Assessing the Environmental Impact of Extensive Beef Production in Grazing Lands of Argentina

Because of environmental constraints,beef cattle was for more than a century the only viable farming option in the extensive semiarid and subhumid lands of Argentina and the main source of nutrients for humans as well.However,a growing concern and criticism have risen today about its possible negative impact on the climate and the environment.These worries tend to affect current public opinions,national policies,and international trade.Based on 40 beef cattle farms scattered across different semiarid and subhumid regions of Argentina,here we evaluated the impact of extensive cattle production on carbon,water,and nutrient pollution.Life-Cycle Assessment(LCA)and Land-Based Assessment(LBA)were the two approaches we used here to compare the environmental impact of beef production.While the environmental footprint(EF)resulting from LCA expresses the impact per unit of food,the environmental balance(EB),derived from LBA,aims at quantifying the impact per unit of land.As such,the EB considers both negative and positive impacts on the farm as an integrated system.Following standardized procedures,we evaluated EF and EB up to the farm gate,leaving aside delocalized post-farm impacts such as those of processing,packaging,and transportation that occur beyond the farm gate.In agreement with previous evidence,our results show that the EF tends to decrease as per-head production increases.Correlation coefficients and statistical significance were the following for carbon(R=−0.574;p<0.01),water(R=−0.561;p<0.01),and N(R=−0.704;p<0.01)and Phosphorus(P)pollution(R=−0.802;p<0.01)footprints.On the contrary,the EB seems to be highly sensitive,and as per-hectare beef production increases.Correlations were the following for carbon emissions(CE:R=0.955;p<0.01),water consumption(WC:R=0.822;p<0.01),nitrogen excretion(NE:R=0.948;p<0.01)and phosphorus excretion(PE:R=0.945;p<0.01).What our results suggest is that the notion of EF is useful to evaluate the environmental impact in intensive beef production systems,and the EB is suitable to assess the impact of the extensive ones.In practice,both approaches provide different perspectives on the environmental-impact problem and they should be complementary used.We concluded that the methodological rigidity of EF does not allow proper discrimination among farms in the extensive systems.On the contrary,the EB approach tended to be highly sensitive to detecting differences between individual farms and farmers,thus allowing the identification of successful options for extensive beef production in terms of public image,policy-making,and commercial opportunities.

Effects of Plant Oil Mixture on Production Performance,Carcass and Beef Quality in Beef Cattle

[Objective] To study the effects of plant oil mixture on production performance, carcass and beef quality in beef cattle. [Method] Single-factor randomized blocks design was used. Sixteen healthy Yanbian yellow bulls having close body weight were selected and randomly divided into four groups, four cattle per group. Been oil, safflower oil and sunflower oil were mixed respectively at a volume ratio of 11：5：4. The oil blend was added to the daily diets of beef cattle respectively at a proportion of 4%, 5% and 6%. The effects of the plant oil mixture on production performance, carcass and beef quality were investigated. [ Result.] Compared with the control cattle, the experimental cattle had significantly lower feed intake （P 〈 0.05）, non-significantly higher efficiency of feed utilization, and significantly lower digestibility of crude fiber and calcium （P 〈 0.05）. With the increasing level of plant oil, the digestibility of dry matter showed a decreasing trend. The digestibility of dry matter was significantly lower in the cattle fed on the plant oil mixture at a level of 6% than in the control （ P 〈 0.05）. The plant oil mixture had no effect on the digestibility of crude protein, ether extract, crude ash, nitrogen-free extract and phosphorus. With the increasing level of plant oil, the serum content of high-density lipoprotein showed an increasing trend. The serum content of high-density lipoprotein was significantly higher in the cattle fed on the plant oil mixture at a level of 6% than in the control （ P 〈 0.05）. With the increasing level of plant oil, the content of total cholesterol showed an increasing trend, whereas the content of low-density lipoprotein showed a decreasing trend. Moreover, other indicators did not change significantly. The experimental cattle had larger eye muscle area and better beef quality than the control group. The content of crude protein and ether extract in beef increased with the increasing level of plant oil. [ Conclusion] The plant oil mixture added to the daily feed decreases intake and digestibility of crude fiber and calcium but has no remarkable effect on production performance of beef cattle. The addition also increases eye muscle area and improves beef quality, thereby improving quality of carcass and beef. The proportion of the plant oil mixture should be added at a proportion lower than 5%.

