围产期奶牛的饲养管理要点

奶牛围产期是指奶牛产前、产时和产后的这一段时期,奶牛围产期虽然时间不长,但围产期是奶牛泌乳周期中承前启后的重要时期,因此,我们必须重视围产期奶牛的精心饲养和科学的管理,才能保证围产期奶牛的健康生长。文章简述了围产期奶牛饲养与管理的要点和注意事项。     

围产期奶牛的生理特点和营养需求

奶牛围产期阶段的饲养管理直接关系到整个泌乳期产奶量以及繁殖能力。本文主要介绍了围产期奶牛的生理与代谢特点,重点阐述了围产期奶牛的营养需要,为奶牛场围产期奶牛的饲养管理提供理论依据。     

茶多酚对围产期奶牛乳腺炎的调节作用及机制

围产期奶牛由于生理变化、高强度代谢及饲粮营养成分的改变，极易造成氧化应激。氧化应激不仅会严重损伤奶牛乳腺、降低奶牛生产性能和繁殖性能，还会严重影响奶牛场和养殖户的经济效益。因此，调控氧化应激降低围产期奶牛乳腺炎发病是实现奶牛健康绿色养殖的关键步骤。茶多酚作为天然抗氧化剂不仅能够提高围产期奶牛的抗氧化性能，减轻围产期奶牛由于氧化应激而导致的乳腺炎症，还能够有效丧失致病菌活性，使围产期奶牛乳腺炎的发病率有所降低。文章综述了围产期奶牛乳腺炎的致病机制与茶多酚对围产期奶牛乳腺炎的调节作用及机制，旨在为后续研究茶多酚预防围产期奶牛乳腺炎提供技术支撑。     

金银花提取物对围产期奶牛乳房炎的防控作用及其机制研究进展

围产期奶牛经历分娩应激、泌乳应激、饲粮结构的改变以及由于营养和饲养管理不当等原因,造成奶牛乳腺炎症,成为制约我国奶牛健康养殖的一个重要因素,严重影响养殖场的经济和社会效益。通过营养调控手段提高围产期奶牛机体的免疫力来降低疾病的发生率,成为奶牛实现健康养殖的重大科学问题。金银花提取物不仅能提高围产期奶牛的抗氧化性能,缓解围产期奶牛氧化应激引起的炎症反应,而且可以通过抑制致病菌的生物活性,进而有效降低围产期奶牛炎症性疾病的发生率。本文围绕围产期奶牛乳房炎的致病机制和金银花提取物预防围产期奶牛乳房炎的潜在作用机制进行综述,旨在为预防围产期奶牛乳房炎和促进健康养殖提供新的技术途径。     

奶牛围产期的饲养管理

围产期是指奶牛产前3周至产后2周这段时间,围产期奶牛要经历妊娠、分娩、泌乳等生理过程,是奶牛生命中最脆弱的阶段,围产期奶牛饲养好坏直接影响到整个泌乳周期产奶性能的发挥,关系到奶牛饲养效益的高低,所以奶牛围产期饲养管理特别重要,必须引起奶牛饲养户的高度重视。     

2008-2009年反刍动物营养研究进展Ⅸ.围产期

围产期是奶牛泌乳和繁殖周期中最为关键的时期,与奶牛的健康状况和生产性能等方面密切相关。笔者综述了2008-2009年发表在CNKI和PubMed数据库及ADSA-ASAS年会中与奶牛围产期方面相关的文献。通过反刍动物围产期生理变化规律的阐述及围产期奶牛日粮营养的调控,对改善围产期动物生产性能和繁殖性能具有重要意义。     

围产期奶牛的能量负平衡及能量代谢障碍性疾病研究

<正>能量负平衡是指物质摄入减少但是奶牛的需求仍在增加,这也是围产期奶牛的能量代谢特点。围产期是奶牛生产全过程中至关重要的组成部分,也是奶牛能量代谢障碍性疾病高发的时期,了解围产期奶牛能量负平衡的现象特征是进行疾病防治的基础。本文对围产期奶牛出现能量负平衡的原因进行了深入的分析,旨在为解决围产期奶牛能量负平衡问题与疾病预防提供新思路。1围产期奶牛能量负平衡的产生原因能量负平衡多高发时期是奶牛日产奶量达到30kg前的     

