Mastitis in Dairy Cattle
Transcript Of Mastitis in Dairy Cattle
South Dakota State University
Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange
Agricultural Experiment Station Circulars
SDSU Agricultural Experiment Station
8-1944
Mastitis in Dairy Cattle
T. M. Olson
South Dakota State University
F. M. Skelton
South Dakota State University
Follow this and additional works at: http://openprairie.sdstate.edu/agexperimentsta_circ
Recommended Citation
Olson, T. M. and Skelton, F. M., "Mastitis in Dairy Cattle" (1944). Agricultural Experiment Station Circulars. Paper 51. http://openprairie.sdstate.edu/agexperimentsta_circ/51
This Circular is brought to you for free and open access by the SDSU Agricultural Experiment Station at Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in Agricultural Experiment Station Circulars by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact [email protected]
Circular 54--Augu•t, 1944
MASTITIS
ID
Dairy Cattle
South Dakota Agricultural Experiment Station
South Dakota State College--Brookings
Table of Cont:ent:s
PREVALENCE OF MASTITIS------------------- ---------------------- ___________
3
MASTITIS DECREA.SES MILi( FLOv\T ---------------------------------------------------- 3 CAUSE OF MASTITIS------------------------- ----- ----------------------- _____ ____ ______________ _ 4
SYMPTOMS ANDHOW TO DETECT MASTITIS------------------------------ 6 Flaky or Lumpy Milk------------------------------- -----------------�--------------- ____________ 6 Swollen Quarter------------------------------------------------------------------------------------------ 7 Unhealthy Appearance _____________ _________________________________ ______ _____ ____ __________ 7 Scar Tissue -------------------------------------------------------------------------------------------------- 7 Streptococci in Milk------------------------------------------------------------------------- ________ 8
HOW MASTITIS SPREADS------------------------------------------------------------------------ 8
PREVENTION AND CONTROL ------------------------------------------------- ------------ 8 Keep Cows Comfortable---------------------------------------------------------------------------- 9 Keep Barns Clean-------------------------------------------------------------------------------------- 9 Milkers ShouldBeHealthy--------------------------------------------------------------------- -- 9
GOOD MILKING PRACTICES________________________ ---------------------------------------- 9
TREATMENT OF MASTITIS---------------------------------------------------------------------- 10 Treat During Dry Period------------------------------- ________________ _____ __________________ 11 Products for Injection-------------------------------------------------------------------------------- 11
MILK FROM MAST!TIS COWS_______ _____________________ _____ ----------- ---------------- 12
Summary
1. Mastitis is usually caused by a specific organism, Streptococ cus agalactiae.
2. Mastitis occurs in one or more of the milking cows in nearly all herds of any size. It is more prevalent in old than in young cows.
3. The most common symptoms of mastitis are: Swollen, in flamed quarters, flakes or lumps of curd in the milk and on the milk strainer pad.
4. Mastitis producing bacteria enter the udder through the streak canal.
5. There are several tests for detecting mastitis in milking cows. The microscopic inspection of milk in which the long chain strep tococci organisms are found is the most dependable.
6. Mastitis can be controlled by testing, observing sanitary prac tices in the barn, use of medicaments, and slaughter of the chronic cases that will not yield to treatment.
Mast:it:is (Garget:) In Dairy Cat:t:le
By T. M. OLSON and F. M. SKELToN1
The control and prevention of diseases and ailments in dairy herds mean more to the success of a well-bred dairy herd than any other single factor. As the herd increases in number and the in dividuals in the herd improve in production, diseases occur more frequently. This is only natural. With larger numbers more ani mals contact each other, increasing the possibilities of infection.
High-produci,ng animals are highly developed and therefore hard working. They cannot withstand the hardships and contagion of disease as can the "boarder cow," which is largely on a mainten ance basis.
Prevalence of Mast:it:is Mastitis is found in small herds of dairy cows as well as in large herds. If all milking herds were checked by means known to de tect mastitis, it is doubtful that any herd of any size would be entire ly negative to all of the tests. Some researchers have estimated that one or more milking cows in nine of ten dairy herds would react positively to at least one of the tests. This positive reaction does not necessarily mean that the cows show evidence of active mastitis. But it does mean that there is danger of mastitis under inducing condi tions, such as bruised udder and lowered resistance. In some herds in which no control measures are practiced, it is not uncommon to find mastitis in 50 to 75 percent of the cows. It is likely to spread further unless control measures are taken.
