饲料原料及加工技术对猪饲料质量的影响(上)

当今养猪生产中,生产者和营养师对日粮能量水平、氨基酸浓度和比例、最佳维生素和微量元素供给等方面都给予了极大的关注。选择价格合适、品质优良的饲料原料,采用适当的原料加工方式来配制饲料,对猪场获益非常重要,但良好饲料加工规范常被大家忽视。本文将讨论加工技术对饲料原料和配合饲料营养价值最大化的影响。     

籽粒苋籽实粉作为肉仔鸡日粮组分的营养价值评定

通过梯度饲养、消化代谢和比较屠宰试验,综合评定了籽粒苋籽实粉对星布罗(Star-bro)肉仔鸡的营养价值和对日粮氨基酸利用率的影响.结果测得籽粒苋籽实粉含可消化粗蛋白质132.75g/kg,表观代谢能13.44MJ/kg;日粮中纳入16％苋籽实粉,显著提高了氨基酸利用率和血浆游离赖氨酸、亮氨酸及甘氨酸浓度,日粮粗蛋白质和能量代谢率分别提高6.91％和5.33％,日粮中营养物质转化为胴体蛋白质、脂肪的效率及料肉比均得到改善.     

饲料原料及加工技术对猪饲料质量的影响(下)

当今养猪生产中,生产者和营养师对日粮能量水平、氨基酸浓度和比例、最佳维生素和微量元素供给等方面都给予了极大的关注。选择价格合适、品质优良的饲料原料,采用适当的原料加工方式来配制饲料,对猪场获益非常重要,但良好饲料加工规范常被大家忽视。本文将讨论加工技术对饲料原料和配合饲料营养价值最大化的影响。     

青霉素菌体蛋白营养价值评定及应用效果研究

分析结果表明：青霉素菌体蛋白含粗蛋白质４１．０％,钙１．４４％,总磷１．１１％,代谢能水平为９．９６ＫＪ／ｇ,５种主要的氨基酸含量如下：赖氨酸１．８４％,蛋氨酸０．６０％,胱氨酸０．６２％,苏氨酸１．７８％,色氨酸０．５０％;表观消化率分别为：８８．４％,９０．７％,６１．９％,８０．４％,９１．４％。通过饲养实验说明,在蛋鸡全价料中添加３％、５％、７％的青霉素菌体蛋白,可获得不低于玉米－豆粕日粮的生产成绩     

药物饲料添加剂杆菌肽耐药性风险评估

本研究旨在为监管部门制定动物源细菌耐药风险管理措施提供理论依据。利用2014年国民体质监测数据、第五次中国总膳食研究数据和欧洲药品管理局官方网站数据,采用抗菌药物风险评估模型,对中国居民经动物性食品摄入杆菌肽的耐药性风险进行点评估。用估算每日摄入量作为杆菌肽膳食暴露量,用危害指数（HQ）进行风险特征描述,反映杆菌肽耐药对人体健康损害的风险等级。结果表明,危害识别得杆菌肽经口毒性极低,但肠球菌、产气荚膜梭菌等致病菌已对杆菌肽产生耐药性,耐药基因可转移至人体肠道菌群。经危害特征描述可知,杆菌肽毒理学每日允许摄入量（ADI）为0.055 mg/（kg·BW）,微生物学ADI为3.9 μg/（kg·BW）。暴露评估发现,中国居民中2~7岁人群杆菌肽的膳食暴露量最高,女性通过摄入乳类的杆菌肽膳食暴露量高于男性。2~7岁人群中,杆菌肽的膳食暴露量以乳类贡献最大,8岁以上人群杆菌肽的膳食暴露量以肉类贡献最大。风险特征描述发现,中国居民中通过摄入肉、蛋、乳等动物性食品的杆菌肽耐药性风险,2~7岁人群HQ分别为男性1.4901、女性1.4121;其他年龄人群均<1。不确定性分析发现,结果不确定性源自缺乏动物性食品杆菌肽残留量监测数据、权威数据发布的滞后性、未考虑水产品等因素。综上动物性食品中药物饲料添加剂杆菌肽耐药性风险,2~7岁人群为高风险,其他年龄段人群为中等风险。针对杆菌肽的耐药性风险,必要时修订动物性食品中杆菌肽的最大残留限量,同时加强对进口动物性食品的杆菌肽耐药性风险管理。     

