Serum IgG Concentrations after Intravenous Serum Transfusion in a Randomized Clinical Trial in Dairy Calves with Inadequate Transfer of Colostral Immunoglobulins

Background: Plasma transfusions have been used clinically in the management of neonates with failure of passive transfer. No studies have evaluated the effect of IV serum transfusions on serum IgG concentrations in dairy calves with inadequate transfer of passive immunity.
Hypothesis: A commercially available serum product will increase serum immunoglobulin concentration in calves with inadequate transfer of colostral immunoglobulins.
Animals: Thirty-two Jersey and Jersey-Holstein cross calves with inadequate colostral transfer of immunoglobulins (serum total protein <5.0 g/L).
Methods: Thirty-two calves were randomly assigned to either control (n = 15) or treated (n = 17) groups. Treated calves received 0.5 L of a pooled serum product IV. Serum IgG concentrations before and after serum transfusion were determined by radial immunodiffusion.
Results: Serum protein concentrations increased from time 0 to 72 hours in both control and transfused calves and the difference was significant between the control and treatment groups ( P < .001). Mean pre- and posttreatment serum IgG concentrations in control and transfused calves did not differ significantly. Median serum IgG concentrations decreased from 0 to 72 hours by 70 mg/dL in control calves and increased over the same time interval in transfused calves by 210 mg/dL. The difference was significant between groups ( P < .001). The percentage of calves that had failure of immunoglobulin transfer 72 hours after serum transfusion was 82.4%.
Conclusions and Clinical Importance: Serum administration at the dosage reported did not provide adequate serum IgG concentrations in neonatal calves with inadequate transfer of colostral immunoglobulins.     

Factors Associated with Failure of Passive Transfer of Colostral Antibodies in Standardbred Foals

The records of 361 Standardbred mares and their 1986 or 1987 foals were evaluated to identify factors associated with failure of passive transfer (FPT) of colostral antibodies in equine neonates. Sixty-five foals (18%) were classified as FPT based on a serum immunoglobulin concentration of less than 400 mg/dl at 24 to 36 hours of age, determined by the glutaraldehyde coagulation test. The potential association of mare- and foal-related factors with FPT were assessed by reviewing a series of multiple logistic regression models. The season in which the mare foaled and foal exam score, a subjective assessment of foal vigor, maturity, and general health, were the primary factors associated with the development of FPT. Foals with FPT were more likely (odds ratio = 3.50; 95% confidence interval = 1.81-6.68) than normal foals to require medical therapy during the first 3 months after parturition.     

Evaluation of Digital and Optical Refractometers for Assessing Failure of Transfer of Passive Immunity in Dairy Calves

Background

Failure of transfer of passive immunity (FTPI) is the underlying predisposing risk factor for most early losses in dairy calves. Refractometers, either optical or digital, can be used to assess FTPI as a part of calf health monitoring program on dairy operations.

Objectives

To evaluate the performance of and differences between digital Brix and optical refractometers for assessing FTPI in dairy calves.

Animals

Two hundred Holstein calves from 1 to 11 days of age.

Methods

A cross‐sectional study was designed to measure serum IgG concentration by radial immunodiffusion (RID) assay, digital Brix and optical refractometers. The correlation coefficients (r) between the 2 refractometers were plotted against each other and against the measured IgG concentration from RID. The Se, Sp, and accuracy of digital Brix and optical refractometers for assessing FTPI using previously recommended cut‐offs were calculated. A receiver operating characteristic curve was created and used to identify the optimal cut‐off for this dataset.

Results

The RID IgG concentration was positively correlated with digital Brix (r = 0.79) and optical (r = 0.74) refractometers. The best combination of Se (85.5%), Sp (82.8%), and accuracy (83.5%) of digital Brix refractometer was at 8.3%Brix. For optical refractometer, the best combination of Se (80%), Sp (80.7%), and accuracy (80.5%) was at 5.5 g/dL.

Conclusions and Clinical Importance

Both refractometers exhibited utility in assessing FTPI in dairy calves.     