Effects of Different Compound Trace Element Premixed Materials on Beef Cattle Production Performance and Anti-oxidation Capacity

In this study,the effects of two types of premixed materials with different combinations of trace elements on the production performance and antioxidant capacity of simmental beef cattle were examined.Fifteen healthy simmental beef cattle of similar weight(approximately 330 kg),the same age(12 months),without castration,and a good physique were divided into three groups,with five beef cattle in each group.Food of Group Ⅰ beef cattle was supplemented with a commercially marketed 5% compound trace element premixture for fine beef cattle.Food of Group Ⅱ beef cattle was supplemented with a 5% compound microelement premixture for beef cattle that was designed to address local nutrient deficiencies and surpluses.In the blank control group,the beef cattle were not fed a premixture.The pretest period was 15 days,and the test period was divided into prefattening(45 days)and postfattening(45 days)stages.Body weight and body size indices were recorded at 1,2 and 3 months,and blood samples were collected regularly.In Group Ⅰ,the daily weight gain increased significantly by 15.7% compared with that of the control group.The largest daily weight gain was in Group Ⅱ,which increased by 31.6% compared with that in the control.During the test period of 90 days,the body size indices of the three different groups increased in different months,with significant increases in the indices for both test groups compared with those of the control.In Group Ⅰ,the activity of CP,the total activity of SOD and Cu-Zn-SOD increased significantly(p<0.05)compared with those in the control group,with a highly significant increase observed in GSH-PX activity(p<0.01).In Group Ⅱ,the increases in the activity of CP and the total activity of SOD and Cu-Zn-SOD were highly significant compared with those in the control group(p<0.01).In addition,a significant increase was observed in GSH-PX activity(p<0.05).Based on pretest results,the concentrations of Cu,Zn,Mo,Mn,Se and Co in the blood of experimental beef cattle were lower than those of the normal range.After feeding for 90 days,the concentrations of Cu,Zn,Mo,Mn,Se and Co in the blood of Groups Ⅰ and Ⅱ were significantly higher than those in the control group(p<0.05).The concentrations of elements in the blood of Group Ⅱ were close to the appropriate levels.Thus,the effects of the specifically designed compound microelement premixture on the prevention of nutrient imbalances and control of beef cattle nutrition metabolism and the production of fattened beef cattle were significant.

Economics of early weaning in northern great plains beef cattle production system

Early removal of the calf from its dam reduces forage needs of the cow-calf enterprise and has been found to improve BW gain and pregnancy rates in the cow herd. However, early weaning may not always be economically viable for producers and the risk should be considered carefully. This study was conducted to evaluate the effect of early and normal weaning of steer and heifer calves on net income at weaning. Calves from Angus xHereforddams were randomly assigned to one of two weaning treatments. Calves were either early weaned (EW) at 80-d of age or remained with their dams until normal weaning (NW) at 213-d of age. Calves assigned to EW treatment received a 17.5% crude protein and 0.82 Mcal/kg net energy diet for approximately 130-d in a drylot. All economic analyses were conducted at normal weaning for both NW and EW calves. At normal weaning, price of steers ($US/kg) was lower (P = 0.003) and weaned steer value ($US/steer) was greater (P P = 0.18) was found in price of heifers ($US/kg) and weaned heifer value ($US/heifer) between NW and EW heifers. Feed cost was increased (P < 0.001) in EW steers and heifers compared to NW calves. Net revenue for both weaned steers and heifers was reduced (P < 0.001) in EW calves due to the feed cost of the growing diet. This study indicates that early weaning calves at 80-d of age decrease weaned calf value and net revenue for the cow-calf segment.

