Scanning electron microscopy aided observations on and therapy of teat canal infections

An examination of teat canal swabs established that 51 teat canals out of 68 quarters of machine milked cows were colonized by Staphylococcus aureus. Only 31 of these quarters yielded milk from which S. aureus could be cultured, and 6 out of the 31 produced milk containing somatic cell counts in excess of 500 000/mℓ. No inhibitory substances could be detected in milk samples 12h after 10 mg of sodium cloxacillin had been deposited in the teat canal on 1-4 successive occasions. Teat canal swabs and milk sample cultures of the same quarters became and remained bacteriologically negative for at least a week after the last treatment. Six quarters, which according to the International Dairy Federation criteria were suffering from subclinical mastitis, became negative after local teat canal therapy. Scanning electron micrographs of one infected teat canal revealed the presence of cocci in depressions and crevices on the epithelial surface, suggesting that such cocci are not always flushed out into milk samples. Teat canal therapy should make a marked contribution to the control of bovine mastitis.This article has been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-Format

Isolation and significance of anaerobic bacteria isolated from cases of bovine mastitis

The role of obligate anaerobic bacteria in the aetiology of mastitis of lactating dairy cows was investigated. Anaerobes were isolated from 12% of lactating mastitic cows, which were representative of 50% of the 10 dairy herds examined. Bacteroides fragilis was the most frequently isolated organism (50%), followed by Peptococcus indolicus (33%), Eubacterium lentum (33%), E. aerofaciens (17%), Propionibacterium granulosum (17%) and an anaerobic Streptococcus sp. (17%). These obligate anaerobes were always isolated together with organisms classically involved in mastitis. It was possible to induce overt clinical mastitis in healthy lactating udders within 24 hours by infection with single pure cultures of anaerobes via the teat canal. All B. fragilis strains were resistant to penicillin G and tetracycline. In addition, one strain was also resistant to ampicillin, cephalothin and amoxicillin. Anaerobic gram positive cocci and bacilli were sensitive to most antibiotics. These findings imply an important role for anaerobes in the aetiology of mastitis.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

The isolation and attenuation of a virus causing rhinotracheitis in turkeys in South Africa

In March 1978, a number of turkeys with severe respiratory symptoms affecting over 80 % of the flock were investigated for a possible causative agent. With the standard techniques used for the isolation of bacteriae, mycoplasmae and viruses, only Mycoplasma gallisepticum, Mycoplasma meleagridis and Newcastle disease virus were isolated. Tracheal organ cultures were subsequently prepared from 27- day-old turkey embryos and inoculated with sinus exudate from affected turkeys. After an incubation period of 4 days a virus was isolated with which the typical symptoms, as observed in the field, could be reproduced in susceptible turkeys after 3-5 days. Following primary isolation in tracheal organ cultures, the virus grew readily in embryonated eggs and Vero cells. With the electron microscope, virus-like particles, varying in size from 40 nm-500 nm, were observed, having a pleomorphic shape and studded with fine surface projections. The virus seems to fall into the family Paramyxoviridae. A vaccine produced from attenuated virus in embryonated eggs afforded good protection against mortalities due to airsacculitis that normally follows on to turkey rhinotracheitis infection. The serological and clinical effects of the virus on chickens are also reported on.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

Effect of heat-stress on conception in a dairy-herd model in the Natal highlands of South Africa

Regression models are proposed for predicting conception rate in a dairy herd under South African and especially Natal conditions. Conception rate (CR%) was related to mean monthly temperature-humidity index (THI) by curvilinear regression equation model; CR% = -812,7 + 28,61THI - 0,2322THI² (P = 0,061), and by linear regression equation model; CR% = 188,0 - 1,906THI (P = 0,023). Conception rate was related to numerical month of the year (M) by: CR% = 44,34 + 6,168M - 0,428M² (P = 0,1 06). Further investigations to test the proposed regression models under various dairy-herd conditions and to improve reproduction in South African dairy herds are needed.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Heat stress in dairy cattle under southern African conditions. II. Identification of areas of potential heat stress during summer by means of observed true and predicted temperature-humidity index values

November-March are the hottest months of the year with the highest monthly mean "temperature-humidity index" (THI) in South Africa and Namibia. These 5 months are associated with severe heat stress in dairy cattle, are of critical importance for their performance and may have great economic implications for the owner as well as for the dairy industry. Firstly, compared with the existing Livestock Weather Safety Index (LWSI), more relevant meteorological data can be generated when mapping South Africa and Namibia according to the LWSI modified for lactating dairy cattle (LDC). Secondly, compared with the observed true THI values alone, more relevant data on heat stress and its deleterious effects on dairy cattle performance, become available when mapping South Africa and Namibia according to the combined observed true and predicted THI values. Minimum precautions against heat stress in dairy cattle are recommended depending on THI values as classified by the LWSI for LDC.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Heat stress in dairy cattle and other livestock under southern African conditions. III. Monthly temperature-humidity index· mean values and their significance in the performance of dairy cattle

Temperature-humidity index (THI) values applicable to South Africa and Namibia have been established during this investigation for each month of the year by means of computerized modelling and mapping techniques. The data indicate that each year heat stress risk areas (HSRA's) expand from August to January and retract from February to July. The THI values classified according to the Livestock Weather Safety Index (LWSI) for lactating dairy cattle (LDC), suggest that, especially during November to March there is the risk of moderate to advanced heat stress in most South African dairy cows. This has important implications for their general health, udder health, production and reproduction. Careful planning of facilities and highly adaptable herd management are required to protect dairy cattle from heat stress.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Turkey meningoencephalitis in South Africa

Turkey meningo-encephalitis is a neuroparalytic disease of turkey’s first described and shown to be caused by a flavivirus in Israel. During 1978 a similar disease was observed in South Africa. In addition to the lesions described in Israel, myocarditis, regression of the ovary and egg peritonitis were constant findings. The similarity in host range, symptoms and pathological changes produced by the virus isolated locally and in Israel and the serological cross-reaction between the 2 virus isolates indicate that they are identical.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

Parameters for the determination and evaluation of heat stress in dairy cattle in South Africa

Not all parameters are trustworthy and practical to use as parameters to determine heat stress in dairy cattle. The temperature-humidity index (THI) is still the best, simplest and most practical index (parameter) for measurement of environmental warmth which cause heat stress in dairy cattle. It is practical, easy to determine and relatively trustworthy to use body temperature and respiratory rate as parameters to determine heat stress in dairy cattle. These physiological parameters must always be used together with THI values to determine and evaluate heat stress in dairy cattle. For practical purposes, plasma cortisol concentration and milk composition cannot be used as parameters to determine heat stress in dairy cattle although good indications of acute or chronic heat stress can be obtained. Vanillic acid is a break-down product of adrenalin found in milk, but before its concentration in milk can be used as an indicator/parameter of heat stress in dairy cows, more about the pharmacodynamics of adrenaline in the milk has to be known. Selection and breeding of dairy cows on the basis of their adaptibility to heat stress using the most practical heat stress parameters will ensure that their offspring will have superior performance in the prevailing environmental conditions.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Bovine mastitis therapy and why it fails : continuing education

Treatment of bovine mastitis depends on the cause, the clinical manifestation and the antibiotic susceptibility of the agent. Mastitis therapy is commonly unsuccessful owing to pathological changes that occur in the udder parenchyma as a result of the inflammatory reaction to mastitogenic bacteria, pharmacokinetic properties of antimicrobial mastitis drugs, mastitogenic bacterial and related factors, and poor animal husbandry and veterinary interventions