Risk Indicators Associated with Subclinical Mastitis in Smallholder Dairy Cows in Tanzania

Smallholder dairy farmers in Tanzania appear to be unaware of the subclinical mastitis situation in their cows. A cross-sectional study was carried out between June and September 2002 on smallholder dairy herds in the Dar es Salaam region. The study objectives were to establish the prevalence of subclinical mastitis and related risk indicators, and to assess their contribution to the occurrence of subclinical mastitis. Three field procedures based on the principles of herd health and production management were followed: clinical, farm and data inspection. The California mastitis test (CMT) was carried out on quarter milk samples to determine the prevalence of subclinical mastitis. A total of 182 lactating cows from 62 herds were investigated. Clinical inspection indicated that 3.8% of the lactating cows had clinical mastitis. Subclinical mastitis was detected in 90.3% of lactating cows screened. Farm inspection revealed that water scarcity, barn size, residual suckling, single udder-towel and dairy labourers as the most substantial (p < 0.05) risk indicators. Although most of the risk indicators studied were not found to be statistically significantly associated with the occurrence of subclinical mastitis, possibly owing to sample size and the presence of confounders, the epidemiological need to address such risk indicators cannot be overemphasized.     

Use of Serum Protein Concentration to Predict Mortality in Mixed-Source Dairy Replacement Heifers

The relationship between serum protein concentration in the 1st week of life and survival to 16 weeks of age was examined in 3,479 Holstein replacement heifers over a period of 10 years on a farm with endemic salmonellosis. Thirty-four percent of calves studied had serum protein concentrations <5.0 g/dL and 60.5% of calves had serum protein concentrations <5.5 g/dL. Cumulative mortality was 7.9%, indicating that calves with marginal passive transfer status can be reared successfully under conditions of endemic salmonellosis. Optimal survival was observed in calves with serum protein concentrations >5.5 g/dL. Calves with serum protein concentrations of 5.0–5.4 g/dL had only a slightly increased relative risk (RR) of mortality (RR = 1.3) compared to calves with serum protein concentrations >5.5 g/dL. The highest RR was experienced by calves with serum protein concentrations <4 g/dL (RR = 4.6) and 4.0–4.4 g/dL (RR = 3.1). Calves with inadequate passive transfer (serum protein concentration <5.0 g/dL), experienced increased mortality until at least 10 weeks of age, indicating that failure of passive transfer has an effect on calf health that extends into the juvenile period. Models in which serum protein concentration was treated either as a continuous variable or as a categorical variable failed to demonstrate any significant interaction between baseline mortality and the RR of mortality. This finding suggests that the RR derived in the present study should be applicable to farms with dramatically different baseline mortality rates.     

Systematic Review and Meta‐Analysis of Diagnostic Accuracy of Serum Refractometry and Brix Refractometry for the Diagnosis of Inadequate Transfer of Passive Immunity in Calves

Background

Transfer of passive immunity in calves can be assessed by direct measurement of immunoglobulin G (IgG) by methods such as radial immunodiffusion (RID) or turbidimetric immunoassay (TIA). IgG can also be measured indirectly by methods such as serum refractometry (REF) or Brix refractometry (BRIX).

Objectives

To determine the accuracy of REF and BRIX for assessment of inadequate transfer of passive immunity (ITPI) in calves.

Design

Systematic review and meta‐analysis of diagnostic accuracy studies.

Methods

Databases (PubMed and CAB Abstract, Searchable Proceedings of Animal Science) and Google Scholar were searched for relevant studies. Studies were eligible if the accuracy (sensitivity and specificity) of REF or BRIX was determined using direct measurement of IgG by RID or turbidimetry as the reference standard. The study population included calves <14 days old that were fed with natural colostrum (colostrum replacement products were excluded). Quality assessment was performed by the QUADAS‐2 tool. Hierarchical models were used for meta‐analysis.

Results

From 1,291 references identified, 13 studies of 3,788 calves were included. Of these, 11 studies evaluated REF and 5 studies evaluated BRIX. The median (range) prevalence of ITPI (defined as calves with IgG <10 g/L by RID or TIA) was 21% (1.3–56%). Risk of bias and applicability concerns were generally low or unclear. For REF, summary estimates were obtained for 2 different cutoffs: 5.2 g/dL (6 studies) and 5.5 g/dL (5 studies). For the 5.2 g/dL cutoff, the summary sensitivity (95% CI) and specificity (95% CI) were 76.1% (63.8–85.2%) and 89.3% (82.3–93.7%), and 88.2% (80.2–93.3%) and 77.9% (74.5–81.0%) for the 5.5 g/dL cutoff. Due to the low number of studies using the same cutoffs, summary estimates could not be obtained for BRIX.

