Earticle

본 연구는 분만난이도 형질에 대한 유전모수를 추정하기 위하여 2018년부터 2020년까지 조사된 2,102건의 분만난이도 자료를 이용하였다. 한우에서 분만난이도 점수는 범주형 데이터로써 1~4점(1=순산, 2=약간 도움, 3=많은 도움, 4=기계사용 혹은 절개수술)으로 조사되었으며, 선형모형 분석을 위해 절단형 정규분포를 이용하여 자료변환을 실시하였다. 유전모수 추정을 위해 고정효과로 분만년도-계절, 송아지 성별, 어미의 산차, 어미의 분만시 연령이 고려되었으며, 개체의 유전효과(직접효과와 모체효과) 및 잔차효과는 임의효과로 모델에 적용하였고, BLUPF90프로그램을 이용하여 유전모수를 추정하였다. 분만난이도 점수는 송아지의 성별이 수컷이고, 초산차이고, 최근 분만한 암소들이 송아지의 성별이 암컷이고, 산차가 높고, 과거에 분만한 암소들에 비해 높게 나타났다. 한우에서 분만난이도에 대한 유전모수를 추정한 결과 직접유전분산(0.0164)은 모체유전분산(0.0018)에 비해 높게 나타났으며, 직접 및 모체효과에 대한 유전력은 각각 0.055와 0.006으로 추정되었다. 본 연구에서 추정된 유전모수값은 한우의 분만난이도 형질에 대한 유전능력평가에 활용될 수 있을 것으로 판단된다.

This study evaluated genetic parameters of direct and maternal effects for calving ease in Hanwoo. A total of 2,102 records for calving ease were collected from 2018 to 2020 from the Hanwoo Genetic Improvement Center in Korea. The calving ease score was rated from 1 to 4 (1=unassisted delivery, 2=assisted easy calving, 3=assisted difficult calving, 4=mechanical or caesarean section) as categorical data, and the data were converted using a truncated normal distribution for linear model analysis. To evaluate the genetic parameters, the birth year-season of calving, the sex of the calf, parity, and the age of the dam at calving were considered as fixed effects, and genetic and maternal effects were considered random effects. The genetic parameters were evaluated using the program BLUPF90. The calving ease scores for male calves, first parity cows, and currently calving cows were much higher than for females, later parities, and past calving cows. The direct genetic variance (0.0164) was higher than the maternal genetic variance (0.0018), and the estimated heritabilities of the direct and maternal effects were 0.055 and 0.006, respectively. The parameters determined here should help with the genetic evaluation of calving ease in Hanwoo.

Diets different in crude protein (CP) and undegraded intake protein (UIP) contents were offered to sheep in a metabolism study to describe their effects on nutrient digestibility and nitrogen (N) metabolism. Six Corriedale sheep (body weight=56.2±2.3 kg) were divided in random within a Latin square design (replicated) to 1 of 3 diets: 1) a low-CP diet (LP; 12.2% CP with 35.1% UIP), 2) high CP with low UIP diet (HPLU; 14.9% CP with 33.7% UIP), and 3) high CP with high UIP diet (HPHU; 15.5% CP with 45.8% UIP). High-protein dried distillers grain and soybean meal were the main CP sources for the adjustment of UIP:DIP in the diets. No significant differences were found in feed consumption and nutrient digestibility; however, a greater proportion of CP was digested in sheep fed the HPLU diet (69.4%; P=0.04). Although N intake was greater in sheep receiving HPLU and HPHU diets, loss of N through fecal or urinary route was not different among sheep, which resulted in the highest (12.7 g/d) and lowest N retention (7.40 g/d) in HPHU- and LP-fed sheep, respectively. In conclusion, although CP or UIP content had marginal effects on feed consumption and whole-tract digestibility of the majority of nutrients, with the increased CP and UIP levels in the diet, the efficiency of N utilization was improved with regard to increased N retention with minimal differences in N excretion, which is important from an economic and environmental standpoint.

