diagnostic results by kit in natural heat after 12 hrs in Hanwoo cows were showed 31.3~75.0% on positive in first heat detection and 33.3~100.0% on positve in second heat detection. In the 1st positive results were significant different (p<0.05), but 2nd positive were not. The results of heat detection showed different result on regional influence and individual cow effects. The pregnancy rates of first trial of heat detection were showed 34.4~78.7% on positive and 21.3~68.8% on negative after the diagnosis by heat detection kit. And the pregnancy rates of next trial of heat detection were showed 33.3~85.7% on positive and 14.3~66.6% on negative after the heat diagnosis. Both positive results of first trial and next trial also were showed significant different (p<0.05), but negative results were not. In positive result, first trial of total pregnancy rates was higher than the next trial of pregnancy, but there showed opposite results on negative results. In conclusion, the optimal heat detection kit is suitable to ordinary Hanwoo cows and it suggested that we have to improve the kit’s accuracy by detecting the materials like proteins related optimal AI time.

Commercial applications of OPU/IVP were to produce embryos and calves from high genetic cows.The aim of this present study was to compare the number of recovered oocytes and cultured in vitro produced embryos from Ovum Pick-up (OPU). OPU derived embryo production was carried out of oocytes by ultrasonographic guided follicular aspiration and then produced in vitro produced blastocysts by IVP culture system. In result, the rate of recovered oocytes was obtained 612 (57.2%) and 451(73.7) G1+G2 grade oocytes. No difference of recovered rate (51.1~62.1%) was seen in six donor. The rate of cleavage and blastocyst development were obtained 320 (70.9%) and 78 (24.4%) that was 3.3±0.4 cleaved embryo and 0.9±0.2 blastocysts per session. Cleavage rate of OPU oocytes in No. 6 donor was 90.6%, significantly (P<0.05) higher than that in the other donors, However, blastocysts was similar (25.8~30.0%). In conclusion, limited numbers of OPU oocytes had competent development when cultured in SOF culture medium

This study investigated the stress-related metabolites and hormones in blood and compared the muscle structure to identify the reason for blood splash in Hanwoo beef. Five slaughter houses were selected based on the region (Seoul, Gimhae, Jungbu, Naju, and Goryung) and a previous blood splash record. In total, three-hundred eighty blood samples (n=380) and forty-two muscle tissues (n=42) of control and blood splash Hanwoo beef were collected during the slaughter process and beef grading. Blood metabolites were analyzed including glucose, lactate, creatinine, urea-N, and hormones such as cortisol and thyroxin. Muscle fiber, fiber bundle, and capillary wall thickness were measured under microscope. The concentrations of blood glucose, lactate, and urea-N were not significantly different between the control and the blood splash samples. Cortisol and thyroxin levels were not significantly different in both samples. In contrast, the creatinine level was significantly increased (p<0.05) in the blood splash samples. There were also no significant differences observed in muscle fiber, bundles, and capillary wall thickness between the control and the blood splash tissues. In conclusion, blood metabolites, hormones, and muscle fiber showed no differences between the control and the blood splash animal. However, increased creatinine levels may be used as an indicator for identifying blood splash prior to slaughter in Hanwoo.

본 연구는 grooming brush의 제공에 따른 한우 암소 육성우의 사양성적, 행동특성, 혈액 내 cortisol 및 혈액성상의 변화를 조사하였다. 6개월령의 암소 육성우(110.63±12.23kg) 32두를 32m2 우방에서 대조 구(non grooming brush), 처리구 1(Chevron angle type grooming brush, CHAT), 처리구 2(Straight type grooming brush, ST) 및 처리구 3(Chevron angle type and Straight type grooming brush, CHAST)으로 처리당 4두씩, 4처리 2반복으로 완전임의 배치하여, 2주간 예비시험 후 8개월간 본 시험 을 실시하였다. 시험결과 grooming brush 제공에 따른 사양성적으로 종료 시 체중과 일당증체량에서 는 대조구 대비 처리구에서 유의적(p<0.05)으로 증가하였고, 사료요구율에서는 대조구에서 가장 낮은 사양성적을 보였다(p<0.05). 행동특성 중 횡화 및 걷기시간은 대조구 대비 grooming brush를 제공한 모든 처리구에 유의적으로 높게 나타났다(p<0.05). 음수행동의 빈도는 처리구 3에서 유의적(p<0.05)으 로 증가하였다. 또한, 몸단장행동인 자기몸 핥기, brushing 행동과 투쟁행동은 대조구에서 다른 처리구 에 비해 유의적으로 증가하였다(p<0.05). 혈액성상에서 헤모글로빈수치는 처리구에서 유의적(p<0.05) 으로 높았고, 스트레스 호르몬인 cortisol 농도는 대조구에서 유의적(p<0.05)으로 높은 수치를 보였다. 따라서, grooming brush 제공에 따른 한우 육성 성적, 행동특성 그리고 혈액 내 cortisol의 변화는 집 단생활을 하는 소의 사회적인 행동에 긍정적인 영향을 미치는 것으로 볼 수 있으며, 스트레스 저감으로 인해 건강한 발육에 기여하는 것으로 나타났다.

