Economic and environmental impacts of changes in culling parity of cows and diet composition in Japanese beef cow–calf production systems

The effects of changes in culling parity of cows and diet composition on economic and environmental outputs in Japanese beef cow–calf production systems were deterministically analyzed using a herd model simulation. The model simulated the annualized net revenue as an economic indicator and the overall environmental index derived from a life cycle assessment (LCA) as an environmental indicator. Biological factors (survivability, growth, reproduction, and feed requirements) and economic factors (returns from sales of live calves and cows’ carcasses and production costs) were included in the model. The model also included modified feed formulation methods, allowing us to analyze the effect of reductions in environmental loads caused by the change in diet compositions. The results of the present study indicated that later culling was economically and environmentally optimal under the current production system, which suggested that the selection of economically optimal culling parity of cows could result in environmentally optimization of the beef cow–calf production system. The difference in feed composition derived from the difference in feed formulation methods did not affect the determination of optimal culling parity, whereas the use of modified feed formulation methods could reduce environmental loads at a higher rate than that of economic benefits. However, the reduction rate of the environmental impact was much higher in the case of selection of the optimal culling parity than in the case of use of modified feed formulation methods, which stressed the importance of choosing the optimal culling parity of cows both from the economic and environmental points of view

Carbon footprint assessment of a whole dairy farming system with a biogas plant and the use of solid fraction of digestate as a recycled bedding material

Biogas generated from livestock manure is a renewable energy source and the digestate is used as a fertilizer. Moreover, dewatered biogas digestate can be used as a bedding material (recycled bedding material). The aims of the present study were to model a whole dairy system with a biogas plant using recycled bedding material and to assess the life cycle greenhouse gas (GHG) emissions. Emissions from the material flow of dairy cattle production, manure treatment and organic fertilizer application to on-farm crops were evaluated. In the emissions from organic fertilizer storage and recycled bedding material production, CH4 emission was decreased by 43.0%, and consequently the system with a biogas plant reduced total GHG emissions by 6.8% compared with conventional slurry storage and straw bedding. The use of recycled bedding material from a biogas plant has the potential to create a resource cycle and to be beneficial as a GHG mitigation strategy

Analysis of growth patterns in purebred kambing Katjang goat and its crosses with the German fawn

The objective of this study was to investigate growth patterns of goats utilizing data from a crossbreeding program involving the exotic German Fawn (GF) and the indigenous Kambing Katjang (KK) goats. Growth curve models and growth curve parameters were compared and analyzed for different genotypes and litter types. A total of 20,393 weight–age data from 208 female goats belonging to various crossbreeding genotypes were individually fitted to four growth curve models (Brody, Bertalanffy, Gompertz and Logistic). The goodness of fit was highest in the Brody model in most cases. A comparison of R2 among genotypes showed that they were highest for KK. There were no significant differences of genotypes for estimated mature weight in the Brody model. The estimated mature weights for KK were significantly lower (P < 0.05) than for GF × KK (F1), backcrosses with 75% GF genes (BC) and F1 × F1 (F2) in the other models. The correlations between estimated mature weights and the maturing rates were lowest for BC. The genotype significantly (P < 0.01) affected the age at the constant degree of maturity (67% and 90% of mature weight) in all models. The BC genotype was the youngest at maturity and KK the oldest. All models well expressed the growth pattern of the target animals when they were older than 2.5 years of age. The results from the present study showed that the growth pattern may be altered by crossbreeding of KK with the GF breed

Simulation of livestock biomass resource recycling and energy utilization model based on dry type methane fermentation system

International Conference of Biomass and Bioenergy 19-20 August 2019, West Java, IndonesiaThis study was aimed at investigating the local livestock biomass volume for dairy farms in Town A, located in eastern Hokkaido, Japan, and at presenting a model of a biogas plant that enables maximizing the use of the available livestock biomass. Using a dairy farm with 250 animals in Town A as a model for a biogas plant based on dry-type methane fermentation system (dry-type biogas plant), we set the operational conditions to an average hydraulic retention time of 20 days, digestion temperature of 55°C, and methane gas yield of 0.12 Nm3 CH4/kg VSA. We compared the biogas production of our presented model with that of a wet-type biogas plant with the same number of animals. The results showed that the dry-type biogas plant produced biogas at 859 Nm3/day, while the wet-type biogas plant produced biogas at 666 Nm3/day. These results indicate that introducing dry-type biogas plants in all dairy farms in Town A would potentially enable semi-solid livestock manure to be processed, which is not amenable to ordinary composting, in addition to the conventional processes being carried out through biogas plants, as well as lead to an increase in the amount of biogas production

