Farmers should focus on milk quality over quantity because milk that contains unsuitable components and/or antibiotic residues, or has a high somatic cell count, cannot be used in food production and thereby results in reduced milk yield. One of the main problems affecting the ultimate milk yield of dairy cows is mastitis. This disease is the most serious economic and health problem associated with dairy cow herds and is a major reason for excessive culling. Therefore, many studies have addressed this problem to further our understanding of the agents causing mastitis and their classification and virulence factors. This review summarizes the current knowledge regarding mastitis prevalence, the characteristics of its main causative agents, and the effects of mastitis on dairy production. The review also intends to provide guidance for future studies by examining external effects influencing dairy production in cows under field conditions.

https://www.mdpi.com/2076-2615/10/12/2212/pdf

Epidemiology and Classification of Mastitis

Bovine mastitis (BM) is the traditional infectious condition in reared cattle which may result in serious repercussions ranging from animal welfare to economic issues. Owing to the high costs associated with preventative practices and therapeutic measures, lower milk output, and early culling, bovine mastitis is accountable for most of the financial losses suffered in cattle farming. Streptococcus agalactiae, Staphylococcus aureus, Streptococcus dysgalactiae and coliform bacteria are the predominant pathogens for bovine mastitis. In addition, the occurrence of BM has been linked to lactation stage and poor management, in the latter case, the poor stabling conditions around udder hygiene. BM occurs throughout the world, with varying rates of Streptococcus agalactiae infection in different regions. Despite the modern techniques, such as the appropriate milking practices that are applied, lower levels of pathogen vulnerability may help to prevent the development of the disease, BM treatment is primarily reliant on antibiotics for both prophylactic and therapeutic purposes. Nevertheless, as a result of the proliferation of bacterial agents to withstand the antibiotic effects, these therapies have frequently proven ineffectual, resulting in persistent BM. Consequently, alternative medicines for the management of udder inflammation have been researched, notably natural compounds derived from plants. This review focuses on BM in terms of its risk factors, pathogenesis, management, the molecular identification of causative agents, as well as the application of ethno-veterinary medicine as an alternative therapy.

Combating Bovine Mastitis in the Dairy Sector in an Era of Antimicrobial Resistance: Ethno-veterinary Medicinal Option as a Viable Alternative Approach

In this paper, the human milk dielectric constant by a microwave sensor has been evaluated. The proposed sensor is result of coupling between a simple microstrip line and a split ring resonator and its resonance frequency is 6 GHz. When up to 30 μl of milk are placed on the sensing area on the sensor, it causes the resonance frequency to shift. Six samples of human milk were measured by a network analyzer, then the dielectric constant of the samples were determined, and three similar samples were measured by the built-in sensor. The proposed microwave sensor has Q-factor of 38 and its sensitivity is 0.17%. The implemented sensor has acceptable performance compared to previous sensors and it can be used to determine the normal behavior of human milk with a simple method and for this work, it requires to small value of sample for measurement. 

Microwave Split Ring Resonator Sensor for Determination of the Fluids Permittivity With Measurement of Human Milk Samples

In this paper, the human milk dielectric constant by a microwave sensor has been evaluated. The proposed sensor is result of coupling between a simple microstrip line and a split ring resonator and its resonance frequency is 6 GHz. When up to 30 μl of milk are placed on the sensing area on the sensor, it causes the resonance frequency to shift. Six samples of human milk were measured by a network analyzer, then the dielectric constant of the samples were determined, and three similar samples were measured by the built‐in sensor. The proposed microwave sensor has Q‐factor of 38 and its sensitivity is 0.17%. The implemented sensor has acceptable performance compared to previous sensors and it can be used to determine the normal behavior of human milk with a simple method and for this work, it requires to small value of sample for measurement.

There are five stages in acid coagulation of milk and most studies miss out on a stage or two depending on the experiments performed. Dielectric studies of milk and various physico-chemical studies...

On the efficacy of dielectric spectroscopy in the identification of onset of the various stages in lactic acid coagulation of milk

An efficient microwave milk pasteurization system requires a rigorous temperature dependent dielectric model of the milk, since the performance of milk pasteurization strongly depends on its dielectric properties. This paper describes the dielectric modelling of cow’s raw milk during batch (Vat) pasteurization which covers the frequencies from 0.2 GHz to 6 GHz. An open-ended coaxial sensor is used for the measurements of dielectric constant, loss factor, and ionic conductivity at temperature range of 25°C to 75°C with an interval of 5°C. Combinations of Cole-Davison and Debye equations are modified to fit the dielectric measurements. It was found that the measured dielectric constant decreased as the frequency increased, while the high temperature processed produce lower in a convergence manner toward 6 GHz. The loss factor exhibited high losses at higher temperature and lower frequencies, as well as converged at 1.9 GHz then diverged up to 6 GHz. Three relaxation processes are dominated at all temperature treatments within the frequency range. The relaxation time, τ, and the activation energy, Q, are modelled based on linear fitting of measured data according to Debye and Arrhenius approaches.

Modelling the dielectric properties of cow's raw milk under vat pasteurization

Mono-mode microwave reactors are usually used to heat substances, especially food. This is because heating using a microwave reactor can sustain the flavor, color, and nutrition of the food. Furthermore, this heating technique is cost-effective and time-saving compared to a conventional heating method. The mono-mode reactor is able to determine the absorption of microwave power accurately on the heated substance versus a multimode reactor. In this chapter, a simple and precise mono-mode microwave reactor is designed and developed especially for research laboratories. The advantage of this reactor is to provide a more accurate calibration process, in order to improve the optimum energy use in the heating process, as well as the temperature of the specimen. The reactor can generate output power from 30 watts to 1500 watts, operating at 2.45±0.03 GHz and capable of accommodating a specimen volume of 780 cm3. Pure water is used as a heated specimen to demonstrate the performance and efficiency of this reactor. Milk Pasteurization and Characterization Using MonoMode Microwave Reactor and Slotted Coaxial Antenna

Cheong Yew Chong

Papers

Modelling the dielectric properties of cow's raw milk under vat pasteurization

Milk Pasteurization and Characterization Using Mono-Mode Microwave Reactor and Slotted Coaxial Antenna