본 연구는 키토산 및 생균제를 급여한 한우의 채끝등심의 품질 및 화학적 특성에 미치는 영향에 대해 조사하기 위해 실시 하였다. 거세한우(n=20)를 시험구별 완전 임의 배치한 뒤 대조구(n=10)는 일반 배합 사료를 급여하고, 처리구(n=10)는 키토산 및 생균제 배합사료(생균제 1%, 키토산 0.1%)를 4개월 동안 급 여하였다. 각 처리구는 1등급을 받은 채끝등심을 이용하였다. 일반성분 결과 수분(64.13~65.00%), 조회 분(1.47~1.69%), 조단백질(19.56~20.25%), 조지방(15.69~15.88%)은 처리구간 유의적인 차이가 없었다. pH, 가열감량, 전단력, 육색 모두 처리구간의 유의적인 차이는 없었으며, 보수력의 경우 대조구(69.60%) 보다 처리구(74.29%)가 유의적으로 높았다(p<0.05). 지방산패도는 처리구간의 유의적인 차이는 없었으 나 휘발성염기태질소 함량은 처리구에서 유의적으로 낮은 함량을 나타내었다(p<0.05). Collagen함량과 anserine 함량은 처리구간의 유의적인 차이는 없었으나, carnosine은 처리구(51.22mg/dry base)가 대 조구(47.08mg/dry base) 보다 유의적으로 높은 함량을 나타내었다(p<0.05). Palmitoleic acid와 다가 불포화지방산 함량은 대조구보다 처리구에서 유의적으로 높았으며, 키토산과 생균제 급여는 한우 채끝 등심의 아미노산과 무기질 함량에는 영향을 미치지 않았다. 따라서 거세 한우에 1% 생균제 및 0.1% 키 토산 배합사료 급여는 한우 채끝등심의 보수력 향상 및 단백질 변패 억제, 기능성 성분인 carnosine 함 량과 다가 불포화 지방산의 함량을 높이는 효과를 보여 추후 이들 성분이 기능성 사료 첨가제로서 사용 가능성이 있을 것으로 사료된다.

This study analyzed the effect on weight and average daily gain, carcass grade, and blood characteristics and immunity in case of dietary addition of pegmatite to Hanwoo steers. Relative to Hanwoo steers, initial body weight was 257.3±11.74 kg (8-months old after birth). Forty-eight Hanwoo steers were fed for 24 months using random arrangement (4 treatment plots×4 heads×3 repeat). The treatment plot (498.75~500.82 kg) had higher weight during the early fattening stage compared with that of the control plot (474.37 kg) (p<0.05). Regarding total cholesterol of the blood, the value was similar to one during initiation of testing, but the value increased gradually based on the progress of fattening. In addition, the triglyceride was considerably low in T2~T3 plots with high addition of pegmatite during the late fattening stage compared with other treatment plots (p<0.05). This study revealed a tendency in the IgG content that represented immunity as the addition of pegmatite became higher (p>0.05). This study found that the treatment plot (441.55~452.10 kg) had higher carcass weight compared with the control plot (436.30 kg). However, this study revealed that the treatment plot (2.30~2.55 points) had higher carcass quantity grade compared with the control plot (2.11 points). This study found that the control plot (3.55 points) had higher carcass quality grade compared with the treatment plot (2.67~3.09 points) (p>0.05). With studies combined, it was determined that dietary addition of pegmatite to the feed as clay minerals in fattening Hanwoo steers would improve feed intake, body weight gain and carcass quantity grade.