Implications of Land Use Land Cover Change and Climate Variability on Future Prospects of Beef Cattle Production in the Lake Victoria Basin

This paper presents the lessons learnt from a research project titled “Improving Beef Cattle Productivity for Enhanced Food Security and Efficient Utilization of Natural Resources in the Lake Victoria Basin” which includes Tanzania, Uganda and Rwanda. The key focus is on the implications of land use land cover change and climate variability on the future prospects of beef cattle production in this region. The study utilizes information and data from natural resources and climate components to deduce the impact of land use and land cover changes on climate variability. Additional analysis is conducted to summarize the land use and land cover data to carry out analysis on climate data using the Mann-Kendal test, linear regression and moving averages to reveal patterns of change and trends in annual and seasonal rainfall and temperature. The findings reveal that the study areas of Rwanda, Uganda and Tanzania in the Lake Victoria Basin (LVB) have changed over time following land cover manipulations and land use change, coupled with climate variability. The grazing land has been converted to agriculture and settlements, thereby reducing cattle grazing land which is the cheapest and major feed source for ruminant livestock production. Although the cattle population has been on the increase in the same period, it has been largely attributed to the fact that the carrying capacity of available grazing areas had not been attained. The current stocking rates in the LVB reveal that the rangelands are greatly overstocked and overgrazed with land degradation already evidenced in some areas. Climate variability coupled with a decrease in grazing resources is driving unprecedented forage scarcity which is now a major limiting factor to cattle production. Crop cultivation and settlement expansion are major land use types overtaking grazing lands;therefore the incorporation of crop residues into ruminant feeding systems could be a feasible way to curtail rangeland degradation and increase beef cattle production.

Antimicrobial usage and resistance in beef production

Antimicrobials are critical to contemporary high-intensity beef production. Many different antimicrobials are approved for beef cattle, and are used judiciously for animal welfare, and controversially, to promote growth and feed efficiency. Antimicrobial administration provides a powerful selective pressure that acts on the microbial community, selecting for resistance gene determinants and antimicrobial-resistant bacteria resident in the bovine flora. The bovine microbiota includes many harmless bacteria, but also opportunistic pathogens that may acquire and propagate resistance genes within the microbial community via horizontal gene transfer. Antimicrobial-resistant bovine pathogens can also complicate the prevention and treatment of infectious diseases in beef feedlots,threatening the efficiency of the beef production system. Likewise, the transmission of antimicrobial resistance genes to bovine-associated human pathogens is a potential public health concern. This review outlines current antimicrobial use practices pertaining to beef production, and explores the frequency of antimicrobial resistance in major bovine pathogens. The effect of antimicrobials on the composition of the bovine microbiota is examined, as are the effects on the beef production resistome. Antimicrobial resistance is further explored within the context of the wider beef production continuum, with emphasis on antimicrobial resistance genes in the food chain, and risk to the human population.

Growth Modeling of Charolais and Serrana Soriana Native Spanish Beef Cattle

The alternative productions, increasingly importance, are based on the rational utilization of the resources, on agreement with the environment and the use of autochthonous breeds that many cases are found in danger of disappearance, due to the tact that their suckling is not economically profitable. A way of predicting and knowing the growth of the animals is using mathematical models. This work presented the results of the estimate of the growth according to the Gompertz-Laird model of males of the atttochthonous breed Serrana Soriana and Charolais. The weight to the birth of the breed calfs Charolais （45.14 kg）, was superior to those of Serrana Soriana （40.13 kg）, and presented a greater relative growth （9.9%） before the inflection point of the growth curve： furthermore it ~as also superior to the maximum decline relative after this point （6%）, Serrana Soriana reached 7 days after the maximum growth point but with a smaller weight （315.05 kg vs 384.76 kg）. It was calculated a weight to the maturity of 1 ,（176.91） kg for Charolais and 856.40 kg for Serrana Soriana.

Modelling Manure Production in Beef Calves: Development, Evaluation, and Application of a Complete vs. Simplified Prediction Model

