An Evaluation of Renal Care received by Human Immunodeficiency Virus (HIV) Patients admitted in a Tertiary Hospital in Sierra Leone.

INTRODUCTION: The burden of HIV is on the rise and patients with HIV are also vulnerable to renal impairment from both acute and chronic causes. This study sets out to evaluate renal care received by such patients. METHODS: The study was conducted at Connaught Hospital, the main tertiary hospital (for medical and surgical cases) in the country. A retrospective review of all admitted patients with HIV between January and December 2019. Data was collected using a well- structured study proforma. RESULTS: A total of 230 patients were admitted with HIV during the study period. The mean age of patients was 36.9 ± (11.5) years with a female preponderance of 61.3%. A vast majority of the patients (54.8%) could afford to do some renal investigations and only 13.9% were seen by renal physicians; 69.1% of patients with azotaemia died while on admission. CONCLUSION: The extent of renal care observed from the study was poor because the majority of the patients were not seen by renal physicians and could not afford renal investigations. Also, the occurrence of renal impairment in patients with HIV suggests a poor prognosis.

INTRODUCTION: Le fardeau du VIH est en augmentation et les patients séropositifs sont également vulnérables à l'insuffisance rénale due à des causes aiguës et chroniques. Cette étude a pour but d'évaluer les soins rénaux reçus par ces patients. MÉTHODES: L'étude a été menée à l'hôpital Connaught, le principal établissement tertiaire (pour les cas médicaux et chirurgicaux) du pays; un examen rétrospectif de tous les patients admis avec le VIH entre janvier et décembre 2019. Les données ont été recueillies à l'aide d'un proforma d'étude bien structuré. RÉSULTATS: Un total de 230 patients ont été admis avec le VIH au cours de la période d'étude. L'âge moyen des patients était de 36,9±(11,5) ans avec une prépondérance féminine de 61,3%. La grande majorité des patients (54,8 %) pouvaient se permettre de faire quelques examens rénaux et seuls 13,9 % ont été vus par des médecins spécialisés dans les maladies rénales; 69,1 % des patients atteints d'azotémie sont décédés pendant leur admission. CONCLUSION: L'étendue des soins rénaux observés dans cette étude est faible car la majorité des patients n'ont pas été vus par des médecins rénaux et ne pouvaient pas se permettre de faire des examens rénaux. De plus, la présence d'une insuffisance rénale chez les patients atteints du VIH suggère un mauvais pronostic. Mots clés: Soins rénaux, patients VIH, Hôpital tertiaire, Sierra Leone.

Acute Pulmonary Embolism in an Intensive Care Unit Setting in Sierra Leone.

INTRODUCTION: In Sierra Leone, the lack of information on pulmonary embolism (PE) limits the access to evidence-based standard of diagnostic work-up and management of the disease. The objective of this study was to describe the clinical characteristics and management of acute pulmonary embolism in our setting and to determine whether the pre-test probability scoring algorithms were used prior to Computed Tomography Pulmonary Angiogram (CTPA) request. METHODS: This retrospective observational study was conducted on CTPA-confirmed PE patients admitted to the Intensive Care Unit, Choithrams Memorial Hospital, in Freetown, Sierra Leone between July 2014 to June 2019. Clinical data, and pertinent investigations related to PE were determined. CTPA findings were correlated with the patient's hemodynamic status. The calculated pretest clinical probability scores (PCPS) for each patient were compared to the CTPA results. RESULTS: CTPA-confirmed PE in the study cohort was 79, with a rate of 16 new PE per year. The frequency of PE was 1.9% of the total hospital admission per year. The mean age was 64.1 ± 17.9 years, median age was 63.3years (range: 23-89 years), with 55.7% of the cohort being females. Dyspnea (78.5%) and tachycardia (69.6%) were the commonest signs and symptoms documented, with immobilization (34.2%) being the prevalent risk factor, while hypertension (48.1%) was the most common co-morbidity. The PCPS algorithm was underutilized, as "Wells Score" was documented in only 9.5% while "modified Geneva score" was never used by hospital physicians. PE with hemodynamic stability was significantly more common than PE with unstable hemodynamic status [55 (69.6%) vs 24 (30.4%), p=0.015]. All patients were managed only with anticoagulants. The overall in-hospital mortality was 17.7%. CONCLUSION: Since PCPS was hardly calculated by doctors in the diagnosis of PE, the study showed that the diagnostic algorithm for suspected PE was infrequently used in clinical practice. The use of empirical judgement by doctors in requesting for CTPA may have accounted for low rate in the diagnosis of PE per year. The establishment of P.E registry in Sierra Leone is imperative.