Risk Assessment of Bacitracin Resistance as a Medicated Feed Additive

The aim of this study was to provide theoretical basis for regulatory departments to formulate risk management measures for bacterial resistance of animal origin.The point assessment method was applied to assess the risk of bacitracin resistance in animal origin foods of Chinese residents,according to the model of risk assessment analysis,based on the data from the monitoring report of the citizen's physiques in China in 2014,the fifth Chinese total diet study and the official website of European Medicine Agency.Dietary exposure to bacitracin was calculated by estimated daily intake,and hazard quotient (HQ) was used in risk characterisation to indicate risk level of health damage exposed to bacitracin.Firstly,through the way of hazard identification,the toxicity of bacitracin by oral ingestion was very low.But the pathogenic bacteria such as Enterococcus and Clostridium perfringens had developed resistance to bacitracin,with the resistance genes easily transferring to the human intestinal flora through bacteria commonness.Secondly,the hazard characterization indicated the toxicological ADI was 0.055 mg/(kg·BW),and the microbiological ADI was 3.9 μg/(kg·BW).Thirdly,exposure assessment showed that the maximum dietary exposure of bacitracin was in 2 to 7 age group among Chinese residents.And that of women through intake of dairy products was higher than men.Among 2 to 7 age group,dairy products contributed most to the dietary exposure of bacitracin,while meat was the largest contributor above 8 years old.Fourthly,risk characterization hazard quotient was 1.4901 for males and 1.4121 for females among Chinese residents aged 2 to 7 by calculation,and <1 among other age groups.Finally,the uncertainty analysis showed that the lack of monitoring data of bacitracin residues in animal foods,the lag of authoritative data collection and release,the absence of consumption data of aquatic products brought uncertainty to the results.In total,the risk of bacitracin resistance as a medicated feed additive through animal foods exposure was high in children aged 2 to 7 and moderate in other age groups.The maximum residue limit standard should be revised appropriately and risk management of bacitracin resistance need to be strengthened in imported animal foods.     

Additionality and Avoiding Grassland Conversion in the Prairie Pothole Region of the United States

Grassland conversion into croplands in the Prairie Pothole Region of the United States is a persistent hurdle toward mitigating climate change. Several carbon offset markets have been designed to reward landowners for keeping lands in their native state when incentives to convert are high. We explore the role of a critical determinant in such programs: the additionality threshold. This factor, if appropriately selected and applied, reduces the participation of landowners that would choose to enroll in the program but would not have converted their land under business-as-usual conditions. Using a simple model relating land quality and land use to economic rents, we simulate potential avoided grassland conversion offset market participation across a range of cropland over pasture rent difference threshold (RDT) values. We find mitigation potential and simulated program costs are widely variable depending on this parameter and assume carbon prices: across the five states studied, the full range is 0.41 tCO₂e • yr⁻¹ (0.2 RDT, $10 •·t⁻¹ carbon price) to 4.6 million tCO₂e • yr⁻¹ (1.2 RDT, $40 tCO₂e • t⁻¹ carbon price), assuming average land use change emissions values for pastureland in the region. Total program costs for these offsets also exhibit a wide range, spanning $2−$120 million • yr⁻¹ depending on parameterization. Results across the full range of RDTs (0.2−2) demonstrate a tendency toward higher RDTs for achieving high levels of avoided emissions, with cost efficiency being maximized in the 1.4−1.8 range for RDTs. A state-level breakdown of results demonstrate the importance of modeling economic trends in land use and setting region-specific additionality thresholds for avoided grassland conversion offsets. Although our study is specific to grassland conversion in one region of the United States, similar offset markets exist elsewhere, where additionality concerns are paramount. We believe our framework can be useful in improving protocol design.     

Assessment of Dietary Rovabio Excel in Practical United States Broiler Diets

The focus of this study was to evaluate a feed enzyme (Rovabio Excel) in diets fed to commercial broilers reared in environments typical to that observed in the US broiler industry and destined to be marketed at BW at or near 2.5 kg. The feed enzyme was tested in diets differing in amino acid and energy composition. The main effect of altered nutrient levels, mainly reduced amino acids, was higher abdominal fat at processing. The formulation addition of the exogenous feed enzyme to diets differing in nutrient contents and energy did not affect broiler live performance or carcass traits. However, the exogenous feed enzyme decreased 14-d mortality in experiment 1 and 41-d mortality in experiment 2 but was without effect on mortality in experiment 3. Future research elucidating any benefits on mortality from the exogenous feed enzyme may aid commercial poultry producers. Further, reducing dietary nutrient levels beyond that considered in this study may allow for exogenous enzyme benefits in broiler live production and carcass traits to be observed as mediated through nutrient liberation.     

Isolation of a New Porcine Enterovirus in the United States

A cytopathogenic virus isolated from an Iowa farm pig with diarrhea was identified as a member of Group 5 of the porcine enteroviruses. Clinical signs observed in other pigs in the herd were diarrhea, debilitation and gauntness. Morbidity and mortality rates were approximately 50% and 3% respectively.

