Mastitis is more commonly thought of as a disease of dairy cows. However, there is no reason that beef cows are immune from the disease; they have the same anatomical parts as a dairy cow; are potentially exposed to more environmental hazards than their dairy counterparts, and do not get examined every day when they are brought in to be milked. The biggest problem with mastitis in beef cows is that it is harder to diagnose for that very reason. We don’t milk our beef herd out once or twice a day: only the calves do that, and they aren’t talking (although they may be trying to communicate a problem, if only we are observant.)
Mastitis is technically an inflammatory condition in one or more of the milking quarters of the cow. 99% of those cases are caused by an infection, and the remaining 1% are caused by a noninfectious etiology: usually an injury. Infections of the mammary tissue may be acute and life threatening, or chronic and subclinical, with little indication there is a problem. Just like in dairy cows, mastitis can have tremendous impact on the individual cow’s performance; in the beef cow it is just reflected not in pounds of milk produced, but in pounds of calf weaned.
Peracute mastitis is a dramatic illness, and is an emergency medical condition. It is characterized by gross swelling in the affect gland or glands, heat, redness, pain, and gross evidence of abnormality in the amount of milk and the consistency of that milk. The milk can appear watery with clumps of material in it, or it can appear as very thick yellow pus. Peracute disease is accompanied by systemic signs of illness: fever, depression, shivering, anorexia (no appetite) and rapid weight loss. These animals are extremely sick with bacterial toxins circulating through their body, and the bacteria causing the mastitis may spread through the blood stream (bacteremia) and settle in a variety of internal organs causing septicemia. Disease this severe often is fatal. Cattle showing severe illness, including high fever (or probably worse, subnormal body temperature) markedly sunken eyeballs indication severe dehydration, severe depression and no rumen contractions, will require extension intervention to survive. Massive amounts of IV fluids, and painkillers may need to be supplemented with systemic antibiotics if the bacteria are believed to have entered the bloodstream.
Acute mastitis is characterized by the same physical signs of inflammation such as swelling, heat, redness and pain, often with some signs of systemic illness such as fever and mild depression.
Subacute mastitis may show some or all of the physical characteristics of the infected mammary gland, but those signs will be less pronounced, and there are no systemic signs of illness.
Subclinical mastitis, by its very nature, is extremely difficult to detect unless you have a very high index of suspicion, and make a point to look specifically for it. There are no outer signs of infection.
The severity of mastitis also depends upon the specific organism infecting the mammary gland, and the individual animal infected. The most common bacteria involved are streptococcus, staphylococcus and the coliforms (E. coli, Klebsiella, Enterbacter and Citrobacter). The coliforms are the most likely to be implicated in peracute mastitis; and often cause what is termed ”watery mastitis”. These families of bacteria are present in the intestinal tracts of all livestock and thus are very common environmental contaminants. The organisms are introduced through the teat opening; and the physical defenses of the teat end are the most important aspect of infection with these organisms. Coliform mastitis is not highly contagious cow to cow. The infected milk may appear to be watery, thus the common term for the coliform infection, but can also be bloody or have large thick clots of inflammatory tissue in the milk. The illness is so severe usually because of the production of toxins (poisons) produced by the coliform bacteria, and not the presence of the actual bacteria.
Acute mastitis is generally not a life-threatening condition, but it is imperative that it be treated vigorously in order to maximize the chance of complete cure with a fully functioning quarter. One of the most important aspects of treatment is stripping the quarter(s) of infected milk at least once per day, and more if possible. Unless the cow is critically ill, systemic antibiotics are the least important part of treatment. The vast majority of injectable antibiotics do not pass into the mammary tissue and milk. For example, ceftiofur (Naxcel, Excenel or Excede) is an excellent antibiotic with no milk withholding in dairy cows: the reason for this is that given in the muscle or under the skin, the antibiotic does not penetrate into the udder or milk at all. The same drug is very effective when administered directly into the quarter (Spectramast) once daily after stripping all milk from the infected gland. In addition to intramammary antibiotics, systemic anti-inflammatory drugs may be necessary, such as IV flunixin (Banamine) or oral aspirin. (Oral aspirin, by the way, is strongly discouraged by the FDA for use in cattle for fear of residues found in the meat.)