Mast:it:is Decreases Milk Flow Mastitis exacts a heavy toll on the profits of the dairyman. Milk production of cows infected with this disease may decrease 20 to 30 percent on the average. Heavy-producing cows having mastitis have been known to drop from an average production of 95 pounds of milk a day to 30 pounds. That is not all. Many cows permanently lose the function of one or more quarters of the udder. Statistics show that about 40 percent of all m'ilk cows marketed in the United States are sold because of defective udders. In addition to these losses, infected cows need extra attention when they are milked, thus adding to the work of the dairyman. Mastitis is a disease that should be eliminated from every dairy herd. Management practices should be taken to keep it out.
1 T. M. Olson, Dairy Husbandman; and F. M. Skelton, Assistant Dairy Husbandman.·
3
4
So11tb Dakota Experi,nent Station Cirwlar 54
Cause of MasHt:is Mastitis is an inflammation of the udder caused by bacteria (germs). The bacteria are found in barns, in materials kept in barns, and on the hands of milkers. They are also on milking machines, particularly on the rubber parts which are allowed to become dirty. When these rubber parts have been used for some time, they fre quently have tiny cracks which cannot readily be seen with the naked eye but are visible under the microscope. These cracks har bor millions of bacteria. Unless the rubber is carefully and thor oughly cleaned, it is an important source of contamination. The germs enter the udder through the teat canal or through cuts, abra sions, or other injuries to the udder. Because the udder of a dairy cow is such a se.nsitive organ, as well as because germs can enter it through bruises, every precaution should be taken not to injure it. The following practices should be followed to avoid injuring the udder.
l. Handle the udder gently.
2. Leave the milking machine on only until the cow has been milked dry, not after she is dry.
3. Follow manufacturers' directions for operating the milking machine. Do not increase the vacuum of a milking machine above what the manufacturers recommend.
4. Be sure that the udder is not injured by being kicked, bunted, or. stepped upon by other cows.
5. Drive cows at a walk. Faster driving causes the udder to swing.
6. Provide enough bedding, otherwise the cows are forced to lie on cold rough floors where the udder is exposed to sharp gutter edges.
7. Use teat tubes, teat dilators, and teat plugs only as a last resort. Drying up an infected quarter is preferable.
8. Milk cows regularly.
9. Be careful when drying off cows.
10. Keep milking machines clean and have good inflations.
Considerable experimental work on mastitis has been done by the South Dakota Station and other experiment stations. It has been definitely established that most of the cases of mastitis show Streptococcus agalactiae. Occasionally staphlococci are found.
When either of these organisms are found in the milk of any quarter, or a large number of leucocytes are found, the presumption is that streptococci or staphlococci were the cause of the mastitic condition. It is apparent that only a trained bacteriologist under-
Maslitis (garget) in Dairy Cattle
5
·' .·. ...._ ':"\,,.-_-..•,;.. :.,;.
, ...
•.
. • .--.-=.. I,'
,,. ,•... • f
.,
._ 1 · r ,,,. I
. .,,-: /.
Cross section of the rear quarters of a cow's udder. A-streak canal, B-teat cistern, C gland cistern, D-milk ducts, E-mammary or secretory tissue, F-median suspensory ligament, G-supra mammary lymph gland, H-skin.
6
Soutb Dakota Expen"ment Station Circ11/ar 54
stands how to prepare the milk so that these organisms can be seen under a microscope. It also requires a trained technician to identify the organisms.
Practical feeders frequently attribute mastitis to heavy feeding, particularly of high-protein feeds. However, no experimental data are available to show that feeds of any kind cause mastitis. Feeding trials in which cottonseed meal was fed in liberal amounts did not indicate that this high-protein feed induced mastitis.
It cannot be said that overfeeding cows on concentrates does not result in trouble. When cows are over-fed on concentrates and go off feed, their resistance is lowered and they may contract any disease. If cows are exposed to heavy infections of mastitis while in this condition, they may come down with an attack of mastitis.
