본 연구는 엘크 암사슴(Cervus canadensis)의 사육방식에 따른 사료섭취량, 체중변화 및 자록의 성장에 미치는 영향을 확인하고 적정 방목강도를 구명하기 위하여 수행되었다. 본 실험에 사용 된 공시가축은 3~4년생 엘크 암사슴 16두(평균체중 : 236.2 ± 15.7 kg)를 이용하였으며, 방목초지는 3년 이상된 톨 페스큐 위주의 기성 혼파초지로서 초종구성은 톨 페스큐(약 50%), 오차드 그라스(약 10%), 켄터기 블루그라스(약 5%)와 피, 바랭이 등으로 구성되었다. 방목초지의 수분함량은 19.51∼22.61%로 방목기간 동안 유사하였으며, 조단백질 함량은 6~7월에 유의적으로 높게 나타났다. 조지방과 조회분 함량은 가을로 갈수록 점차 증가하였으며, NDF와 ADF함량은 각각 53.65∼60.18%과 26.08∼29.10% 로 조사되었다. 실험기간동안 보충사료 섭취량은 월별로 처리구 사이에 유의적인 차이가 나타나지 않았으나, 조사료와 총 건물섭 취량은 5월을 제외하고 처리구 사이에 유의적인 차이가 나타났다 (p<0.05). 특히 8월에는 GR처리구의 조사료 섭취량이 급격히 감소하였는데, 여름철 환경변화에 따른 것으로 사료된다. 반면, 9월 포유를 위해 부족한 영양소를 섭취하기 위해 사초섭취량이 급격히 증가하였다. 우리 연구에서 암사슴의 채식패턴은 수사슴과 차이를 보였으며, 이는 실험기간 자록의 이유 및 포유기간에 따른 영향을 받은 것으로 사료된다. 본 실험에서 사양방식에 따른 엘크 암사슴의 체중은 유의적 차이가 나타나지 않았으나, GR처리구에서 자록의 성장률이 빠른 것으로 나타났다. 그러나, GR처리구에서 BF처리구에 비해 낮은 이유율이 나타나 분만 전후 사사사육을 통해 이유율을 높여주는 것이 필요할 것으로 판단되며, 목지 내에서 분만 시 포유경험이 있는 산차가 높은 암사슴을 이용하고 방목강도를 높여주는 것이 이유율을 향상시키는 데 도움을 줄 수 있을 것으로 사료된다. 엘 크 암사슴의 방목강도는 연평균 15두/ha로 나타났는데, 이는 다마 암사슴(Dama dama)에 비해서는 체중대비 높게 나타났으나, 엘크 수사슴에 비해서는 낮은 수치를 보여주었다. 이러한 결과는 기성초지 이용으로 인해 사초의 생산성이 감소한 결과로 사료되며, 앞으로 방목초지의 혼파방법과 기성초지의 비배관리 등을 통해 초지 활용성을 높일 수 있는 연구가 추가적으로 필요할 것으로 사료된다.

Data on the crude protein requirements of elk doe are nonexistent and the data are essential for their management in Korea. Therefore, this study was conducted to evaluate the crude protein requirement for maintenance of elk doe. Three female elk deer were used in 3 × 3 Latin square design with three diets containing three levels of crude protein (CP) that contained low crude protein (approximately 12%), medium crude protein (15%), and high crude protein (18%). Each three elk doe trials included a 14-day preliminary period and a 5-day collection period. Crude protein intake was 4.83, 6.26, and 9.00 g/d for 12%, 15%, and 18% of CP level, respectively. Crude protein balances were 1.04, 1.41, and 4.14 for 12%, 15%, and 18% of CP level, respectively. The maintenance requirement for CP from the regression equation between CP intake and CP balance were 3.70 g/BW0.75.