Subacute mastitis: while harder to detect because the signs are far less obvious, still requires treatment; this is often a mastitis that starts shortly after weaning, and smoulders until the next calving, when it may manifest as a more acute form. If discovered at the time around weaning, this can be treated with dry cow mastitis preparations, that are designed to stay in the udder for a prolonged period of time. These products will have a prolonged milk and meat withholding period. While the milk withholding is unimportant in the beef cow, meat withholding requirements must be carefully followed.
Subclinical mastitis will be virtually undetectable without specifically examining the milk, and so will not be discussed in any length here.
Even mild cases of mastitis, if untreated, commonly result in complete destruction of the mammary tissue with subsequent scarring and atrophy of the gland. Sometimes the scarring is limited to the teat canal, resulting in an inability to remove what milk is produced by that gland.
Every beef herd will have cases of mastitis; the question becomes whether these cases are detected when the animal first succumbs or much later when the infection has done its damage and the quarter is no longer functional. Fortunately, mastitis in beef cows usually only involves a single quarter, and the remaining 3 quarters compensate for the decreased production.
Size and shape of the teats and the udder can play a big roll in the susceptibility to mastitis. In general, the larger the diameter of the teat, the greater the risk of pathogens entering . Pointed teat ends have the greatest resistance to infection, but this is a relatively rare conformation. The most common configuration for the teat end is somewhat rounded; this has intermediate resistence to infection. A flat teat end (rarely seen) has the least resistance.
Large, pendulous udders are also more susceptible to mastitis: they hang lower to the ground and may actually drag through mud and manure in wet weather, and are more prone to self-inflicted injuries from hooves when laying down or rising. Once the teat is cut or nicked, bacteria are free to enter the mammary gland.
Flies are instrumental in spreading disease-causing organisms from manure pack to the teat orifice. They also irritate the teat end; moving the bacteria from the skin surface into the deeper tissue. Confinement , as well as dirt, manure pack and filth all increase the risk of mastitis. Animals widely dispersed on grass pasture with good fly control run a far lower risk of disease.
Flies can also spread contagious organisms from cow to cow, or teat to teat but generally in the beef cow, the calf is the guilty culprit that spreads the bacteria from one quarter to another. There are cows that will permit cross-suckling; and in some cases “hit or miss” attempts to nurse an unrelated cow can result in the spreading of mastitis cow to cow.
Older cows are at increased risk of mastitis, primarily due to deterioration of the mammary suspension, and enlarging teat size. Many of these older animals will have low-slung, broken-down bags with high likelihood of contact with the ground. Another group that seems predisposed to mastitis are younger, high-producing cows that tend to leak milk around the time of calving.
Bacteria can enter the udder during all stages of lactation, but the greatest risk for mastitis is the first month after calving and the immediate drying off period right after weaning. Unless careful attention is paid to the cow herd immediately post-weaning, this is very easy to miss, and may not be detected until the following year when the weaning weight of the infected cow’s calf is significantly reduced from the year before. Sometimes those smouldering infections that started after weaning will “blow Up in your face” at the next calving, with a sick cow or an obviously mastitic udder. It has been show that infusing the teats of beef cows with standard dry-cow treatments at weaning will effectively eliminate many infections present at weaning, but has no significant effect on new infections . This is surprising, since dry-cow treatment has been a standard in the dairy industry to prevent new infections. This is probably due to the protracted average dry period in the beef cow (160 day dry) versus the much shorter dry period in the dairy cow (60 day dry.)
A treatment recommended to prevent mastitis in the dry cow period has been to allow the weaned calves access to their dams one last time 1-2 days following weaning when the udder is distended with milk. While there is some logic to this approach (the now desperate calves will totally strip the udder of all milk that may be fostering a low number of pathogens) I find this approach impractical with the number of calves that we routinely wean. Reuniting dams with offspring and having to separate them again literally doubles what is already a lot of work. Breeders with a small number of calves to wean might want to consider this approach.
Prevention of mastitis involves any number of important factors: selecting for good udder and teat conformation being of primary importance. The cleaner the cow’s environment, the less likely the transfer of the organisms that cause mastitis. Nutrition needs to be adequate to keep the dry cow in good condition. Her body will preferentially supply the calf she carries with everything it needs, to her detriment if necessary. If she loosing body condition prior to calving, she will be more stressed and her immune system will become depleted, making her a candidate for any number of infections, including mastitis.
