高产奶牛日粮中苜蓿干草适宜添加量

国内最新研究成果表明在高产奶牛(305天产奶量大于7000千克)日粮中使用9千克苜蓿干草并采用合理的日粮配方可以使产奶量提高到9000千克以上，并取得最佳经济效益。这项技术将彻底改变我国目前“秸秆 精料”饲养方式导致的奶牛产奶量低、经济效益低的现状，实现奶牛饲养方式向“苜蓿干草 玉米青贮 精料”模式即“苜蓿型奶牛业”的改变。在这种模式下，高产奶牛305天产奶量可提高到     

奶牛日粮中添加镁的重要性

镁在反刍动物新陈代谢中起着重要的作用，它既参与酶反应，又参与蛋白质的合成。日粮中镁的含量过低或其生物利用率降低都会引起泌乳奶牛的低镁症。相反，日粮中镁的含量过高会导致奶牛采食量下降、腹泻、产奶量下降。     

苜蓿干草在奶牛日粮中的适宜添加量

苜蓿产草量高,适口性好,营养价值列牧草之首,所以又称为"牧草之王".它不仅含有丰富的蛋白质、矿物质和维生素等重要的营养成分,而且含有动物所需的必需氨基酸、微量元素和未知生长因子.在相同的土地上,紫花苜蓿比禾本科牧草所收获的可消化蛋白质高2.5倍左右,矿物质高6倍左右,可消化养份高2倍左右,而且含有其他饲草缺少的维生素和钙、磷等,是饲料中的上品.与其他粮食作物相比,单位面积营养物质的产量也较高,是奶牛生产中廉价高效饲料资源.农户如果利用优质苜蓿干草饲养奶牛,每吨苜蓿可转化为1.0～1.5t鲜奶,产生效益1 500～2 300元,可增值1 000～1 800元.此外,紫花苜蓿喂奶牛,不但可以提高产奶量,还可以提高奶牛健康水平,减少生殖疾病和消化疾病,可以延长奶牛利用年限.     

苜蓿干草在奶牛日粮中的适宜添加量

苜蓿产草量高，适口性好，营养价值列牧草之首．所以又称为“牧草之王”。它不仅含有丰富的蛋白质、矿物质和维生素等重要的营养成分，而且含有动物所需的必需氨基酸、微量元素和未知生长因子。在相同的土地上，紫花苜蓿比禾本科牧草所收获的可消化蛋白质高2．5倍左右，矿物质高6倍左右，可消化养分高2倍左右，而且含有其他饲草缺少的维生素和钙、磷等，是饲料中的上品。与其它粮食作物相比，单位面积营养物质的产量也较高，是奶牛生产中廉价高效饲料资源。农户如果利用优质苜蓿干草饲养奶牛，每吨苜蓿可转化为1～1．5吨鲜奶，产生效益1500～2300元，可增值1000～1800元。此外，紫花苜蓿喂奶牛，不但可以提高产奶量，还可以提高奶牛健康水平，减少生殖疾病和消化疾病．可以延长奶牛使用年限。     

苜蓿干草在奶牛日粮中的适宜添加量

苜蓿干草以产量高、适口性好，营养价值高而倍受广大奶牛养殖者的青睐，而且苜蓿干草能提高奶牛的健康养殖水平．减少生殖疾病和消化疾病，延长奶牛的利用年限。但苜蓿干草如何科学的添加却是一个值得探讨的问题![编者按]     

苜蓿干草在奶牛日粮中的适宜添加量

苜蓿产草量高,适口性好,营养价值列牧草之首,所以又称为牧草之王。它不仅含有丰富的蛋白质、矿物质和维生素等重要的营养成分,而且含有动物所需的必需     

苜蓿干草在奶牛日粮中的适宜添加量

苜蓿产草量高,适口性好,营养价值列牧草之首,所以又称为“牧草之王”。它不仅含有丰富的蛋白质、矿物质和维生素等重要的营养成分,而且含有动物所需的必需氨基酸、微量元素和未知生长因子。在相同的土地上,紫花苜蓿比禾本科牧草所收获的可消化蛋白质高2．5倍左右,矿物质高6倍左右,可消化养分高2倍左右,而且含有其他饲草缺少的维生素和钙、磷等,是饲料中的上品。     