본 연구의 목적은 한우 도체형질과 등심에 대한 일반성분(수분, 조지방, 조단백질, 조회분) 분석을 통 한 등심의 영양학적 가치와 유전모수 추정을 통한 개량형질 적용 가능성을 확인하기 위하여 실시하였 다. 본 연구에 이용된 공시 재료는 한우 후대검정우 47차부터 57차까지 실시한 2,033두에 대하여 등심 1㎏을 시료를 채취하여 분석한 자료를 이용하였다. 연구결과 한우 도체형질인 도체중, 등심단면적, 등 지방두께, 근내지방도에 대한 유전력은 각각 0.37, 0.51, 0.44, 0.57로 추정되었으며, 일반성분 분석인 수분, 조지방, 조단백질, 조회분에 대한 유전력은 각각 0.62, 0.64, 0.58, 0.12로 추정되었다. 그리고, 도체형질과 일반성분간의 유전상관은 도체중과 조지방에서 0.35, 근내지방도와 수분, 조지방, 조단백 질, 조회분에서 각각 -0.966, 0.964, -0.924, -0.664으로 고도의 유전상관을 보였다. 수분과 조지방, 조단백질간의 유전상관은 각각 -0.998, 0.969로 분석되었으며, 조지방과 조단백질에서 -0.979로 고도 의 유전상관을 보였다. 일반성분 분석치인 수분, 조지방, 조단백질에서 고도의 유전력을 보였으므로, 개 량형질 이용 가능성이 있을 것으로 사료된다.

The study was conducted to investigate the effects of feed withdrawal on gastrointestinal weight, digestive condition, and carcass yield. The effects were studied in 36 HANWOO and 245 pigs. The weight of the gastrointestinal tract decreased with fasting time in both HANWOO and pigs. No significant differences in weight of HANWOO stomachs, intestinal tracts, and carcass yields were observed throughout the experimentals. Among pigs, significant differences in gastrointestinal tract weight were observed when comparing short fasting time (4 h) with long fasting time (above 12 h) (p<0.05). HANWOO and pigs showed no significant differences in carcass yield during fasting times. These results suggested that feed withdrawal for 16 and 12 hours is appropriate for HANWOO and pigs.

복분자, 갈근 및 녹차 추출분말이 각각 1%(w/w)로 첨가된 조미액으로 제조된 한우 육포의 품질특성 및 항산화 활성을 비교하였다. 복분자, 갈근 및 녹차 추출분말이 첨가된 조미액의 항산화 활성은 무첨 가구에 비해 유의적으로 높았다. 식물류 추출분말이 첨가된 육포의 전단가는 대조구에 비해 유의적으로 낮았으며, 색차(ΔE)는 시료 간에 미미하였으며, 전반적인 기호도는 녹차 추출분말이 첨가된 육포 (G-BJ)에서 다소 높게 평가되었다. 육포의 저장과정 중 수분활성도는 저장 2주째에 대조구에서 유의적 으로 증가되었으나, 식물 추출분말이 첨가된 육포는 저장 1주에 비해 유의적인 증감을 보이지 않았다. 저장 4주 경과 후에는 모든 시료에서 수분활성도가 다소간 증가되는 경향이었다. 식물 추출분말이 첨가 된 육포를 4주간 실온에 저장하는 동안 지질과산화물의 함량은 유의적으로 증가하였다. G-BJ는 4주간 저장되었을 때 2주간 저장된 시료에 비해 유의적인 증가 현상을 보이지 않았다. 식물 추출분말이 첨가 된 육포의 항산화 활성은 대조구에 비해 유의적으로 높았으며, 특히 G-BJ에서 가장 높았다. 한우 육포 의 제조 시 식물 추출분말의 첨가는 육포의 전단가 감소와 항산화 활성을 증가시킴으로써 육포의 품질 향상에 효과적일 것으로 예상된다.