The importance of good udder and teat conformation in brood cows cannot be overemphasized. Pendulous udders may drag in the mud and large, coke-bottle size teats often accompany these poor, low-hung udders. Anything that hinders the calf from nursing on a quarter will also predispose to mastitis and this type of udder is mastitis waiting to happen. Calves will have a hard time finding the teats if they are hanging below the cows hocks, and may physically have a difficult time learning how to nurse on banana-sized teats. If the calf fails to empty the quarter and bacteria do manage to find their way into that unmilked portion of the udder, the remaining milk makes an ideal culture medium for infectious organisms. The fact that the calf doesn’t strip the quarter many times per day just allows that infection to fester for a longer period of time. Any cow that has a calf requiring assistance to nurse needs to be examined closely for signs of mastitis, and it the problem is related to poor udder conformation, any calf out of that cow should be relegated to your beef program, and not retained in your breeding herd (and needless to say, not sold to anyone else for their breeding program.)
Ideal udder conformation starts with an udder carried very tightly to the body wall. The median suspensory ligament is a broad band of elastic tissue that attaches from the pubic bone and extends down through the center of the mammary gland, attaching to the flat side of each quarter and essential dividing the udder in half front to back. This is the most important suspensory apparatus of the udder, and it needs to be strong. It is responsible for keeping the udder suspended off the ground (hopefully well above the hocks) and if doing its job adequately, is also responsible for maintaining the teats perpendicular to the ground.The teats themselves should be medium in length and cylindrical in appearance, with the diameter being consistent from the top of the teat to the bottom: the teat end should be rounded. They should be placed in the middle of each quarter and point perpendicular to the ground. Ideally they will all appear the same shape and length, with the floor of the udder remaining flat and parallel to the ground.
Calves nursing cows with mastitis will generally avoid the infected quarter. This may be do to a bad taste to the milk, or the cow may actively discourage nursing do to pain. Although there may be cases when infected milk could cause illness in the calf, this is unlikely; the calf is reluctant to nurse on that quarter, but even if it is allowed to do so, the acid environment of the stomach (abomasum) will kill most bacteria present. If the calf did nurse the gland with mastitis, this could be an advantage as it would keep the gland stripped out of milk far more efficiently than a human milker could.
Worst case scenario in the event of mastitis is death of the cow. This is relatively rare in beef cattle. However, total loss of function of one or more quarters is a very real outcome, with what can be dramatic decreases in weaning weights. Loss of one quarter is surmountable: ofter the remaining 3 quarters will compensate and total milk production will be only slightly affected. Loss of 2 quarters is obviously more serious. Heavy producing cattle may still raise an adequate calf, but it will have a noticably decreased weaning weight from previous calves. Loss of 3 quarters is catastrophic: the calf will be stunted, assuming it survives, and will require supplemental milk if it is to do well. Needless to say, loss of all 4 quarters requires the calf be totally bottle raised or grafted onto a nurse cow. If the cow is valuable enough, she can become an embryo donor, but the factors that lead up to loss of the quarters must be seriously considered prior to such an undertaking. If mastitis was related to udder and teat conformation failures, the cow should not ever be considered as a donor.
Possible sequelae of mastitis include complete recovery, abscessation of the infected tissue with rupture and drainage of pus, scarred teat canal with inability to express milk from it, scarred mammary tissue with eventual atrophy of the affected gland, or sloughing of the entire quarter. Sloughing of the entire quarter that has suffered from dry gangrene (loss of blood supply) after a case of acute mastitis post-calving. The affected tissue is actually dead, and is being expelled from a large rent in the skin of the quarter. This cow had recovered from the acute mastitis, and this occurred about 1 week later. The tissue of the quarter resembled leather and had no apparent feeling left. Thecow was unaware that the dog was trying to speed up the process. The large lesion eventually healed uneventfully.
Mastitis is actually common in all breeds of beef cattle, and herd incidence can run from 5-25% of animals. Observation of both cows and the nursing behavior of calves can aid in identification of affected cows. With attention to detail, mastitis can be identified and treated successfully without loss of function.
Treatment for mastitis in the lactating beef cow
- stripping the affected gland daily or twice per day
- approved intramammary antibiotics as directed
- antiinflammatory drugs such as IV flunixin (Banamine)
- IV fluids if necessary
- Systemic antibiotics if necessary (remember, these do not penetrate into the milk well if at all)
- Establishing drainage of inflammatory tissue (pus, necrotic material) if necessary
Treatment for mastitis in the beef cow immediately post weaning:
· Application of approved dry cow mastitis treatment in each affect quarter
· Allowing weaned calves to nurse the cow 1-2 days post-weaning with or without application of dry cow treatment immediately following.