奶牛子宫免疫系统研究

由于产后奶牛子宫免疫系统容易受损并且普遍发生子宫内细菌感染,所以奶牛经常会发生子宫类疾病。世界各国奶牛子宫类疾病的发病率存在着很大的差异。子宫感染的发生取决于奶牛的免疫状态及入侵细菌种类及数量。了解奶牛子宫免疫系统组成及其调节有助于快速有效的诊断和治疗相关的子宫疾病。     

奶牛子宫内膜炎的防治措施

奶牛子宫内膜炎是奶牛产后普遍发生的子宫炎症,继续发展会成为子宫炎和化脓性子宫炎,常引起全身感染而发展成为败血症,该病是导致奶牛不孕的主要原因,严重影响奶牛产业效益。近两年的统计结果显示,舟曲县仅有的30头奶牛规模的奶牛场子宫内膜炎的发病率为11%。笔者根据多年的诊疗经验,认为防治奶牛子宫内膜炎的有效方法有子宫灌注     

奶牛子宫内膜炎的防治

奶牛子宫内膜炎是奶牛产后普遍发生的子宫炎症,继续发展会成为子宫炎和化脓性子宫炎,常引起全身感染而发展成为败血症,该病是导致奶牛不孕的主要原因。近两年的统计结果显示,新疆石河子4个500头规模的奶牛场子宫内膜炎的发病率为11%,占不孕奶牛总数的68%。由此可见由子宫内膜炎造成的繁殖障碍引起的经济损失相当严重。     

奶牛子宫内膜炎的防治措施

奶牛子宫内膜炎是奶牛产后普遍发生的子宫炎症，继续发展会成为子宫炎和化脓性子宫炎，常引起全身感染而发展成为败血症，该病是导致奶牛不孕的主要原因。近两年的统计结果显示，新疆石河子四个500头规模的奶牛场子宫内膜炎的发病率为11％，占不孕奶牛总数的68％。由此可见由子宫内膜炎造成的繁殖障碍引起的经济损失相当严重。     

奶牛子宫内膜炎的防治

<正>奶牛子宫内膜炎是奶牛产后普遍发生的子宫炎症,继续发展会成为子宫炎和化脓性子宫炎,常引起全身感染而发展成为败血症,该病是导致奶牛不孕的主要原因。近两年的统计结果显示,新疆石河子4个500头规模的奶牛场子宫内膜炎的发病率为11%,占不孕奶牛总数的68%。由此可见由子宫内膜炎造成的繁殖障碍引起的经济损失相当严重。     

奶牛子宫内膜炎的诊治

奶牛子宫内膜炎是奶牛在产后普遍发生的子宫内膜的炎症,一般发病率为20％-35％,如不及时治疗,会发展成为子宫炎和化脓性子宫炎。子宫内膜炎多集中在产后2周内出现。在产后早期阶段,多达93％的牛发生子宫细菌污染,但是多数污染被自动清除,至产后46-60d时,感染率降到39％,该病对奶牛业的危害非常严重,经常造成巨大的经济损失。     

奶牛子宫内膜炎的病因、症状及防治

1 病因分析 微生物感染是引起奶牛子宫内膜炎的主要原因,分娩时或产后,微生物可以通过各种感染途径侵入,主要是由环境中的非特异性细菌引起,还有某些特异性病原微生物,这些细菌可短期或长期存在于奶牛子宫内.在发生难产、胎衣不下、子宫脱出、流产时,会使子宫弛缓、复旧延迟,均易引起子宫内膜炎.     

奶牛产后子宫内膜炎的诊治

奶牛产后子宫内膜炎,通常是子宫粘膜发生粘液或化脓性炎症,为产后或流产后最常见的一种生殖器官疾病. 一、病因 难产、胎衣不下、阴道(子宫)脱出、输精操作不当、环境不好、感染某些疾病均可导致牛产后子宫内膜炎的发生.     

奶牛血浆PGFM浓度变化与子宫内膜炎关系的研究

奶牛子宫内膜炎是奶牛产后多发性疾病之一，产后子宫感染是一种非特异性感染，主要的致病菌有分泌型化脓菌（Arcanobacterium pyogenes）、埃希氏大肠杆菌及其他多种革兰氏阴性厌氧菌。子宫内膜炎对奶牛业有重要的经济影响，若能早期识别出对子宫内膜炎易感性较高的奶牛，并提高对子宫内膜炎患牛的诊断率，将会明显的减少因产后子宫感染所带来的损失。     

