提高奶牛干物质采食量的技巧

(1)每天食槽的空置时间不应超过2~3小时;(2)奶牛挤奶后要立即饮水45~67升;(3)每头奶牛应有45~70厘米的食槽空间;(4)栓系式的牛舍颈链有足够的长度,散放式牛舍头架不要卡得太紧;(5)剩料的重量不应大于3%~5%;(6)饲料应凉爽且有甜香味,不要在食槽中堆积、发热、变酸;(7)食槽表面应光滑;(8)注意牛只的防暑降温,在夏季6%的饲料应在晚上饲喂,或多喂几次;(9)日粮应配置平衡以确保各种营养成分(白天至少应有40%的牛进行反刍);(10)定期进行肢蹄修整;(11)注意日粮的蛋白质平衡;(12注意日粮的纤维平衡,酸性洗涤纤维应保持在19$%之间,中性洗涤纤维应在…     

奶牛如何在炎热天气下保持采食量

保持一定的产奶量 ,尤其在较长时间的热应激状态下保持一定的产奶量是养牛的难点 ,因为高温能使采食量和产奶量下降。加强环境管理是降低热应激作用的最有效的方法。提高奶牛舒适度的首选措施包括遮荫、扇风、喷水、池泡等。而适当的饲喂方式也能改善暑天的采食状况。以下一些基本的营养措施可减轻暑热对采食量的影响 :１饮用水 :天气炎热时 ,保证奶牛的足量饮水十分关键。饮水量的下降会限制干物质的摄取（ＤＭＩ）及产奶。ＮＲＣ指出 ,当环境温度由５０ （ ＝１ ８×℃ ３２）升至９５ 时 ,产奶能力为６０磅的奶牛的饮水量几乎要增加…     

夏季如何提高奶牛干物质采食量

干物质对奶牛的生长和生产性能十分重要。夏季奶牛受热应激的影响,干物质采食量下降,产奶量也受到影响。针对这一问题,分析影响夏季奶牛干物质采食量的因素,并提出提高奶牛采食量的具体方法。     

提高奶牛干物质采食量

前言：了解奶牛干物质采食情况，是配合日粮满足其营养需要的基本先决条件。     

影响奶牛干物质采食量的因素

影响采食量的因素很多，主要有口粮因素、生理因素、环境因素和遗传因素。     

反刍动物采食量测定方法的研究进展

在单位时间内反刍动物实际采食的饲草(料)数量称为反刍动物的采食量。据研究发现,反刍动物的采食过程是一个动态的过程,是由生物和非生物因素共同、相互的影响过程。准确地计算和测定反刍动物的采食量,是制定反刍动物的良好的营养方案的基础;是确定其补饲的重要依据。研究反刍动物的采食量对整个畜牧产业有重要的作用。本文对反刍动物在自由进食状态下的采食量的影响因素进行了阐述,并对其采食量的测定方法进行了深入的探讨和研究。     

提高奶牛干物质采食量的技术措施

围产期奶牛,特别是高产奶牛普遍处于能量负平衡状态,容易导致生产性能降低和酮病、脂肪肝等代谢病的发生。通过育种、改善日粮和使用添加剂等技术措施,可提高奶牛的干物质采食量（dry matter intake,DMI）,在一定程度上提高奶牛的生产性能和改善奶牛的健康状况。作者对奶牛采食量的意义及其影响因素进行了叙述,并提出了一些可以提高奶牛采食量的技术措施。     

散养成年奶牛的采食量与分栏问题的研究

１　前言随着奶牛业的迅速发展,以高效率、集约化、低成本为特征的散放饲养奶牛场在各地应运而生。由于散放饲养奶牛场在我国起步较晚,故许多技术问题尚待探索研究。散养奶牛群较大,为合理组织饲料,提高产奶量,需对其进行分栏饲养。目前很多牛场对散养奶牛的分栏完全是沿用栓系奶牛的分栏方法,即按牛的生理阶段分栏。虽然奶牛处于同一生理阶段,但因个体大小、生产水平和采食量不同,其所需要的营养也不同。若为散放饲养,喂给同一种饲料,必然会造成某些奶牛营养过剩,浪费饲料,而另一些奶牛则营养不足,从而影响产奶水平。因此,对…     

