Invited review: Selective treatment of clinical mastitis in dairy cattle.

Treatment of clinical mastitis (CM) and use of antimicrobials for dry cow therapy are responsible for the majority of animal-defined daily doses of antimicrobial use (AMU) on dairy farms. However, advancements made in the last decade have enabled excluding nonsevere CM cases from antimicrobial treatment that have a high probability of cure without antimicrobials (no bacterial causes or gram-negative, excluding Klebsiella spp.) and cases with a low bacteriological cure rate (chronic cases). These advancements include availability of rapid diagnostic tests and improved udder health management practices, which reduced the incidence and infection pressure of contagious CM pathogens. This review informed an evidence-based protocol for selective CM treatment decisions based on a combination of rapid diagnostic test results, review of somatic cell count and CM records, and elucidated consequences in terms of udder health, AMU, and farm economics. Relatively fast identification of the causative agent is the most important factor in selective CM treatment protocols. Many reported studies did not indicate detrimental udder health consequences (e.g., reduced clinical or bacteriological cures, increased somatic cell count, increased culling rate, or increased recurrence of CM later in lactation) after initiating selective CM treatment protocols using on-farm testing. The magnitude of AMU reduction following a selective CM treatment protocol implementation depended on the causal pathogen distribution and protocol characteristics. Uptake of selective treatment of nonsevere CM cases differs across regions and is dependent on management systems and adoption of udder health programs. No economic losses or animal welfare issues are expected when adopting a selective versus blanket CM treatment protocol. Therefore, selective CM treatment of nonsevere cases can be a practical tool to aid AMU reduction on dairy farms.

Selective treatment of nonsevere clinical mastitis does not adversely affect cure, somatic cell count, milk yield, recurrence, or culling: A systematic review and meta-analysis.

Treatment of clinical mastitis (CM) contributes to antimicrobial use on dairy farms. Selective treatment of CM based on bacterial diagnosis can reduce antimicrobial use, as not all cases of CM will benefit from antimicrobial treatment, e.g., mild and moderate gram-negative infections. However, impacts of selective CM treatment on udder health and culling are not fully understood. A systematic search identified 13 studies that compared selective versus blanket CM treatment protocols. Reported outcomes were synthesized with random-effects models and presented as risk ratios or mean differences. Selective CM treatment protocol was not inferior to blanket CM treatment protocol for the outcome bacteriological cure. Noninferiority margins could not be established for the outcomes clinical cure, new intramammary infection, somatic cell count, milk yield, recurrence, or culling. However, no differences were detected between selective and blanket CM treatment protocols using traditional analyses, apart from a not clinically relevant increase in interval from treatment to clinical cure (0.4 d) in the selective group and higher proportion of clinical cure at 14 d in the selective group. The latter occurred in studies co-administering nonsteroidal anti-inflammatories only in the selective group. Bias could not be ruled out in most studies due to suboptimal randomization, although this would likely only affect subjective outcomes such as clinical cure. Hence, findings were supported by a high or moderate certainty of evidence for all outcome measures except clinical cure. In conclusion, this review supported the assertion that a selective CM treatment protocol can be adopted without adversely influencing bacteriological and clinical cure, somatic cell count, milk yield, and incidence of recurrence or culling.

Effects of rumen-native microbial feed supplementation on milk yield, composition, and feed efficiency in lactating dairy cows.