Symptoms and How to Detect Mastitis
It is important that the milker recognize mastitis in its early stages, because if the cow is to be cured or the disease controlled, action must be taken as soon as possible after the infection is
Flaky or lumpy milk. Two types of abnormal milk are due to mastitis. One is caused when the udder of a heavy producing cow becomes chilled. If the cows have been housed in a warm barn and are allowed to lie down outside on the cold ground, some of them may produce flaky or lumpy milk for one or two milkings, and then the milk becomes normal again. This is a non-infectious type of mastitis. However, it is well to make certain that it has cleared up, as this condition may also be the beginning stages of an infecti ous type of mastitis. The only certain method of identifying masti tis is to have the milk tested by a competent laboratory technician.
The infectious type is more difficult to recognize unless regular tests are made on the milk. However, there are symptoms that a close-observing herdsman will recognize as the beginning stages of mastitis.
J\!lastitis (garget) in Dairy Catrle
7
Swollen quarter. A swollen quarter, particularly if it is feverish, is an indication of inflammation. Milk out such a quarter, using a strip cup or strip plate to note whether there are any flakes or !umps resembling milk curd. If the milk is abnormal, it should be milked into a separate pail in which some disinfectant has been placed to kill any bacteria that may be present. Do not strip the abnormal milk on the floor. Such stripping spreads the infection to other cows.
Unhealthy appearance. In some types of mastitis the first symp tom noticed is that the cow fails to eat. Her temperature is above normal. She looks listless, her hair becomes rough and dry and her eyes dull. She may not milk half as much as she did on the previous milking. If nothing is done the cow may recover in a few days or she may die. With this type of mastitis the cow will very likely lose the function of one or more quarters and give much less milk for the balance of the lactation and during subsequent lactations.
In other cases the inflammation may persist until the quarter breaks open and discharges pus. This is an insanitary, unsightly condition in a cow that is producing milk for human consumption. Get the services of a veterinarian as soon as the cow is observed to be off feed. If she isn't worth keeping, dry her up and sell her for slaughter. Don't sell her to a dairyman. Unless she is treated and cured, she may not be worth keeping as a milk cow. Moreover, she becomes a potential spreader of mastitis.
Scar tissue. In many cases mastitis may not be detected until scar tissue has formed in the udder. When the udder is infected with mastitis the mammary tissue is replaced with scar tissue. An expe rienced dairyman can discover this tissue in the udder of a cow by palpating (handling) the udder. Obviously the udder must be milked dry before palpating. Lumps in the udder or hard resistant tissue usually indicate mastitis, or that the disease is temporarily arrested. This type of an udder should not be confused with a "meaty" udder, which is natural to some cows. Many dairymen who have experimented with mastitis think that palpating the udder is one of the easiest and most effective means of determining the disease.
Streptococci in milk. There are several laboratory tests by which mastitis can be detected. These tests are determined on the milk from the cow and should be performed by qualified technicians. They are bromthymol blue, chloride, microscopic, and Hotis tests.
8
South Dakota Experiment Statio11 Cirwlar 54
When the properly incubated and stained milk samples are ex amined under the microscope and long chain streptococci organ isms are found, infection is present in the udder. In much of the ex perimental work which is being done on mastitis, a positive micro scopic test is the best evidence that the cow has mastitis.
How Mast:it:is Spreads
The spread of infectious mastitis is largely by specific bacteria. Various types of bacteria are responsible for mastitis but many re search workers have found that 90 percent of mastitic cases are caused by Streptococcus agalactiae. When these bacteria are present in the udder, they are given off in the milk. Then they can be found on the milker's hands, the teat cups and dairy utensils. If the milk from the cows having mastitis is milked into the bedding or the gutter, the dust in the barn air becomes laden with mastitic bac teria. Flies may carry the bacteria from the teats of one cow to an other and thus spread the infection.
The bacteria enter the healthy udder through the teat canal. The sphincter muscles (circular muscles at the end of the teat) are more relaxed during and right after milking, therefore there is more likelihood of the bacteria entering the udder during or soon after the milking process.
Many milking cows and virgin heifers have the bacteria in the udder. All that is necessary to bring on mastitis is some inducing factor, such as bruising, butting or otherwise injuring the mam mary tissue, or even lowering the vitality or disease-resisting ability of cows. Cows which have recently freshened or have had attacks of diseases and therefore have a lower resistance, may suddenly have an attack of mastitis. Cows which become chilled when they drink cold water or are exposed to cold winds or inclement weath er, may also have an attack of mastitis.