There has been increased interest in quantifying the manure production of livestock, primarily driven by public authorities, who aim to evaluate the environmental impact of livestock production, but also at the farm level, to manage manure storage and availability of fertilizer for crop production. Moreover, current manure production estimates from intensively reared beef calves are higher than actual production due to changes in farming systems, advances in animal genetics and feed efficiency. This study aims to redefine and update manure production estimates in intensively reared beef calves to predict manure production as a policy and planning tool, as there are no current models available. A trial was conducted to collect data on manure production during the growing-finishing period (243 d) of 54 Limousine calves (from 346.7 to 674.0 kg live weight, LW). Such data were used to develop two models to predict manure excretion: (1) a complex mechanistic model (CompM), and (2) a simplified empirical model (SimpM). Both models were evaluated against an independent dataset including a total of 4,692 animals on 31 farms and 5 breeds. Results from CompM require interpretation because the model does not output a single value but a range of manure production (minimum, medium and maximum), and would therefore be more suitable for professional use. The SimpM could be considered simple, reliable, and versatile for predicting manure excretion at farm level. SimpM could be refined and improved by including data from other studies on beef cattle with distinct characteristics and management.

Feed profile analysis of oil palm‐integrated beef cattle farming systems by metabolic energy budgeting and implications for beef production and pastoral system design

Background:Oil palm is a tropical crop with worldwide plantings approaching 20 million ha and large areas in Indonesia,Malaysia and Thailand.The plantations are readily managed as silvopastoral systems incorporating cattle grazing(Oil Palm Silvopastoral System for Cattle,OPSC)but there is a need for analytical tools and data to understand system herbage supply and feed conversion efficiency(FCE).Methods:Metabolic energy budgeting was used to estimate herbage harvested by cattle in three OPSC subsystems,9 and 12 years after oil palm establishment,and FCE of the subsystems was determined.Understorey herbage was also analysed for nutritive value,botanical composition and herbage accumulation within one grazing‐regrowth cycle.Results:The herbage‐harvested estimate was 2.0−2.4 t dry matter(DM)ha^(-1) year^(-1) for 9 year old subsystems and 1.4-1.7 tDMha^(-1) year^(-1) for a 12 year old subsystem.Herbage metabolisable energy(ME)was 8.3−8.5 MJ kg^(-1) DM and crude protein(CP)was 15%-16%DM.FCE values for subsystems ranged from 32 to 94 kg DM kg^(-1) liveweight‐gain.Conclusions:Herbage DM yield is declining,while herbage ME is marginal but CP is adequate.FCE is suboptimal but can be optimised by defining the trajectory of declining herbage production with canopy closure as plantations age and matching stocking rate to herbage supply using a comparativestocking‐rate‐type statistic.

Report on a breeding objective that may reduce the carbon footprint of extensive cow-calf production systems

Most measurements for beef improvement in South Africa are per individual (weaning weight, calving interval, growth rate, etc.). A measurement that expresses performance per constant unit, e.g. kilogram calf weaned per Large Stock Unit (LSU) can eventually be translated to kilogram calf produced per kg CO2 equivalent. A LSU is defined as a bovine requiring 75 MJ Metabolisable Energy (ME) per day. If more kilogram weaner calf can be produced per LSU (KgC/LSU), the carbon footprint of beef can be reduced. This study used breed average values to investigate the KgC/LSU for the 30 beef and dual purpose breeds in South Africa. The breeds were categorized in the following breed types: Sanga (indigenous to South Africa) Sanga derived, Zebu, Zebu derived, British and European. No relationship was found between cow weights and KgC/LSU, indicating that it is independent of cow weight between breeds. However, when the data is summarized into breed types, the Sanga and European breed types produce the least KgC/ LSU and Sanga derived breed types the most. This high value of the Sanga derived breeds is probably due to retained heterosis. Composite breeds are mostly intermediate to parental breeds for individual traits but superior for composite traits and KgC/LSU is a composite trait. These calculations were only done on breed averages. A genetic analysis on a breed level to estimate genetic parameters for this trait, and its genetic correlations with other traits now needs to be done before a decision can be taken whether selection for KgC/LSU will be feasible. The ultimate aim with a trait like this is to reduce the carbon footprint of weaner calf production since more kilogram calf will be produced per LSU (constant feed unit).