The objective of this study was to evaluate the effects of two rumen-native microbial feed supplements (MFS) on milk production, milk composition, and feed efficiency. A total of 90 multiparous cows between 40 and 60 d in milk were enrolled in a randomized block design study. Within each block (baseline milk yield), cows were randomly assigned to: control (no microbial feed supplementation), MFS1 (0.33 g/kg total mixed ration [TMR] of an MFS containing a minimum of Clostridium beijerinckii at 2 × 106 CFU/g and Pichia kudriavzevii at 2 × 107 CFU/g), or MFS2 (0.33 g/kg TMR of a MFS containing a minimum of C. beijerinckii at 2 × 106 CFU/g, P. kudriavzevii at 2 × 107 CFU/g, Ruminococcus bovis at 2 × 107 CFU/g, and Butyrivibrio fibrisolvens at 2 × 107 CFU/g). Cows were housed in a single group and fed the study diets ad libitum for 270 d. Individual milk yield was recorded using electronic milk meters, and milk fat and protein were measured using optical in-line analyzers at each of two daily milkings. Treatment and treatment by time effects were assessed through multiple linear regression analyses. Treatment effects were observed for milk and energy-corrected milk (ECM) yields, milk fat and protein yields and concentrations, dry matter intake (DMI), and feed efficiency; those effects were conditional to time for milk yield, DMI, and feed efficiency. Overall, milk, ECM, fat, and protein yields were higher for MFS2 compared with control cows (+3.0, 3.7, 0.12, and 0.12 kg/d, respectively). Compared with MFS1, milk yield was higher and protein yield tended to be higher for MFS2 cows (+2.9 and 0.09 kg/d, respectively). In contrast, MFS1 cows produced 0.17 and 0.08 units of percentage per day more fat and protein than MFS2 cows, and 0.07 units of percentage per day more protein than control cows. Dry matter intake and feed efficiency were higher for MFS2 cows compared with MFS1 cows (+1.3 kg/d and 0.06, respectively), and feed efficiency was higher for MFS2 cows compared with control cows (+0.04). Where observed, treatment by time effects suggest that the effects of MFS2 were more evident as time progressed after supplementation was initiated. No effects of microbial supplementation were observed on body weight, body condition score, somatic cell count, or clinical mastitis case incidence. In conclusion, the supplementation of MFS2 effectively improved economically important outcomes such as milk yield, solids, and feed efficiency.

This study evaluates the effects of two rumen-native microbial feed supplements (MFS) on milk yield, composition, and feed efficiency in lactating dairy cows. Ninety multiparous Holstein cows between 40 and 60 d in milk were assigned to control (no microbial feed supplementation), MFS1 (Clostridium beijerinckii and Pichia kudriavzevii), or MFS2 (C. beijerinckii, P. kudriavzevii, Ruminococcus bovis, and Butyrivibrio fibrisolvens) total mixed ration supplementation. Overall, MFS2 cows had higher milk and milk component yields than control and MFS1, while MFS1 cows had higher milk component concentrations than control and MFS2. Feed efficiency was higher for MFS2 compared with control and MFS1 cows. Microbial feed supplementation improved economically important outcomes such as milk yield, solids, and feed efficiency.

Evaluation of rapid culture, a predictive algorithm, esterase somatic cell count and lactate dehydrogenase to detect intramammary infection in quarters of dairy cows at dry-off.

Our objective was to compare four tests to standard milk culture followed by MALDI-ToF in quarters of cows at dry-off. Cows (n = 432) were randomly selected from seven U.S. dairy herds already participating in a multi-site clinical trial in summer 2018. Aseptic foremilk samples were collected from quarters (n = 1728) two days prior to dry-off, and subjected to index and reference tests. The four index tests included rapid culture, a predictive algorithm, an esterase strip test measuring somatic cell count (SCC) and a cow-side lactate dehydrogenase (LDH) test. Rapid culture was performed by inoculating quarter milk samples onto a commercial rapid culture plate. Plates were evaluated by technicians after 30-40 h of incubation at 37 ± 2 °C. Quarters were classified as infected if any bacterial growth was observed. For the algorithm test method, all quarters were classified as infected if the cow met any of the following criteria: 1) any Dairy Herd Improvement Association (DHIA) test with a SCC > 200,000 cells / ml during the current lactation or 2) two or more clinical mastitis cases during the current lactation. Esterase-SCC and cow-side LDH tests involved adding milk to the test strip and reading for color changes. For esterase-SCC and cow-side LDH tests, low (≥250 cells / ml and ≥100 U / L) and high (≥500 cells / ml and ≥200 U / L) thresholds were used to classify quarters as infected or not. Composite samples (4 × 2 mL quarter-milk samples commingled) were also tested for rapid culture, esterase-SCC and cow-side LDH tests, such that if a composite sample was positive, then all quarters contributing to that sample were classified as infected. The reference test was traditional aerobic culture conducted in an accredited laboratory using MALDI-ToF for identification of isolates. Traditional culture was only conducted on quarter-milk samples, and consequently, IMI was always considered at the quarter-level. Unconditional logistic regression was used to estimate sensitivity (SE), specificity (SP), apparent prevalence, positive predictive values (PPV) and negative predictive values (NPV) for each index test. Cohen's Kappa (κ) was used to measure agreement between tests. Algorithm, esterase-SCC and cow-side LDH tests had poor agreement with the reference test (κ ranging from 0.01 to 0.12), while rapid culture had fair agreement (κ = 0.28). No test had concurrently high SE and SP. Negative predictive values were moderate to high for all tests.