INTRODUCTION: En Sierra Leone, le manque d'informations sur l'embolie pulmonaire (EP) limite l'accès à des normes de diagnostic et de prise en charge de la maladie fondées sur des preuves. L'objectif de cette étude était de décrire les caractéristiques cliniques et la prise en charge de l'embolie pulmonaire aiguë dans notre établissement et de déterminer si les algorithmes de notation de la probabilité pré-test étaient utilisés avant la demande d'angiographie pulmonaire par tomodensitométrie (CTPA). MÉTHODES: Cette étude observationnelle rétrospective a été menée sur des patients atteints d'EP confirmée par CTPA admis à l'unité de soins intensifs, Choithrams Memorial Hospital, à Freetown, Sierra Leone, entre juillet 2014 et juin 2019. Les données cliniques, et les investigations pertinentes liées à l'EP ont été déterminées. Les résultats du CTPA ont été corrélés avec l'état hémodynamique du patient. Les scores de probabilité clinique prétest (PCPS) calculés pour chaque patient ont été comparés aux résultats du CTPA. RÉSULTATS: Le nombre d'EP confirmées par CTPA dans la cohorte étudiée était de 79, avec un taux de 16 nouvelles EP par an. La fréquence de l'EP était de 1,9 % du nombre total d'hospitalisations par an. L'âge moyen était de 64,1 ± 17,9 ans, l'âge médian de 63,3 ans (fourchette : 23-89 ans), 55,7 % de la cohorte étant des femmes. La dyspnée (78,5 %) et la tachycardie (69,6 %) étaient les signes et symptômes les plus fréquemment documentés, l'immobilisation (34,2%) étant le facteur de risque prévalent, tandis que l'hypertension (48,1 %) était la comorbidité la plus courante. L'algorithme PCPS était sous-utilisé, le " score de Wells " n'étant documenté que dans 9,5 % des cas, tandis que le " score de Genève modifié " n'était jamais utilisé par les médecins hospitaliers. L'EP avec stabilité hémodynamique était significativement plus fréquente que l'EP avec état hémodynamique instable [55 (69,6 %) vs 24 (30,4 %), p=0,015]. Tous les patients ont été traités uniquement par anticoagulants. La mortalité globale à l'hôpital était de 17,7 %. CONCLUSION: Étant donné que le PCPS était rarement calculé par les médecins pour le diagnostic de l'EP, l'étude a montré que l'algorithme diagnostique pour l'EP suspectée était rarement utilisé dans la pratique clinique. L'utilisation d'un jugement empirique par les médecins pour demander un CTPA peut expliquer le faible taux de diagnostic de l'EP par an. L'établissement d'un registre de l'E.P. en Sierra Leone est impératif. Mots-clés: Embolie pulmonaire, caractéristiques cliniques, gestion, Sierra Leone.

Persistent left superior vena cava in a 29-year-old lady with Ebstein's anomaly and complete heart block. A case report and literature review.

