Mastitis in lactating animals is a painful infection of the mammary gland, resulting in decreased milk production. If left untreated mastitis infections can destroy the mammary tissue and even be fatal to the animal. Most cases of mastitis start with poor hygiene. Muddy pens and dirty bedding are perfect places for mastitis causing organisms to lie in wait. In the case of dairies, contagious mastitis can easily be spread through milking equipment and poor sanitation. It’s easy to point the finger at this, that or the next thing as a cause for mastitis, but for the most part, mastitis should really be considered as a disease “caused by man with symptoms in the animal.” Mastitis should be viewed as an environmental issue and not necessarily the animal’s fault. In other words, we are responsible for most of the mastitis that our animals get.
Mastitis can affect any dairy animal, not just cows. As Flo Hawley, owner of Chapel Hill Creamery in North Carolina knows, it’s important to keep a close eye on the health of your animals.
Photo by Susan P. Tullock
As with many illnesses, an ounce of prevention is worth a pound of cure. This holds true with mastitis, as well. Working to prevent the disease pays off a whole lot more handsomely than having to treat it.
The prevention of mastitis centers around good hygiene and proper nutrition to support and improve the immune system. If you keep your housing, stalls, pens and bedding clean and if you bolster the immune system with proper nutrition, vitamins and minerals, the chances of mastitis causing organisms finding their way into your lactating animals will be greatly reduced.
Mastitis causing organisms come in two kinds: Environmental and Contagious.
Environmental mastitis is probably the most common form, usually coming from coliform bacteria found in mud, manure, wet bedding and other moisture laden material that a lactating mother may be lying in. When a baby comes to nurse on a muddy teat or nipple, any foreign organism can quickly be spread right up the milk canal and into the mammary gland where it finds a perfect environment to live and multiply. As with any infectious challenge, the host’s immune system moves quickly to destroy the invading organism with white blood cells. Similar to our getting a cold, often the body is able to fight it off and in several days we generally feel better. The same will often happen with a mastitis infection. However, if the challenge is overwhelming to the host, the invading organism begins to destroy tissue and the animal can become quite sick.
Contagious mastitis is caused by organisms that live on an animal’s skin (including humans) and are spread by equipment or by hand. You will generally only find contagious mastitis problems in milking barn environments where cows, goats and sheep are milked with automatic equipment. Staphylococcus and streptococcus bacteria species are the predominant organisms involved with contagious mastitis. In a milking barn environment careful attention to hygiene is very important. Washing and disinfection of teat cups between animals will greatly reduce the transmission of these bacteria as will the washing of your hands before you handle another animal. Whether inside or outside the barn, the key to avoiding the spread of mastitis is cleanliness.
Mycoplasma mastitis is a third type of mastitis that’s becoming a greater challenge, mostly in larger dairy herds. This mastitis is highly contagious and has been found to be particularly insidious because it appears to spread by way of blood stream/lymph node/mucosal pathways. So in the case of a dairy cow, it may infect one quarter of an udder this month, and sometime later when you think the cow is cured, show up in another quarter. The staph and strep strains do not spread in that manner. Mycoplasma does not respond to antibiotic treatment, and the only known way to eradicate it from a herd is by culling cows.
Mastitis causing organisms are basically opportunistic. If the immune system of an animal is good, there’s much less of a chance that she will become infected. Proper nutrition before and after your animals give birth will greatly reduce the possibility of coming down with mastitis. Dietary energy and calcium supplementation are key to supporting the immune system.
All animals undergo an immune challenge when they give birth and begin lactation. High levels of a hormone called cortisol are released when animals give birth. Cortisol has a direct suppressive affect on the immune system. Other management factors such as excessive handling, over-crowding, or moving and shipping will contribute to stress levels and immune challenges.
The onset of milk production requires a lot more energy in an animal’s diet. If that energy is deficient, your cow, goat or sheep will quickly begin using her own fat reserves which increases the transfer of specific types of fatty acids to the liver. Those fatty acids must be converted to glucose in the liver in order for an animal to derive energy from them. If the dietary energy deficit is large enough the liver will be overwhelmed by the fat and products called ketones are produced which act to suppress immunity. Increasing dietary energy is the only way to avoid or reduce this immune challenge.
Calcium has long been recognized as an important mineral in the diets of lactating animals and extra calcium is needed in lactating diets since there’s so much calcium in milk. Its major function in the body is for bone formation but it’s also required for proper muscle contraction. Everything from proper feed digestion to expulsion of fetal membranes after birth, to proper teat sphincter closure after milking is controlled by calcium. If calcium is low in the body, the muscles don’t work right. Calcium is also involved in the immune cell response. Calcium plays a pivotal role in signaling a cell to bring in antibodies to fight off an invading bacteria at the cellular level.
The California Mastitis Test is quick and easy to use for cow owners.
If you’re in the business of producing dairy products for human markets, whether it be cow, goat or sheep, you need to be very diligent about keeping mastitis under control. An animal’s first immune response to an infection is to produce what is called somatic cells or leukocytes which are essentially white blood cells. Health departments use the somatic cell count (SCC) as a means to determine the bacterial level and safety threshold of milk. You as a producer need to keep your SCC as low as possible both for the health of your animals and for the marketability of your dairy products.
The dairy industry has been using a simple cow-side test for many years called the California Mastitis Test (CMT). The test is quick and easy to conduct and anyone who milks animals should keep a kit around to periodically screen the milk. The test estimates the number of white blood cells in the milk with the use of a reagent that’s added to a small sample of milk. The reagent will react to high levels of white blood cells by forming a purple gel. The gel will become thicker as the SCC increases. This test reportedly works on any specie’s milk that has high white blood cells counts. Any dairy health or equipment supplier should be able to direct you to finding a CMT test kit.
Treatment of mastitis is problematic since many of the bacteria respond either poorly or not at all to antibiotics. Streptococcus agalactiae (strep ag) is the one organism that can be completely eradicated from a herd with antibiotics. Coliform and staph species respond poorly and mycoplasma doesn’t respond at all. Often, the best treatment is increased milking frequency to rid the mammary of the infected milk along with the use of pain relievers and anti-inflamatory drugs. Treating your lactating animals with antibiotics requires that the milk is withheld from human markets for a specified period of time. Those who are producing organically certified dairy products are not allowed to use antibiotics at all. Your choices for treating mastitis are limited to homeopathic products. Once an animal is infected with these organisms it’s difficult to get rid of them. As with any infectious challenge, good health and nutrition is the body’s best defense in eliminating invasive organisms.
The best way, of course, to manage mastitis is to never let your animals get it in the first place. Clean maternity, nursing and milking environments, following proper milking procedure protocol and feeding your animals properly will make that happen. Avoiding mastitis in your animals is really up to you.