Conclusions and Clinical Importance

Despite their widespread use on dairy farms, evidence about the optimal strategy for using refractometry, including the optimal cutoff, are sparse (especially for BRIX). When using REF to rule out ITPI in herds, the 5.5 g/dL cutoff may be used whereas for ruling in ITPI, the 5.2 g/dL cutoff may be used.     

Evaluation of a Whole Blood Glutaraldehyde Coagulation Test for the Detection of Failure of Passive Transfer in Calves

The accuracy of a commercially available whole blood glutaraldehyde clot test in the detection of failure of passive transfer (serum immunoglobulin [Ig]G₁ < 1,000 mg/dL) in neonatal calves was evaluated. Serum samples were obtained from 242 calves ranging in age from 1 to 8 days, and comparisons were made with serum lgG₁ concentrations determined by radial immunodiffusion. Both the sensitivity and specificity of the currently marketed whole blood glutaraldehyde clot test are inadequate for routine diagnostic use. Concerns regarding test sensitivity are the most problematic. Sensitivity varied from 0.41 to 0.00, depending on the choice of test endpoint. Specificity varied from 0.85 to 1.00, depending on the choice of test endpoint. Regression analysis demonstrated that the relationship between serum lgG₁ concentration and the glutaraldehyde clot results, although significant (P< .10), was of negligible biological relevance ( r ² = .034). J Vet Intern Med 1996; 10:82–84. Copyright © 1996 by the American College of Veterinary Internal Medicine .     

乳品中硫氰酸盐的来源及其风险分析

硫氰酸盐曾作为生鲜奶的保鲜剂被广泛使用,但因其毒性,已被我国列为乳及乳制品中的非法添加物质.鉴于硫氰酸盐的毒性作用,我们对市售乳品的硫氰酸盐含量进行风险监测,并对乳品中硫氰酸盐可能对人类健康造成的危害进行风险分析,结果发现852个监测样品中的硫氰酸含量均小于10mg/kg,其中25.9％样品的硫氰酸根含量低于1 mg/kg,仅有6.24％的样品含量在5～10mg/kg之间.由此,我们分析了乳品中硫氰酸盐的可能来源,认为852个市售乳制品中的硫氰酸盐主要来源于动物生鲜乳的自身本底,系非法添加的可能性极低.     

奶牛真胃变位发病原因研究进展

奶牛真胃变位的发病原因可能与真胃壁中肠道神经元功能性紊乱有关,这对揭示奶牛真胃变位的发病机制有重要意义.真胃变位奶牛肠道神经元的一氧化氮合酶活性升高,乙酰胆碱敏感性降低,真胃的运动力减弱和排空机能受损可能与这种异常关系有关,即抑制肠道神经元的增强活性,皱胃肌肉的胆碱能神经敏感性降低.流行病学调查和试验研究已证实真胃迟缓和真胃扩张是奶牛真胃变位的主要原因,同时,品种、遗传背景、双胎、泌乳早期阶段(特别是第1周)富含高精料日粮而缺乏优质粗饲料、代谢紊乱性疾病(酮病、脂肪动员增加、胰岛素抗药性)和其他并发疾病(子宫内膜炎、乳房炎、蹄病)等都是真胃变位发生的诱发因素.     

Risk Factors for Dairy Cow Mastitis in the Central Highlands of Ethiopia

This study, with the objective of assessing the effect of risk factors on dairy cow mastitis in the central highlands of Ethiopia, was undertaken between February and September 2001 in the urban and peri-urban areas of Addis Ababa, Ethiopia. A prevalence study and questionnaire survey were carried out simultaneously. Clinical examination of lactating udders and California mastitis test (CMT) determined clinical and subclinical mastitis, respectively. Risk factors for subclinical and clinical mastitis were identified from data on animals and farm management by chi-square analysis and subsequent logistic regression. Cows aged at least 8 years, with poor body condition, with at least 8 parities and in at least the eighth month of lactation had a significantly higher risk for subclinical mastitis (p < 0.05). The risk was reduced for cows up to their third parity in good body condition and for cows receiving dry cow therapy. Cows aged at least 4 years, or with at least 8 parities, cows in at least the fourth month of lactation, cows with poor body condition, leaking milk or previous udder infections had a significantly higher risk of clinical mastitis (p <0.05). The risk was reduced by the use of separate towels for udder cleaning and by drying off at the end of lactation. Most of the risk factors were in agreement with previous reports. However, stage of lactation and drying-off style were in contrast to others. Further research is needed to identify the interrelationship between production level, specific pathogens and management risk factors.     