Duration of growth depression and pathogen shedding in experimentally reproduced poult enteritis syndrome.

An experimental study was conducted to determine the duration of growth depression and virus shedding in turkey poults after oral inoculation with intestinal contents from birds affected with poult enteritis syndrome (PES). Poults at day 14 of age were divided into four groups (groups A, B, C, and D) of 40 poults each and inoculated orally with unfiltered supernatant, filtered supernatant, sediment suspended in phosphate-buffered saline (PBS), or PBS alone (control), respectively. The poults were observed daily for clinical signs, and their growth response, pathology, and pathogen shedding were examined at 10, 20, 30, 40, and 50 days postinoculation (DPI). Body weights of eight poults in each group were recorded at each of these intervals followed by euthanasia. Dullness, depression, and diarrhea were observed in birds inoculated with supernatant or sediment suspension. All three treatments significantly reduced body weight gain of poults compared with the control group; average weight loss was 14%. Gross pathologic changes consisted of pale distended intestines with watery contents and distended ceca with frothy and watery contents. Astrovirus and rotavirus were detected in the inoculum by reverse transcription (RT)-PCR, whereas Salmonella was identified on bacterial isolation. Both viruses were detected in treated poults by RT-PCR for up to 10 and 40 DPI, respectively. Of the three treatments, sediment suspension caused maximal decrease in weight gain as well as greatest pathologic lesions followed by unfiltered supernatant and filtered supernatant. These findings suggest a role for bacteria in increasing the severity of PES. Lower weight gain in treated poults (compared with controls) at 9 wk of age also indicates that PES-affected poults may not reach normal weight at marketing, leading to economic losses for the producer.

A retrospective study on poult enteritis syndrome in Minnesota.

A retrospective study was conducted to determine the occurrence of poult enteritis syndrome (PES) in Minnesota from January 2002 to December 2007. PES is an infectious intestinal disease of young turkeys between 1 day and 7 wk of age and is characterized by diarrhea, depression, and lethargy with pale intestines and/or excessively fluid cecal contents. During the study period, samples from 1736 turkey flocks were submitted to the Minnesota Veterinary Diagnostic Laboratory for disease investigation. Of these, 151 flocks (8.7%) were PES positive. Cases of PES were seen throughout the year with higher prevalence in fall. The PES was statistically associated with age with higher occurrence in poults less than 3 wk of age. Rotavirus, small round virus (SRV), Salmonella, nonhemolytic Escherichia coli, Enterococcus, and Eimeria oocysts were detected alone or in different combinations. Reovirus and adenovirus were found in one flock each. The most commonly identified pathogens were Salmonella (85 flocks) and rotavirus (73 flocks). Of PES-affected flocks, 39 (25.8%), 66 (43.7%), and 37 (24.5%) had one, two, and three or more pathogens, respectively. Rotavirus, SRV, and reovirus occurred mostly in poults of less than 6 wk of age while Salmonella, E. coli, and Eimeria were seen in poults of all age groups. Minimum age for rotavirus detection was in 2-day-old poults. Histopathologically, moderate to severe mixed intestinal villus or lamina propria inflammatory infiltrates, necrosis of distal villus tips in intestinal specimens, and mild to severe lymphocellular depletion in thymus, bursa, and spleen were seen. Antimicrobial sensitivity patterns of bacterial isolates from PES-affected flocks revealed maximum sensitivity to trimethoprim/sulfamethoxazole and ceftiofur and a varying degree of resistance to other antimicrobials.

Use of Rapid Culture Systems to Guide Clinical Mastitis Treatment Decisions.

