矿物质和维生素对奶牛繁殖的影响

奶牛对矿物质需求的种类很多,起主要作用的有;钙、磷、锰、铜、碘、锌、硒.维生素中对奶牛生长繁殖影响大的是维生素A、维生素E、维生素D、维生素B等.上述矿物质和维生素是维持奶牛正常生长繁殖必不可少的营养成分.如果奶牛缺乏矿物质和维生素,不但影响奶牛的生长发育,最重要的是影响繁殖能力、降低产奶量.因此,在饲喂时,应加强对各类饲草料的合理搭配,保证奶牛对矿物质和维生素的正常需求.     

屡配不孕奶牛血清维生素A、E及铜、锰、锌水平的检测分析

本试验采用原子吸收光谱法和荧光吸收光谱法对14头屡配不孕奶牛和10头正常奶牛血清铜、锰、锌及维生素A、维生素E水平进行检测分析,旨在了解重庆市某奶牛场奶牛屡配不孕与血清中部分微量元素及维生素水平的关系。结果显示,屡配不孕奶牛血清锌、维生素A和维生素E含量与正常奶牛相比差异显著(P0.05),血清铜、锰含量与正常奶牛无明显差异(P0.05)。从检测结果分析推测,血清锌、维生素A和维生素E水平过低可能是造成奶牛屡配不孕的原因之一。     

奶牛维生素A缺乏症的研究进展

维生素A是奶牛体内重要的微量营养素之一,维生素A对于奶牛的生产性能、繁殖性能和机体免疫等方面都有十分重要的作用.然而,集约化的饲养方式使得日粮中青绿饲料的比例逐渐下降,导致奶牛出现临床维生素A缺乏症状的可能性增加.这使得人们对反刍动物维生素A营养的研究逐渐深入.本文从维生素A的生理功能、维生素A缺乏的诊断指标和预防几个方面综述奶牛维生素A缺乏症的进展,为奶牛维生素A缺乏症的研究提供理论基础.     

维生素E与奶牛乳房炎

维生素Ｅ属于脂溶性维生素 ,由于脂溶性维生素没有水溶性维生素来源广泛 ,因此 ,在许多植物中维生素Ｅ的含量甚微。奶牛机体对脂溶性维生素Ａ、维生素Ｅ、维生素Ｄ、维生素Ｋ3 的摄入量较为敏感。因此 ,奶牛日粮中能否提供满足需要量的维生素Ｅ ,将直接影响奶牛机体的健康状况。目前 ,奶牛维生素Ｅ需求量是根据能有效预防营养性疾病的发生而制定的 ,然而 ,最近许多研究证实 ,增加奶牛维生素Ｅ的摄入量 ,并且超过其推荐量 ,能显著改善奶牛的健康状况与繁殖能力 ,降低奶牛乳房炎的发病率。1　维生素Ｅ对奶牛乳房炎发生的影响奶牛乳房炎病因复…     

维生素E与奶牛乳房炎

<正> 最近许多研究证实,增加奶牛维生素E的摄入量,并且超过其推荐量,能显著改善奶牛的健康状况与繁殖能力,降低奶牛乳房炎的发病率。维生素E对奶牛乳房炎发生的影响奶牛乳房炎病因复杂,许多学者对其进行了多年的研究。Atroshi等研究发现,乳房炎患牛血浆和乳汁中的维生素E浓度明显低于健康奶牛。Batra等也证实,当奶牛发生乳房炎时,其血浆和乳汁中的维生素E浓度明显降低,而且这种低的维生素E浓度在乳房炎发生之前就已经存在。上述试验结果表明,并非乳房炎的发生致使患牛血浆和乳汁中的维生素E浓度降低,而是低浓度的维生素E容易诱发奶牛乳房炎。     

瘤胃保护性维生素A对奶牛生产性能和免疫机能的影响

为了评价过瘤胃保护维生素A微胶囊在奶牛生产中的应用效果,试验将32头中国荷斯坦奶牛随机分为4组,试验组在奶牛1%预混料中分别添加24 IU/kg(试验1组)、32 IU/kg(试验2组)、64 IU/kg(试验3组)瘤胃保护性维生素A微胶囊,对照组添加未处理维生素A微胶囊32 IU/kg,测定奶牛产奶量、乳品质、乳中维生素A含量、乳中体细胞数和免疫球蛋白水平。结果表明:与添加未处理维生素A微胶囊相比,添加瘤胃保护性维生素A微胶囊可以增加奶牛产奶量,降低奶牛体细胞数,增加乳中维生素A含量。     

