• Asian-Australasian Journal of Animal Sciences
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• 제22권5호
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• pp.747-755
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• 2009

The feed resource for animals is a major cost determinant for profitability in livestock production enterprises, and thus any effort at improving the efficiency of feed use will help to reduce feed cost. Feed conversion ratio, expressed as feed inputs per unit output, is a traditional measure of efficiency that has significant phenotypic and genetic correlations with feed intake and growth traits. The use of ratio traits for genetic selection may cause problems associated with prediction of change in the component traits in future generations. Residual feed intake, a linear index, is a trait derived from the difference between actual feed intake and that predicted on the basis of the requirements for maintenance of body weight and production. Considerable genetic variation exists in residual feed intake for cattle and pigs, which should respond to selection. Phenotypic independence of phenotypic residual feed intake with body weight and weight gain can be obligatory. Genetic residual feed intake is genetically independent of its component traits (body weight and weight gain). Genetic correlations of residual feed intake with daily feed intake and feed conversion efficiency have been strong and positive in both cattle and pigs. Residual feed intake is favorably genetically correlated with eye muscle area and carcass weight in cattle and with eye muscle area and backfat in pigs. Selection to reduce residual feed intake (excessive intake of feed) will improve the efficiency of feed and most of the economically important carcass traits in cattle and pigs. Therefore, residual feed intake can be used to replace traditional feed conversion ratio as a selection criterion of feed efficiency in breeding programs. However, further studies are required on the variation of residual feed intake during different developmental stage of production.

• Asian-Australasian Journal of Animal Sciences
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• 제24권1호
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• pp.17-27
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• 2011

A selection experiment for reduced residual feed intake (RFI) in Yorkshire pigs consisted of a line selected for lower RFI (LRFI) and a random control line (CTRL). Longitudinal measurements of daily feed intake (DFI) and body weight (BW) from generation 5 of this experiment were used. The objectives of this study were to evaluate the use of random regression (RR) and nonlinear mixed models to predict DFI and BW for individual pigs, accounting for the substantial missing information that characterizes these data, and to evaluate the effect of selection for RFI on BW and DFI curves. Forty RR models with different-order polynomials of age as fixed and random effects, and with homogeneous or heterogeneous residual variance by month of age, were fitted for both DFI and BW. Based on predicted residual sum of squares (PRESS) and residual diagnostics, the quadratic polynomial RR model was identified to be best, but with heterogeneous residual variance for DFI and homogeneous residual variance for BW. Compared to the simple quadratic and linear regression models for individual pigs, these RR models decreased PRESS by 1% and 2% for DFI and by 42% and 36% for BW on boars and gilts, respectively. Given the same number of random effects as the polynomial RR models, i.e., two for BW and one for DFI, the non-linear Gompertz model predicted better than the polynomial RR models but not as good as higher order polynomial RR models. After five generations of selection for reduced RFI, the LRFI line had a lower population curve for DFI and BW than the CTRL line, especially towards the end of the growth period.

• 한국컴퓨터정보학회논문지
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• 제26권10호
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• pp.139-145
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• 2021

본 논문에서는 소의 사료 취식량(Feed Intake), 반추(Rumination), 발정기(In Heat) 모니터링 기술을 이용하여, RFI(Residual Feed Intake) 모니터링 및 신진대상 이상을 예측하는 웨어러블 디바이스 및 PC용 웹과 스마트폰 어플리케이션을 이용한 모니터링 시스템을 설계하고 구현하였다. 본 시스템의 개발로 농장주는 경제적 효율성의 증가가 기대된다. 사료 섭취량을 분석하면, 소의 체중에 근거한 추천 사료량과 소가 섭취하는 사료량과의 차이를 확인할 수 있으며, Metabolic disorder(신진대사 이상)에 대한 조기 발견이 가능할 것으로 예상된다. 본 논문의 결과물을 사용하는 농장주는 가장 효율적인 성과를 나타내는 소를 구별할 수 있으며, 소의 표피(목)에 부착하는 웨어러블 장치로부터 입력되는 6축 모션 센서 신호와 웨어러블 장치에 부착된 마이크를 통해 입력되는 소의 목넘김 소리를 통해서 소의 반추와 사료섭취량을 측정할 수 있다. 향후에는 심박, 호흡 등의 추가적인 생체신호를 측정할 수 있도록 개선 작업을 진행할 예정이다.