季节温度变化对奶牛日粮营养采食量的影响

试验以10头奶牛，分别在春季、夏季进行采食量试验以研究环境温度对奶牛日粮营养物质进食量的影响。根据饲料中AIA含量及进食量、粪中AIA排出量计算其青贮采食量。结果表明，奶牛春季、夏季的营养物质采食量有明显差异。环境温度对奶牛日粮营养物质进食量有显著影响（p〈0.05）。     

Cholecystokinin mediates depression of feed intake in dairy cattle fed high fat diets

Two experiments were conducted to investigate the effects of 1) different concentrations of dietary fat and 2) i.v. administration of a cholecystokinin receptor antagonist (MK-329) on feed intake and plasma concentrations of hormones and metabolites in dairy cattle. In Experiment 1, 4 lactating Holstein cows were used in a 4 x 4 Latin square design. Treatments were diets with 1) no fat added, 2) 30 g fat/kg feed (calcium salts of long-chain fatty acids as fat supplement), 3) 60 g fat/kg, and 4) 90 g fat/kg added. Cows were fed once daily a diet of concentrate, corn silage, alfalfa haylage, and alfalfa pellets. Dry matter intake decreased linearly with increasing concentrations of dietary fat (P < 0.0001). Overall plasma concentrations of nonesterified fatty acids (P < 0.0001), triacylglycerol (P < 0.0006), and cholecystokinin (P < 0.02), increased linearly with each level of dietary fat, but there was a linear decrease in plasma insulin (P < 0.0008). In Experiment 2, 4 nonpregnant and nonlactating Holstein heifers were used in a cross-over design in a 2 x 2 factorial arrangement of treatments. Treatments were diet (fatty acids, 27 g/kg vs 103 g/kg diet dry matter) and i.v. injections (MK-329 vs vehicle). Heifers were fed once daily a total mixed ration of corn silage, cracked corn and soybean meal with or without fat supplement. Diets were switched by period and either MK-329 (70 microg/kg body weight) or its vehicle was injected i.v. at 2 hr postfeeding. Daily dry matter intake was decreased by feeding the high fat diet (P < 0.02) but was not affected by injections. Injection of MK-329, however, increased dry matter intake by 92% in heifers fed the high fat diet during the first 2 hr postinjection compared to vehicle injection. Plasma pancreatic polypeptide concentration was increased by the high fat diet at 2 hr postfeeding (P < 0.02) but was lowered by MK-329 at 1 hr postinjection (P < 0.001). Plasma insulin was lowered by the high fat diet (P < 0.01) but was not affected by injections. The elevated plasma cholecystokinin concentration may have mediated depressed feed intake of dairy cattle fed the high fat diets.     

奶牛日粮中离子平衡的研究进展

随着反刍动物营养代谢理论和日粮平衡技术的深入研究,在充分考虑日粮能量蛋白平衡、氨基酸平衡(理想蛋白模式)和钙磷平衡后,日粮离子平衡(dietarycationanionbalance,DCAB)的重要性逐渐得到了研究者的重视。研究表明,日粮中离子平衡水平与动物的采食量及氨基酸的代谢等有密切的     

纤维素酶对奶牛营养的研究进展

纤维素是植物细胞壁的组成成分 ,是一种有 β - 1,4 -葡萄糖苷键组成的多聚糖 ,随之也成了自然界中最丰富的多糖资源之一。纤维素酶是催化纤维素水解成较小的寡糖或者低聚糖的一种酶 ,它通过破坏纤维素内部的糖苷键而起作用 ,主要由各种各样的细菌和真菌 (包括需氧菌和厌氧菌 )等产生。纤维素酶具有高效性和安全性 ,是当前开发非常规饲料及提高现有常规饲料资源利用率和提高畜禽生产性能的重要途径之一。纤维素酶作为饲料添加剂 ,从作用机制和实际生产中看 ,都是良好的添加剂。为充分利用纤维素这一丰富的饲料资源 ,目前我国已利用微生物发酵法生产纤维素酶来降解纤维素 ,在技术研究开发方面已初见成效     