Prevent:ion and Cont:rol "An ounce of prevention is worth a pound of cure" is even more applicable in the case of mastitis than most other diseases, because the disease attacks the udder, a highly sensitive organ and is very difficult to cure when it can be cured at all. Therefore, the dairyman should be exceedingly careful in managing to prevent mastitis from entering the herd.
Jl1astitis (garget) i11 Dairy Cattle
9
Keep cows comfortable. No successful dairyman will permit his cows to be milked or handled in such a manner that they are in jured in any way. Every precaution should be taken to make the cows comfortable. Feed them and care for them so that they can resist slight infections.
A cow's physical condition should be watched so carefullv that as soon as she is ailing she will be cared for. If she needs the services of a veterinarian, call one immediately. If she needs home treat ment, see that she gets it.
Keep barns clean. Sanitation is highly important in the manage ment of a dairy herd. A slovenly, untidy barn is no place to produce a food as precious as milk. Sanitation not only means a superior product but goes a long way in keeping the herd healthy enough to ward off minor infection. Cleanliness of milking machines, barns, dairy utensils, and the milkers and others who handle the milk should be beyond question.
Milkers should be healthy. The organisms which produce septic sore throat in human beings can grow in the udder of cows and cannot be distinguished from the Streptococcus agalactiae under the microscope. Therefore, no one with sore throat or any other communicable disease should be permitted to milk cows or handle the milk. It should always be kept in mind that milk is a very good medium for growth of all bacteria. Therefore every precaution should be observed to prevent contamination.
Good Milking Pradices
Gentleness in milking and handling the cows is important. A rough hand-milker or one who does not understand the operation of a mechanical milker will frequently bring on mastitis. Once it is in the herd, the same type of person will cause mastitis to spread. Careless milking and herd management are probably the greatest factors contributing to the occurrence and spread of mastitis in dairy herds.
The cow should be comfortable and entirely at ease when she is being milked. Anything which might scare her or cause her to become nervous and excited when being milked must be avoided. Avoid injury to the cow's teats and udder.
If a teat has been stepped on or otherwise injured, the use of a milking tube to get the milk from the injured quarter usually re-
Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange
Agricultural Experiment Station Circulars
SDSU Agricultural Experiment Station
8-1944
Mastitis in Dairy Cattle
T. M. Olson
South Dakota State University
F. M. Skelton
South Dakota State University
Follow this and additional works at: http://openprairie.sdstate.edu/agexperimentsta_circ
Recommended Citation
Olson, T. M. and Skelton, F. M., "Mastitis in Dairy Cattle" (1944). Agricultural Experiment Station Circulars. Paper 51. http://openprairie.sdstate.edu/agexperimentsta_circ/51
This Circular is brought to you for free and open access by the SDSU Agricultural Experiment Station at Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in Agricultural Experiment Station Circulars by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact [email protected]
Circular 54--Augu•t, 1944
MASTITIS
ID
Dairy Cattle
South Dakota Agricultural Experiment Station
South Dakota State College--Brookings
Table of Cont:ent:s
PREVALENCE OF MASTITIS------------------- ---------------------- ___________
3
MASTITIS DECREA.SES MILi( FLOv\T ---------------------------------------------------- 3 CAUSE OF MASTITIS------------------------- ----- ----------------------- _____ ____ ______________ _ 4
SYMPTOMS ANDHOW TO DETECT MASTITIS------------------------------ 6 Flaky or Lumpy Milk------------------------------- -----------------�--------------- ____________ 6 Swollen Quarter------------------------------------------------------------------------------------------ 7 Unhealthy Appearance _____________ _________________________________ ______ _____ ____ __________ 7 Scar Tissue -------------------------------------------------------------------------------------------------- 7 Streptococci in Milk------------------------------------------------------------------------- ________ 8
HOW MASTITIS SPREADS------------------------------------------------------------------------ 8
PREVENTION AND CONTROL ------------------------------------------------- ------------ 8 Keep Cows Comfortable---------------------------------------------------------------------------- 9 Keep Barns Clean-------------------------------------------------------------------------------------- 9 Milkers ShouldBeHealthy--------------------------------------------------------------------- -- 9
GOOD MILKING PRACTICES________________________ ---------------------------------------- 9
TREATMENT OF MASTITIS---------------------------------------------------------------------- 10 Treat During Dry Period------------------------------- ________________ _____ __________________ 11 Products for Injection-------------------------------------------------------------------------------- 11
MILK FROM MAST!TIS COWS_______ _____________________ _____ ----------- ---------------- 12
Summary
1. Mastitis is usually caused by a specific organism, Streptococ cus agalactiae.
2. Mastitis occurs in one or more of the milking cows in nearly all herds of any size. It is more prevalent in old than in young cows.
