Food production and the energy crisis

The principal raw material of modern U.S. agriculture is fossil fuel, whereas the labor input is relatively small (about 9 hours per crop acre). As agriculture is dependent upon fossil energy, crop production costs will also soar when fuel costs increase two- to fivefold. A return of 2.8 kcal of corn per 1 kcal of fuel input may then be uneconomical. Green revolution agriculture also uses high energy crop production technology, especially with respect to fertilizers and pesticides. While one may not doubt the sincerity of the U.S. effort to share its agricultural technology so that the rest of the world can live and eat as it does, one must be realistic about the resources available to accomplish this mission. In the United States we are currently using an equivalent of 80 gallons of gasoline to produce an acre of corn. With fuel shortages and high prices to come, we wonder if many developing nations will be able to afford the technology of U.S. agriculture. Problems have already occurred with green revolution crops, particularly problems related to pests (57). More critical problems are expected when there is a world energy crisis. A careful assessment should be made of the benefits, costs, and risks of high energy-demand green revolution agriculture in order to be certain that this program will not aggravate the already serious world food situation (58). To reduce energy inputs, green revolution and U.S. agriculture might employ such alternatives as rotations and green manures to reduce the high energy demand of chemical fertilizers and pesticides. U.S. agriculture might also reduce energy expenditures by substituting some manpower currently displaced by mechanization. While no one knows for certain what changes will have to be made, we can be sure that when conventional energy resources become scarce and expensive, the impact on agriculture as an industry and a way of life will be significant. This analysis is but a preliminary investigation of a significant agricultural problem that deserves careful attention and greater study before the energy situation becomes more critical.     

Safety and efficacy of a modified-live canine coronavirus vaccine in dogs

The safety and the efficacy of a modified-live (ML) canine coronavirus (CCoV) vaccine strain 257/98-3c was evaluated in 14 dogs seronegative and virus negative for CCoV. For the safety test, four dogs were inoculated, two by intramuscular and two by oronasal route, with 10 times the vaccinal dose. During the observation period (28 days) all dogs did not display any local or systemic reaction. For the efficacy test, eight dogs were vaccinated by intramuscular (four dogs-group A) or by oronasal route (four dogs-group B). Two dogs were maintained as non-vaccinated controls. In the dogs of group A, vaccinal virus was not detected in faecal samples by virus isolation (VI) and by PCR assay, while in the dogs of group B, the virus was revealed for six median days only by PCR. Twenty-eight days later, the vaccinated and control dogs were challenged with a field CCoV strain. After the challenge, the vaccinated dogs did not display clinical signs and the dogs of group A shed virus for 5.5 median days, evaluated by VI, and for 10 median days evaluated by PCR. Virus shedding was not observed, both by VI and PCR assay, in the dogs of group B. The two control dogs displayed moderate clinical signs and the virus was detected by VI for 14.5 median days starting from day 3 post-challenge (dpc 3) and by PCR assay for 23 median days starting from dpc 1.     

The inter- and intra-observer reliability of a locomotion scoring scale for sheep

A seven point locomotion scoring scale, ranging from 0=normal locomotion to 6=unable to stand or move, has been developed. To test the between and within observer reliability of the scale, 65 movie clips of sheep with normal and varying degrees of abnormal locomotion were made. Three observers familiar with sheep locomotion were trained to read the movie clips. Thirty clips were randomly selected and used to test between and within observer agreement. There was high inter-(intra-class correlation coefficient [ICC]=0.93, weighted kappa [kappa(w)]=0.93) and intra-(ICC=0.90, kappa(w)=0.91) observer reliability, with no evidence of observer bias. The main between score differences were for scores 0 (normal) and 1 (uneven posture and shortened stride but no head movement). The results indicate that the locomotion scoring scale using groups of defined observations for each point on the scale was reliable and may be a useful research tool to identify and monitor locomotion in individual sheep when used by trained observers.     

ITSPE教学模式在《动物营养学》课程教学中的应用

《动物营养学》是动物科学专业的主干课程。随着现代畜牧业对创新型人才的需求,以及“新农科“背景下畜牧学学科自身在产学研创融合方面发展的需要,该课程教学改革势在必行。基于动物营养学课程特点,以“如何教好”和“如何学好”该课程为目的,探讨了互联网教学(Internet teaching)、团队协作(Team cooperation)、学术研讨(Seminar)、生产实践(Production practice)和全方位评价(Evaluation in all dimensions)相结合的ITSPE教学模式,激发了学生学习主动性、创造性和团队协作意识,教学质量得到提高。     

纤维素酶及其应用研究进展

综述了纤维素酶的结构、来源,以及纤维素酶在反刍动物、猪禽、水产动物饲养和饲料加工调制领域的应用.概述了纤维素酶在其他领域的应用以及纤维素酶基因的克隆与表达.     