奶牛慢性子宫内膜炎的早期预防与治疗

1发病原因慢性子宫内膜炎多数由急性炎症转化而来,但也有一开始即为慢性炎症,多与病原有关。病原主要是一些非特异性细菌感染,如链球菌、葡萄球菌、大肠杆菌。此外,还有棒状杆菌、单胞菌等,衣原体和霉形体也可感染。在一些特异性病原,如布氏杆菌、结核分枝杆菌、牛传染性鼻气管炎病毒、牛病毒性腹泻病毒等感染时也可发生子宫内膜炎。1.1奶牛机体因素奶牛在间情期、围产期等特定生理阶     

Rationale for treatment of endometritis in the dairy cow

Endometritis is an inflammation of the uterine lining that is commonly initiated at parturition. The degree of its effect on fertility varies with the severity of the inflammation, the time required for resolution of endometrial lesions, and the extent of permanent changes that impair endometrial gland functions and/or alter the uterine and/or oviductal environment. The primary nonspecific organisms associated with endometrial pathology are Corynebacterium pyogenes and the gram-negative anaerobes. The majority of postpartum dairy cows have some degree of endometritis but resolve it by 40 to 50 days post partum. Cows with certain periparturient disorders involving the reproductive tract and/or a defective host immune mechanism may acquire persistent infections that impair subsequent fertility. Not all infertile cows or all cows with positive uterine cultures have endometritis. Cows recovering from C. pyogenes endometritis may require 1 month after clearance of the organism for fertility to be restored. These cows, as well as many cows with slightly delayed uterine involution at 30 days post partum, do not benefit from antimicrobial therapy. The effect of endometritis varies between herds. It is associated with prolongation of calving intervals that can vary from less than 2 weeks to 2 months or more. The cost of days open beyond 80 to 110 days post partum is currently estimated to be $2.00 to $2.25 per day. Evaluation of the bovine genital tract is best conducted by a rectal examination combined with a vaginal speculum examination. Cows selected for therapy for endometritis should meet the strict requirements of a grossly enlarged uterus and a severely abnormal uterine discharge. Induction of estrus is the treatment of choice whenever possible. When antimicrobial therapy is indicated, tetracycline is recommended for intrauterine use during the early postpartum period when mixed bacterial populations are present. Commonly used doses are 2 to 3 gm. For systemic signs of illness, systemic administration of penicillin has been recommended. Twice daily doses of 5000 to 10,000 IU of penicillin per kg may be necessary to maintain therapeutic blood concentrations. Systemic administration of an antimicrobial is necessary to achieve therapeutic concentrations in the oviducts, cervix, and vagina. With chronic endometritis due to C. pyogenes, intrauterine administration of 1 to 1.5 X 10(6) IU of procaine penicillin G has been recommended. Multiple daily treatments are desirable. Milk from treated cows should be tested for penicillin before it is added to bulk tank milk. It still is not clear whether antimicrobial therapy is cost effective.(ABSTRACT TRUNCATED AT 400 WORDS)     

Neutrophil function and energy status in Holstein cows with uterine health disorders

The objectives of this study were to investigate the associations between peripheral blood neutrophil (PMN) function, energy status, and uterine health in periparturient dairy cows. Data were collected from 83 multiparous Holstein cows. Blood samples for PMN function determination were collected weekly from 1 week prior to calving (week -1) through 4 weeks after calving and again at 8 weeks after calving. Energy metabolites were measured and dry matter intake (DMI) was determined from weeks -2 to 5 to evaluate energy status of cows during the periparturient period. All cows were examined for uterine health disorders. Blood PMN killing ability was evaluated by determining myeloperoxidase activity and cytochrome c reduction activity in isolated blood PMN's. For cows that were diagnosed with puerperal metritis and subclinical (SC) endometritis and puerperal metritis, blood PMN functions were significantly (P<0.05) impaired during the periparturient period, compared to cows with normal uterine health. Cows with subclinical endometritis and puerperal metritis or SC endometritis also had significantly (P<0.01) higher NEFA and significantly (P<0.001) lower DMI during the periparturient period, and significantly (P<0.05) higher BHBA during early lactation, compared to cows with normal uterine health. Neutrophil function was also significantly (P<0.01) impaired in cows with peripartum negative energy balance, which was characterized by elevated blood levels of NEFA and decreased DMI. Decreased PMN function and energy balance were associated with uterine health disorders and the decreases in PMN function and energy balance occurred prior to parturition and prior to the detection of these uterine disorders.     