3. The most common symptoms of mastitis are: Swollen, in flamed quarters, flakes or lumps of curd in the milk and on the milk strainer pad.
4. Mastitis producing bacteria enter the udder through the streak canal.
5. There are several tests for detecting mastitis in milking cows. The microscopic inspection of milk in which the long chain strep tococci organisms are found is the most dependable.
6. Mastitis can be controlled by testing, observing sanitary prac tices in the barn, use of medicaments, and slaughter of the chronic cases that will not yield to treatment.
Mast:it:is (Garget:) In Dairy Cat:t:le
By T. M. OLSON and F. M. SKELToN1
The control and prevention of diseases and ailments in dairy herds mean more to the success of a well-bred dairy herd than any other single factor. As the herd increases in number and the in dividuals in the herd improve in production, diseases occur more frequently. This is only natural. With larger numbers more ani mals contact each other, increasing the possibilities of infection.
High-produci,ng animals are highly developed and therefore hard working. They cannot withstand the hardships and contagion of disease as can the "boarder cow," which is largely on a mainten ance basis.
Prevalence of Mast:it:is Mastitis is found in small herds of dairy cows as well as in large herds. If all milking herds were checked by means known to de tect mastitis, it is doubtful that any herd of any size would be entire ly negative to all of the tests. Some researchers have estimated that one or more milking cows in nine of ten dairy herds would react positively to at least one of the tests. This positive reaction does not necessarily mean that the cows show evidence of active mastitis. But it does mean that there is danger of mastitis under inducing condi tions, such as bruised udder and lowered resistance. In some herds in which no control measures are practiced, it is not uncommon to find mastitis in 50 to 75 percent of the cows. It is likely to spread further unless control measures are taken.
Mast:it:is Decreases Milk Flow Mastitis exacts a heavy toll on the profits of the dairyman. Milk production of cows infected with this disease may decrease 20 to 30 percent on the average. Heavy-producing cows having mastitis have been known to drop from an average production of 95 pounds of milk a day to 30 pounds. That is not all. Many cows permanently lose the function of one or more quarters of the udder. Statistics show that about 40 percent of all m'ilk cows marketed in the United States are sold because of defective udders. In addition to these losses, infected cows need extra attention when they are milked, thus adding to the work of the dairyman. Mastitis is a disease that should be eliminated from every dairy herd. Management practices should be taken to keep it out.
1 T. M. Olson, Dairy Husbandman; and F. M. Skelton, Assistant Dairy Husbandman.·
3
4
So11tb Dakota Experi,nent Station Cirwlar 54
Cause of MasHt:is Mastitis is an inflammation of the udder caused by bacteria (germs). The bacteria are found in barns, in materials kept in barns, and on the hands of milkers. They are also on milking machines, particularly on the rubber parts which are allowed to become dirty. When these rubber parts have been used for some time, they fre quently have tiny cracks which cannot readily be seen with the naked eye but are visible under the microscope. These cracks har bor millions of bacteria. Unless the rubber is carefully and thor oughly cleaned, it is an important source of contamination. The germs enter the udder through the teat canal or through cuts, abra sions, or other injuries to the udder. Because the udder of a dairy cow is such a se.nsitive organ, as well as because germs can enter it through bruises, every precaution should be taken not to injure it. The following practices should be followed to avoid injuring the udder.
l. Handle the udder gently.
2. Leave the milking machine on only until the cow has been milked dry, not after she is dry.
3. Follow manufacturers' directions for operating the milking machine. Do not increase the vacuum of a milking machine above what the manufacturers recommend.
4. Be sure that the udder is not injured by being kicked, bunted, or. stepped upon by other cows.
5. Drive cows at a walk. Faster driving causes the udder to swing.
6. Provide enough bedding, otherwise the cows are forced to lie on cold rough floors where the udder is exposed to sharp gutter edges.