Introduction: Persistent Left Superior Vena Cava (PLSVC) is a rare congenital vascular anomaly that may occur alone or in combination with complex congenital heart anomalies and dangerous arrhythmias. We report the first case in the literature of combined PLSVC, Ebstein's Anomaly (Type A) and complete atrioventricular block in an adult female, being successfully managed with permanent pacemaker implantation in Sierra Leone. Case summary: We present an interesting case of a 29-year-old female, referred to the cardiology clinic on account of breathlessness, dizziness, and recurrent syncope. Physical examination revealed a pulse rate of 39 bpm, jugular venous pulse with occasional cannon waves, and grade 3/6 pansystolic murmur in the tricuspid valve area. An electrocardiogram confirmed complete atrioventricular block with junctional escape rhythm, while Transthoracic Echocardiogram (TTE) confirmed Ebstein's Anomaly (Type A) and moderate tricuspid regurgitation. PLSVC was discovered as an incidental intraprocedural finding. Deploying a pacemaker lead through this venous anomaly from the left side was futile. Nevertheless, we used a right sided approach that resulted in a successful permanent pacemaker implantation with optimal and stable parameters. Conclusion: This rare case report highlights the practical challenges often encountered in the practice of cardiology during pacemaker and other cardiac device implantation. Cardiologists and critical care physicians should be acquainted with the venous anomaly of PLSVC, its variants, and procedure-associated risks, for better clinical decision making.

Prevalence, Awareness and Risk Factors of Hypertension among Health Workers at the Connaught Teaching Hospital, Sierra Leone.

BACKGROUND: Hypertension among the health workforce is a major public health problem due to its high prevalence and dire consequences. This study aimed to determine the prevalence of hypertension, awareness, and related cardiovascular risk factors among health workers in a Teaching Hospital in Sierra Leone. METHODS: This was a cross-sectional descriptive study conducted among 250 health workers. A modified World Health Organization Non-Communicable Disease (WHO NCD) questionnaire was used to collect information on the socio-demographic characteristics, anthropometric, and lifestyle variables. RESULTS: The prevalences of hypertension and pre-hypertension were 37.2% and 22.4% respectively. The level of hypertension awareness was 36.6 %. The univariate logistic regression showed a significant crude odds ratio for gender, age, marital status, smokers, alcohol, extra sugar to tea/coffee, years of employment, weight, Waist Circumference, Hip Circumference, and Waist-Hip-Ratio (WHR) in the prediction of hypertension. The multivariate logistic regression revealed that male sex (AOR = 1.89; C.I 95%: [0.01- >20], p = 0.002), duration of employment (AOR = 0.36; C.I 95%: [0.17- 0.94], p = 0.01), and Waist Circumference (WC) (AOR = 1.46; C.I 95%: [0.58 - 3.68], p = 0.017), were positive predictors of hypertension. Males were about 2 times more likely to have hypertension, (AOR = 1.89; C.I 95%: [0.01- >20]). Participants with abnormal Waist Circumference (WC) were 1.5 times more likely to have hypertension (AOR = 1.46; C.I 95%: [0.58 - 3.68]). CONCLUSION: The prevalence of hypertension in this study population was slightly higher than the 34.8% reported for the general population even though this study population is relatively younger. The level of awareness was low. This calls for the implementation of an effective workplace health education program to improve lifestyle and reduce the risk of cardiovascular diseases.

Seismic observations, numerical modeling, and geomorphic analysis of a glacier lake outburst flood in the Himalayas.

Glacial lake outburst floods (GLOFs) are a substantial hazard for downstream communities in vulnerable regions, yet unpredictable triggers and remote source locations make GLOF dynamics difficult to measure and quantify. Here, we revisit a destructive GLOF that occurred in Bhutan in 1994 and apply cross-correlation-based seismic analyses to track the evolution of the GLOF remotely (~100 kilometers from the source region). We use the seismic observations along with eyewitness reports and a downstream gauge station to constrain a numerical flood model and then assess geomorphic change and current state of the unstable lakes via satellite imagery. Coherent seismic energy is evident from 1 to 5 hertz beginning approximately 5 hours before the flood impacted Punakha village, which originated at the source lake and advanced down the valley during the GLOF duration. Our analysis highlights potential benefits of using real-time seismic monitoring to improve early warning systems.