苜蓿干草在奶牛日粮中的适宜添加量

苜蓿产草量高,适口性好,营养价值列牧草之首,所以又称为“牧草之王”。它不仅含有丰富的蛋白质、矿物质和维生素等重要的营养成分,而且含有动物所需的必需氨基酸、微量元素和未知生长因子。在相同的土地上,紫花苜蓿比禾本科牧草所收获的可消化蛋白质高2.5倍左右,矿物质高6倍左右,可消化养分高2倍左右,而且含有其他饲草缺少的维生素和钙、磷等,是饲料中的上品。与其他粮食作物相比,单位面积营养物质的产量也较高,是奶牛生产中廉价高效饲料资源。农户如果利用优质苜蓿干草饲养奶牛,每吨苜蓿可转化为1～1.5吨鲜奶。苜蓿喂奶牛,还可以提高奶牛健…     

合肥地区黑白花奶牛日粮锌适宜添加量的研究

合肥地区黑白蓊奶牛中度缺锌，当在日粮中加锌后，奶牛产乳量、血清锌、轿清碱性磷酸酶活性和乳锌含量显著或极显著地提高；该地共奶牛日粮锌适宜添加量为３０－６０ｐｐｍ通过在奶牛日粮中加适量锌，可增加乳锌含量，进而可提高牛奶的营养和保健价值。     

肉鸡日粮中蛋氨酸适宜添加量的研究

在玉米——豆饼型肉鸡日粮中,往往缺乏蛋氨酸,添加少量的合成蛋氨酸,可以达到提高蛋白质利用率的目的。在这方面,国内外均有不少报道,但由于试验日粮组成不同,以及评定指标、试验条件等方面的原因,所以报道的蛋氨酸适宜添加量也不尽相同。为探求在玉米——豆饼型肉鸡低蛋白质日粮中的蛋氨酸适宜添加量,我们用30只10周龄的肉鸡作试验。采用评定蛋白质营养价值比较灵敏的氮代谢指标,进行了在同一基础日粮条件下的三种蛋氨酸添加量,两种粪尿排泄物收集方法的氮平衡试验。试验结果表明,在本试验所用的肉鸡后期低蛋白质(粗蛋白质含量为17.02%)基础日粮中,添加0.2%的蛋氨酸是比较适宜的。     

Magnesium status of dairy cows

Abstract

Extract

Madam:– Magnesium has been identified as an important mineral in the nutrition of dairy eows and reeent findings in New Zealand(1 Young, P.W., Rys, G. and O'Connor, M.B. 1981. Hypomagnesemia and dairy production. Proc. N.Z. Soc. An. Prod., 41: 61–67.  [Google Scholar]) emphasize this importance. For example, a large survey of dairy animals(2 Young, P.W., O'Connor, M.B. and Feyter, C. 1979. Importance of magnesium in dairy production. 30th Ruakura Farmers Conf. Proc. MAP, : 110–120.  [Google Scholar]) showed one-third of almost one million cows could be suffering from hypomagnesemia. A separate survey (3 1984. Surveillance. Bovine hypomagcsemia, 11: 5–7. Published by the Ministry of Agriculture and Fisheries Private Bag, Wellington [Google Scholar])> involving 76 farms estimated that supplementing with magnesium to prevent hypomagnesemia would have produced a net benefit of between $1,600 and $4,250 per farm. The cost/benefit ratio was remarkably high and ranged from 11–28.     