维生素缺乏对奶牛的影响

维生素对奶牛至关重要,是奶牛生长、发育、生产过程中不可缺少的营养成分之一。维生素缺乏可引起犊牛的生长发育受阻,而且会影响到奶牛的繁殖性能和机体的免疫力。现简要介绍几种维生素的缺乏对奶牛造成的影响,以供同行参考。     

巧用青饲料冬养奶牛的几招

青饲料是催奶的好饲料,实验证明每日喂青草的奶牛．比喂干草的奶牛多产奶0．5千克。因为青饲料不仅含有丰富的蛋白质和碳水化合物,还能供给奶牛所需要的各种维生素。奶牛需要维生素,虽然用量很少,但对奶牛的健康和产奶情况却影响很大。当维生素缺少时,轻的危害奶牛健康。降低产奶量,重的可致营养代谢病,以至死亡。     

维生素与奶牛饲养

<正>1维生素在奶牛养殖中的作用近年来,人们对于维生素在提高反刍动物免疫力和健康水平方面所起的作用日益关注,下面就将维生素营养在奶牛健康、繁殖和奶质方面的作用简介如下。1.1维生素E和乳房健康乳腺炎是一种在奶牛中常见的疾病,而且在所有     

奶牛维生素A的营养研究

主要总结了最近维生素A与奶牛营养的研究,探讨维生素A和奶牛营养之间的关系。     

黄体酮和维生素治疗奶牛不孕症的试验

对198头输精三个情期以上未受胎又无明显生殖系统异常、营养状况良好的适龄母牛随机分成五组,在相同的饲养管理条件下进行饲养,进行治疗不孕试验研究。结果表明,清宫又补维生素AD、E及孕激素的试验组受胎率最高。     

犏牛补饲维生素E的试验

对多元杂交不同组合犏母牛补饲维生素E,结果表明：通过补饲维生素E后,西黄牦犏牛子宫内膜炎的发病率比对照组降低20％,荷黄牦犏牛的比对照组降低30％,西黄牦犏牛和荷黄牦犏牛乳房炎的发病率均比对照组降低30％。给犏母牛补饲维生索E能显著提高犊牛初生重和犊牛产后成活率,对母牛产奶量影响不明显。     

Plasma vitamin C concentration is not related to the incidence of ketosis in dairy cows during the early lactation period

Many animals including cattle can synthesize vitamin C from glucose. The objective of this study was to investigate plasma vitamin C concentration in ketotic cows during the early lactation period because glucose supply for vitamin C synthesis might be limited in these cows. We measured plasma beta-hydroxybutyrate (BHBA) concentration in 118 cows within 2 months after parturition. Subclinical/clinical ketosis was quantitatively determined using a plasma BHBA threshold of 1,200 microM. Plasma glucose concentration was lower in the ketotic cows than in the control cows but plasma vitamin C concentration did not differ between the control and the ketotic cows. Then we measured plasma vitamin C, BHBA and glucose levels in 7 cows during the periparturient period. Plasma BHBA increased and plasma glucose decreased after parturition but plasma vitamin C did not change. These results indicate that plasma vitamin C is not related to the incidence of ketosis in the early lactation period. We suggest that ketotic cows have the ability to produce vitamin C to meet its requirement in the early lactation period although glucose supply is not sufficient for milk production. Vitamin C synthesis is possibly given a high metabolic-priority for glucose in lactating cows.     

日粮添加维生素D3对围产奶牛外周血免疫球蛋白及T细胞亚群的影响

选用16头胎次接近的围产期奶牛,采用完全随机试验设计,研究日粮中额外添加维生素D3(10万IU/(d.头))对围产期奶牛血常规、免疫球蛋白和T细胞亚群CD4 、CD8 的影响。结果表明在日粮中添加VD3可以极显著提高外周血中红细胞、白细胞、血红蛋白含量(P<0.01)。与对照组相比,添加VD3提高血小板数目、淋巴细胞百分比、单核细胞百分比、中性粒细胞绝对值和单核细胞绝对值,但差异不显著(P>0.05)。试验组IgGI、gM和IgA与对照组相比有升高趋势,但差异不显著(P>0.05);试验组细胞亚群的数量均极显著高于对照组(P<0.01)。结果提示,日粮中添加VD3可以缓解围产期奶牛免疫球蛋白和免疫细胞下降的现象。     