The selective treatment of clinical mastitis based on culture results can reduce antibiotic use by more than 50% without sacrificing treatment efficacy. Local laboratories reporting results in a 24-hour period, or adoption of on-farm milk culture systems, allow producers to make strategic treatment decisions. On-farm culture systems are most reliable when used to classify infections in broad diagnostic categories such as no growth, gram-positive, or gram-negative growth. Diagnostic accuracy is crucial for on-farm culture systems to be efficacious and economically advantageous. Quality assurance is necessary for the success of on-farm culture systems.

Comportamiento de la epidemia de VIH en Cuba / Behavior of the HIV epidemics in Cuba

Introducción: La infección por el VIH/sida es considerada un problema de la salud pública a nivel mundial. Los primeros diagnósticos ocurrieron en 1981 y desde entonces el número de infectados se ha incrementado. Cuba no está ajena a este fenómeno y se continúa trabajando para detener el avance de la epidemia en el país. Objetivo: Caracterizar el comportamiento de la epidemia de VIH en Cuba y elaborar un modelo pronóstico para los próximos años. Métodos: El universo estuvo constituido por todos los diagnósticos de personas de nacionalidad cubana infectadas por el VIH desde 1986 hasta 2010. La información fue obtenida de la base de datos de VIH/sida del Ministerio de Salud Pública de Cuba. Se analizó la epidemia tomando en cuenta los componentes de la serie cronológica. Para la modelación del pronóstico se empleó el alisamiento exponencial con dos parámetros. Para el procesamiento y análisis se utilizaron los paquetes estadísticos SPSS versión 11.5, Statistic versión 6.0, Econometric Views versión 4.0 y el programa MapInfo Profesional versión 7.5. Resultados: Se consideró que no existió aleatoriedad en la serie cronológica, pero sí que existía un patrón cíclico. La tasa de incidencia de VIH presentó una tendencia ascendente, aumentando un 90,70 % con respecto a los años extremos de la serie. La relación hombre/mujer se presentó como una mujer diagnosticada por cada 4 hombres. El 56,87 % de los diagnosticados eran homobisexuales, la mayoría del sexo masculino. El grupo de edades más afectado fue el de 20-24 años. La capital del país reportó la mayor tasa de incidencia de casos. Los municipios más afectados son urbanos y de alta densidad poblacional. Conclusiones: La incidencia del diagnóstico de personas VIH positivas mantiene una tendencia ascendente a expensas de los hombres que tienen sexo con otros hombres. El grupo de edades con mayor incidencia corresponden al de 20 a 24 años. La mayor cantidad de casos generalmente provenía de regiones urbanas y densamente pobladas.

Introduction: The HIV/AIDS infection is considered a public health problem around the world. The firsts diagnostics were made in 1981, and since that the number of infected persons has increased. Cuba is not free from to this phenomenon and we continue working to stop the advance of the epidemics in the country. Objective: Characterizing the behavior of the HIV epidemics in Cuba and making a prognostic model for the following years. Methods: The universe was formed by all the diagnoses of Cuban people infected with the HIV between 1986 and 2010. Data were obtained from the HIV/AIDS data base of the Public health Ministry of Cuba. We analyzed the epidemics taking into account the components of the chronologic series. For making the model of the prognostic we used the exponential smoothening with two parameters. For processing and analyzing data we used the statistic packages SPSS version 11.5, Statistic version 6.0, Econometric Views version 4.0 and the program MapInfo Professional Version 7.5. Results: We considered that there was not any randomization in the chronologic series, but there it was a cyclic pattern. The HIV incidence rate showed a growing tendency, increasing 90,70 % with respect of the extreme years of the series. The relation man/woman was one woman diagnosed per four men. The 56,87 % of the diagnosed people were homo-bisexual ones, most of them male. The most affected age group was the 20-24 years-old group. The capital of the country reported the biggest incidence rate of cases. The most affected municipalities were urban and had a high population density. Conclusions: The incidence of the HIV positive people's diagnosis maintains an increasing tendency due to the men having sex with other men. The age group with higher incidence is the 20-24 years-old one. The bigger quantity of the cases stems from urban and densely populated regions.