Assessment of magnesium intake according to requirement in dairy cows

To date, no specific hormonal regulation system has been identified for homoeostatic control of the essential mineral Mg. In cattle, the maintenance of physiological plasma Mg concentration depends on gastrointestinal absorption, primarily from the rumen, which serves as a pool for covering the requirement. Whereas a possible surplus (absorption greater than requirement) is rapidly excreted by the kidneys, a shortage (absorption lower than requirement) cannot be compensated for by mobilization from the large Mg pool in bones or soft tissue, so that the maintenance of the necessary physiological Mg concentration in plasma relies on continuous and sufficient absorption. Our knowledge concerning the site and mechanisms of Mg absorption has improved during the last few decades, and meta‐analyses of the absorption of Mg in dairy cows have shown that the K content has a pronounced negative effect on Mg digestibility. The current recommendations of Mg intake propose a constant percentage of Mg and emphasize the depressive effect of high potassium (K) intake on Mg absorption. The current knowledge about the antagonism between K intake and Mg absorption allows a more flexible solution which includes the K content of the diet. An assessment of Mg intake is proposed that incorporates the improved knowledge of Mg absorption, metabolism and requirement. Within this framework, an equation is derived that allows a prediction of the amount of Mg required to compensate for dietary K content, the goal being to avoid both possible undernutrition or an unnecessary surplus of dietary Mg.     

奶牛营养平衡与需要量

随着我国奶牛业的快速发展,奶牛对日粮营养平衡的要求越来越高,而正确理解奶牛的营养需要对制定营养平衡的日粮配方非常重要。本文主要从能量、蛋白质、纤维、矿物质和维生素方面探讨奶牛的适宜营养需要量。     

Energy intake and requirement of dairy cows during the whole year

It is argued that in view of the many new methods in dairy farming an economic model of the dairy farm should be available to improve advisory work. Some quantitative data concerning the dairy cow needed for such a model are given. They deal with a net energy feeding value of grass, hay, silage, artificially dried grass and concentrates estimated with a feed evaluation system based on results obtained with lactating cows. Also data on the requirements for net energy and for long forage dry matter are given, again obtained with such cows. Finally information is given on voluntary intake of forage dry matter at pasture, from fresh grass fed indoors, from various preserved forages including forage pellets, as influenced by milk yield and condition of the cow and by kind of forage and level of concentrates fed. Special attention has been paid to the precision of the information. These data are used to predict both the maximal and minimal amounts of long forage which can be fed in the stall period without loss of production, and the additional quantities of concentrates needed. For the grazing cow the problem of the adjustment of voluntary intake of grass to milk yield and amount of concentrates fed is studied. It is concluded that the information is sufficient to develop an economic model of a dairy farm. For its development grassland research should supply data on pasture yield in terms of digestible organic matter when the forage is fed to sheep at the maintenance level, and the economists should add data on costs of food and labour.     

Blindness in dairy cows

Extract

Blindness in dairy cows due to various causes has often been observed. This report instances threecases occurring on one property within a period of two months. Of the animals concerned, all Jersey cows, one was home bred and the other two were purchased.     

Ketonuria in dairy cows

In 3337 dairy cows, urine was examined for ketone bodies by help of Bililabstix during the first and second phase of lactation and in the eighth to the ninth and a half month of pregnancy; at the same time needed supply of energetic nutrients in 175 summer and 308 winter feed rations was calculated. Intensity and frequency of ketonuria in lactating cows fed winter rations is significantly higher than in those fed green feeds; it decreases significantly with a phase of lactation and with milk production. On the contrary, cows in late pregnancy have higher intensity and frequency of ketonuria (32.9%) when fed green feeds than when fed winter rations (30.7%). In winter feed rations energy input was significantly lower, percentage of deficient feed rations at a relatively broader caloric-protein ratio was higher than in summer season. The highest deficits of energy and digestible nitrogen compounds were observed in cows in the first phase of lactation. Discussion concerns the causes and mechanisms of different ketonuria in groups of dairy cows in relation to deficit of energetic nutrients, caloric-protein ratio, to the level of glycaemia, non-esterified fatty acids in plasma, triglycerides of plasma and to the state of liver function.