Stroke in Sierra Leonean Africans:Perspectives from a Private Health Facility.

BACKGROUND: Several stroke studies in West Africans have demonstrated a high proportion of haemorrhagic stroke and poor outcomes. This may be due to the socioeconomic status of patients and inadequate clinical care. Outcomes may well be different if more informed patients treated in better facilities are studied. OBJECTIVE: To study the pattern of stroke and stroke outcomes in African patients attending a private hospital in Sierra Leone METHODS: 150 consecutive African stroke patients admitted to a private hospital in Sierra Leone were studied. Demographic details, risk factors, clinical features including blood pressure were recorded. CT scans, ECG, serum cholesterol, and blood sugar were done. Patients were reviewed at day 30 and Rankin scores allocated. Two sample independent t-test was used to compare means, and chi square to compare variables. RESULTS: Hypertension was the most common risk factor present in 77.6% of patients prior to admission with diabetes in 29.5%. Other risk factors include previous stroke (11.7%), smoking (6.3%), hypercholesterolemia (23.4%), high alcohol intake (28.8%) and lack of exercise according to self-evaluation (87.5%). 76.3% of patients had ischaemic and 18.2% haemorrhagic stroke. 41% of patients aged 50 years or less had haemorrhagic stroke and 9.3% of patients had atrial fibrillation. In-patient mortality was 10.6%. CONCLUSION: Stroke types and outcomes are different from those generally reported from the sub-region. This may well be due to the population studied, and the level of care provided by a private facility. Socio-economic factors, literacy and clinical care are likely determinants of stroke types and outcomes in African patients. . More detailed studies to confirm the effects of socioeconomic factors on stroke pattern and outcomes in Africa are needed.

Evaluation of convalescent whole blood for treating Ebola Virus Disease in Freetown, Sierra Leone.

BACKGROUND: Convalescent blood therapy has been a promising form of treatment for Ebola Virus Disease (EVD), but less attention has been focused on it for treatment. METHOD: We assessed the effectiveness of convalescent whole blood (CWB) in the treatment of consented EVD patients. We recruited 69 subjects in December 2014 up to April 2015, at the 34 Military Hospital in Wilberforce and the PTS 1 Ebola Treatment Unit in Hastings, Freetown. Forty-four were given CWB, and 25 who consented but preferred to be exempted from the CWB treatment were used to compare clinical outcomes. All were given routine treatment used at the Ebola Treatment Unit. RESULTS: One of 44 subjects treated with CWB dropped out of the study and 31 recovered while 12 succumbed to the disease with a case fatality rate of 27.9%. For the group that was given routine treatment without CWB, 11 died with a case fatality rate of 44%. There was a significant difference between admission viral load and viral load after the first 24 h of treatment with convalescent whole blood (P < 0.01). The odds ratio for survival with CWB was 2.3 (95% CI, 0.8-6.5). CONCLUSION: CWB is promising for treating EVD in resource-poor settings, especially in the early phases of outbreaks when resource-mobilization is done. Even though our sample size was small and the evaluation was not randomised, our results contribute to existing evidence that convalescent whole blood could be considered as a useful candidate for treating EVD. Further studies that are randomised will be required to further assess the efficacy of CWB as treatment option during any EVD outbreak.

Posterior Reversible Encephalopathy Syndrome and Eclampsia in a Primigravid Woman: The First Reported Case from Sierra Leone.

Posterior Reversible Encephalopathy Syndrome (PRES) is a clinico-neuroradiological entity with neurological symptoms and characteristic radiologic findings. It may complicate eclampsia either during pregnancy or in the puerperal period and it is a very serious neurological condition manifesting as acute headache,impairment of consciousness, seizures, cortical blindness and occasionally, focal neurological signs accompanied by a typical CT or MR imaging pattern.A 30 years old right handed primigravida housewife was managed for PRES and this is the first reported case in Sierra Leone. Clinicians in Africa should consider this diagnosis in all cases of eclampsia in order to reduce the morbidity and mortality that may result from delayed diagnosis.