Inflammation in the bovine female reproductive tract

Inflammation of the reproductive tract of a cow occurs when the physical and functional barriers to contamination are breached or specific infection occurs. Commonly, contamination occurs at parturition and to a lesser extent at estrus. Uterine contamination following calving is common, but most healthy cows are able to clear the uterus of bacteria in the first 2 to 3 wk after calving. Persistent infections are more likely to be caused by Actinomyces pyogenes. Specific venereal infections tend to be more host-adapted and produce a lower grade inflammation. Nonspecific bacterial contamination of the endometrium generally induces a neutrophilic influx into the stratum compactum and uterine lumen. Neutrophils phagocytize bacteria with the aid of opsonins in the uterine fluid. Mast cells and eosinophils may also contribute to the inflammatory reaction, which may damage the surface epithelium and release vasoactive substances that allow leakage of serum antibodies into the uterine secretions. Specific antibodies of immunoglobulin (Ig) isotype A, M, G1, and G2 in uterine secretions have been described. In model species, the immune capability of the uterus is influenced by steroid hormones, especially estradiol, which increases secretory component and both IgA and IgG content in uterine secretions and increases the activity of antigen-presenting cells in the uterus. Similar cyclic fluctuations in immune components have been described for cows, including changes in the population of subsurface cytotoxic and helper T cells and changes in the expression of major histocompatibility II antigen on surface cells.     

Risk factors for abomasal displacement in dairy cows.

OBJECTIVE: To determine whether various periparturient events or 305-day milk production during the previous lactation period were associated with abomasal displacement in dairy cows. DESIGN: Retrospective, case-control study. ANIMALS: 75 pairs of case and control cows from 3 university-owned and 3 commercial dairy herds. PROCEDURE: Cows with abomasal displacement were matched with control cows on the basis of herd of origin, breed, age, and calving date. Frequency of specific periparturient events during the period from 2 weeks prior to parturition to diagnosis of abomasal displacement, as well as milk production during the preceding lactation period, were compared between case and control cows. RESULTS: Multivariate analyses indicated that case cows were significantly more likely to have had retained placenta, ketosis, a stillborn calf, metritis, twins, or parturient paresis than were control cows. Dystocia, mastitis, and milk production during the previous lactation period were not associated with abomasal displacement. CLINICAL IMPLICATIONS: Results indicated that a variety of periparturient events were associated with development of abomasal displacement among dairy cows.     

Efficacy of immunologic assays for the detection of Johne's disease in dairy cows fed additional energy during the periparturient period.

This study was designed to evaluate if the immunosuppression typically observed during the immediate periparturient period (3 weeks before and after calving) in dairy cows influences the effectiveness of diagnostic tests for the detection of Johne's disease; and, if providing additional energy to the cows during this period would minimize any immunosuppressive effects. Twelve dairy cows naturally infected with Mycobacterium paratuberculosis were fitted with rumen cannulas in late gestation and assigned to treatment groups: control, n = 6; or stuffed, n = 6. Cows in the control group were allowed to consume feed ad libitum. Cows assigned to the stuffed treatment group were also fed ad libitum but received additional total mixed ration by manually stuffing their rumens with refused feed to maintain a dry matter intake of 2% body weight/day before calving and 2.5% body weight/day after calving. Parturition had a significant impact on immune function with significant reductions in M. paratuberculosis-specific antibodies detected in the serum and milk regardless of treatment group. Similarly, in vitro immunoglobulin production was decreased at calving for both treatment groups. In addition, stuffing cows modulated cell-mediated immune function by reducing antigen-specific lymphocyte proliferation and interferon-gamma production after calving. Shedding of M. paratuberculosis in the milk was apparent in 58% (7/12) of cows after parturition with no difference noted between control and stuffed animals. Parturition had no major effect on fecal shedding of cows regardless of treatment. These data suggest that parturition had a significant effect on immune function parameters including diagnostic tests for paratuberculosis. Furthermore, providing additional energy to cows with Johne's disease did not preclude immunosuppressive effects during the periparturient period.     

Comparison of cholesterol levels among lipoprotein fractions separated by anion-exchange high-performance liquid chromatography in periparturient Holstein–Friesian dairy cows

Changes in lipoprotein profiles occur in dairy cows during the periparturient period and in cows with transition cow disease. Here, the lipoprotein profiles of Holstein–Friesian dairy cows during the periparturient period were obtained by anion-exchange, high-performance liquid chromatography to evaluate the usefulness of lipoprotein profile evaluation during the periparturient period and in cows with fatty liver and milk fever. Lipoprotein levels (including total and high- (HDL-C) and low-density lipoprotein (LDL-C) cholesterol) in 10 healthy cows were low 4 weeks prepartum, with the lowest values at calving or within 1 week of calving; the values increased at 8 weeks postpartum. The lipoprotein levels were measured in 16 cows diagnosed with fatty liver (n=10) or milk fever (n=6) and compared to 10 healthy dairy cows. A significant difference was observed in HDL-C between healthy cows (at calving and 1 week postpartum), and the fatty liver and milk fever cows. Cows with fatty liver and milk fever had a lower mean HDL-C than the 10 healthy dairy cows at calving and 1 week postpartum. HDL-C might be a good indicator of energy balance for differentiating healthy cows from those with transition cow disease.     