• 농업생명과학연구
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• 제50권1호
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• pp.147-153
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• 2016

사료이용 측면에서 유지 및 성장에 필요한 섭취량과 체내에 이용되지 않은 섭취량으로 구분할 수 있으며, 체내에 이용되지 않은 섭취량을 잔류사료섭취량(Residual Feed Intake; RFI)이라 한다. 본 실험은 국내 종돈의 RFI 유전모수를 추정하기 위해 2001년부터 2014년까지 태어난 Duroc종 8,696두의 검정자료를 활용하였다. 일당증체량과 RFI의 육종가 상관관계는 -0.2로 음의 상관으로 조사되었는데(P>0.01), RFI를 낮추면 일당증체량 개량에도 긍정적인 영향을 줄 수 있는 것으로 사료된다. 회귀추정 방식에 따른 RFI1(일당증체량)과 RFI2(일당증체량, 등지방두께)의 유전력은 각각 0.37, 0.45로 고도의 유전력을 나타내었다. 향후 국내에서도 개체단위 사료섭취량 측정으로 추정된 RFI를 개량에 활용한다면 농가 수익 개선에 많은 도움을 줄 수 있을 것으로 판단된다.

• Animal Bioscience
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• 제36권7호
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• pp.1067-1074
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• 2023

Objective: Better feed efficiency can be achieved by selecting rabbit genotypes with lower residual feed intake (RFI) under high ambient temperatures. Methods: Two genotypes of rabbits (Jabali, Saudi local breed and imported, Spanish V-line) were used to derive RFI and to investigate the relationship between RFI and productive traits. In total, 250 animals (125 each) were housed in individual wire mesh cages in a semi-closed rabbitry. Growth performance, feed criteria, carcass evaluation, biochemical blood analysis, and immune responses were determined. Results: Superiority in growth performance, feed efficiency, carcass characteristics, and cellular immunity was recorded in the Jabali breed compared to the V-line genotype. According to regression analysis, a significant effect of daily body weight gain was found, upon computing the expected feed intake in both genotypes. Moreover, mid-body weight^0.75 had a significant effect only in the Jabali breed. Positive correlation coefficients between RFI and dry matter feed intake or feed conversion ratio were found. The same trend in this relationship between RFI and productive traits was observed in some cases for both genotypes. An opposite trend in correlations was observed in the studied genotypes for some traits. Conclusion: The results suggest that the relationship between RFI and productive traits must be taken into consideration in rabbit breeding programs under the prevailing environment. However, further studies are required to investigate the effect of rabbit genotype and environmental factors on computing RFI.

• Asian-Australasian Journal of Animal Sciences
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• 제30권2호
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• pp.167-170
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• 2017

Objective: The feed intake (FI) and feed efficiency are economically important traits in ducks. To obtain insight into this economically important trait, we designed an experiment based on the residual feed intake (RFI) and feed conversion ratio (FCR) of a random population Pekin duck. Methods: Two thousand and twenty pedigreed random population Pekin ducks were established from 90 males mated to 450 females in two hatches. Traits analyzed in the study were body weight at the 42th day (BW42), 15 to 42 days average daily gain (ADG), 15 to 42 days FI, 15 to 42 days FCR, and 15 to 42 days RFI to assess their genetic interrelationships. The genetic parameters for feed efficiency traits were estimated using restricted maximum likelihood (REML) methodology applied to a sire-dam model for all traits using the ASREML software. Results: Estimates heritability of BW42, ADG, FI, FCR, and RFI were 0.39, 0.38, 0.33, 0.38, and 0.41, respectively. The genetic correlation was high between RFI and FI (0.77) and moderate between RFI and FCR (0.54). The genetic correlation was high and moderate between FCR and ADG (-0.80), and between FCR and BW42 (-0.64), and between FCR and FI (0.49), respectively. Conclusion: Thus, selection on RFI was expected to improve feed efficiency, and reduce FI. Selection on RFI thus improves the feed efficiency of animals without impairing their FI and increase growth rate.

• Animal Bioscience
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• 제34권10호
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• pp.1600-1606
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• 2021

Objective: This study was conducted to enhance our understanding of nitrogen (N) metabolism and mammary amino acid (AA) utilization in lactating cows with divergent phenotypes of residual feed intake (RFI). Methods: Fifty-three multiparous mid-lactation Holstein dairy cows were selected for RFI measurements over a 50-d experimental period. The 26 cows with the most extreme RFI values were classified into the high RFI (n = 13) and low RFI (n = 13) groups, respectively, for analysis of N metabolism and AA utilization. Results: Compared with the high RFI cows, the low RFI animals had lower dry matter intake (p<0.01) with no difference observed in milk yield between the two groups (p>0.10). However, higher ratios of milk yield to dry matter intake (p<0.01) were found in the low RFI cows than in the high RFI cows. The low RFI cows had significant greater ratios of milk protein to metabolizable protein (p = 0.02) and milk protein to crude protein intake than the high RFI cows (p = 0.01). The arterial concentration and mammary uptake of essential AA (p<0.10), branched-chain AA (p<0.10), and total AA (p<0.10) tended to be lower in the low RFI cows. Additionally, the low RFI cows tended to have a lower ratio of AA uptake to milk output for essential AA (p = 0.08), branched-chain AA (p = 0.07) and total AA (p = 0.09) than the high RFI cows. Conclusion: In summary, both utilization of metabolizable protein for milk protein and mammary AA utilization are more efficient in cows with lower RFI than in the high RFI cows. Our results provide new insight into the protein metabolic processes (related to N and AA) involved in feed efficiency.