全株玉米青贮饲料的制作及在肉牛养殖中的应用

全株玉米青贮饲料在养殖中的应用范围越来越广,但在实际操作中仍然存在不少问题。本文总结了全株玉米的制作方法及在肉牛养殖中的应用,旨为广大收贮企业规范制作全株玉米青贮饲料及肉牛养殖场户科学饲喂提供参考。

磁化水对6月龄肉牛生产性能及血清指标的影响

试验旨在研究磁化水对6月龄肉牛生产性能及血清指标的影响。将同一批6月龄左右、体重约300 kg的西门塔尔架子牛212头,随机分为2组。对照组(110头牛)饮用普通水,试验组(102头牛)饮用磁化水。试验期87 d。结果显示,与普通水相比,磁化水的pH值提高了7.91%,总硬度和耗氧量降低了0.36%和13.70%,磁化前后水的菌落总数和大肠杆菌数均为0。与对照组相比,试验组10 d的平均日采食量和平均日增重分别增加了4.41%和5.36%(P>0.05)。与对照组相比,试验组血清超氧化物歧化酶和过氧化氢酶活性分别提高了32.82%(P<0.05)和73.36%(P<0.01),丙二醛含量降低,免疫球蛋白A、免疫球蛋白G和免疫球蛋白M含量分别提高了13.85%、3.21%和5.99%,血清尿素氮含量增加了30%(P<0.05),总蛋白含量降低了34.53%(P<0.01),血清胰岛素、生长激素和促生长激素释放激素水平分别提高了10.73%、13.00%和5.04%。研究表明,水被磁化后水质有所改变,磁化水能够增加肉牛采食量和体重,增强血清抗氧化水平、免疫力和生长相关激素水平。

我国地方肉牛品种差异化高质量发展模式探究

近年来,肉牛产业比较效益较低,受猪牛肉市场价格非常态联动以及地方品种普遍的生产效益较低等因素影响,肉牛产业发展的支撑效应逐渐弱化。该文解析了新常态下我国肉牛产业的新特征,并对地方品种支撑肉牛产业差异化发展新模式进行了探究,提出了我国地方肉牛差异化高质量发展模式的关键举措。

日粮中添加不同益生菌水平对肉牛生产性能和肠道菌群的影响

该研究旨在评估在肉牛日粮中添加不同水平的益生菌对肉牛生产性能和肠道菌群的影响。本试验选择体重相近(320±20)kg、健康的西门塔尔杂交肉牛72头,随机分为4组。试验Ⅰ、Ⅱ、Ⅲ和Ⅳ组。结果表明,在试验期结束时,与试验Ⅰ组相比较,试验Ⅱ、Ⅲ和Ⅳ组的平均日增重和平均日采食量显著增加(P<0.05),而各组之间的料肉比没有显著差异(P>0.05);与试验Ⅰ组相比较,添加益生菌的试验Ⅱ、Ⅲ和Ⅳ组可显著提高肉牛中肠道乳酸杆菌的含量(P<0.05),同时显著降低肠道中大肠杆菌的含量(P<0.05),但添加益生菌对肠道中的双歧杆菌和总需氧菌含量无显著差异(P>0.05)。本研究结果表明,在肉牛日粮中添加2%的复合益生菌发酵培养物,能够显著改善肉牛的生产性能,包括增加日增重和改善饲料转化率,对肠道菌群结构具有正向调节作用。

基于体外产气法的不同种类菌糠肉牛日粮效果评价

试验旨在通过体外产气法对用不同食用菌菌糠设计的低成本肉牛日粮配方进行效果评定。试验采用单因素试验设计,以不同种类菌糠全混合日粮(TMR)为发酵底物,设计对照(CON)、香菇、木耳、平菇、元蘑、白玉菇、榆黄蘑、羊肚菌、杏鲍菇处理,通过体外产气法,根据产气量、产气参数、发酵参数和营养物质体外消化率等指标,结合隶属函数进行综合分析。结果表明:①在发酵4~10 h时,CON产气量显著高于其他处理(P<0.05);在发酵12~16 h时,木耳处理、白玉菇处理、榆黄蘑处理、羊肚菌处理产气量均显著低于CON(P<0.05);在发酵48 h时,木耳处理、元蘑处理、白玉菇处理、榆黄蘑处理、羊肚菌处理产气量均显著低于CON(P<0.05)。②除木耳处理和元蘑处理外,其他处理理论最大产气量均显著高于CON(P<0.05);除元蘑处理外,其他处理产气速率均显著低于CON(P<0.05)。③CON和杏鲍菇处理pH显著高于其他处理(P<0.05);各处理氨态氮(NH3-N)、挥发性脂肪酸(VFA)和甲烷产量均无显著差异(P>0.05)。④除香菇处理和平菇处理外,其他处理可消化有机物(DOM)、有机物降解率(OMD)、代谢能(ME)值均显著低于CON(P<0.05)。⑤在体外发酵24 h时,除香菇处理和平菇处理外,其他各处理营养物质体外消化率均显著低于CON(P<0.05);在体外发酵48 h时,除香菇处理、平菇处理和杏鲍菇处理外,其他各处理营养物质体外消化率均显著低于CON(P<0.05)。综合分析认为,不同种菌糠肉牛日粮的瘤胃发酵参数和降解特性存在一定差异,其中香菇和平菇菌糠具有作为肉牛日粮的潜力。