Tuberculous effusive-constrictive pericarditis.

Infection with Mycobacterium tuberculosis and the human immunodeficiency virus has reached epidemic proportions in South Africa. Cardiac involvement occurs in approximately one per cent of patients suffering from active tuberculosis. This concerns predominantly pericardial involvement, resulting in chronic pericardial effusions, cardiac tamponade and constrictive pericarditis. Effusive-constrictive pericarditis is a clinical haemodynamic syndrome in which constriction by the visceral pericardium occurs in the presence of a tense effusion in a free pericardial space. We present a patient who was diagnosed with this condition, and highlight the value of contrast-enhanced magnetic resonance imaging in demonstrating the underlying structural and functional abnormalities.

Abnormal diastolic and systolic septal motion following pericardiectomy demonstrated by ciné DENSE MRI.

Constrictive pericarditis can lead to paradoxical interventricular septal motion. Displacement encoding with stimulated echoes (DENSE) magnetic resonance imaging (MRI) provides a method for quantifying myocardial motion and strain. A case of constrictive pericarditis is presented and the diastolic 'septal bounce' is clearly evident in both anatomical and DENSE ciné MRI images. (See video link to full-text electronic article). The postoperative systolic septal wall-motion abnormality of cardiac surgery is portrayed with greater precision by DENSE than anatomical ciné MRI images.

The use of organic acids to combat Salmonella in poultry: a mechanistic explanation of the efficacy.

Salmonella is a human pathogen that is commonly found in poultry products. It is possible to decrease chicken carcass and egg contaminations by adding organic acids to the feed or drinking water at appropriate times. Medium-chain fatty acids are more antibacterial against Salmonella than short-chain fatty acids. The antibacterial effect of these acids is species specific. Bacteria that are unable to decrease intracellular pH accumulate organic acid anions in accordance with the pH gradient across their cell membranes. The short-chain fatty acid butyrate specifically down-regulates expression of invasion genes in Salmonella spp. at low doses. Also medium-chain fatty acids and propionate decrease the ability of Salmonella spp. to invade epithelial cells, in contrast to acetic acid. Because not all bacteria are affected in a similar fashion by organic acids, it may be possible to use probiotic and prebiotic bacteria to achieve beneficial effects. If diets can be designed to stimulate organic acid production in the caecum, it may be possible to control Salmonella spp. via even easier and more cost-effective measures, compared with addition of acids to feed or drinking water.

Factors affecting the activity of bovicin HC5, a bacteriocin from Streptococcus bovis HC5: release, stability and binding to target bacteria.

AIMS: To determine the factors affecting the release, stability and binding of bovicin HC5 to sensitive bacteria. METHODS AND RESULTS: Stationary phase Streptococcus bovis HC5 cultures had little cell-free bovicin HC5 activity until the final pH was <5.0, and even more bacteriocin was released by treatment with acidic NaCl (pH 2.0, 100 mmol l(-1)). Cultures grown with Tween 80 had more cell-free bovicin HC5 than untreated controls, but this nonionic detergent enhanced activity rather than release. Bovicin HC5 binding to S. bovis JB1 (a susceptible strain) was greater at pH values <6.0. Bovicin HC5 bound other sensitive Gram-positive bacteria, but not Gram-negative species. Cultures retained most of their activity for 35 days, but only if the final pH was <5.6. If the final pH was >5.6, peptidases destroyed much of the activity. CONCLUSIONS: Bovicin HC5 remains cell associated until the culture pH is <5.0, but it can be easily dissociated from the cell surface by acidic NaCl. It is highly stable in acidic environments and only binds sensitive bacteria at pH values <6.0. SIGNIFICANCE AND IMPACT OF THE STUDY: Streptococcus bovis HC5 does not have generally regarded as safe status. However, bovicin HC5 has a broad spectrum of activity and sensitive bacteria do not become resistant. Based on these results, bovicin HC5 may be a useful bacteriocin model.