过瘤胃胆碱对围产期奶牛营养作用的研究进展

本文通过研究围产期奶牛的代谢特点,阐述了胆碱的生物学功能及其在瘤胃中的代谢机理,同时论述了过瘤胃胆碱对围产期奶牛的营养作用。旨在为应用过瘤胃胆碱缓解奶牛能量负平衡,减少围产期奶牛营养代谢病发病率,提高奶牛生产性能,延长奶牛利用年限奠定理论参考依据。     

围产期奶牛的饲养管理

奶牛围产期对整个奶牛泌乳周期生产性能发挥非常重要,奶牛围产期的生理变化非常明显,容易感染多种疾病,严重的会对整个泌乳时期的产奶量,同时也会降低新生牛犊的健康状态。所以,对围产期的奶牛尽量选择具有针对性和科学性的管理措施,以保障奶牛正常发挥生产性能。本文主要分析了围产期奶牛的生理特点,介绍了奶牛围产前期和围产后期的饲养管理要点,供参考。     

围产期奶牛饲喂及保健措施

围产期是指产前3周至产后3周,此时是奶牛饲养的关键阶段。围产期奶牛管理的成败决定了随后泌乳期的成败。据调查奶牛疾病75%是由于围产期管理不善引起的,常见的疾病如胎衣不下、子宫内膜炎、脂肪肝、酮病、乳房炎、乳房水肿、奶牛产后瘫痪等。很多奶牛养殖户只注重奶牛产奶高峰期的管理,而忽略了围产期饲养管理。     

围产期奶牛低血钙症的发生及预防措施研究进展

围产期奶牛经历妊娠后期、分娩和泌乳等一系列生理变化,抵抗力下降,容易诱发奶牛产后诸多疾病,其中低血钙症就是本阶段易发的疾病之一.本文就围产期奶牛低血钙症的发生原因、危害、影响因素及目前的预防措施进行了总结,为奶牛围产期的饲养管理提供相应的理论参考.     

Relationship of hepatic lipidosis to health and performance in dairy cattle

In a field study of 80 cows in 9 dairy herds, serial liver biopsies were performed over the peripartum period to determine degree of hepatic lipidosis. Cattle were separated into categories of mild, moderate, and severe hepatic lipidosis on the basis of maximal amounts of hepatic triglyceride that accumulated during this period. Number of cattle with mild, moderate, and severe hepatic lipidosis were 52, 16, and 12, respectively. Cattle with severe hepatic lipidosis had greater concentrations of hepatic triglyceride before calving and after parturition, and greater serum nonesterified fatty acid concentrations and body condition loss after parturition than cattle with mild hepatic lipidosis. Rate of disease and culling and death rate because of disease were greater in cattle with severe hepatic lipidosis. Cattle with severe hepatic lipidosis had reproductive performance equal to clinically normal cattle; however, cattle with moderate hepatic lipidosis had increased days to conception, possibly related to greater milk production.     

Growth and Development Symposium: Inflammation: Role in the etiology and pathophysiology of clinical mastitis in dairy cows

Genetic selection for increased milk production in dairy cattle was not associated with an attenuated inflammatory response. The systemic and local inflammatory responses contribute to altered metabolism, reduced production performance, and increased cull rate of lactating dairy cows with clinical mastitis. More aggressive inflammatory responses were observed during the peripartum period when compared with cows in late lactation after an intramammary challenge with purified lipopolysaccharide. The epidemiology of clinical mastitis indicates that the greatest incidence is observed during the peripartum period; therefore, an enhanced inflammatory response with concomitant suppression in other immune responses may be involved in the etiology and severity of the clinical mastitis observed in peripartum cows. Milk production losses and compositional changes are observed among all mammary quarters from a cow with clinical mastitis, but the responses are more severe and sustained among infected quarters. The infected mammary quarters reflect both the systemic and local reactions, whereas uninfected quarters represent only the systemic response. The systemic effects of the inflammatory response include reduced DMI, hyperthermia, and changes in whole-body nutrient partitioning affecting mammary epithelial substrate availability, whereas local inflammatory effects include energetic requirements of the increased inflammatory leukocyte pool, decreased synthetic capacity of mammary epithelium independent of substrate availability, and paracellular leakage of milk components from the alveolar lumen into the extracellular fluid. Research has focused on improving host immunological defenses, attenuating the inflammatory response, or improving the resolution of the disease state to limit the deleterious effects during clinical mastitis. This paper highlights the role inflammation plays in the etiology and pathophysiology of clinical mastitis as well as potential management strategies to reduce or prevent those losses.     

