본 연구의 목적은 우리나라 Jersey 암소 56두로부터 조사된 체고 데이터에 대해 성장 모형을 추정하고, 추정된 체고 성장 모형의 모수를 활용하여 우리나라 Jersey 암소의 체고 성장 기초 자료를 제공하고자 실시하였다. 추정된 Gompertz, von Bertalanffy, Logistic 및 Brody 모형의 체고 성장 곡선 함수식은 각각      ,         ,          및       이었다. 추정된 Gompertz, von Bertalanffy 및 Logistic 모형의 모수를 이용하여 성장 특성을 분석한 결과 변곡점 월령이 각각 -0.3880, -5.235 및 -0.426월로 성장 기간 중 존재하지 않았다. Gompertz, von Bertalanffy, Logistic 및 Brody 모형에 대한 오차 평균 제곱합은 각각 14.189, 14.083, 14.730 및 14.011로 추정되었으며, 모형 결정 계수는 각각 0.971, 0.972, 0.970 및 0.972로 추정되었 다. 각 모형의 오차 평균 제곱합과 모형 결정 계수의 결과를 종합해보면 Brody 모형이 Jersey 암소의 체고 성장 곡선에 적합도가 좋은 것으로 판단된다.

본 연구는 우리나라 Jersey 암소 41두로부터 측정된 체중 데이터를 이용해 Gompertz, von Bertalanffy 및 Logistic 모형의 성장 곡선을 추정하고, 추정된 성장 곡선의 모수를 활용하여 Jersey 암소의 성장 특성에 대해 알아보고자 실시하였다. 추정된 Gompertz, von Bertalanffy 및 Logistic 모형의 성장 곡선 함수식은 각각    ,         및          이었다. Gompertz, von Bertalanffy 및 Logistic 모형에 대해 변곡점은 각각 10.719, 8.4292 및 14.618 개월로 추정되었고, 변곡점 체중은 각각 208.514, 211.347 및 203.548kg으로 추정되었으며, 최대 증체율은 각각 20.851, 21.192 및 21.993 (kg/월)로 추정되었다. 오차 평균 제곱합과 모형 결정 계수의 결과를 종합해보면 von Bertalanffy, Gompertz 그리고 Logistic 모형 순으로 Jersey 암소 성장 곡선에 적합도가 높은 것으로 판단된다.

The objective of the present study was to determine the best model to describe and quantify the changes in live body weight, height at withers, height at rump, body length and chest girth of Holstein cows raised under Korean feeding conditions for 50 months. The five standard growth models namely polynomial linear regression models, regression of growth variables on the first and second-order of ages in days (model 1) and regression of growth variables on age covariates from first to the third-order (model 2) as well as non-linear models were fitted and evaluated for representing growth pattern of Holstein cows raised in Korean feeding circumstances. Nonlinear models fitted were three exponential growth curve models; Brody, Gompertz, and von Bertalanffy functional models. For this purpose, a total of 22 Holstein cows raised in Korea used in the period from April 2016 to May 2020. Each model fitted to monthly growth curve records of dairy cows by using PROC NLIN procedure in SAS program. On the basis of the results, nonlinear models showed the lower root mean square of error (RMSE) for live body weight, height at withers, height at rump, body length and chest girth (12.22, 1.95, 1.55, 4.04, 2.06) with higher correlation coefficiency (R2) values for live body weight, height at withers, height at rump, body length and chest girth (0.99, 0.99, 0.99, 1.00, 1.00). Overall, the evaluation of the different growth models indicated that the Gompertz model used in the study seemed to be the most appropriate one for standard growth of Holstein cows raised under Korean feeding system.

Barley is an important cereal gain which is traditionally used in some nations of Asia and North Africa, and there has been growing interest in using barley as an ingredient in food due to their nutritional value and high content of phyto-constituents. However, no study report on comparative feed value between sprouted barley, cornflake and alfalfa hay. Therefore, in this study we aimed to evaluate the chemical composition, amino acid profile and mineral content of 6 day sprouted barley fodder (SBF) compared with cornflake and alfalfa hay using by AOAC method, as an alternative feed ingredient. Results showed that SBF had higher content of crude protein, acid detergent insoluble crude proteins and neutral detergent insoluble crude protein than alfalfa hay and cornflake; cornflake had higher crude fiber, neutral detergent fiber content than SBF and alfalfa hay; alfalfa hay had higher crude fiber, crude ash, acid detergent fiber, neutral detergent fiber and lignin level than SBF and cornflake. Also, significant differences were found on amino acid content among them (p<0.01). The most abundant amino acid in SBF was glutamate (123 g/kg DM), which is higher than in alfalfa hay (1.27%) or cornflake (1.58%). However, methionine (1.33%) and cysteine (1.53%) were the least abundant amino acids in SBF compared with cornflake or alfalfa hay. Furthermore, our study results exhibited that SBE comprise a good sources of minerals including ferrous (90.01 mg/kg) followed by zinc (20.50 mg/kg), magnesium (0.20 mg/kg) and sodium (0.03 mg/kg) as compared to cornflake and alfalfa hay. The present research findings, confirmed that the nutritional values of SBF are comparable to those of cornflake and alfalfa hay. Hence, SBF can be a better alternative feed ingredient for cornflake or alfalfa hay. However, feeding trials will be required to determine acceptability of SBF for ruminant production.