본 연구는 대한민국 중부내륙 지역에서 수수-수단그라스 교잡종(SSH)의 건물수량(DMY) 추세를 알아보기 위해 수행하였다. 메타데이터(n=388)는 농촌진흥청의 신품종 적응성 실험의 다양한 보고서로부터 수집되었다(1988-2013년). 추세를 결정하기 위해 효과는 시계열 모델링을 사용하여 자기상관함수(ACF) 및 부분 ACF의 상관도에서 자기회귀(AR) 및 이동평균(MA)에 의해 추정되었다. 그 결과, 연도별 건물수량 추세는 해마다 조금 증가하는 것으로 나타났고, ARIMA(1,1,0)이 과거 추세를 설명하는 최적 모형임을 확인하였다. 이것은 SSH의 DMY추세가 과거 2년간의 변화와 연관성이 높고 3년 이전의 변화는 연관성이 없음을 의미하였다. 비록 이러한 추세에 대한 환경적 원인을 고려하기 위해 온도, 강수 및 일조와 같은 기상변수의 연도별 추세도 확인하였지만 뚜렷한 연관성은 찾을 수 없었다. 그러므로 기상변수에 대해 특정 생장단계를 고려하는 보다 정밀한 가공 및 정의가 요구된다. 특히 단기간에 피해를 줄 것으로 예상되는 폭우와 태풍이 추세에 미치는 영향에 대한 연구가 진행 중이며 본 연구에서 확인한 모델이 중요한 역할을 할 것으로 보인다. 또한 향후 연구에서는 기후뿐 아니라 토양 및 재배기술과 같은 환경적 요인을 추가할 계획이다.

This study aimed to determine the trend in dry matter yield (DMY) of a new sorghum-sudangrass hybrid (SSH) in the central inland regions of Korea. The metadata (n=388) were collected from various reports of the experiments examining the adaptability of this new variety conducted by the Rural Development Administration (1988–2013). To determine the trend, the parameters of autoregressive (AR) and moving average (MA) were estimated from correlogram of Autocorrelation function (ACF) and partial ACF (PACF) using time series modeling. The results showed that the trend increased slightly year by year. Furthermore, ARIMA (1, 1, 0) was found to be the optimal model to describe the historical trend. This means that the trend in the DMY of the SSH was associated with changes over the past two years but not with changes from three years ago. Although climatic variables, such as temperature, precipitation, and sunshine were also considered as environmental factors for the annual trends, no clear association was observed between DMY and climates. Therefore, more precise processing and detailed definition of climate considering specific growth stages are required to validate this association. In particular, research on the impact of heavy rainfall and typhoons, which are expected to cause damage in the short term, on DMY trends is ongoing, and the model confirmed in this study is expected to play an important role in studying this aspect. Furthermore, we plan to add the environmental factors such as soil and cultivation management as well as climate to our future studies.

This study was conducted to assess the effect of acidification of pig slurry on nitrogen (N) mineralization and its environmental impacts during pig slurry fermentation. Different inorganic and organic acids were used to acidify pig slurry. Four treatments including non-acidified pig slurry (control), pig slurry acidified with sulfuric acid, lactic acid, and citric acid were allocated with three replications. The total N content in the acidified pig slurry was higher than non-acidified pig slurry after fermentation. Acidification tended to increase total N content in pig slurry. Ammonium N (NH4+-N) released from pig slurry was obviously increased at 7 days after incubation, representing 61.4%, 36.8%, and 37.4% increase in the acidified pig slurry with sulfuric acid, lactic acid, and citric acid, respectively. Nitrate N (NO3--N) in the acidified pig slurry with sulfuric acid was the highest throughout the experiment period, but non-significant effect of organic acid. A large portion of ammonia (NH3) emission occurred within 10 days, corresponding to more than 55% of total NH3 emission. Total cumulative NH3 emission during the experimental period was lower 91% (2.9 mg N kg-1), 78% (7.3 mg N kg-1), and 81% (6.2 mg N kg-1) in the acidified pig slurry with sulfuric acid, lactic acid, and citric acid, respectively, than non-acidified pig slurry (32.7 mg N kg-1). These results suggest that acidification of pig slurry (particularly with sulfuric acid) can be faced as a good strategy to reduce NH3 emission without depressing the mineralization process.