We reviewed information on dairy cattle production systems in the tropics, the factors involved, and their influence on milk composition. Genetic factors had greater influence on milk production; specialized breeds produced more milk, and there was an inverse relation between the content of fat, protein, total solids, and the amount of milk produced. Season was related to the availability of forage, and the type of grazing system. Greater pasture area increased individual production, while a greater supply of feed concentrate did not increase milk production. The number of calvings positively affected milk production through the fifth calving, with subsequent declines in production. Milk production increased to a maximum and then declined as lactation progressed. Specialized systems had higher production and better hygienic milk quality; milking and container equipment are critical for maintaining milk sanitary quality. Factor interaction is highly complex, preventing the generation of specific recommendations and general principles applicable to the specific conditions for each system.
相似文献 |
|||||||
|
|||||||
|
共查询到20条相似文献，搜索用时 59 毫秒
1.
乳牛吮乳癖俗称“偷奶吃”,即早已断奶的青年牛或成乳牛在安静休息状态时吸吮自身奶或放入运动场后吸吮其他牛只的奶。乳牛吮乳癖现象几乎存在于每个奶牛场,虽对乳牛业没有造成重大危害,但对乳牛奶产量及乳房健康都有一定的影响。笔者对本场乳牛群进行了调查。现报告如下。 相似文献
2.
3.
随着奶牛产业的迅速发展,如何提高饲料利用率,增强牛体健康,减少奶牛常见疾病的发生,增加奶产量,提升牛奶品质,已经成为现代奶牛养殖行业和牛奶生产经营企业最广泛关注的问题。为此,笔者进行了在奶牛日粮中添加"牧平"以观其效的试验。结果表明,试验组比对照组奶产量提高了11.7%,乳蛋白率和乳脂率分别提高了12.8%、9.6%,体细胞数降低了49.38%,蹄病和乳房炎的发生率分别下降了15.72%和14%。说明"牧平"能有效提高奶产量和奶品质,降低临床乳房炎、肢蹄病的发生。 相似文献
4.
随着中国WTO的加入，牛奶产量和质量将放在奶牛场同样重要的位置上。由于各奶牛场挤奶间隔时间长短不一，所以每一阶段挤出的牛奶脂含量就不同。有的牛奶加工厂一般要求每一阶段牛奶的含脂率相差在±０．０５％，符合标准的，对奶农可奖励０．１元／kg，低于２．５％拒收。因此，奶牛场（户）要提高经济效益及生奶质量，必须从以下方面严格要求：１健康的奶源一般刚从健康乳牛乳房挤出的牛奶细菌不多，而患有乳房炎的乳牛，由于受到细菌的感染，往往其产的牛奶的卫生质量差，细菌数超标。乳房炎可分二类，一类是临床性，其生产的牛奶，用… 相似文献
5.
饲养乳牛的直接目的就是为了生产牛奶，但乳牛配种妊娠与否直接关系到牛奶产量问题。本人从事乳牛冷配工作20年，累计冷配母牛达3万多头次。现从以下几点谈谈提高母牛冷配受胎率的体会。 相似文献
6.
无 《河南畜牧兽医(综合版)》2019,(9):7-8
牛奶是人们尤其是婴幼儿的主要营养食品,牛奶中残留抗生素会危害饮用者身体健康。我国颁布的生鲜乳生产收购管理办法明确规定,在规定用药期和休药期内的奶畜产的生鲜乳不得销售。香港卫生署也提出输港生牛奶中不能有抗生素残留。为了了解乳牛停药后抗生素在生奶中残留时间和市售牛奶中抗生素残留情况,为乳牛场把握乳牛最佳挤奶时间,减少污染乳源造成浪费以及为加强乳品卫生监督监测提供科学依据,笔者对用药后牛奶中抗生素残留进行监测,现分析如下。 相似文献
7.
据西方报刊报道,国外采用生物工程技术繁殖牲畜良种,大幅度地增产奶、肉、蛋白质,防治牲畜疾病和提供饲料蛋白——取得了巨大经济效益,并显示了有根本改造畜牧业的巨大潜力。一、繁殖良种,使美全国奶牛头数减少,而牛奶产量增加一倍美国通过认真选择最优良品种的公牛,广泛采用冷冻精液、人工授精技术,来繁殖产奶量最高的乳牛——使得平均牛奶产量增 相似文献
8.
9.
1950年至今,日本黑白花乳牛由20万头发展到211万头,已基本满足牛奶消费需要,所以近年刻意注重乳牛质量的提高。这一方面依靠乳检中心对提出申请的牛只进行产奶量、乳脂率、无脂固形分率、奶中体细胞数的测试;同时,由国家鉴定委员对乳牛进行正确的体型外貌评定。数据均由电子计算机进行处理。 相似文献
10.