The effect of a ruminal nitrogen (N) deficiency in dairy cows: evaluation of the cornell net carbohydrate and protein system ruminal N deficiency adjustment.

Twenty-four multiparous and fifteen first lactation Holstein cows averaging 263 days in milk and weighing 614 kg were fed diets adequate or deficient in ruminal nitrogen (N), based on predictions of the Cornell Net Carbohydrate and Protein System (CNCPS). After adjustment to a low crude protein (CP) total mixed rations (TMR; 12.6% CP), the cows were allocated to 13 blocks based on lactation number, milk production, body condition score, and body weight. Within each block, cows were randomly assigned to one of the 3 treatment (TRT) diets (9.4, 11.1 and 14.1% CP for TRT 1, 2, and 3, respectively). All diets contained the same proportion of high moisture corn, chopped grass hay, and minerals, with urea substituted for corn silage as needed to reach the three CP levels. The TRT diets were then fed to the cows for 4 wk. Milk production was significantly affected by TRT: 15.5, 18.8, and 21.7 kg/d for TRT diets 1, 2, and 3, respectively. DMI was increased significantly as the percentage of CP increased from 9.4 to 14.1% CP: 17.6, 20.0, and 21.2 kg/d for TRT diets 1,2, and 3, respectively. CNCPS predictions for production (with and without the N adjustment for ruminal N deficiency) of metabolizable protein (MP) allowable milk were compared with observed milk production. Using the average individual weekly cow data from all 3 TRT, we found that the CNCPS accounted for 72 and 68% of the variation in MP allowable milk without and with the N deficiency adjustment, respectively. The overall mean bias without the N adjustment was 3.3 kg of milk (over prediction model bias of 14.6%, P < 0.001), and the N adjustment reduced the model over-prediction bias to 0.01 kg of milk (P = 0.96).

The enrichment of a ruminal bacterium (Megasphaera elsdenii YJ-4) that produces the trans-10, cis-12 isomer of conjugated linoleic acid.

AIMS: To isolate predominant ruminal bacteria that produce trans-10, cis-12 conjugated linoleic acid (CLA) from linoleic acid (LA). METHODS AND RESULTS: Mixed bacteria from ruminal contents of a cow fed grain were enriched with DL-lactate and trypticase. They produced more trans-10, cis-12 CLA than those that were not enriched (7 vs 2 microg mg protein(-1), P < 0.05). Enrichments had an abundance of large cocci that produced trans-10, cis-12 CLA from LA. Strain YJ-4 produced the most trans-10, cis-12 CLA (approx. 7 microg mg protein(-1)) and 16S rDNA sequencing indicated that YJ-4 was a strain of Megasphaera elsdenii. Megasphaera elsdenii T81 produced approx. 4 microg trans-10, cis-12 CLA mg protein(-1) while strains B159, AW106 and JL1 produced < 0.5 microg mg protein(-1). The trans-10, cis-12 CLA production of YJ-4 was first order with respect to cell concentration (0-800 microg protein ml(-1)), but kinetics were not first order with respect to substrate concentration. CONCLUSIONS: Some M. elsdenii strains produce significant amounts of trans-10, cis-12 CLA. SIGNIFICANCE AND IMPACT OF THE STUDY: Trans-10, cis-12 CLA appears to cause milk fat depression in cattle fed diets supplemented with grain and polyunsaturated fatty acids, but predominant ruminal bacteria that produced trans-10, cis-12 CLA from LA had not previously been isolated.

The effect of ruminal fluid preparations on the growth and health of newborn, milk-fed dairy calves.