혈청을 이용한 분석은 다양한 질병 진단의 지표로 이용 된다. 혈청의 분리 방법, 저장시간 및 온도에서 부적절한 혈액 처리는 사이토카인의 농도와 생화학 검사결과에 영 향을 줄 수 있다. 본 연구에서는 한우를 공시하여 혈청 분 리 시기, 저장 시간과 온도가 사이토카인 및 생화학 검사 결과에 미치는 영향을 조사 하였다. 혈액은 경정맥에서 채 취하여, 26±3℃에서 1~2시간 방치 후 분리조건을 다음과 같이 4개의 그룹 (a-d)으로 나뉘어 진행하였다. a) 혈청 분 리하여 보관(대조구), b) 혈청분리 후 아이스박스 2시간 방 치 후 보관, c) 아이스박스 2시간 방치 후 혈청분리, d) 24 시간 4℃ 방치 후 혈청분리, 이러한 조건으로 분리된 혈청 은 분석 전까지 –70℃ 보관 하였다. 혈청 분리시기, 아이스 박스 또는 4℃ 저장 시간 및 온도에 따라 IFN-γ는 유의적 인 차이를 보이지 않았고, TNF-α의 농도는 그룹 a-c에 비 해 그룹 d에서 유의적(p<0.05)으로 낮아졌다. 또한 albumin, total protein의 농도는 그룹 a보다 d에서 유의적 (p<0.01)으로 높았고, magnesium, calcium에서도 유사한 결과를 보였다(p<0.05). 그러나 G-GTP의 경우 다른 그룹에 비해 그룹 d에서 유의적(p<0.05)으로 가장 낮아졌다. 그러 므로 시료채취 시 농가와 실험실의 거리를 고려하여 온도와 저장시간이 혈청 내 사이토카인 및 생화학 농도에 미치 는 영향을 최소화 하여 연구 수행을 진행해야 될 것으로 사료된다.

본 연구는 한우의 전장유전체 내에 존재하는 단일염기 다형성(SNP)에 대해 DNA chip 분석을 통해 각 개체의 유 전자형을 파악하고, SNP 표지인자간 연관불평형의 크기를 알아보기 위해 실시하였다. 강원도에서 사육되고 있던 한 우 거세우 139두의 조직을 채취하여 DNA를 추출하였으 며, Bovine SNP50K BeadChip 분석을 이용하여 분석에 사 용 가능한 최종 35,769개의 SNP 표지인자를 얻어 연관성 분석을 실시하였다. 분석에 이용된 SNP 표지인자의 총 길 이는 2499.26Mb이었고, 전장 유전체에서 평균 대립유전자 빈도(MAF)는 0.273이었으며, SNP 표지인자간의 평균 거 리는 0.060과 0.082 사이에 분포하였다. 강원지역 내 한우 거세우를 이용하여 확인한 본 실험 결과는 기존의 전국의 한우를 대상으로 한 연구결과와 유사한 패턴을 보였다. 50Kb 이하로 인접한 거리를 갖는 SNP 표지인자들의 연관 불평형 값(r2)이 0.2 초과인 인자가 34%로 나타났다. 또한 SNP 표지인자간 거리가 멀수록 측정값이 떨어지는 지수형 식의 그래프를 보였다. 염색체별로 구분한 40kb 이하로 인 접한 SNP표지인자의 연관불평형 값(r2)은 0.2 이하로 나타 난 것이 총 7개(13, 15, 19, 23, 25, 28, 29번 염색체)였다. 종 합하여 볼 때, 본 연구 결과는 강원한우의 유전적 개량을 이 용한 기초자료로서 활용될 수 있을 것이며, 유전적 개량을 이용한 육종시스템에 도움을 줄 수 있을 것으로 기대된다.

The present study was conducted to investigate the effect of different heights from liquid nitrogen (LN2) vapor on sperm motility and morphology after frozen-thawing. Two ejaculates were collected from 2 fertile Hanwoo bulls (A and B) by using artificial vagina at Hanwoo Research Institute. After collection, ejaculates were transferred to laboratory immediately and diluted with semen extender (Optixcell, France). Sperm dilutions were extended to a final concentration of 40 x 106 sperm/ml, and cooled at 4°C for 4 h and loaded to 0.5 ml straws. The straws were divided into 2 groups. Straws were placed in 3 or 9 cm of LN2 vapor for 14 min and then plunged into LN2 tank and cryopreserved until evaluation. Sperm motility and motility parameters (total motility, VSL with 25μm≥, VCL, VSL, VAP, LIN, STR, WOB, ALH and BCF) were evaluated by sperm class analysis (SCA, IVOS, Spain) after frozen-thawed. In bull A, 3cm group showed higher percentages of total motility, VSL with 25μm and VAP compared those with 9cm group (98.0 vs. 93.4%, 62.4 vs. 54.0% and 98.6 vs. 93.2%, 3 vs. 9 cm, irrespectively; p<0.001). In bull B, frozen-thawed sperm of 3cm group showed higher percentages of VSL with 25μm, VCL, VSL, VAP and BCF compared with those of 9cm group (43.5 vs. 26.0%, 123.8 vs. 111.6 μm, 62.9 vs. 57.3 μm and 81.5 vs. 72.5 μm; 3 vs. 9 cm, irrespectively; p<0.001). The viability and acrosomal integrity of spermatozoa were evaluated by Trypanblue/Giemsa staining method divided into 4 groups; live and intact acrosome (LIA), live and damaged acrosome (LDA), dead intact acrosome integrity (DIA), dead damaged acrosome (DDA). In bull A, frozen-thawed sperm of 3 and 9cm groups showed no significant difference in LIA, LDA, DIA and DDA. In bull B, 3 cm group showed higher LIA and lower DIA compared with those of 9 cm group (73.2 vs. 23.7% and 23.7 vs. 32.2%, 3 vs. 9 cm, irrespectively; p<0.001). We suspected that 3 cm vapor on LN2 vapor might be affected positively spermatozoa viability and acrosomal integrity compared with 9 cm group. In conclusion, semen freezing procedure in the present study will improve sperm quality after frozen thawing.