This study was conducted to investigate the effect of supplementary feeding levels on livestck and forage productivity and grazing intensity in Elk stags (Cervus canadensis). A fifteen 2-year-old Elk stags about 195 kg were randomly assigned to one of three dietary treatments (five animals per treatment). The dietary treatments consisted of a feeding concentrate of 1.0% of body weight (T1), 1.5% of body weight (T2) and 2.0% of body weight. Total dry matter intake (TDMI) was increased with increased with an increasing supplementary feeding levels. Average daily gain (ADG) were significantly increased with an increasing supplementary feeding levels (p<0.05) and reached a maximum on July and was lower in spring than autumn. The velvet antler production was no differences among treatment groups. Forage productivity of pasture and crude protein content were highest on May and decreased thereafter, however, crude fiber content was the reversed. The grazing intensity of Elk stags was increased in spring (38 to 59 head per ha) than summer and autumn (13 to 32 head per ha). The average grazing intensity of Elk stags ranged from 21 to 34 head per ha, which is affected by supplementary feeding levels. This result suggests that feeding supplementary diet at 1.5 % of body weight was needed to maintain the stable wight gain in antler growing periods and control the proper grazing intensity of Elk deer stags.

엘크 수사슴의 체중 성장곡선 및 일당증체량을 추정하기 위하여 국립축산과학원 가축유전자원센터에서 사육중인 엘크 수사슴 183두의 체중-일령 자료 1,509개에 대해 비선형 회귀식인 Gompertz와 Logistic 모형을 적용하였다. 추정된 엘크 수사슴 성장곡선 모수인 성숙체중(A), 성장비율(b)과 성숙률(ｋ)은 Gompertz 모형의 경우 각각 335.5±1.415kg, 2.18±0.045와 0.0025±0.00005였고, Logistic 모형에서는 330.5±1.337kg, 5.46±0.209와 0.0355±0.00009였다. 적합도 검정을 위한 결정계수(R2)는 두 모형에서 큰 차이가 없어 두 모형 다 적합한 것으로 나타났다. 다만, 실제 측정값과 추정값에 대한 차이인 평균제곱근 오차 값이 엘크 암사슴에 비해 크게 나타났으며 따라서 엘크 수사슴의 낙각 및 번식기 체중 증감을 고려한 성장곡선 모형에 대한 추가적인 연구가 필요할 것으로 판단된다. 엘크 수사슴에서 Gompertz 모형으로 추정된 함수식은 f(t)=335.5Xe^-2.18e^-0.0025t였고, Logistic 모형의 경우 F(t)=330.5X(1+5.465e^-0.00355t)^-1였다. 각 모형에서 제1차 도함수로 유래된 일당증체량 곡선은 Gompertz 모형의 경우 F'(t)=0.0025Xf(t)X1n(335.5/f(t)), Logistic 모형의 경우f'(t)=0.0036Xf(t)X[1-f(t)/330.5]였다. 이 함수식을 통해 도출된 엘크 수사슴에서 최대 증체량을 나타내는 시기인 315~478.3일령, 123.4~165.3㎏ 도달 전후에는 보다 세심한 사양관리가 필요할 것으로 보인다. 본 연구에서 도출된 엘크 수사슴의 성장곡선 모수 추정값, 변곡점 및 변곡점 도달일령 등은 사슴산업 종사자들이 사양관리 및 육종계획을 수립하는 데에 도움이 될 수 있을 것으로 사료된다.

The objective of this study was to estimate the growth curve parameters of body weight for female Elk. Weight and age data from 115 does raised at the Animal Genetic Resources Research Center in Korea were used in this study. The growth curve parameters were estimated from a nonlinear regression using Gompertz and Logistic models. Mature weight (A), growth ratio (b) and maturing rate (k) of female Elk were 214.1±2.17 kg, 2.12±0.0045 and 0.0043±0.00011, respectively, according to the Gompertz model. They were 208.3±2.17 kg, 5.56±0.234 and 0.0065±0.00017, respectively, according to the Logistic model. The goodness of fit determined by R2 was higher in the Gompertz model than that in the Logistic model. The growth curve functions obtained from the Gompertz and Logistic models in female Elk were f(t)=214.1×e-2.124×e-0.00484×t and f(t)=208.3×(1+5.561×e-0.00651×t)-1, respectively. The absolute growth rate functions from the Gompertz and Logistic models in female Elk were f'(t)=0.0043×f(t)×1n(214.1/f(t)) and f'(t)=0.0065×f(t)×[1-f(t)/208.3]respectively. The growth pattern of female Elk generated from this study can be useful in determining the most appropriate feeding plans and the best breeding strategies for deer.