富铜饲料产品的应用现状研究

铜是维持动物生长必需的微量元素。随着无抗理念的普及,有机铜饲料的开发与利用逐步成为饲料行业的研究焦点。近年来,以微生物酵母为载体,利用生物发酵技术,通过微生物酵母吸附微量元素铜,实现新型富铜饲料产品绿色、高效、精准应用,实现微生物发酵技术与微量元素绿色开发有机结合,为新型饲料产品的研发和利用提供参考。     

土壤异质性施肥对玉米马铃薯间作体系养分吸收与利用特征的影响

【目的】土壤养分异质性能显著影响植物的生长,而异质性施肥是造成土壤养分异质性的主要方式。为研究异质性施肥对单、间作系统养分吸收和利用特征的影响。【方法】对玉米马铃薯间作群体进行不同养分分布施肥,研究不同作物对异质性施肥养分的吸收与利用规律。【结果】不论单作还是间作,土壤养分空间异质性均能增加玉米和马铃薯的养分积累量;在间作群体中,土壤异质性施肥能极显著地降低玉米养分利用率(P<0.01),而对马铃薯仅磷利用率达到显著降低(P<0.05),但在单作群体中养分异质性施肥仅对马铃薯磷(P=0.027)和钾(P=0.013)的利用率有显著降低的作用;在间作群体种间行内提高施肥量能极显著地提高土地当量比(LER)(P=0.003)。【结论】土壤养分空间异质性施肥(种间高肥)有利于玉米马铃薯间作群体对养分的吸收与利用,能提高复合产量15%。     

不同演奏形式的乐曲对犊牛生长性能及血液生化指标的影响

为探究不同演奏形式的乐曲对犊牛生长性能及血液生化指标的影响，试验选取7日龄体重相近、健康的32头母犊牛，将其随机分为对照组(无乐曲播放)、管乐组、弦乐组及弹拨组，每组设8个重复，试验期为49 d。试验期间，计算每天饮奶量及开食料采食量，并对犊牛新鲜粪便或肛门处残存粪便进行评分，同时记录犊牛的初始体重和最终体重，测定体尺指标。试验第28,49天颈静脉采血，测定血液生化指标及激素指标。结果表明：除试验第8～14,36～42天外，弹拨组的饮奶量均显著高于对照组(P<0.05);弦乐组在第1～7,22～28,43～49天时饮奶量显著高于对照组(P<0.05)。除试验第1～7,22～28天，弹拨组的开食料采食量均显著高于对照组(P<0.05),弦乐组在第8～14,15～21,29～35,43～49天时开食料采食量显著高于对照组(P<0.05)。弦乐组与弹拨组的体重和胸围增加量均显著高于对照组(P<0.05),弹拨组的体高增加量显著高于对照组(P<0.05)。对照组粪便评分在第1～7,8～14,15～21,22～28天均显著高于弹拨组(P<0.05),在第...     

一株毕赤酵母菌MC-1降解呕吐毒素、生物学特性及初步应用

呕吐毒素（DON）是危害动物健康的霉菌毒素之一，本研究旨在分离出能够降解DON的益生菌，以期应用于动物饲料中降解DON。本研究从普洱茶叶中分离出一株益生菌，经16S rDNA基因序列比对确定该菌株为毕赤酵母菌MC-1菌株；其在含有DON(1 mg/L)发酵液中DON降解率为59.21%。此外研究了毕赤酵母菌MC-1生物学特性，活性成分定位和应用试验。结果表明：毕赤酵母菌MC-1具有耐盐、耐酸、耐胆盐及在模拟消化液中存活的特性；其发酵上清液（DON 1 mg/L） DON降解率为54.76%，该菌株与（DON 1 mg/kg）豆粕共同发酵48 h后DON降解率为46.79%。综上，毕赤酵母菌MC-1能够用于动物发酵饲料中降解DON。     

基于猪体外仿生消化技术研究聚乙二醇对高单宁高粱养分降解效率的影响

[目的]本文旨在探究聚乙二醇对高粱养分降解效率的影响，并筛选聚乙二醇的适宜添加剂量。[方法]通过体外仿生消化技术模拟高粱原料在猪前肠道的化学酶消化作用和后肠道的微生物发酵过程，设计完全随机试验，在高单宁高梁(单宁含量为50 mg·g^-1儿茶素当量)原料中添加0、25、50、100和250 mg·g^-1的聚乙二醇为试验处理，每个处理5个重复，测定养分降解效率。[结果]聚乙二醇显著降低高粱原料中可检测的缩合单宁含量(P<0.05)。在胃蛋白酶、胃蛋白酶-胰液素或胃蛋白酶-胰液素-微生物发酵作用下，随着聚乙二醇添加比例的增加，高粱的风干物质、总能和氮素的消失率均呈现线性增加(P<0.05);其中25 mg·g^-1聚乙二醇处理组的养分消失率显著高于对照组(P<0.05),但是显著低于其他处理组(P<0.05);除胃蛋白酶处理过程中的氮素消失率外，50、100和250 mg·g^-1的聚乙二醇(聚乙二醇添加量/高粱单宁含量比值分别为1、2和5)处理组之间的高粱养分消失率无显著差异(P&g...