7. Use teat tubes, teat dilators, and teat plugs only as a last resort. Drying up an infected quarter is preferable.
8. Milk cows regularly.
9. Be careful when drying off cows.
10. Keep milking machines clean and have good inflations.
Considerable experimental work on mastitis has been done by the South Dakota Station and other experiment stations. It has been definitely established that most of the cases of mastitis show Streptococcus agalactiae. Occasionally staphlococci are found.
When either of these organisms are found in the milk of any quarter, or a large number of leucocytes are found, the presumption is that streptococci or staphlococci were the cause of the mastitic condition. It is apparent that only a trained bacteriologist under-
Maslitis (garget) in Dairy Cattle
5
·' .·. ...._ ':"\,,.-_-..•,;.. :.,;.
, ...
•.
. • .--.-=.. I,'
,,. ,•... • f
.,
._ 1 · r ,,,. I
. .,,-: /.
Cross section of the rear quarters of a cow's udder. A-streak canal, B-teat cistern, C gland cistern, D-milk ducts, E-mammary or secretory tissue, F-median suspensory ligament, G-supra mammary lymph gland, H-skin.
6
Soutb Dakota Expen"ment Station Circ11/ar 54
stands how to prepare the milk so that these organisms can be seen under a microscope. It also requires a trained technician to identify the organisms.
Practical feeders frequently attribute mastitis to heavy feeding, particularly of high-protein feeds. However, no experimental data are available to show that feeds of any kind cause mastitis. Feeding trials in which cottonseed meal was fed in liberal amounts did not indicate that this high-protein feed induced mastitis.
It cannot be said that overfeeding cows on concentrates does not result in trouble. When cows are over-fed on concentrates and go off feed, their resistance is lowered and they may contract any disease. If cows are exposed to heavy infections of mastitis while in this condition, they may come down with an attack of mastitis.
Symptoms and How to Detect Mastitis
It is important that the milker recognize mastitis in its early stages, because if the cow is to be cured or the disease controlled, action must be taken as soon as possible after the infection is
Flaky or lumpy milk. Two types of abnormal milk are due to mastitis. One is caused when the udder of a heavy producing cow becomes chilled. If the cows have been housed in a warm barn and are allowed to lie down outside on the cold ground, some of them may produce flaky or lumpy milk for one or two milkings, and then the milk becomes normal again. This is a non-infectious type of mastitis. However, it is well to make certain that it has cleared up, as this condition may also be the beginning stages of an infecti ous type of mastitis. The only certain method of identifying masti tis is to have the milk tested by a competent laboratory technician.
The infectious type is more difficult to recognize unless regular tests are made on the milk. However, there are symptoms that a close-observing herdsman will recognize as the beginning stages of mastitis.
J\!lastitis (garget) in Dairy Catrle
7
Swollen quarter. A swollen quarter, particularly if it is feverish, is an indication of inflammation. Milk out such a quarter, using a strip cup or strip plate to note whether there are any flakes or !umps resembling milk curd. If the milk is abnormal, it should be milked into a separate pail in which some disinfectant has been placed to kill any bacteria that may be present. Do not strip the abnormal milk on the floor. Such stripping spreads the infection to other cows.
Unhealthy appearance. In some types of mastitis the first symp tom noticed is that the cow fails to eat. Her temperature is above normal. She looks listless, her hair becomes rough and dry and her eyes dull. She may not milk half as much as she did on the previous milking. If nothing is done the cow may recover in a few days or she may die. With this type of mastitis the cow will very likely lose the function of one or more quarters and give much less milk for the balance of the lactation and during subsequent lactations.
In other cases the inflammation may persist until the quarter breaks open and discharges pus. This is an insanitary, unsightly condition in a cow that is producing milk for human consumption. Get the services of a veterinarian as soon as the cow is observed to be off feed. If she isn't worth keeping, dry her up and sell her for slaughter. Don't sell her to a dairyman. Unless she is treated and cured, she may not be worth keeping as a milk cow. Moreover, she becomes a potential spreader of mastitis.
