影响青贮饲料质量的因素

青贮饲料是奶牛饲养中不可缺少的常规饲料，提高青贮质量是饲养高产奶牛的关键，也是降低成本的重要方面，影响青贮质量的因素很多，主要分为影响青贮原料的因素和影响青贮发酵条件的因素，本文对此作一简述。一、影响青贮原料的因素１．牧草作物与品种：作物或牧草在植物分类上科、属、种不同，其营养成分（干物质、蛋白质、脂肪、纤维、矿物质、无氮浸出物、能量等）含量也不同。在同一种中不同的栽培品种（四倍体与二倍体；早熟品种与晚熟品种）其营养成分含量亦不同，因此要选择适合本地区的优质饲料品种来制作青贮。２．生长期：品种确…     

Factors influencing the quantity and quality of colostrum in the cow

It is well established that the survival of newborn calves is dependent on their absorbing adequate amounts of maternal immunoglobulin from colostrum. The level of immunity is influenced by the time of feeding after birth and the quantity and quality of the available colostrum. Several factors affect either the quantity or quality of colostrum. The yield of colostrum varies with breed but perhaps more significantly with age, heifers giving much less colostrum than cows. Poor nutrition during winter months causes a marked drop in colostral quantity and often in the early spring a large number of suckler cows give insufficient colostrum to protect their calves from disease. Colostral quality in terms of immunoglobulin concentration is unaffected by yield but varies considerably between individual cows.Much of the present evidence is equivocal and there are many subjects for further research. A detailed study should be carried out, particularly in beef cattle, to establish which breed has the highest yield of colostrum. More research should be directed to establish the minimum plane of nutrition necessary to maintain colostrum quantity and quality.

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Kurzfassung Die Tatsache, dass die Lebensfähigkeit neugeborener Kälber von der Aufnahme von genügend mütterlichen Immunoglobinen aus dem Kolostrum abhängt, ist wohlbekannt. Das Immunitätsniveau wird von der Säugezeit nach der Geburt und von der Menge und Qualität des verfügbaren Kolostrums beeinflusst. Mehrere Faktoren wirken entweder auf die Menge oder die Qualität des Kolostrums ein. Die Menge variiert mit der Rasse, aber vielleicht noch wichtiger mit dem Alter, da Färsen viel weniger Kolostrum geben als Kühe. Unzureichende Fütterung während der Wintermonate verursacht einen starken Fall der Kolostralleistung; in den ersten Frühjahrstagen gibt eine grosse Anzahl von Ammenkühen oft nicht genug Kolostrum, um die Widerstandsfähigkeit ihrer Kälber gegen Krankheiten zu sichern. Im Sinne von Immunoglobulinkonzentration wird die Qualität des Kolostrums nicht von seiner Menge beeinflusst, doch variiert sie beträchtlich zwischen einzelnen Kühen.Viele gegenwärtige Resultate sind zweideutig und viele Probleme müssen noch bearbeitet werden. Es bedarf auch einer vertieften Studie, insbesondere bei Fleischrindern, um festzustellen, welche Rasse die höchste Kolostralleistung hat. Man müsste auch Untersuchungen anstellen, um das minimale Fütterungsniveau fur die Erhaltung der Qualität und der Menge des Kolostrums zu ermitteln.

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Resume Le fait que la survie des veaux nouveau-nés dépend de leur pouvoir d'absorber une quantité adéquate d'immoglobulines maternelles par le colostrum, est bien établi. Le niveau d'immunité est influencé par le temps de la tétée après la naissance, et par la quantité ainsi que la qualité du colostrum disponible. La production de colostrum varie, selon la race, mais peut-être l'âge est plus significatif, puisque les génisses donnent beaucoup moins de colostrum que les vaches. Une alimentation de qualité inférieure pendant les mois d'hiver cause une baisse importante de la quantité de colostrum, et souvent, beaucoup de vaches nourrices donnent trop peu de colostrum, aux premiers jours du printemps, pour protéger leurs veaux contre les maladies. La qualité du colostrum n'est pas effectée par le niveau de production, en termes de concentration d'immunoglobulines, mais elle varie considérablement entre les individus.L'évidence actuelle est équivoque, et beaucoup de sujets demandent encore des recherches. Il faudrait une étude approfondie pour établir la race à production de colostrum la plus élevée, surtout chez les bovins de boucherie. Il faudrait aussi des recherches plus poussées pour établir le niveau minimum nutritionnel nécéssaire pour maintenir la quantité et la qualité du colostrum.