玉米芯+芦苇草不同组合对西杂肉牛生产性能及血液生化指标的影响

为研究日粮中添加不同比例玉米芯、芦苇草对西门塔尔杂代肉牛生长性能、血清生化指标的影响,试验选择体重500 kg左右的健康西门塔尔杂交肉牛32头,随机分为4组,每组8头,每头为一个重复。对照组为添加4%玉米芯+4%芦苇草基础TMR日粮,试验1组、2组、3组基础TMR日粮中玉米芯和芦苇组合比例分别为8%玉米芯+4%芦苇草、6%玉米芯+6%芦苇草、4%玉米芯+8%芦苇草,预饲期15 d,正式期60 d。结果表明:试验1组、2组、3组平均日增重分别比对照组提高了27.03%、3.60%、22.52%(P> 0.05),平均料重比分别比对照组降低了16.67%、12.34%、22.05%(P> 0.05)。试验2组尿素氮含量分别比对照组、1组、3组降低了28.16%、27.67%、35.20%,差异显著(P <0.05);试验2组甘油三酯(TG)含量比3组降低了43.90%(P <0.05);结果提示,在肉牛育肥后期饲粮中添加适量玉米芯和芦苇草,可一定程度提高西门塔尔杂交肉牛平均日增重,降低料重比,促进机体对蛋白质的吸收代谢,可降低饲料成本,提高养殖效益,建议全混合日粮中添加4%~8%玉米芯+4%~6%芦苇草为宜。

机会成本视角下新疆肉牛养殖的全要素生产率测度——基于DEA-Malmquist指数分析

在传统肉牛养殖全要素生产率的研究中,机会成本的考量往往被忽视。然而,不考虑机会成本会导致对养殖户在肉牛养殖中的隐性投入被忽略,从而无法真实地反映肉牛养殖的全要素生产率。为了准确测算新疆肉牛养殖的全要素生产率,在以2008—2022年新疆肉牛主产值为产出指标,以仔畜费、饲草料费、人工费为投入指标的基础上引入机会成本要素,采用DEA-Malmquist指数从静态和动态视角对新疆肉牛养殖的技术效率和技术进步的相关情况进行分析。结果表明:从静态角度来看,新疆肉牛养殖的水平并不高,收益较低,主要受到规模效率的影响,个别年份受到纯技术效率的影响,说明在目前的养殖规模和技术水平下,新疆肉牛养殖的效益尚未达到理想状态,仍有较大的提升空间;从动态角度来看,新疆肉牛养殖全要素生产率变动的主要原因是技术进步,说明随着新技术的不断应用和推广,新疆肉牛养殖的生产效率有望得到进一步提升。最后,从优化养殖规模和布局、加强技术创新与推广、加大对职业养殖户的培育等3个方面提出促进新疆肉牛产业高质量发展的的对策建议。

动物福利在肉牛生产中的应用现状与展望

规模化、集约化肉牛养殖方式在一定程度上可以降低生产成本,是提高生产效益的有效途径。然而,集中式、拴系式、高密度的生产方式下,常常导致肉牛的动物福利得不到有效保障,会对肉牛的生长和健康产生不利影响。改善肉牛动物福利可提高生产性能和养殖效益,实现绿色健康可持续发展。文章介绍了动物福利的概念、肉牛在饲养管理中的福利标准要求,以及在肉牛养殖过程中动物福利的重要意义,同时对我国肉牛生产福利的研究发展进行了展望,以期为生产实际提供指导和参考。