Relationship between haptoglobin, serum amyloid A, and clinical status in a survey of dairy herds during a 6-month period

BACKGROUND: Haptoglobin and serum amyloid A are major acute phase proteins in cattle. Dairy cattle often develop pathologic conditions in the peripartum period; acute phase proteins may be useful in their diagnosis. OBJECTIVES: The purpose of this study was to compare the accuracy of serum haptoglobin (Hp) and serum amyloid A (SAA) concentrations with clinical health status for diagnosing disease during the peripartum period in dairy cattle. METHODS: Dairy cows from 4 herds were evaluated every 15 days over a 6-month period. Health status was determined by thorough clinical examination. Haptoglobin and SAA concentrations were measured in serum using validated methods and the results were classified as positive or negative based on defined cutoff points. Disease prevalence, sensitivity, and specificity were compared using clinical examination as the gold standard. RESULTS: A total of 1896 samples from 158 cows were analyzed. Significant increases in mean Hp and SAA concentrations were observed in the week following parturition in both primiparous and multiparous cows, although high interindividual variability was observed. Both Hp and SAA had low sensitivity but higher specificity in determining disease status compared with clinical examination. Increased concentrations of Hp and SAA were found in <10% of samples from clinically healthy cows, except in the week after parturition. CONCLUSIONS: Haptoglobin and serum amyloid A should be used with caution as markers of inflammation in the week after calving. Poor sensitivity in other postpartum periods could be related to the higher incidence of chronic (vs acute) inflammation. Haptoglobin may be appropriate for routine screening, but further work needs to be done to assess its value as an indicator of herd health.     

Constraints on dairy cattle productivity at the smallholder level in the Philippines

Survey data on dairy cattle production were gathered in two sites [Site I (three-year survey) and Site II (two-year survey)] in Southern Luzon, Philippines. Crossbred (Holstein-Friesian x Sahiwal) dairy cows (n = 122) managed by smallholder farmers belonging to five primary cooperatives under the federation of dairy farmers, were monitored monthly for milk production, feed intake and availability, and reproduction and health status. The purpose of the survey was to identify constraints to productivity. The reproductive status of the cows was monitored by measuring milk and plasma progesterone concentrations by radioimmunoassay and rectal palpation of the ovaries. Plasma concentrations of selected metabolites [beta-hydroxybutyrate (BHB), inorganic phosphorus, albumin, globulin, urea] were also measured at one month before calving and at one month and 2-3 months postpartum, to determine if these could serve as biochemical indicators of nutritional stress. A long calving interval (CI = > 400 days) was identified as the major constraint to productivity of dairy cattle on smallholder farms. The three main problems related to this reproductive constraint were: (1) poor breeding management, in particular lack of accurate estrus detection; (2) repeat breeding, i.e. three or more services were required before conception; and (3) poor ovarian function, shown by some cows with lose progesterone levels. An important cause of these problems was undernutrition, particularly at critical periods of the cow's reproductive life, reflected in the slow recovery from loss in body weight and condition score during the early postpartum period and the increased plasma BHB values at peripartum period in some cows, indicative of negative energy balance, and the flat lactation profile. These findings are useful and relevant as a database in the development of an appropriate management scheme aimed toward improving dairy cattle production and productivity at smallholder level. It highlights the importance of estrus detection, good breeding management and the use of a practical strategic nutritional supplementation, particularly during stressful periods in the cows's reproductive life.     

Type 1 and type 2 immune response profiles of commercial dairy cows in 4 regions across Canada

Diseases of dairy cattle have adverse implications for both the dairy industry and animal welfare. Understanding adaptive immune response profiles of cattle on a national scale will provide insight into the potential for improving health and decreasing disease. The objectives of the present study were to evaluate immune response phenotypes of Holstein cows outside the peripartum period and to determine if antibody isotype bias to putative type 1 and type 2 test antigens is maintained. The cows, housed on commercial farms in 4 key dairy regions across Canada, were immunized with test antigens to measure their ability to mount cell-mediated immune responses (CMIR) and antibody-mediated immune responses (AMIR). Delayed-type hypersensitivity (DTH) was used as an indicator of CMIR and primary and secondary serum antibodies of the immunoglobulin (Ig) G1 and IgG2 isotypes were used to determine AMIR to the test antigens. Immune response phenotypes varied significantly among regions, herds, and cows. Cows in Alberta had significantly higher DTH responses and secondary responses to the type 2 test antigen than those in other regions. However, cows in Alberta had significantly lower primary antibody responses. It was found that Alberta had the lowest incidence of mastitis caused by Escherichia coli and Staphylococcus aureus compared with other regions. The IgG1/IgG2 antibody isotype ratio confirmed the nature of the test antigens. This was the first study to evaluate adaptive immune response profiles and disease incidence of dairy cows on a national scale and it therefore provides a glimpse of the current situation in Canada.     