Effect of micronutrient supplementation around calving on the plasma cortisol levels of Murrah buffaloes and Sahiwal and Karan Fries cows

Micronutrients when fed around peripartum may reduce the stress induced by cortisol. With this objective, 24 Sahiwal (SW) and 24 Karan Fries (KF) cows and 24 Murrah (Mu) buffaloes were taken and divided into four groups of six each. Vitamin E (VE), zinc (Zn) and copper were supplemented from 30 days pre- to 30 days postcalving in groups 1, 2 and 3. Animals without supplementation served as control. Blood sampling was done on days 30, 15, 7 and 3 precalving; at calving; and on days 3, 7, 15 and 30 postcalving. Plasma cortisol levels were measured by ELISA. Supplementation of VE and Zn significantly (P?<?0.05) reduced plasma cortisol levels at calving and at 30 days postcalving. KF cows exhibited best results with VE, whereas SW cows and Mu buffaloes responded best to Zn. Copper increased the peripartum cortisol levels. Reduction in cortisol levels may help in keeping the animal healthy and stronger to fight immuno-suppression generally observed around the period of peripartum.     

Role of antioxidants and trace elements in health and immunity of transition dairy cows

A number of antioxidants and trace minerals have important roles in immune function and may affect health in transition dairy cows. Vitamin E and beta-carotene are important cellular antioxidants. Selenium (Se) is involved in the antioxidant system via its role in the enzyme glutathione peroxidase. Inadequate dietary vitamin E or Se decreases neutrophil function during the perpariturient period. Supplementation of vitamin E and/or Se has reduced the incidence of mastitis and retained placenta, and reduced duration of clinical symptoms of mastitis in some experiments. Research has indicated that beta-carotene supplementation may enhance immunity and reduce the incidence of retained placenta and metritis in dairy cows. Marginal copper deficiency resulted in reduced neutrophil killing and decreased interferon production by mononuclear cells. Copper supplementation of a diet marginal in copper reduced the peak clinical response during experimental Escherichia coli mastitis. Limited research indicated that chromium supplementation during the transition period may increase immunity and reduce the incidence of retained placenta.     

Vitamin D receptor amounts across different segments of the gastrointestinal tract in Brown Swiss and Holstein Frisean cows of different age

During different stages of lactation, different requirements of calcium have to be met depending on the milk amount. Vitamin D receptors (VDR) regulate calcium homeostasis by increasing the entry of Ca into blood from bone stores and dietary sources. The purpose of this study was to investigate if age and breed of cows influence VDR amounts across different segments of the gastrointestinal tract. Thirty-six cows were used (18 Brown Swiss, 18 Holstein Friesan, both > 5.5 years or < 4.5 years). Tissue specimens of the intestines were collected from the cows. Formaldehyde-fixed and microwave-treated paraffin sections were used for VDR immunohistochemistry employing a biotinylated monoclonal rat antibody and streptavidin peroxidase technique. The results showed that nuclei and cytoplasm of enterocytes stained positively for VDRs. Strongest immunoreactions were observed in intermediate and basal glandular cells. No significant differences were observed between the different groups. Vitamin D receptors immunoreactivities were prominent in duodenal mucosa, lower in jejunum and in colon, decreased further in ileum and were lowest in caecum. Decreases in number of positively marked cells and staining intensities resulted in reduced immunoreactions. The results of this study indicate that VDR are highly expressed at the site of maximal intestinal calcium absorption. No significant influence of age and breed was observed. The animals used were not in a negative Ca balance. The cows were all in the stage of late or mid lactation. During these periods, the Ca requirements are low and the diets are high in Ca concentration; and the animals are adapted to these circumstances. Passive absorption in adult animals seems to dominate when Ca intake is adequate or high. The active absorption may play a considerably more significant role during the peripartal period, when Ca homeostatic mechanisms are challenged because of tremendous Ca demand at the initiation of lactation.     