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Riassunto E'un fatto ben accertato che la sopravvivenza dei vitelli neonati dipende dall'assorbimento di una adeguata quantità di immunoglobuline materne attraverso il colostro. Il livello immunitario è a sua volta influenzato dal momento in cui si ha la poppata dopo la nascita e dalla quantità e qualità del colostro fornito. Svariati fattori influiscono sia sulla quantità che sulla qualità del colostro. La produzione di questo varia infatti a seconda della razza, ma varia forse anche in misura maggiore in rapporto all' età; le giovenche, infatti, producono molto meno colostro delle bovine di età superiore. Un apporto alimentare insufficiente durante i mesi invernali causa una notevole caduta della quantità di colostro e spasso, all'inizio della primavera, un gran numero di bovine in lattazione ne producono in quantità non sufficiente ai fini della protezione dei vitelli contro le malattie. La qualità del colostro in termini di concentrazione di immunoglobuline non viene influenzata dal livello di produzione, ma varia in modo considerevole da bovina a bovina.Gran parte dei dati oggi disponibili è oggetto di dubbio, ed esistono molti campi da sottoporre ad ulteriori indagini. Sarebbe necessario eseguire uno studio dettagliato, specie nelle bovine da carne, per stabilire quale razza ha la più alta produzione di colostro. Altre ricerche andrebbero indirizzate a stabilire il valore minimo alimentare necessario per il mantenimento del livello quanti-qualitativo del colostro.

     

影响反刍动物粗饲料品质的因素

本文综述了影响反刍动物粗饲料品质的因素,如品种、成熟阶段、收获期等,为合理改善粗饲料品质提供参考。     

影响哺乳动物细胞核移植效率的因素

本文对哺乳动物胚胎细胞体细胞核移植克隆技术中显微操作的基本环节,以及细胞周期阶段对细胞核移植克隆胚胎效率影响的研究进行综述。     

Factors influencing the food preference of cats

Four individual preference tests were carried out using the same 10 castrated adult cats. The main questions investigated were: (i) do the cats prefer diets having one dominant taste or diets made from a relatively wide range of compounds of animal origin and (ii) can the preference be connected to one taste? In test 1 a dry diet (K) made by a world-renowned company having a beef taste was compared with four others (I, II, III, IV) dry foods prepared at the authors' institute in order to prevent any one of the mixtures having a predominant taste. In test 2 diets I, II, III and IV were compared with each other in the absence of diet K. In test 3 another four diets with different dominant tastes (fish, liver, poultry with fat addition and poultry without fat addition) were investigated. In test 4 the same three tastes (beef, fish and poultry) were compared with each other by using diets of three world-renowned companies. From the results the following conclusions can be drawn. Cats undoubtedly use smell in the detection and selection of food. If cats find the odour of a certain food is significantly more attractive than that of the other, they will consume it exclusively and without tasting the less attractive food. If none of the diets are especially attractive, according to smell, cats will also taste the foods and make their decision on the basis of both senses. Diets having one dominant taste result in a higher feed intake than that reached by diets without a dominant taste. If a diet is manufactured well, its dominant taste may have less effect on diet consumption. Food preference does not seem to be connected to one exclusive taste but is significantly influenced by other factors connected to the manufacturing of the diets.     