Effects of feeding intensity during the dry period on leukocyte and lymphocyte sub-populations, neutrophil function and health in periparturient dairy cows

The objective of this investigation was to study (1) the numbers of leukocytes, (2) the proportions of lymphocytes expressing CD4, CD8, WC1, B or IL2R and (3) neutrophil phagocytosis and oxidative burst activity in blood around parturition in three groups of dairy cows fed different levels of a total mixed ration during the last eight weeks before calving. All cows were fed ad libitum during the first eight weeks of lactation. Serum concentration of the acute phase protein serum amyloid A (SAA), the milk somatic cell count (SCC) and disease incidence were also recorded. Special emphasis was given to the weeks just before and just after calving as dairy cows are known to be immune suppressed during this period. Dry period diet had only minor effects on leukocyte numbers, and did not influence neutrophil phagocytosis and oxidative burst. In addition, no effect was observed on disease incidence or SAA concentrations. However, an increase in the proportion of B-lymphocytes and a decrease in the proportion of WC1+ T lymphocytes were observed after calving in cows fed high or low energy rations during the dry period, but not in cows fed a medium energy ration. The weeks just before and after parturition were characterised by neutrophilia, eosinopenia, lymphopenia and monocytosis, but time had no effect on neutrophil phagocytosis and oxidative burst. The proportions of CD4+, CD8+, B+ and IL-2R+ lymphocytes increased in early lactation relative to the mid dry period. In addition, the concentration of SAA increased dramatically at calving. The results emphasise the need for more studies to clarify the complex interactions between nutrition and immunity during the peripartum period in dairy cattle.     

奶牛围产期低血钙症的发生及营养调控措施

文章介绍了围产期奶牛的生理状况及低血钙症的发生机理、危害、影响因素等,提出通过营养调控手段预防奶牛围产期疾病发生、改善奶牛健康状况的措施.通过合理的营养调控手段可以降低奶牛围产期低血钙症的发生几率,促进奶牛健康,提高奶牛养殖的经济效益.     

Quantification of pericaudal adipocyte diameter in dairy cattle during peripartum: a complementary method to study energetic status using conventional histology

The energetic status of high‐yielding Holstein‐Friesian dairy cattle was studied during peripartum under field conditions using body condition score (BCS), glycemia, seric ß–hydroxybutyrate and adipose tissue cellularity. This last method was tested as a complementary tool for energetic status assessment. Biopsies of pericaudal subcutaneous adipose tissue were obtained from 25 multiparous animals at 28 days before and 21 days after parturition. Samples were routinely processed for histological examination and stained with haematoxylin and eosin (H&E). The mean diameter of adipocytes (MDA) was measured with the aid of a digital image processor. During the same period, blood samples were collected weekly for metabolite determinations. The MDA at 28 days pre‐partum and 21 days post‐partum were 72.1 vs. 66.2 μm respectively (p = 0.055), and the corresponding BCS at these moments was 3.32 vs. 3.19 (p = 0.068). At ?28 days pre‐partum, the BCS was positively correlated with MDA (Pearson’s r = 0.521, p = 0.016) and with glycemia (Pearson’s r = 0.404, p = 0.056). Correlations between BCS and MDA, and between BCS and glycemia, with ß–hydroxybutyrate although not significant, suggest that routine histological preparations of biopsies from subcutaneous adipose tissue could be included as an easy and valuable tool for research purposes to evaluate metabolic adaptation of dairy cows to peripartum, as well as the incidence of metabolic disorders and productive performance.     

The seroprevalence of Johne's disease in Georgia beef and dairy cull cattle.

Beef and dairy cattle serum samples, collected during 2000 at sale barns throughout Georgia, were obtained from the Georgia State Brucellosis Laboratory and were used to conduct a retrospective epidemiological study. Statistical samplings of 5,307 sera, from over 200,000 sera, were tested for antibodies to Mycobacterium avium ssp. paratuberculosis, (Johne's disease) using a commercial enzyme-linked immunosorbent assay test kit. An overall period seroprevalence in all classes of cattle tested was 4.73%. The period seroprevalence in dairy cattle was 9.58%, in beef cattle it was 3.95%, and in cattle of unknown breed it was 4.72%. It was concluded that the seroprevalence of Johne's disease in cull beef and dairy cattle in Georgia is economically significant.