The present study was designed to determine the effect of barn or cycle of grazing on changes of biochemical metabolites in prepartum and changes of milk composition in postpartum of dairy cows. For this purpose, a total of sixteen 25 months old Holstein primiparous dairy cows were allocated in two groups (n=8) with an average body weight of 571.61 ± 35.30 kg (Barn) and 578.10 ± 39.20 kg (Grazing). The study was conducted from June 2018 to October 2018. Results revealed that barn raised dairy cows had a higher increase in their serum albumin and calcium level on day 14 prepartum. However, the level of palmitic acid, saturated fatty acid increased significantly, and the level of fat, oleic acid, γ-linoleic acid, arachidonic acid and unsaturated fatty acids decreased significantly in barn raised dairy cow’s milk on day 14 postpartum. There were no significant differences observed with respect to all other biochemical metabolites, fatty acids and minerals between barn raised and cycle grazing dairy cows during prepartum and postpartum. Our study results could serve to a better understanding of barn raised cow with respect to changes of biochemical metabolites in prepartum and changes of milk composition, fatty acids and minerals content in grazing dairy cows in postpartum for estimating their physiological status.

An experiment was carried out to assess the effect of feed selenium-lysine (Se-Lys) supplementation on milk compositions and serum biochemical indices in Saanen dairy goats in Korea. A total of twelve 36 months old Saanen lactating dairy goats (47±6.21 kg) fed the similar dry matter intake twice a day at 2% of BW (DMI) (10.9% moisture of concentrate and 19% moisture of roughage), milk yield (2.5 kg/d) and parity (2) were randomly selected and subjected for the present study, divided into two groups with six goats in each group. The goats in the control group received rice hulls (10 g/ day) only, and did not receive Se-Lys; goats in the treatment group were fed 0.06 g of Se-Lys with 10 g of rice hulls every day before feeding roughage for six weeks. The milk sample was collected every week, and its compositions were analyzed. The results of the present study showed that there is no significantly increased milk production in Se-Lys treated group goats when compared with control group goats. But, Se-Lys treatment significantly increased the milk protein content (3.98±0.16%), fat (3.72±0.27%), lactose (4.07±0.14%), total solids (12.51±0.28%) and urea (14.42±1.45 mg/dl) content as compared to the control group goats (p<0.05). The somatic cell counts (207,740±28.81 cells/ml) were significantly lower in the Se-Lys treated group than in the control group (p<0.05). Also, the results of the current study showed that supplementation of Se-Lys were significantly decreased the blood biochemical indices of IL-6 (34.34±6.04 pg/ml), TNT-α (0.56±0.22 ng/ml), MDA (5.07±1.03 ng/ml), GPx-1 (9.07±5.17 ng/ml), sCD4 (2.64±1.02 ng/ml) and sCD8 (5.08±2.08 ng/ml) level when compared with without addition of Se-Lys group dairy goats (p<0.05). On the other hand, the selenoprotein P (1,580.18±127.62 ng/ml) level was significantly higher in Se-Lys supplemented group than in the control group (p<0.05). Based on the study results, it was concluded that feed Se-Lys supplementation may improve milk yield with positively improved protein, fat, lactose, total solids, urea content, and biochemical indices without negative effects on milk production traits.

genetic selection has resulted in modern dairy cow with very high milk yields but reduced fertility, due mainly to an increase in reproductive disorders. The study was conducted to estimate the proportion of reproductive disorders among dairy cattle. The factors analyzed were; milk yield, cow parity, periparturient disorders, and reproductive status. The result of this study showed the incidence of reproductive disorders in high yielding dairy cows was prevalent. Repeat breeding was the major postpartum reproductive problem comprising (42.3%) of the samples. Higher reproductive disorders were also associated with lower parity. These disorders subsequently reduced reproductive performance by prolonged intervals from calving to first artificial insemination and from calving to pregnancy. Abnormalities in the reproductive system such as repeat breeder, silent heat, anestrous and ovarian cysts, as well as lower fertility have been recorded during the summer months (June to August). In conclusion, the study revealed that incidence of repeat breeder is mostly prevalent in dairy cows. Moreover, the incidence of reproductive disorders was higher in summer season and hence appropriate preventive and or therapeutic measures as per the type of abnormalities need to be undertaken.