• Animal Bioscience
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• 제34권10호
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• pp.1684-1694
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• 2021

Objective: This study investigated the association between feed efficiency, physicochemical properties, flavor precursors and biomolecules in the thigh meat of Korat (KR) chickens. Methods: The feed intake and body weight of individual male KR chickens were recorded from 1 to 10 weeks old to calculate the individual residual feed intake (RFI) of 75 birds. At 10 weeks of age, chickens with the 10 highest (HRFI) and lowest RFI (LRFI) were slaughtered to provide thigh meat samples. The physicochemical properties (ultimate pH, water holding capacity [WHC], drip loss) and flavor precursors (guanosine monophosphate, inosine monophosphate (IMP), adenosine monophosphate and inosine) were analyzed conventionally, and Fourier transform infrared spectroscopy was used to identify the composition of biomolecules (lipids, ester lipids, amide I, amide II, amide III, and carbohydrates) and the secondary structure of the proteins. A group t-test was used to determine significant differences between mean values and principal component analysis to classify thigh meat samples into LRFI and HRFI KR chickens. Results: The physicochemical properties of thigh meat samples from LRFI and HRFI KR chickens were not significantly different but the IMP content, ratios of lipid, lipid ester, protein (amide I, amide II) were significantly different (p<0.05). The correlation loading results showed that the LRFI group was correlated with high ratios of lipids, lipid esters, collagen content (amide III) and beta sheet protein (rg loading >0.5) while the HRFI group was positively correlated with protein (amide I, amide II), alpha helix protein, IMP content, carbohydrate, ultimate pH and WHC (rg loading >0.5). Conclusion: The thigh meat from chickens with different RFI differed in physiochemical properties affecting meat texture, and in the contents of flavor precursors and biomolecules affecting the nutritional value of meat. This information can help animal breeders to make genetic improvements by taking more account of traits related to RFI.

• Asian-Australasian Journal of Animal Sciences
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• 제21권7호
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• pp.961-966
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• 2008

Direct and maternal genetic parameters for production traits in 1,642 pigs and maternal genetic correlations among production (1,642 pigs) and feed efficiency (380 boars) traits were estimated in 7 generations of a Duroc population. Traits studied were daily gain (DG), intramuscular fat (IMF), loineye area (LEA), backfat thickness (BF), daily feed intake (FI), feed conversion ratio (FCR) and residual feed intake (RFI). The RFI was calculated as the difference between actual and predicted feed intake. The predicted feed intake was estimated by adjusting the initial test weight, DG and BF. Data for production traits were analyzed using four alternative animal models (including direct, direct+maternal permanent environmental, or direct+maternal genetic+maternal permanent environmental effects). Direct heritability estimates from the model including direct and all maternal effects were $0.41{\pm}0.04$ for DG, $0.27{\pm}0.04$ for IMF, $0.52{\pm}0.06$ for LEA and $0.64{\pm}0.04$ for BF. Estimated maternal heritabilities ranged from $0.04{\pm}0.04$ to $0.15{\pm}0.05$ for production traits. Antagonistic relationships were observed between direct and maternal genetic effects ($r_{am}$) for LEA (-0.21). Maternal genetic correlations of feed efficiency traits with FI ($r_g$ of FI with FCR and RFI were $0.73{\pm}0.06$ and $0.90{\pm}0.05$, respectively) and LEA (rg of LEA with FCR and RFI were $-0.48{\pm}0.05$ to $-0.61{\pm}0.05$, respectively) were favorable. The estimated moderate genetic correlations between direct and maternal genetic effects for IMF and LEA indicated that maternal effects has an important role in these traits, and should be accounted for in the genetic evaluation system.

• Asian-Australasian Journal of Animal Sciences
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• 제30권1호
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• pp.51-56
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• 2017

Objective: The objective of this study was to evaluate the intake and nutrient digestibility, nitrogen balance and ruminal ammonia nitrogen in lambs of diets containing different levels of residual frying oil. Methods: Levels of 0, 20, 40, 60, and 80 g/kg dry matter (DM) base of residual frying oil in the diets of lambs were evaluated. Five castrated lambs with initial body weights of $36.8{\pm}3.3kg$, distributed in a Latin square ($5{\times}5$) design, were used. Results: There was a decreasing linear effect on the intake of DM, organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), total carbohydrates (TCH), and nonfibrous carbohydrates (NFC). There was an increased linear intake of ether extract (EE). The apparent digestibility of DM, OM, CP, NDF, TCH, and NFC, as well as urine nitrogen excretion, nitrogen balance and ruminal parameters, were not influenced by different levels of residual frying oil in the diet. EE digestibility presented a crescent linear effect. Conclusion: It can be concluded that the addition of residual frying oil to the diets of sheep can affect nutrient intake without affecting the digestibility of most nutrients (with the exception of EE), nitrogen balance and ruminal ammonia nitrogen concentration.