The objective of this study was to determine the effect of oral doses of ruminal fluid (RF) on the growth and health of newborn, milk-fed heifer dairy calves (0 to 6 wk of age). Calves given 8 ml of RF each day until weaning gained more weight and had fewer scours than controls that did not receive RF. Because RF that was exposed to oxygen or was autoclaved also gave a response, it is unlikely that the preparations were acting as a probiotic. When the RF was centrifuged to separate the cells (RFC) from the fluid (RFS), both fractions had similar activity, and this result indicated that the response was not nutritional; that is, 1) RFC supplied a small amount of protein (approximately 8 mg/d), but RFS had much less protein, and 2) RFS had volatile fatty acid, but RFC had little if any volatile fatty acid. However, both RFS and RFC had bacterial polysaccharide, and bacterial polysaccharide has strong antigenic properties. In the first three studies, treated calves were given RF preparations each day until weaning (6 wk), but a subsequent experiment indicated that calves given autoclaved RF for only 5 d (d 1 to 5) also had greater body weight gains during the first 2 wk of life and fewer scours than untreated controls. Given that the dosage of RF was small and the material could be autoclaved to prevent disease transmission, RF supplementation could be a practical tool for improving calf health.

The mechanism of carbonate killing of Escherichia coli.

AIMS: To define the mechanism of carbonate killing in Escherichia coli. METHODS AND RESULTS: Sodium carbonate (150 mM) and ethylenediaminetetracetic acid (EDTA, 60 mM) both killed E. coli K-12 when the pH was 8.5, but ammonium chloride (150 mM) was ineffective. EDTA was a 5-fold more potent agent than carbonate, but some of this difference could be explained by ionization. At pH 8.5, only 1.6% of the carbonate is CO(-2), but nearly 100% of the EDTA is EDTA(-2). CONCLUSION: As carbonate and EDTA had similar effects on viability, cellular morphology, protein release and enzymatic activities, the antibacterial activity of carbonate seems to be mediated by divalent metal binding. SIGNIFICANCE AND IMPACT OF THE STUDY: Cattle manure is often used as a fertilizer, and E. coli from manure can migrate through the soil into water supplies. Previous methods of eradicating E. coli were either expensive or environmentally unsound. However, cattle manure can be treated with carbonate to eliminate E. coli, and the cost of this treatment is less than $0.03 per cow per day.

Effect of monensin on the performance and nitrogen utilization of lactating dairy cows consuming fresh forage.

We conducted a lactation trial with a fresh forage diet in order to evaluate 1) the effects of monensin on nitrogen metabolism, and 2) the Cornell Net Carbohydrate and Protein System (CNCPS). Thirty Holstein cows in midlactation (eight fitted with ruminal fistulas) were gradually introduced to a fresh forage diet. A concentrate mix based on corn meal was fed before the a.m. and p.m. milking times 0730 and 1730 h, then the fresh forage was fed at 0830 and 1830 h. Fifteen cows each were allocated to a control (no monensin) and a treatment group receiving 350 mg/cow per day of monensin in the p.m. concentrate feeding. A 7-d fecal and urine collection period and a 3-d rumen sampling period were conducted with the fistulated cows. After the lactation study was concluded, the fistulated cows were fed forage regrowth and a 3-d rumen sampling period was repeated. Monensin increased milk production by 1.85 kg. Milk fat and protein concentrations decreased and milk fat and protein yields increased, but the effects were nonsignificant. Monensin did not significantly affect DMI. Ruminal ammonia and the acetate-to-propionate ratio decreased with the addition of monensin in both fed forages. Monensin decreased fecal N output, and increased apparent N digestibility by 5.4%. Because of the decrease in ruminal ammonia and increase in apparent N digestibility, we concluded monensin was sparing amino acids from wasteful rumen degradation with a fresh forage diet. The precision of the CNCPS in predicting performance was high (r2 = 0.76), and the bias was low (overprediction of 3.6%). These results indicate that the CNCPS can be used for dairy cows consuming fresh forage and gives realistic predictions of performance.