This study was conducted to investigate the effect of pasture grazing and barn feeding system on the growth performance, weight gain and velvet antler productivity in Elk. Twelve 5-year-old elk stags about 273 kg were stratified by weight and randomly assigned by feeding system (a pasture grazing and a barn feeding, n=6). The average feed intake were not signigicant difference between two groups. Average daily gain for grazing and barn feeding group was 0.25 g and 0.29 g respectively, showing no significant difference. Velvet antler yield for grazing and barn feeding group was 7,700 g and 6, 960 g respectively, with no significant difference. In conclusion grazing group was better than barn feeding group in feed intake, body weight gain and velvet antler productivity. However, there were no statistical significant difference between the two group. These results may serve as the basis for further study of deer feeding system in Korea and further study needed to examine the grazing intensity and economic efficiency.

This study was conducted to determine the effect of dietary whole-crop barley silage on the daily feed intake, daily weight gain, velvet antler yield and economic efficacy in elk during growth. A total of 21 elk (average BW 303 kg, 5 years old) were allotted randomly to three treatments. The three treatments were T1 (hay diet), T2 (whole-crop barley silage), and T3 (50% hay + 50% whole-crop barley silage). The average daily weight gain of T3 was higher than the others throughout the entire experimental period. The average daily feed intake of elk in decreasing order was as follows; T1>T3>T2. The velvet antler yield was higher in T3 group (8,585 g) compared with T1 (8,037 g) and T2 (7,713 g). However, there were no significant differences in the average daily feed intake, average daily weight gain, or velvet antler yield (p>0.05). In economic efficacy, T3 was gained about 29~43% more value than T1 or T2. In conclusion, the mixed feeding of 50% hay and 50% whole-crop barley silage was more effective than feeding hay of barley alone, in terms of average daily weight gain, velvet antler yield, and economic efficacy in elk.

We investigated the effect of glutathione supplementation on feed intake, body weight loss, behavior change and economic analysis of elk bull in breeding season. Sixteen elk bulls (5-year-old, average weight; 330 kg) after antler cutting were divided into 2 groups. Eight bulls in each group (control and glutathione group) were fed experimental diet at a level of 0.85 percent of body weight and 6 mg glutathione per kg body weight. As a result, weight-loss of control animal during experimental study (from September to November) was 42.6±19.2 kg while that of glutathione-supplemented group was 20.6 ±19.9 kg. Compared to control group, glutathione-fed group had prevented the body weight loss by 5.2% (p<0.05). Although the feed intake of elk voluntarily decreases during breeding season, daily DM intake per head was 5.59 and 5.80kg in control and glutathione-fed group, respectively. While the statistical difference in feed intake between two groups was not observed, feed intake tended to increase in glutathione-fed group. In economic analysis, additional cost of 99,000 KRW per head was spent due to the cost of glutathione because of its import. Changes in behavior such as crying, deer whistles, whistling intensity and frequency of accident were lower in glutathione-fed group compared to control. During breeding season, use of glutathione as feed supplement could suppress body weight loss and accidents in deer farm.

Artificial insemination and embryo transfer is one of the most important factors affecting to the production of fawn from deer nuclear transfer in the field of deer farms. This study* was conducted to establish the production technology of nuclear transfered embryo in deer. For estrus synchronization or superovulation tretments in flower deer and elk, each 10 does were inserted into the vagina for 14 days with CIDR (Pfizer New Zealand Ltd., NZ) for elk and Ring-CIDR (Bioculture Co., Ltd., Korea) for flower deer, and then those inserted devices were removed. The estrus synchronization of each 6 does were induced by the intramuscular injection of PGF2α (25 mg/head) and PG600 (hCG 200IU + PMSG 400IU, Intevet, Holland). Then, the superovulation of each 4 does of flower deer and elk was induced by additional injection of FSH (200 mg/ head) twice with an interval of 24 hours , respectively. Follicular oocytes were collected from each 2 does superovulated after 48 hours since the injection of PG600 and FSH. In the meantime, the ovarian response and the number of the collected ovarian follicles were investigated with the surgical operations. As a result, the average number of the collected ovarian follicles were 8.5 and 9.0 in flower deer and elk, respectively. The ovarian follicles collected from each two does were cultured in vitro for 48 hours with m-DMEM medium, and then the cell fusion was carried out after the nuclear transfer by the antler cell. As a result, 5 out of 18 ovarian follicles collected from 2 elk does were reached on the MII stage, but there was no generation resulting from the nuclear transferred embryos by the antler cell after enucleation. In 2 flower does, 7 out of 17 ovarian follicles were reached to the MII stage, but one of them was developed to parthenogenetic embryo as well despite a case of fusion from the nuclear transferred embryo. Embryos were collected in a surgical way on the 7th day after artificial insemination, numbers of average embryos collected were 2.5 and 3.0 in each 2 flower deer and elk does superovulated, respectively. The collected two embryos were transplanted to each 2 does synchronized. As a result, a head of fawn was produced from only one elk doe, where as a head of fawn were delivered from one out of 4 elk does artificial inseminated. Given these findings, we consider that more or less of problems might have occurred in vitro culture system of ovarian follicles in the production of nuclear transfered deer embryos. In addition, the greatest reason why both the aetificial insemination and embryo transfer failed was considered attributable to stress due to anesthesia and catching.