Presently, the first pregnancy age of dairy heifers attended National Dairy Herd Improvement Program (NDHI) in Korea has increased, and more research have been requested to evaluate the possibility of decreasing the first pregnancy age of dairy heifers. Accordingly, this study was investigated the effects of the month of age at the first service and pregnancy on the reproductive efficiency of Holstein heifers. For these, the reproductive performance of heifers was analyzed by evaluating the effects of first insemination service at 12-14 months of age (12 month old), 15-16 months of age (15 month old), 17-19 months of age (17 month old), and > 20 months of age (20 month old) in Holstein heifers. The service numbers per conception in the first insemination months were 1.85±1.22, 1.59±0.77, 1.58±0.72, and 1.76±0.97 times at 12, 15, 17 and 20 months of age, respectively. The conception rates in the first service were 51.2, 57.8, 54.8, and 52.9% at 12, 15, 17 and 20 months of age, respectively. The conception ages were 453.2±78.9, 512.1±75.9, 590.1±98.0, and 713.0±74.5 days in the heifers serviced firstly at 12, 15, 17 and 20 months of age, respectively. There was significantly difference in the conception age among groups (p<0.05). The cumulative conception rates in the heifers serviced firstly at 12, 15, 17 and 20 months of age were 51.21, 57.8, 54.8 and 53.0% by the first service, 29.8, 30.1, 32.3, 23.5% by the second service, and 19.0, 12.1, 12.9 and 23.5% by the third service, respectively. The service numbers per conception in the first pregnancy months were 1.31, 1.55, 2.0, 2.05 times at 12, 15, 17 and 20 months of the first service age, respectively. The service numbers per conception in the 12 and 15 months of age were significantly lower than those in the 17 and 20 months of age (p<0.05). The rates of repeat-breeder were 6.0, 11.3, 22.0, and 41.0% in the heifers serviced firstly at 12, 15, 17 and 20 months of age, respectively. These results demonstrate that first pregnancy of Holstein heifers should be conducted at 15 months of age, because the age at first pregnancy in heifers can be substantially influenced through implementation of reproductive management and performance.

This study aimed to improve the reproductive efficiency of dairy herds by comparison and analyzing estrous appearance rate, conception and non-conception rate according to the stage of lactation using the lactation and reproductive records of average (less than 10,000 liters milk in 305 days) and high yielding (more than 10,000 liters milk in 305 days) Holstein cows (n=102). Milk production and reproduction data were collected between January 2010 and December 2012 from Holstein cows kept in the commercial dairy farms. Average (n=32) and high yielding (n=24) Holstein cows used to analyze the relationship between milk yield and reproductive performance. Our results showed that estrous appearance rate according to the stage of lactation was 25.0% (30∼59d), 40.6% (60∼ 89d), 25% (90∼110d) and 9.4% (>111d) in average yielding cows and 16.7% (30∼59d), 20.8% (60∼89d), 12.5% (90 ∼110d) and 50.0% (>111d) in high yielding cows, respectively. Conception rate according to the stage of lactation was 87.5% (30∼59d), 61.5% (60∼ 89d), 75.0% (90∼110d) and 66.7% (>111d) in average yielding cows and 25.0% (30∼59d), 0% (60∼89d), 33.3% (90∼ 110d) and 50.0% (>111d) in high yielding cows, respectively. Days between parturition and conception was 23.7% (<149d), 0% (150∼209d) and 0% (>210 d) in average yielding cows and 69.0% (<149 d), 77.8% (150∼209d) and 38.9% (>210d) in high yielding cows, respectively. Conception rate from 110 days postpartum in high yielding cows was 41.7% (110∼150d), 50.0% (151∼180d) and 50.0% (>181d). Body condition score (BCS) in 120 days postpartum was 2.64±0.1 in average yielding cows and 2.28±0.1 in high yielding cows, respectively.

본 시험은 포도부산물의 첨가가 젖소의 산유량, 유성분 및 혈액 성상에 미치는 영향을 조사하기 위하여 실시하였다. 비유중기 젖소 8두(평균 월령: 89.8, 평균 유기: 164.4, 평균 산차: 2.8산)를 공시하였으며, 포도부산물을 첨가하지 않은 대조구와 1일 1 kg을 첨가한 시험구로 두 처리구를 설정하여 3주간 급여하였다. 유지방, 유단백, 유당 및 총 고형물 함량은 처리간에 차이가 없었다. 그러나 산유량은 포도부산물 을 첨가한 처리구가 23.13 kg/d으로 대조구의 21.16 kg/d에 비해 높은 반면(p<0.05), 체세포 수는 대조구가 포도부산물 처리구에 비해 높았다(p<0.05). 혈중 glucose, alanine aminotransferase, total protein 및 blood urea nitrogen 함량은 처리구간 차이가 없었으나, AST와 총콜레스테롤 함량은 대조구 (123.75 IU/L, 200.82 mg/dl)가 포도부산물 처리구(95.34 IU/L, 180.63 mg/dl)에 비해 높았다(p<0.05). 이상의 결과에서, 다양한 생리활성을 가진 포도부산물은 젖소를 위한 기능성 사료로 이용 가능성이 높을 것으로 사료된다.