The OPU technology has been largely used in order to enhance genetic improvement in domestic animals. This study demonstrated that OPU in Hanwoo can be used for the effective technique to improve the reproductive efficiency. This experiment showed the longest times of OPU ever carried out in Hanwoo. In this study four donors were selected from Hanwoo by using DNA extraction and SNP maker. Individual donors have genes which are CAPN1, CAST and FASN and that contain dominant position. CAPN1, CAST genes are often thought to be related with tenderness and FASN gene is thought to be associated with oleic acid which is identified a monounsaturated fatty acid found naturally in many plant and animal products. In experiment 1, OPU technique was used to evaluate the influence of the number of oocytes recovery rate per session. Totally 50 times OPU sessions were performed and oocytes recovery at every 10 times session was evaluated. In case of H4, the OPU session could be done around 30 times after her calving. Compared to the average number of oocytes recovery, H1 was more efficient than H3. Considering this results, the current study showed that animals have considerable individual variation in numbers of oocytes. In this study, the average recovery rate in Hanwoo is similar to the recovery rate of the Bos Taurus. Individual donors have no significant difference among group for recovery rate during 30 sessions. However, Thoese showed significant decrease in the number of oocytes recovery rate after 40 session of OPU treatment. Therefore we conclude that the Hanwoo donor is considered to be suitable for 30 times of OPU treatment. In experiment 2, OPU technique was used to evaluate the influence of the number of recovery rate monthly. The average number of oocytes recovery rate showed no significantly difference for five months. However, the number of oocytes recovery rate decreased significantly during three months after first five months experiments. In experiment 3, whether donors are parity or non-parity, the average number of oocytes recovery rate was checked. However, we could not find any significant result from this experiment. In experiment 4, the developmental rate of in vitro produced embryos from OPU was compared with that from slaughterhouse. From this, cleavage rate of oocytes from OPU is significantly less than that from slaughterhouse. In conclusion, this study included a thorough analysis of oocytes and embryo production by OPU from Hanwoo. OPU can be successfully performed under a continuous regime for 8 month in Hanwoo. The current study shows the clear proof that OPU could be adopted to produce oocytes and embryos of better quality as an advanced technique replacing the usage of MOET in Korea. Finally, elucidation the basis for numerous oocytes obtained from Hanwoo may contribute to a better understanding of reproductive physiology in cattle.

Although assisted reproductive technology (ART) has been developed in many mammalian species including cows, the only embryo preservation technology that is available is cryopreservation. In the present study, small molecules were used to preserve embryos at room temperature. The basic medium for embryo preservation consisted of 1% BSA non-cryopreservation medium (BNC) instead of fetal bovine serum (FBS). To maintain survival and prevent damage during embryo storage, three candidate small molecules were selected—CHIR99021, Y-27632 and Thiazovivin—and their concentrations were optimized. Then, the embryos in the small molecule supplemented preservation medium were stored at room temperature. The viability and hatching rate of embryos stored at 10°C were greater for Y-27632-BNC and CHIR99021+Y-27632-BNC compared to BNC. However, the rate was lower for Thiazovivin-BNC compared to BNC. Although there were no surviving embryos after storage at 20°C, the viability and hatching rate of embryos significantly increased in Y-27632-BNC and CHIR99021+Y-27632-BNC compared to BNC. The mechanism by which small molecules enhance survival of embryos during storage was investigated, and expression of heat shock protein 70 was observed to increase. The findings of this work may be useful in improving ART in the agricultural field.