We investigated the effect of glutathione supplementation on body weight gain, feed intake, velvet antler yield and economic analysis in elk bulls. A total 14, 2-year old male elks were divided into 2 groups with control or glutathione treatment. Elks were fed concentrate feed at the level of 1.5% relative to body weight (3.1 kg). and allowed to consumed hay as roughage ad libitum. Glutathione was supplemented at the level of 6 mg/kg. Average daily gains (ADG) for 2-years old elks were 234.1± 7 and 247.6±22 kg in control and glutathione fed groups, respectively. Treated group had higher ADG than control (p<0.05). Individual daily DM intakes were 5.34±0.70 and 5.64±0.71 kg in control and glutathione supplemented groups, respectively. Glutathione-fed group showed an additional intake of 298 g on an average. Production of velvet antlers for elk yearlings was 4,229±720 g and 4,653±960 g in control and glutathione supplemented groups respectively. Analysis of economics efficiency revealed 8% higher revenue index in glutathione supplemented groups. In conclusion, glutathione supplementation showed increase of DM intake and ADG in elk bulls, and could also increase velvet antler production.

Abnormal prions are infectious agents involved in a neuro-degenerative disease, which occurs naturally such as Chronic Wasting Disease (CWD) in deer and elk, Bovine Spongiform Encephalopathy (BSE) in cattle, Scrapie in sheep and goats and Creutzfeldt-Jakob Disease (CJD) in humans. The cellular prion protein of the elk consists of 233 amino acids (residues 25-257), which represents an autonomous folding unit with three α-helices and two-stranded anti-parallel β-sheets. Here, we demonstrated elk-recPrP (Elk recombinant prion protein) which can be obtained as follows; (1) Cloning of elk PrP gene, (2) Expression of a histidine-tagged full-length elk PrP by induction with IPTG in E. coli and (3) Purification by affinity chromatography using Ni-NTA agarose resin. In Western blot and ELISA analysis, elk-recPrP showed specific activity against anti-PrP monoclonal antibody. Thus, our elk-recPrP would be a useful tool for the understanding of basic structure and mechanism studies of PrPSC formation.

We investigated the effect of glutathione supplementation on feed intake, body weight gain, velvet antler yields and economics of elk yearling. Fourteen elk yearlings were divided into 2 groups. Seven yearlings in each group (control and treatment) were fed with 1.5-2.5 percent body weight (%BW) of concentrate feed for elk, voluntary intake of hay as roughage and 6 mg/kg body weight (KBW) of glutathione. The results were as follows. Average daily gain (ADG) for control elk yearlings for first 1.5 month was 0.46 kg, while that of glutathione supplemented was 0.55 kg. Although glutathione fed group had higher ADG compared to control group (p<0.05), ADG after 1.5 month showed no difference. In spring, daily DM intake per elk yearlings was 3.98 and 4.24 kg for control and glutathione supplemented groups, respectively. The statistical differences in feed intake between two groups were not observed. However, feed intake tends to increase in glutathione fed group. Production of velvet antlers for elk yearlings were 911±256 and 1066±357 g for control and glutathione supplemented groups, respectively. Statistical difference between two groups was not observed due to the high variation. In economic analysis, additional 109,110 KRW per head for the cost of glutathione resulted in 2 percent higher revenue index due to the increased antler production. In conclusion, feeding glutathione to elk deers effectively increased DM intake and ADG of elk yearlings. Glutathione supplementation in feed might increase velvet antler production as well as ADG.