Scar tissue. In many cases mastitis may not be detected until scar tissue has formed in the udder. When the udder is infected with mastitis the mammary tissue is replaced with scar tissue. An expe rienced dairyman can discover this tissue in the udder of a cow by palpating (handling) the udder. Obviously the udder must be milked dry before palpating. Lumps in the udder or hard resistant tissue usually indicate mastitis, or that the disease is temporarily arrested. This type of an udder should not be confused with a "meaty" udder, which is natural to some cows. Many dairymen who have experimented with mastitis think that palpating the udder is one of the easiest and most effective means of determining the disease.
Streptococci in milk. There are several laboratory tests by which mastitis can be detected. These tests are determined on the milk from the cow and should be performed by qualified technicians. They are bromthymol blue, chloride, microscopic, and Hotis tests.
8
South Dakota Experiment Statio11 Cirwlar 54
When the properly incubated and stained milk samples are ex amined under the microscope and long chain streptococci organ isms are found, infection is present in the udder. In much of the ex perimental work which is being done on mastitis, a positive micro scopic test is the best evidence that the cow has mastitis.
How Mast:it:is Spreads
The spread of infectious mastitis is largely by specific bacteria. Various types of bacteria are responsible for mastitis but many re search workers have found that 90 percent of mastitic cases are caused by Streptococcus agalactiae. When these bacteria are present in the udder, they are given off in the milk. Then they can be found on the milker's hands, the teat cups and dairy utensils. If the milk from the cows having mastitis is milked into the bedding or the gutter, the dust in the barn air becomes laden with mastitic bac teria. Flies may carry the bacteria from the teats of one cow to an other and thus spread the infection.
The bacteria enter the healthy udder through the teat canal. The sphincter muscles (circular muscles at the end of the teat) are more relaxed during and right after milking, therefore there is more likelihood of the bacteria entering the udder during or soon after the milking process.
Many milking cows and virgin heifers have the bacteria in the udder. All that is necessary to bring on mastitis is some inducing factor, such as bruising, butting or otherwise injuring the mam mary tissue, or even lowering the vitality or disease-resisting ability of cows. Cows which have recently freshened or have had attacks of diseases and therefore have a lower resistance, may suddenly have an attack of mastitis. Cows which become chilled when they drink cold water or are exposed to cold winds or inclement weath er, may also have an attack of mastitis.
Prevent:ion and Cont:rol "An ounce of prevention is worth a pound of cure" is even more applicable in the case of mastitis than most other diseases, because the disease attacks the udder, a highly sensitive organ and is very difficult to cure when it can be cured at all. Therefore, the dairyman should be exceedingly careful in managing to prevent mastitis from entering the herd.
Jl1astitis (garget) i11 Dairy Cattle
9
Keep cows comfortable. No successful dairyman will permit his cows to be milked or handled in such a manner that they are in jured in any way. Every precaution should be taken to make the cows comfortable. Feed them and care for them so that they can resist slight infections.
A cow's physical condition should be watched so carefullv that as soon as she is ailing she will be cared for. If she needs the services of a veterinarian, call one immediately. If she needs home treat ment, see that she gets it.
Keep barns clean. Sanitation is highly important in the manage ment of a dairy herd. A slovenly, untidy barn is no place to produce a food as precious as milk. Sanitation not only means a superior product but goes a long way in keeping the herd healthy enough to ward off minor infection. Cleanliness of milking machines, barns, dairy utensils, and the milkers and others who handle the milk should be beyond question.
Milkers should be healthy. The organisms which produce septic sore throat in human beings can grow in the udder of cows and cannot be distinguished from the Streptococcus agalactiae under the microscope. Therefore, no one with sore throat or any other communicable disease should be permitted to milk cows or handle the milk. It should always be kept in mind that milk is a very good medium for growth of all bacteria. Therefore every precaution should be observed to prevent contamination.
Good Milking Pradices
Gentleness in milking and handling the cows is important. A rough hand-milker or one who does not understand the operation of a mechanical milker will frequently bring on mastitis. Once it is in the herd, the same type of person will cause mastitis to spread. Careless milking and herd management are probably the greatest factors contributing to the occurrence and spread of mastitis in dairy herds.
The cow should be comfortable and entirely at ease when she is being milked. Anything which might scare her or cause her to become nervous and excited when being milked must be avoided. Avoid injury to the cow's teats and udder.
If a teat has been stepped on or otherwise injured, the use of a milking tube to get the milk from the injured quarter usually re-