Vitamin D3 supplementation of cull cows: effects on longissimus and semitendinosus muscle tenderness

Previous studies have shown that supplementation of vitamin D3 to cow diets for 4 to 10 d before slaughter lowers Warner-Bratzler shear force (WBSF) values and increases sensory tenderness scores in beef cuts. The present study was conducted to evaluate the effects of vitamin D3 supplementation on muscle calcium concentration, WBSF values, and sensory tenderness ratings of LM and semitendinosus (ST) muscles from cull, predominately Angus, cows (eight cows per treatment). Treatments included 0 (control), 5 million IU, or 7.5 million IU of vitamin D3 supplemented daily for 7 d preslaughter. Twenty-four hours after slaughter, 2.54-cm-thick LM and ST muscle steaks were cut; aged for either 0, 7, 14, or 21 d (ST steaks aged for 7 d only); and frozen at -20 degrees C for WBFS and sensory analysis. Mean values for LM calcium concentration tended to increase (P = 0.14) with vitamin D3 supplementation (154, 176, and 183 microig/g, fresh basis, for 0, 5, and 7.5 million IU/d, respectively). After 7 d of aging, LM steaks from cows fed 7.5 million IU had lower (P < 0.05) WBSF values than 7-d steaks from controls and cows fed 5.0 million IU/d aged 7 d; however, vitamin D3 supplementation had no (P > 0.05) effect on WBSF values of ST steaks aged 7 d. Vitamin D3 supplementation did not (P > 0.05) affect sensory tenderness ratings for either LM or ST steaks at any aging period. Aging, however, had a linear (P < 0.001) effect on tenderness, with an increase in tenderness as aging time increased from 0 to 21 d. Thus, results from the present study indicate that vitamin D3 supplementation, at these levels and duration before slaughter, provided little benefit to muscle tenderness of beef from cull cows.     

Field trials on the prophylaxis of intramammary infections in pregnant heifers

The study was carried out in 5 farms on 174 pregnant heifers. Clinical examination of the udder and bacteriological tests of quarter secretion were performed between the 8th and 3rd week before parturition, and then the animals were divided into a control group (64 heifers) and 3 experimental groups and immediately treated. A group of 32 experimental heifers was injected once with antioxidants (Vitamin A--600,000 i.u.; Vitamin D3--200,000 i.u.; Vitamin E--1.5 mg/kg b.w., Selenium--0.022 mg/kg b.w., i.m.). The next group (26 heads) was intramammary infused with antibiotic DC product (cloxacillin). Heifers from last experimental group (52) were injected with lysosyme dimer in a single dose of 0.02 mg/kg b.w. Clinical and bacteriological examinations were made during the first week after calving. The presence of bacteria was found in secretion of 22.6-38.9% udder quarters in 56.2-71.2% of pregnant heifers. The number of infected quarters (cows) did not change distinctly in the first week after calving except the lysozyme dimer group, where a decrease by 30% was noted. The percentage of quarters with elevated somatic cell count was higher in antibiotic DC group and closely similar in the other groups. None of examined methods showed an acceptable prophylactic effect. Clinical mastitis cases during first week after parturition were mostly caused by Escherichia coli, Staph. chromogenes, Staph. simulans, Staph. aureus, Staph. hyicus, Str. uberis, Str. acidominimus and Enterococcus faecalis.     

Congenital joint laxity and dwarfism: A feed-associated congenital anomaly of beef calves in Canada

Five feeding trials were performed on three ranches to determine if a distinctive, recurring, congenital anomaly in beef calves was associated with feeding clover or grass silage without supplementation to pregnant cows overwinter. The anomaly, termed congenital joint laxity and dwarfism, was characterized at birth by generalized joint laxity, disproportionate dwarfism, and occasionally, superior brachygnathia. The anomaly had been documented for several consecutive years on these ranches and affected 2-46% of the calf crop.

Pregnant cows were divided randomly into feeding groups, and the number of abnormal calves in each group was tabulated. Supplementation of the overwinter grass/clover silage diet with hay (2.5-4.5 kg/head/day) and rolled barley (0.75-1.5 kg/head/day) eliminated the problem. Supplementation of grain, without hay, was not as effective. Varying the proportions of grass and clover in the silage, and the age of the silage, did not alter the teratogenic potency of silage. Vitamin D₃ supplementation did not reduce the risk of the condition. The definitive cause of congenital joint laxity and dwarfism was not determined.