A Group 5 porcine enterovirus had not been previously isolated in North America according to the Western Hemisphere Committee on Animal Virus Characterization.

     

中草药添加剂在猪生产中的应用研究

中草药添加剂具有无药物残留、促生长等多方面优势,在我国的养猪业中发挥着越来越重要的作用。文章综述了猪用饲料添加剂在猪生产中的仔猪生长、猪的育肥、猪的繁殖性能等方面的作用,并指出了现阶段存在的问题。     

中草药添加剂在猪生产中的应用研究

中草药添加剂具有无药物残留、促生长等多方面优势,在我国的养猪业中发挥着越来越重要的作用。文章综述了猪用饲料添加剂在猪生产中的仔猪生长、猪的育肥、猪的繁殖性能等方面的作用,并指出了现阶段存在的问题。     

Assessment of the economic impact of porcine reproductive and respiratory syndrome on swine production in the United States

OBJECTIVE: To estimate the annual cost of infections attributable to porcine reproductive and respiratory syndrome (PRRS) virus to US swine producers. DESIGN: Economic analysis. SAMPLE POPULATION: Data on the health and productivity of PRRS-affected and PRRS-unaffected breeding herds and growing-pig populations were collected from a convenience sample of swine farms in the midwestern United States. PROCEDURE: Health and productivity variables of PRRS-affected and PRRS-unaffected swine farms were analyzed to estimate the impact of PRRS on specific farms. National estimates of PRRS incidence were then used to determine the annual economic impact of PRRS on US swine producers. RESULTS: PRRS affected breeding herds and growing-pig populations as measured by a decrease in reproductive health, an increase in deaths, and reductions in the rate and efficiency of growth. Total annual economic impact of these effects on US swine producers was estimated at dollar 66.75 million in breeding herds and dollar 493.57 million in growing-pig populations. CONCLUSIONS AND CLINICAL RELEVANCE: PRRS imposes a substantial financial burden on US swine producers and causes approximately dollar 560.32 million in losses each year. By comparison, prior to eradication, annual losses attributable to classical swine fever (hog cholera) and pseudorabies were estimated at dollar 364.09 million and dollar 36.27 million, respectively (adjusted on the basis of year 2004 dollars). Current PRRS control strategies are not predictably successful; thus, PRRS-associated losses will continue into the future. Research to improve our understanding of ecologic and epidemiologic characteristics of the PRRS virus and technologic advances (vaccines and diagnostic tests) to prevent clinical effects are warranted.     

美国苜蓿草产业成功经验对甘肃省苜蓿草产业之借鉴

美国是全世界苜蓿（Medicago spp.）种植面积和出口量最多的国家,其生产和贸易对于我国来说有许多值得借鉴的地方。甘肃省是中国苜蓿种植面积最大的省份,近些年苜蓿草产业发展迅猛,但由于发展时间较短,还存在诸多问题。本文深入分析了美国苜蓿生产与贸易现状、总结其成功经验,并以此为借鉴,结合对甘肃省苜蓿草产业存在的突出问题的综合分析,进一步提出促进甘肃省苜蓿草产业健康发展的对策建议。     

Survey of veterinary extension in the United States

OBJECTIVE: To assess veterinary extension in the United States as perceived by veterinary extension personnel. DESIGN: Cross-sectional survey. SAMPLE POPULATION: Extension veterinarians in the United States. PROCEDURE: 2 surveys were designed and mailed to extension veterinarians listed by the USDA and the American Association of Extension Veterinarians. RESULTS: 34 states had > or = 1 extension veterinarian. The majority (> 60%) of extension veterinarians did not commit time to resident education and were not involved in research activities. Paradoxically, 23% of responding extension veterinarians did not report extension work. Programs for food animal producers, horse owners, and companion animal owners were provided by 100, 63, and 37% of states, respectively. Continuing education (CE) programs were provided for food animal veterinarians, equine veterinarians, and companion animal veterinarians by 96, 63, and 52% of states, respectively. Challenges facing veterinary extension included limited recognition of veterinary extension activities by universities, lack of university personnel to support CE programs, and decreased support for companion animal extension programs. CONCLUSIONS AND CLINICAL RELEVANCE: Extension veterinarians need to identify and clearly articulate the mission of veterinary extension, develop more collaborative programs across regions, and continue to serve as catalysts to bring diverse constituents together. Extension veterinarians must distinguish their mission not solely as information transfer, which can be accomplished in a variety of ways outside of extension, but as a coherent and consistent program of education and policy developed on a national level and distributed locally.