본 연구는 홀스타인, 한국재래산양 및 한우유로부터 glycomacropeptide(GMP)를 분리하였으며, 각 GMP의 trypsin 가수분해물의 혈소판응집 억제 효과를 in vitro 상에서 알아보았다. 홀스타인, 한국재래산양 및 한우의 GMP는 분자량이 모두 약 20 KDa이었으며, sialic acid 함량은 각각 36.86±2.36, 37.98±1.27 및 31.19±1.87㎍/mg이었다. 또한 모든 개체의 GMP에서 tyrosine이 검출되었다. 홀스타인, 한국재래산양 및 한우 GMP의 trypsin 가수분해물에 의한 혈소판 응집 억제율은 반응 30초에 4.02, 5.51 및 12.77%로 각각 나타나 시간이 경과할수록 감소하는 경향을 보였다. 혈소판의 현미경 관찰 결과 가수분해물 첨가 후 혈소판 수가 증가하였으나, 첨가 후 30초가 경과한 시점부터 혈소판 수가 감소하기 시작하여 120초 후에는 관찰 할 수 없었다. 본 실험 결과 bovine 및 caprine GMP의 trypsin 가수분해물에서 혈소판 응집을 억제할 수 있는 small peptide가 있는 것으로 생각되며, 향후 이러한 연구는 심근경색증 및 뇌혈전증을 예방할 수 있는 생리활성 물질로 이용될 수 있을 것이라 생각된다.

본 연구는 젖소에 있어서 Lipopolysaccharide의 처리가 착유우의 면역 반응에 미치는 영향을 구명하기 위하여 처리구 5두 및 대조구 3두를 공시하여 LPS 처리후 시간의 경과에 따른 PMNL의 비율, PMNL의 생존율 및 탐식 PMNL의 비율 등을 분석하였다. PMNL의 비율에 있어서, 처리전(0시간째)에는 대조구 및 처리구가 각각 41.0% 및 47.2%였으나 24시간째에는 41.7% 및 72.1%, 48시간째에는 41.0% 및 81.6%, 72시간째에는 44.3% 및 79.0%로 24시간째, 48시간째 및 72시간째에 공히 처리구가 대조구에 비하여 유의적(p<0.01)으로 높은 경향을 나타내었다. 대조구와 처리구의 PMNL의 생존율은 처리시간에 따른 차이가 없었다. 탐식 PMNL의 비율에 있어서, 처리전(0시간째) 및 처리 후 24시간째에는 대조구와 처리구간에 유의적인 차이를 나타내지 않았으나 48시간째에는 각각 1.1% 및 7.7%로 처리구가 대조구에 비하여 유의적(p<0.05)으로 높은 경향을 나타내다가 72시간째에는 유의적인 차이를 나타내지 않았다.

본 연구는 후산정체 젖소에 있어서 Lipopolysaccharide(LPS)의 처리가 번식 성적에 미치는 영향을 구명하기 위하여 분만 후 12시간이 경과하여도 후산이 배출되지 않은 홀스타인 개체 33두 및 대조구 12두에 대하여 분만후 20일째에 LPS 100 g을 자궁 내에 주입한 다음 7일후에 발정이 발현되었을 때 인공수정을 실시하여 다음과 같은 결과를 얻었다. 후산정체 젖소에 있어서 첫 수정에 의한 수태율은 대조구의 경우 공시한 12두가 모두 첫 수정에 의해 수태가 되지 않았고 처리구는 33두중 11두가 수태되어 33.3%의 수태율을 나타내었다. 후산정체 젖소에 있어서 대조구 및 처리구의 분만후 수태까지의 일수는 각각 149.6±34.3일 및 53.0±12.5일로 처리구가 대조구에 비하여 유의적(p<0.01)으로 단축되는 경향을 나타내었다. 후산정체 젖소에 있어서 대조구 및 처리구의 수태당 종부 횟수는 각각 3.6±0.8회 및 2.1±0.3회로 처리구가 대조구에 비하여 유의적(p<0.05)으로 낮은 경향을 나타내었다.