影响畜产品安全性的因素及其对策

随着世界工业化进程的加速，环境中的有毒有害物质越来越多，对人类的食品安全构成了严重威胁。近几年，世界先后发生了诸多有关食品卫生的事件，如英国的“疯牛病”，香港”的“禽流感”，欧洲的“二恶英”以及我国一些省区出现的“瘦肉精”等食品卫生安全问题，引起了国际社会的广泛关注和高度重视，各国均采取了相应的对策强化监督管理。     

苜蓿质量预测方法研究进展

苜蓿(Medicago sativa)质量是影响苜蓿干草价格的重要因素,而适时收获是把握苜蓿干草质量的重要环节。在科学种植管理条件下,对田间苜蓿质量提前判断,对准确收获目标质量苜蓿干草、保证经济效益意义重大。苜蓿产业较为发达的美国常用GDD和PEAQ法来预测田间苜蓿质量,以判断春季苜蓿的收获时间。当GDD为700～750时(5℃以上积温),苜蓿的NDF含量接近40%,当GDD增加220(7d后),NDF含量达到45%;PEAQ法中指出,NDF和ADF含量可以通过在具有随机样方中茎秆最高植株的茎长测量和判断样方中最成熟植株的成熟度来预测。GDD和PEAQ法对杂草较少、长势健康的苜蓿田生产质量预测比较准确。     

影响孵化率和孵化问题的因素

受精率 正常情况下,受精率是决定孵化成绩的最重要的因素.在佐治亚州所做的一项研究中,连续6年(1984～1989)对15个肉鸡孵化场的种鸡孵化成绩进行了测定.鸡群平均未受精率为7.25%,这是种蛋不能出雏的最大的单项原因.     

Use of biochemical and biophysical indicators in muscles (m. longissimus dorsi) obtained by harpoon biopsy in predicting the quality of pork

Forty-two pigs (German Landrace and commercial hybrids) were subjected to harpoon biopsy. A possibility of using the biochemical (adenosine triphosphate, creatine phosphate, glucose-6-phosphate, glucose, lactate, glycogen) and biophysical (pH value, R-value, water-binding capacity) parameters of muscle (m. longissimus dorsi) for forecasting the quality of pork was demonstrated. The post-mortem processes were simulated in muscle bioptate (1 hour of incubation at 39 degrees C). The highest correlations with meat quality in slaughtered animals (pH) were recorded in adenosine triphosphate, creatine phosphate, R-value, pH value, lactate and glycogen. No significant differences were found between the left and right side of the muscle (m. longissimus dorsi) in the studied parameters.     

影响饲料酶活力测定的因素分析

近年来，在畜牧类学术期刊上，关于饲料酶的研究报道很多。但是，它们绝大多数是探讨酶的作用机理和动物饲喂应用试验，很少涉及酶活的分析测定，这种现象对于饲料酶的生产和推广应用都是很不利的。判断饲料酶质量优劣的标准主要是酶的催化活力和稳定性而不是饲养效果。因为影响后者的因素很多，酶的作用只是其中一个方面。常用的饲料酶主要有植酸酶、淀粉酶、蛋白酶和非淀粉多糖酶四大类。经过科研工作者多年的艰苦努力，植酸酶、淀粉酶和蛋白酶的测定分析方法目前已基本成熟。近期内，我国饲料工业协会将颁布测定饲料用植酸酶活力的行业标…     

Factors influencing the international spread of equine diseases.

In an era of increasing globalization, the risk of spread of infectious diseases in humans and animals, including equids, has never been greater. International movement of equids and trade in semen are the most important factors responsible for the dissemination of various equine pathogens. Other factors that can or do have the potential to influence the global distribution of equine infectious diseases include: multinational trade agreements, emergent diseases, mutation of pathogens, climate related phenomena, migration of amplifying/reservoir hosts or vectors, availability of new vectors, vaccine contamination and agroterrorism. The relative importance of each of these factors is considered in relation to the spread of equine diseases.