Differences in Escherichia coli culture conditions can have a large impact on the induction of extreme acid resistance.

A recently isolated Escherichia coli strain (3TF4) survived an acid shock that mimicked the low pH of the human gastric stomach (pH 2, 1 h), but this survival was highly influenced by prior growth conditions. Only 0.01% of the stationary phase cells that had been grown anaerobically in a carbonate medium (2 mg glucose and 0.25 mg yeast extract per ml, 40 mm sodium carbonate, final pH 6.5) survived the acid shock, and the survival of exponential phase cultures was even lower (0.0001%). Small amounts of Trypticase (1.5 mg/ml) increased the survival as much as 5000-fold, but cultures that were provided with higher concentrations of Trypticase (7.5 mg/ml) did not reach the stationary phase in 24 h and were more acid sensitive. Sodium acetate (50 mm) also increased acid resistance, and the increased acid shock survival was greater for the cells that had reached the stationary phase (100 versus 1000-fold, respectively). E. coli 3TF4 cultures that had been grown aerobically in Luria broth were already so acid resistant (survivals greater than 40%) that they did not respond to sodium acetate. E. coli 3TF4 cultures that were refrigerated (5 degrees C, 7 days) were nearly as acid resistant as those that were immediately subjected to acid shock (pH 2.0, 1 h).

The effect of various carbonate sources on the survival of Escherichia coli in dairy cattle manure.

Manure slurries (n = 3) prepared from the feces and urine of lactating dairy cattle (1 part urine, 2.2 parts feces, and 6.8 parts distilled water) had an initial pH of 8.6 +/- 0.1; dissolved carbonate concentrations of 48 +/- 4 mm, and Escherichia coli counts of 5.9 +/- 0.7 logs per ml slurry. The pH of untreated slurries declined to pH 7.0 +/- 0.1 by the 10th day of incubation, and the E. coli count increased approximately 10-fold (P < 0.05). When slurries were treated with Na2CO3, K2CO3, NaHCO3 or Na2CO3.NaHCO3 (0 to 16 g/kg slurry), the dissolved carbonates increased in a linear fashion, but only Na2CO3 and K2CO3 (8 g/kg or greater) or Na2CO3.NaHCO3 (16 g/kg) ensured an alkaline pH. Even relatively low concentrations of Na2CO3 or K2CO3 (8 or 12 g/kg) caused a decrease in E. coli viability (P < 0.05), and E. coli could not be detected if 16 g/kg was added (day 5 or 10 of incubation). Na2CO3.NaHCO3 also caused a decrease in E. coli viability, (P < 0.05), but some E. coli (approximately 104 cells per g) were detected on day 10 even if the concentration was 16 g/kg. NaHCO3 did not prevent the decrease in pH or cause a decrease in E. coli numbers (P > 0.05). Calculations based on the Henderson-Hasselbalch equation (pH and dissolved carbonates) indicated that little E. coli killing was noted until the dissolved carbonate anion concentrations (CO3-2) were greater than 1 mm, but bicarbonate anion (HCO3-) concentrations as high as 180 mm did not affect E. coli viability. These results are consistent with the idea that carbonate anion has antimicrobial properties and can kill E. coli in dairy cattle manure.

Factors that alter rumen microbial ecology.

Ruminant animals and ruminal microorganisms have a symbiotic relationship that facilitates fiber digestion, but domestic ruminants in developed countries are often fed an abundance of grain and little fiber. When ruminants are fed fiber-deficient rations, physiological mechanisms of homeostasis are disrupted, ruminal pH declines, microbial ecology is altered, and the animal becomes more susceptible to metabolic disorders and, in some cases, infectious disease. Some disorders can be counteracted by feed additives (for example, antibiotics and buffers), but these additives can alter the composition of the ruminal ecosystem even further.