全棉籽影响奶牛生产性能的研究进展

为了开发利用新的饲料资源,促进畜牧业持续健康发展,文章综述了全棉籽的营养价值以及在奶牛生产中的应用研究,以期指导畜牧业生产。     

The estimation of nutritive value of dairy cattle feed

A survey is given of different methods used for the estimation of the net energy lactation and the digestible crude protein content of forages (grass hay, grass silage, maize silage) as well as tuber crops (fodder beet, turnips, raw potatoes), by-products (dried sugarbeet pulp, pressed sugarbeet pulp), compound feeds and raw ingredients for dairy cattle. The following methods are discussed: --methods only based on chemical parameters: crude fibre and cell walls. --methods using rumen fluid from fistulated animals: the two step in vitro digestibility technique, the Hohenheim Futterwert test. --methods using enzyme (cellulase) preparations. --the near infrared reflection spectroscopy. The estimation of the energy value of raw ingredients is discussed more in detail. Formulas for the rapid calculation of the energy value of pulp and tubers are reported. The results obtained at the National Institute for Animal Nutrition in Melle-Gontrode with the two step in vitro digestion technique and a developed cellulase method are illustrated more in detail.     

Ingestion and mastication of feed by dairy cattle.

For fiber in dairy cattle diets to be effective it must be masticated initially during feeding and again during rumination. Time spent chewing is directly related to saliva secretion, which helps buffer the rumen environment and optimizes fiber digestion. Reduction in feed particle size occurs during chewing, which is a prerequisite for passage of feeds from the forestomach, but the extent of particle breakdown during chewing depends upon the feed. Manipulating the dietary concentration of plant cell walls or the physical form of forage can alter chewing behavior and rumen function of the dairy cow, thereby optimizing productivity.     

Fine mapping quantitative trait loci for feed intake and feed efficiency in beef cattle

Feed intake and feed efficiency are economically important traits in beef cattle because feed is the greatest variable cost in production. Feed efficiency can be measured as feed conversion ratio (FCR, intake per unit gain) or residual feed intake (RFI, measured as DMI corrected for BW and growth rate, and sometimes a measure of body composition, usually carcass fatness, RFI(bf)). The goal of this study was to fine map QTL for these traits in beef cattle using 2,194 markers on 24 autosomes. The animals used were from 20 half-sib families originating from Angus, Charolais, and University of Alberta Hybrid bulls. A mixed model with random sire and fixed QTL effect nested within sire was used to test each location (cM) along the chromosomes. Threshold levels were determined at the chromosome and genome levels using 20,000 permutations. In total, 4 QTL exceeded the genome-wise threshold of P < 0.001, 3 exceeded at P < 0.01, 17 at P < 0.05, and 30 achieved significance at the chromosome-wise threshold level (at least P < 0.05). No QTL were detected on BTA 8, 16, and 27 above the 5% chromosome-wise significance threshold for any of the traits. Nineteen chromosomes contained RFI QTL significant at the chromosome-wise level. The RFI(bf) QTL results were generally similar to those of RFI, the positions being similar, but occasionally differing in the level of significance. Compared with RFI, fewer QTL were detected for both FCR and DMI, 12 and 4 QTL, respectively, at the genome-wise thresholds. Some chromosomes contained FCR QTL, but not RFI QTL, but all DMI QTL were on chromosomes where RFI QTL were detected. The most significant QTL for RFI was located on BTA 3 at 82 cM (P = 7.60 x 10(-5)), for FCR on BTA 24 at 59 cM (P = 0.0002), and for DMI on BTA 7 at 54 cM (P = 1.38 x 10(-5)). The RFI QTL that showed the most consistent results with previous RFI QTL mapping studies were on BTA 1, 7, 18, and 19. The identification of these QTL provides a starting point to identify genes affecting feed intake and efficiency for use in marker-assisted selection and management.     