家畜生産システムにおける雌畜の淘汰戦略を評価するシミュレーションモデルの開発と適用

京都大学0048新制・論文博士博士(農学)乙第12657号論農博第2764号新制||農||1003(附属図書館)学位論文||H24||N4698(農学部図書室)29735京都大学大学院農学研究応用生物科学専攻(主査)教授 廣岡 博之, 教授 祝前 博明, 教授 久米 新一学位規則第4条第2項該当Doctor of Agricultural ScienceKyoto UniversityDA

Application of the modified feed formulation to optimize economic and environmental criteria in beef cattle fattening systems with food by-products

A simplified ration optimization method was applied to a beef cattle fattening system to evaluate the utilization of food by-products under various situations. The method was extended to reduce feed costs (i.e., economic factors) and nitrogen and phosphorus excretions (i.e., environmental factors) by introducing penalty coefficients of nitrogen and phosphorus contents in each ingredient of the diet in the objective function in traditional linear programming. Six regional food by-products, five commercial concentrates and two roughages were used as ingredients of the fermented total mixed ration. Constraints for the feed formulation were based mainly on nutrient requirements in the Japanese Feeding Standard for Beef Cattle. The replacement price (or acquisition cost) of food by-products was defined as the maximum price of food by-products when the feed cost with the use of food by-products was below the cost with the use of conventional concentrates. The results showed that although the replacement prices were not greatly affected by the penalty levels, they were associated with the changes in the substitution rate of food by-products for concentrates and the price of concentrates. The replacement prices were about 16 (yen/kg, as-fed basis) against the present price level of concentrates, when food by-products were substituted for a half of concentrates. Feed compositions were altered and nitrogen and phosphorus excretions were decreased by the changes of penalties, in spite of the small change in the replacement price of food by-products. Both nitrogen and phosphorus penalties greatly reduced the nitrogen and phosphorus excretions, indicating that nitrogen and phosphorus penalty coefficients should be introduced together in the objective function in order to reduce both excretions efficiently

Interspecific comparison of allometry between body weight and chest girth in domestic bovids

ウシ科家畜における体重と胸囲の関係の種間比較 --自然淘汰や人為選抜による形態の進化--. 京都大学プレスリリース. 2017-07-12.The sizes of body parts often co-vary through exponential scaling, known as allometry. The evolution of allometry is central to the generation of morphological diversity. To make inferences regarding the evolved responses in allometry to natural and artificial selection, we compared allometric parameters (slope and intercept) among seven species and breeds of domestic bovids using cross-sectional ontogenetic data and attempted to interpret the differences in these parameters. The allometric slopes were not different among some species, whereas those between breeds within species were, indicating that the slopes were typically invariant but could be changed under strong, specific selection. With the exception of yak, the differences in the intercept independent of the slopes (the alternative intercept) among species might better correspond to their divergence times than the differences in allometric slope, and the remarkably higher alternative intercept found in yaks can be explained by their unique morphological evolution. These findings provide evidence that differences in the alternative intercept can retain traces of the phylogenetic changes derived from differentiation and evolution

Effect of feeding tamarind kernel powder extract residue on digestibility, nitrogen availability and ruminal fermentation in wethers

Objective This study was to examine in vivo digestibility, nitrogen balance and ruminal fermentation of tamarind (Tamarind indica) kernel powder extract residue (TKPER) compared to soybean products and by-products in wethers. Methods Four wethers with initial body weight (BW) of 51.6±5.5 kg were assigned in a 4×4 Latin square design to investigate nutritional characteristics of TKPER, dry heat soybean (SB), dry soybean curd residue (SBCR) and soybean meal (SBM) feeding with ryegrass straw (R) at a ratio of 1:1 at 2% of BW in dry matter (DM) on a daily basis. Results The digestibility of DM, crude protein, and ether extract (EE) of TKPER-R diet were 57.0%, 87.0%, and 86.0%, respectively. Higher non-fiber carbohydrates digestibility was observed in TKPER-R diet (83.2%) than in SB-R diet (73.9%, p<0.05). Wethers fed the TKPER-R diet had lower retention of nitrogen (N) and ruminal ammonia nitrogen (NH3-N) contents at 4 h after feeding than those fed the SBM-R diet (p<0.05), which had values similar to the SB-R or SBCR-R diet. The TKPER feeding had higher propionate (C3) and lower butyrate content, as well as lower acetate to propionate ratio (C2:C3) in rumen fluid than SBM feeding at 4 h after feeding (p<0.05). Conclusion TKPER did not bring any side effect to the wethers although it was lack of fiber, and could be used as a high protein and energy ingredient in concentrate with appropriate roughage to meet the fiber requirement for ruminants