3 Clinical Signs and Diagnosis of Mastitis

Transcript

Hi Vets,

In the last class, we have seen about the Microbiota of the udder, the Defense Mechanism of the udder, and Pathogenesis.

So in this lesson, that is lesson-3, we will see about the Clinical signs of Mastitis and the Diagnosis of Mastitis.

So Mastitis can be classified

Based on Epidemiology as Contagious and Environmental.

Based on Inflammation as Clinical and Sub-clinical and

Again on Severity as Acute, Chronic, and Peracute.

Contagious Mastitis is one, which spreads from the disease to a quarter to a healthy quarter or even from the diseased animal to the healthy animal, mostly during milking. Examples of this Contagious Mastitis causing organism are:

Staphylococcus and Corynebacterium.

Environmental Mastitis commonly the Pathogen will be in the cow’s environment and may be in the soil, bedding, or water. So the common pathogens are Streptococcus and Escherichia Coli. So second definition is based on Clinical signs; we have seen it has Clinical and Sub-clinical Mastitis.

Sub-clinical Mastitis can be defined as inflammation of the udder in the absence of any physical changes in the milk and also in the udder. It will not be usually visualized by the farmer. In some cases, he may report only the reduction in milk yield.

whereas Clinical Mastitis is farmer identified disease, he can very well identify changes in the milk or in the udder even in the animal.

So, the Clinical Mastitis can be further divided into 3 based;

Abnormal Secretion

Abnormal Quarter and

Abnormal Cow.

In Abnormal secretion, we may find flakes or watery milk or even blood tinge in the milk but there won’t be any change in the udder or in the animal.

In Abnormal udder;

There may be Inflammation of the udder, that is swollen or rigorous.

There may be pain on palpation and

There may be local or diffused fibrosis and

In an abnormal cow, the animal will show signs of toxemia, there may be pyrexia, there may be inheritance and even there may be recumbency.

And in ChronicMastitis, the udder may be regressed, feeling empty, and there may be scanty secretion or even no secretion and on careful palpation, you will be able to feel the fibrosis.

In clinical examination; we have to examine all the quarters and the teat for similarity or any inflammation or fibrosis and we have to check the secretion for any changes and we have to check for the confirmation of the teat, whether are there any deviation or convergence are to be considered.

Field tests include pH, Strip cup test, White site test, California Mastitis test, and others. So normally the pH of milk should be within the range of 6.3 to 6.7, so if the pH is more than 6.7 or less than 6, it can be considered Mastitis even without any changes in the milk.

And CMT is considered the cheapest and best reliable field site test, wherein the principle is that the CMT reagent will lie in the cell and interact with the DNA which coagulates to form gel formation. So here we have to take 5 ml of milk with an equal quantity of the reagent and we have to stir it with this toothpick and the result should be read within 20 to 30 seconds.

And for the Strip cup test, we have to use a black cup which will show the presence of any clots or any other change in the milk well.

And the other test is Electrical conductivity which is based on the increased level of Sodium and Chloride in the milk even in the subclinical level of damage to the udder, in such conditions the electrical conductivity will be increased.

Somatic cell count is another field site test that can be done for individual animals or even for bulk tank milk, so

• if the reading is less than 1 lakh it is taken as normal
• if the reading is more than 2 lakhs it is considered the presence of Mastitis and
• if the reading is more than 3 lakhs it requires examination of that individual animal

The other test is the White side test, wherein we have to take a few drops of milk on a glass slide and we have to add the same quantity that is two or three drops of 4% percent Sodium Hydroxide and stir well, it will lead to the formation of clots or clumps or aggregation, that indicates the presence of Mastitis.

The other test is the Rapid Catalyst test, though it is an old method of testing, that is also giving reliable results. So in that again we have to take two or three drops of milk on a glass slide and add an equal quantity of 9% Hydrogen Peroxide and within one minute, you can see the bubble formation which indicates a positive case.

The next is Bacterial Isolation and Identification, wherein we have to go for culturing a specific medium that can be used for diagnosing or isolating specific bacteria and it has limitations like all the bacteria cannot be identified because low growing bacteria and some bacteria cannot be cultivated cannot be diagnosed with this method.

If we collect from a milking machine, there is another test called the String test, wherein we collect the milk from the positive pressure side of the machine, which indicates the presence of Mastitis at a herd level.

And coming to Culture Interpretation, if the culture is positive in the first week- that is on a day 0 and if it is negative on 7, 21, and 28, it is taken as negative, and if it is negative for the first test and if it is positive for the subsequent test that indicates new Intra memory infection. And the presence of 3 or 4 sites of bacteria is considered Contamination.

Diagnosis:

And the other advanced techniques include PCR and many variants of PCR and among these 16s rRNA sequencing and whole metagenome sequencing are considered authentic or reliable methods of Diagnosis.

Apart from that, we have Eliza, Biomarkers, Biosensors, and Protein-based Diagnosis. So, coming to another useful animal site test Ultrasonography, helps a lot. So, by doing Ultrasonography will be able to assess, even there is any damage to the udder or if there is any fibrosis to the udder, or if there is any obstruction in the teat kennel, so these things can be identified by ultrasonography.

These are some of the videos and pictures, which show the clinical condition and normal ones. Again, with ultrasound, we can assess whether that particular quarter is functional or not. so, for that, we have to administer 10 to 20 international units of Oxytocin and we can examine the functioning of the teat.

So, if you focus on the Lactiferous ducts on the collection tubules, you can find the accumulation of milk. So, in this case you can see the collection of milk, so this is functional. It won’t be like this in cases of the diseased or completely fibrous quarter, where there is no functioning. So, in this lesson, we have seen the Clinical signs, Classification, and Diagnosis of Mastitis.

And in the next class, we will see about the Treatment of Mastitis.

Thank you!