Mastitis in Post-Partum Dairy Cows

Transition from the dry period to lactation is a high risk period for the modern dairy cow. The biggest challenge at that time is mastitis. Environmental bacteria are the most problematic pathogens around parturition. Coliforms are able to cause severe infections in multiparous cows, and heifers are likely to be infected with coagulase-negative staphylococci. During the periparturient period, hormonal and other factors make the dairy cows more or less immunocompromised. A successful mastitis control programme is focused on the management of dry and calving cows and heifers. Clean and comfortable environment, proper feeding and adequate supplementation of the diet with vitamins and trace elements are essential for maintaining good udder health. Strategies which would enhance closure of the teat canal in the beginning of the dry period and would protect teat end from bacteria until the keratin plug has formed decrease the risk for mastitis after calving. Dry cow therapy has been used with considerable success. Yet, a selective approach could be recommended rather than blanket therapy. Non-antibiotic approaches can be useful tools to prevent new infections during the dry period, in herds where the risk for environmental mastitis is high. Vaccination has been suggested as a means to support the immune defence of the dairy cow around parturition. In some countries, implementation of Escherichia coli core antigen vaccine has reduced the incidence of severe coliform mastitis after calving.     

Use of a uterine pessary to prevent infection of the uterus of the cow after parturition

A uterine pessary containing penicillin, streptomycin, formosulphathiazole and ethinyloestradiol, was assessed for its efficacy in reducing the frequency and severity of uterine infections in cows after parturition. Fifteen pluriparous Holstein Friesian cows had pessaries inserted into the uterus within 24 hours after calving. Compared with 14 similar untreated cows there were significant reductions in the number infected by Actinomyces pyogenes and in the number exhibiting abnormal uterine discharges.     

Advancing parity is associated with high milk production at the cost of body condition and increased periparturient disorders in dairy herds

The objectives of this study were to determine the effects of parity on milk production, body condition change, periparturient health, and culling in Korean dairy herds. The data utilized included; milk yield, body condition score, cow parity, calving condition, periparturient disorders, culling, and reproductive status, which were recorded from 1290 calvings in eight dairy herds. The mean milk yield in cows over 305 days increased with increasing parity (p < 0.01). Cows with parities of 3, 4, and 5 or higher lost more body condition than those with a parity of 1 during month 1 of lactation (p < 0.01), and body condition recovery by cows with parities of 4 and 5 or higher was slower (p < 0.01) than recovery by cows with parities of 1, 2, or 3 until month 3 of lactation. The risk of retained placenta, metabolic disorder, and endometritis also increased with advancing parity (p < 0.05). Moreover, the incidence of ovarian cysts was lower in cows with a parity of one than in cows with greater parities (p < 0.01). Culling rate due to reproductive failure also increased with advancing parity (p < 0.01). These results suggest that parity increases milk yield, body condition loss during early lactation, the risk of periparturient disorders, and culling due to reproductive failure in dairy herds.     

Risk factors for udder edema and its association with lactation performance on primiparous Holstein cows in a large Florida herd, U.S.A

The objective of this study was to determine risk factors for udder edema (case–control study) and to evaluate the association of udder edema in primiparous Holstein cows with their lactation performance (cohort study). Values for the first 10 test day for milk yield, fat, protein, and somatic cell counts (SCC) linear score as well as mature equivalent (ME) 305 days milk yield, fat, protein, SCC linear score, and incidences of periparturient diseases from a computerized farm recording system were compared between primiparous cows with and without udder edema. Data consisted of 118 dairy heifers with udder edema, induced for parturition, and treated with diuretics and 889 control heifers that received no treatment. Primiparous cows giving birth to male calves, were 1.72 (1.01, 3.24; 95% CI) times more likely to develop udder edema than cows giving birth to female calves. Primiparous cows calving in winter season were 3.68 (1.09, 12.5; 95% CI) times more likely to develop udder edema than cows calving in summer. For each extra 10 cm in height the odds of udder edemas was 1.23 (1.03, 1.47; 95% CI). The first test day DHIA milk yield was lower in cows that developed udder edema (3.6 kg/day) than in normal cows. However, the subsequent test days and ME measurements were not statistically different between groups. Cows with udder edema were 1.62 (1.18, 2.14; 95% CI) times more likely to develop udder edema in the second lactation than control animals. It is concluded that the gender of the offspring, calving season and height at parturition were significant risk factors for udder edema. Only milk yield on the first DHIA test day was lower in cows with udder edema than in cows without udder edema.