日粮添加包被氯化铵对围产期奶牛健康的影响

本试验旨在探讨在围产前期日粮中添加包被氯化铵(美宝安)对奶牛健康的影响.试验采用分阶段环比比较,根据奶牛尿液pH值和产后瘫痪情况调整日粮DCAD值:不添加美宝安、仅饲喂基础日粮,此期有62头围产牛,为试验前阶段;日粮添加180g美宝安,此期有30头围产牛,为试验开始阶段(DCAD1);日粮添加180g美宝安+70gCa...     

肉犊牛小肠黏膜免疫相关细胞的数量变化研究

分别选择1、4、6月龄各4头利杂犊牛的十二指肠、空肠、回肠,利用组织化学法和图像分析法研究犊牛小肠的上皮内淋巴细胞、杯状细胞和肥大细胞的数量变化.结果显示在同一月龄犊牛的小肠的上皮内淋巴细胞数量由十二指肠向空肠、回肠逐渐减少,而杯状细胞的数量逐渐增加,肥大细胞的密度逐渐降低.在1、6月龄犊牛十二指肠、空肠、回肠的上皮内淋巴细胞数量之间差异极显著(P＜0.01);4月龄十二指肠的上皮内淋巴细胞数量最多(P＜0.01).在1月龄犊牛十二指肠、空肠、回肠杯状细胞的数量差异极显著(P＜0.01);4和6月龄犊牛十二指肠和空肠之间的杯状细胞的数量差异不显著(P＞0.05),但二者与犊牛回肠杯状细胞的数量差异极显著(P＜0.01).各年龄犊牛十二指肠、空肠、回肠的肥大细胞密度差异极显著(P＜0.01),4月龄时犊牛小肠的肥大细胞密度最低.结果提示犊牛的黏膜免疫水平可能与其机体的发育相一致.     

中国规模化牧场后备奶牛饲养管理现状

后备奶牛饲养管理是牧场牛群管理工作的重要组成部分.调研结果显示,在我国规模化牧场中,饲喂常乳的牧场占比最高,为70.6％,饲喂代乳粉的牧场占比达57.7％,并有38.5％的牧场饲喂废弃乳.在牛奶饲喂量方面,有6％的牧场哺乳期喂奶量在300kg/头以下,大部分牧场(48.8％)喂奶量在400～600kg/头之间,也有部分...     

Risk factors for mortality associated with respiratory disease among Menz and Horro sheep in Ethiopia

A retrospective case-control study was conducted on 6718 sheep of two breeds (2772 Horro and 3946 Menz) on risk factors for mortality associated with respiratory disease (MARD) in Ethiopia, based on data collected between October 1993 and December 1997. Potential risk factors examined were breed, gender, age, month, and air temperatures.Fifty-four per cent of total deaths in the flock could be attributed to respiratory disease and the annual MARD rate ranged between 6.3 and 19.0%. There was significant breed (P<0.0001) and gender (P<0.0001) difference in MARD. The Horro breed had a higher (P<0.0001) annual MARD than the Menz breed (16.5+/-0.18 vs. 12.4+/-0.15%). A higher (P<0.0001) proportion of males suffered than females (15.1+/-0.23% vs. 13.8+/-0.13%). Age was also an important risk factor for MARD: there was a strong polynomial relationship (R(2)=0.91, P<0.0001) between MARD and age; the risk of being young if a sheep was a MARD case was high. MARD was high between October and March but relatively low between the months of April and September. There was a significant (P<0.05) negative cubic relationship (R(2)=0.49) between monthly MARD and monthly average minimum air temperatures. There was also a significant (P<0.01) positive exponential relationship (R(2)=0.61) between monthly MARD and average monthly daily deviation between maximum and minimum air temperatures.Timely health and management interventions focusing on these factors are necessary to alleviate losses from MARD. Understanding variations in MARD risk within a population can enhance early response to potential outbreaks, reducing losses.