11.
为掌握牦牛乳常规营养成分以及不同成分间的相关关系,为下一步牦牛乳用性能选育提供理论基础,本试验对青海高原型牦牛纯放牧条件下(7月底)牦牛乳成分进行了测定,利用SPSS软件对各营养成分间的相关性进行了分析。结果表明∶纯放牧条件下,牦牛乳乳脂率为7.42±1.8956%,乳蛋白率为3.91±0.1619%,乳糖为5.88±0.2375%,非脂乳固体为10.78±0.4238%,密度为1033.45±2.3144kg/m^3,冰点为-0.7377±0.0346℃,盐为0.82±0.041%,电导率为4.74±0.0821s/m。相关性分析表明乳脂肪与密度和盐呈极显著负相关,乳蛋白质、乳糖、非脂乳固体、密度、盐两两间呈极显著正相关(P<0.01),冰点与乳糖、乳蛋白、非脂乳固体呈极显著负相关(P<0.01),冰点与密度和盐没有相关性,电导率与各乳成分之间没有相关性。 相似文献
12.
For food evaluation the determination of the number of Staphylococcus aureus (hereinafter S. aureus) colonies is insufficient in view of present scientific knowledge. The results, advantages and shortcomings of diagnostic methods are demonstrated on an example of three methods of detection of staphylococcal enterotoxins in milk and milk products. 133 strains were investigated by the method of biotyping of S. aureus strains. Four strains of S. aureus were included in biotype A, seven xin-producing strains were isolated seventeen times by detection of 96 S. aureus strains were not included in any biotype, the other strains belonged to biotypes C and E. This method can be used as an auxiliary method of evaluation of foods containing S. aureus bacteria. The agar-gel precipitation method of enterotoxin detection in isolated strains of S. aureus has just restricted validity. The enteroto-strains. The main shortcoming of this method is a fact that the result concerning the isolated strains need not be identical with the result of enterotoxin detection in food. Direct assays of staphylococcal enterotoxins in milk and milk products using an enzymoimmunological method seem to be the most promising, mainly due to their high sensitivity (0.0001-0.001 micrograms.ml1-) and other advantages. Positive and negative results are presented on an example of two model trials with winter sheep milk cheese. 相似文献
13.
随着人们生活水平不断提高,对奶的需求也在逐步增加,乳牛饲养在辽宁省迅速发展起来.为满足市场需求解决供求之间的矛盾,在大力发展乳牛数量的同时,要不断改进乳牛的培育方法. 相似文献
14.
用气相色谱 质谱联用仪(GC MS)对牦牛乳、黑白花奶牛乳、犏牛乳及牦牛乳制品（奶油、酥油、曲拉、酸奶）中的脂肪酸组成进行了测定。结果表明,牦牛乳中功能性脂肪酸,如共轭亚油酸（CLA）、亚油酸（LA）、α 亚麻酸（ALA）、γ 亚麻酸（GLA）占总脂肪酸的比重均显著高于犏牛乳和黑白花奶牛乳（P＜0.05）;犏牛乳中ω 6/ω 3 PUFA的比值（1.55）略高于牦牛乳（1.54）,差异不显著（P＞0.05）,但都在最佳膳食平衡比值范围内,黑白花奶牛乳中ω 6/ω 3多不饱和脂肪酸（PUFA）的比值（11.33）超过了推荐最佳比值。加工处理能够改变乳制品脂肪酸的构成,如牦牛乳奶油中检测出原奶中所不含的一种亚油酸（18:2Δ8c,11c）。酥油主要以不饱和脂肪酸（UFA）为主,而曲拉主要以饱和脂肪酸（SFA）为主,牦牛酸奶中没有检测到GLA。 相似文献
15.
Ramírez-Rivera E. J. Rodríguez-Miranda J. Huerta-Mora I. R. Cárdenas-Cágal A. Juárez-Barrientos J. M. 《Tropical animal health and production》2019,51(6):1295-1305
16.
17.
18.
Milk immunoglobulins were extracted from the stained cream layer of positive milk ring tests from experimentally inoculated or naturally infected cows. IgA was always found, associated with IgM in most cases (15/17) and with IgG in a smaller number of cases (11/17). An additional incubation at 20 degrees C for 18 h gave clearer positive and negative results and a lower limit of detection than that of the usual milk ring test. 相似文献
19.
The survival of Brucella abortus in milk and milk products 总被引：1，自引：0，他引：1
|
| 设为首页 | 免责声明 | 关于勤云 | 加入收藏 |
|
Copyright©北京勤云科技发展有限公司 京ICP备09084417号 |