日粮中添加维生素E对肉牛生长性能、肌肉品质以及经济效益的影响

文章旨在研究日粮中添加维生素E对肉牛生长性能、肌肉品质以及经济效益的影响。试验将45头健康、均重(407.89±21.24)kg的20月龄西杂公牛随机分为3组,每组15个重复,每个重复1头。试验为期97 d,预饲期7 d,正试期90 d。试验日粮在基础日粮中添加0,800和1600 IU/kg的维生素E。试验结果:与对照组相比,1600 IU/d维生素E组肉牛的末体重(FBW)显著提高3.10%(P<0.05),平均日增重(ADG)显著提高13.27%(P<0.05),平均日采食量(ADFI)显著提高6.59%(P<0.05);与对照组相比,800和1600 IU/d维生素E组肉牛的料肉比分别显著降低4.17%和5.95%(P<0.05),此外,维生素E对肉牛的屠宰率和净肉率均无显著影响(P>0.05)。1600 IU/kg维生素E组肉牛肌肉的大理石花纹评分显著高于其他两组(P<0.05);1600 IU/kg维生素E组肉牛肌肉的剪切力显著低于其他两组(P<0.05);1600 IU/kg维生素E组肉牛肌肉的谷氨酸和甘氨酸显著高于其他两组(P<0.05);此外,熟肉率、pH48 h、系水力、天冬氨酸、酪氨酸、丙氨酸、苯丙氨酸含量无显著影响(P>0.05)。额外添加维生素E后,饲料单价分别为1.61、1.66和1.71元/kg(P<0.05);结合采食量后,1562.02、1615.01和1768.31元(P<0.05);综合计算毛利润为1008.65、1075.07和1146.99元。结论:维生素E(1600 IU/kg)对肉牛生长和肉质具有一定的改善作用,同时该组肉牛经济收益最高。

不同青贮饲料对安格斯肉牛屠宰性能、血清生化指标和肝脏脂质代谢的影响

试验旨在探究不同青贮饲料对安格斯肉牛屠宰性能、血清生化指标和肝脏脂质代谢的影响。试验将45头月龄相近、体重(567.68±23.62)kg的安格斯公牛随机分为3组,每组15个重复,每个重复1头。分别饲喂由青贮玉米、苜蓿和高粱构成的试验日粮,试验为期80 d(预饲期8 d,正试期72 d)。结果表明,与玉米青贮组相比,苜蓿青贮组FBW显著提高4.00%、ADG显著提高19.28%、料重比显著降低13.23%(P<0.05);苜蓿青贮组肉牛的肾脂率和大网膜脂率均显著高于玉米青贮组和高粱青贮组(P<0.05);此外,不同青贮对肉牛胴体重、屠宰率、心脂率、净肉重、净肉率和眼肌面积无显著影响(P>0.05)。苜蓿青贮组肉牛血清葡萄糖含量显著高于玉米青贮和高粱青贮组(P<0.05);苜蓿青贮组肉牛血清甘油三酯含量显著低于玉米青贮和高粱青贮组(P<0.05);苜蓿青贮和高粱青贮组肉牛血清总蛋白含量显著高于玉米青贮组(P<0.05);此外,不同青贮对安格斯肉牛血清总胆固醇、球蛋白、白蛋白、高密度脂蛋白和低密度脂蛋白含量均无显著影响(P>0.05)。苜蓿青贮组肉牛肝脏FAS基因表达水平显著高于玉米和高粱青贮组(P<0.05);苜蓿青贮组和高粱青贮组肉牛肝脏CPT1基因表达水平显著高于玉米青贮组(P<0.05);苜蓿青贮组肉牛肝脏PPAR-γ基因表达水平显著高于玉米和高粱青贮组(P<0.05);此外,不同青贮对肉牛肝脏LPIN1基因表达无显著影响(P>0.05)。结论:本试验数据显示,苜蓿青贮可增加安格斯肉牛的脂质沉积。在本试验条件下,苜蓿青贮对安格斯肉牛的育肥效果最佳。