苜蓿草粉替代奶牛饲料中部分精料的效果试验

选择年龄、体重、胎次、生理状况、产奶量、健康状况相近的20头奶牛,随机分为4组(即对照组、试验1组、试验2组和试验3组),每组5头,进行为期60 d的饲养试验。试验1组、试验2组和试验3组的饲料配方是在对照组饲料配方的基础上,分别用10%、20%和30%的苜蓿草粉替代相应的精料。试验结果表明,试验1组、试验2组和试验3组和对照组相比,产奶量分别提高5.60%、8.75%和10.82%,经济效益提高14.82%、25.12%和33.06%。     

Simultaneous Bayesian estimation of genetic parameters for curves of weight,feed intake,and residual feed intake in beef cattle

Rates of gain and feed efficiency are important traits in most breeding programs for growing farm animals. The rate of gain (GAIN) is usually expressed over a certain age period and feed efficiency is often expressed as residual feed intake (RFI), defined as observed feed intake (FI) minus expected feed intake based on live weight (WGT) and GAIN. However, the basic traits recorded are always WGT and FI and other traits are derived from these basic records. The aim of this study was to develop a procedure for simultaneous analysis of the basic records and then derive linear traits related to feed efficiency without retorting to any approximation. A bivariate longitudinal random regression model was employed on 13,791 individual longitudinal records of WGT and FI from 2,827 bulls of six different beef breeds tested for their own performance in the period from 7 to 13 mo of age. Genetic and permanent environmental covariance functions for curves of WGT and FI were estimated using Gibbs sampling. Genetic and permanent covariance functions for curves of GAIN were estimated from the first derivative of the function for WGT and finally the covariance functions were extended to curves for RFI, based on the conditional distribution of FI given WGT and GAIN. Furthermore, the covariance functions were extended to include GAIN and RFI defined over different periods of the performance test. These periods included the whole test period as normally used when predicting breeding values for GAIN and RFI for beef bulls. Based on the presented method, breeding values and genetic parameters for derived traits such as GAIN and RFI defined longitudinally or integrated over (parts of) of the test period can be obtained from a joint analysis of the basic records. The resulting covariance functions for WGT, FI, GAIN, and RFI are usually singular but the method presented here does not suffer from the estimation problems associated with defining these traits individually before the genetic analysis. All the results are thus estimated simultaneously, and the set of parameters is consistent.     

Development of a model for the prediction of feed intake by dairy cows: 1. Prediction of feed intake

A study was undertaken to develop a model for the prediction of dry matter intake by lactating Holstein Friesian dairy cows. To estimate the model parameters, a calibration dataset was compiled with the data from 32 feeding experiments conducted at 9 different sites. The database contained weekly information on 1507 lactating Holstein Friesian dairy cows regarding their diet composition and feed analysis, together with their individual voluntary feed intake, milk yield (MY), milk composition, parity, days in lactation and days pregnant.Dry matter intake was predicted from feed and animal characteristics. The feed chemical composition and digestibility can be related to feed degradation, bulk volume, intake rate, palatability and other factors influencing feed intake. Therefore, the data of standard feed analysis were used to estimate the satiety value of numerous commonly used feeds and forages. The satiety value is the measure of the extent to which a feed limits intake. The cows' ability to process the intake-limiting satiety value-units is expressed as the feed intake capacity, which is predicted from parity, days in milk and days of pregnancy which are indicators of the size and physiological state of the cow. This study shows that feed intake can be predicted using a limited number of easy-to-measure inputs that are available on commercial farms, yet reasonably biologically sound. Because the model inputs are not related to animal output (milk yield or body weight), future extension of the intake model with models for the prediction of animal performance is possible.