Mastitis Management

Mastitis is a general term used to describe inflammation and/or infection in the tissues of the udder.  It can be caused by a number of different bacteria, and may present clinically or sub-clinically.

 

From our experience, the majority of cases of mastitis in goats are sub-clinical, meaning there will be no obvious physical signs that the goat is unwell or that there are quality issues with the milk.  Where this is the case, you may only be aware that you have an infected animal by an abnormal milk quality result from your processor.

​

Clinical mastitis is identifiable via noticeable changes in udder size, shape or appearance, being hot and/or swollen and abnormally firm to the touch, or through milk that is visibly 'wrong'.  Milk that is thin and watery, thick and creamy, or contains lumps, chunks or stringy bits is an indication of mastitis.  An animal who is 'looking off', coming into the shed in a different order than normal, not wanting to come in at all, or is abnormally kicky during milking should be checked for mastitis. Having regular milkers in the shed who become familiar with the animals and their udders is an invaluable asset when it comes to mastitis identification.

 

Sub-clinical mastitis can be difficult to identify without testing, particularly as some types of bacteria will only be shed periodically by the infected animal, so an infected animal may test negative one day but positive the next .  If your bulk somatic cell count (SCC) suddenly increases unexpectedly or you receive an APC (Aerobic Plate Count) or Coliform milk grade alert, there is a high chance you have an infected animal in the herd.  An APC test result is a total bacterial count and does not in itself tell you what kind of bacteria you are dealing with. if you get this in conjunction with a Coli grade, you most likely have one or more animals with an e-coli infection.    Some e-coli infections remain sub-clinical and may only be identified through milk samples, whilst others will have milk that is slightly bubbly in appearance when stripped.

​

Testing for Mastitis

Strip checking and RMT's

Strip checking the milk i.e. stripping out a few squirts from each udder (preferably onto a dark surface) and visually assessing the milk is the first step in identifying milk quality issues as it is quick and easy.  If strip checking does not show any abnormalities, an RMT can be done.

​

RMT stands for Rapid Mastitis Check.  It is performed by mixing equal amounts of milk with a particular solution that will react with Somatic Cells. Somatic cells are produced in higher numbers when an animal is under stress, for example when they are unwell with mastitis.  When looking at RMT results, it is important to remember that animals will also produce high levels of somatic cells when they are stressed for other reasons such as when they are cycling or post-kidding, and in instances of low milk volume, somatic cell numbers will also be more concentrated in the sample. 

​

Milk with a high Somatic Cell Count (SCC) will turn the RMT solution gluggy.  A slightly thickened result with no other indicators of mastitis is unlikely to an issue, however, if the solution become so thick and 'snot' like that it does not pour freely from the tester, it is highly likely that the milk is affected by a quality issue.

​

Milk Cultures

If neither strip checking nor RMTing the animals helps to identify the source of your problem, plating milk cultures will be needed.  You can begin with taking single samples of 'suspect' animals, have these tested by a lab or using an on-farm culturing set up, and see if this brings about any bacterial results.  Alternatively, depending on your farm's housing and milking setup, you can take a sample from the vat at the end of each herd and look for the sample in which the bacteria levels spike to help narrow the issue down to a particular group.  In a herringbone shed, you can take a sample from each doe in each row, allocating a specific colour/mark combination to each animal in the row and culture these samples, again to narrow the list of potential culprits down to a smaller group size. Once a particular herd or row has been identified as having an infected animal, you can then take individual or smaller group samples until you (hopefully) identify the animal causing the grade or high SCC result.

​

Prevention of Mastitis

Mastitis infections typically come from bacteria within the environmental or from bacteria living on, and transmitted between, the goats themselves.   In a housed environment, the bedding is the prime source of environmental bacteria but it can also come from dirty yard or race water splashing up onto udders (particularly as the animals leave the milking shed as the teat canals are still partially open after being milked).  Keeping the housing barns, laneways and yards clean and tidy is important in reducing the prevalence of environmental mastitis.

​

Once a mastitis infection takes hold in the udder, it can be transmitted to other goats, either as a contagious organism that is passed from goat to goat, contamination of the bedding from leaking udders or via the milking process (contaminated milk remaining in the cups and then being transferred to the next goat cupped with the same set).  If a goat has been identified as having mastitis, she should be removed from the main herd and milked last. If this is not feasible, she should be milked into a test bucket and the cups should be thoroughly rinsed before being paced on the next goat.  If your housing allows for it, first lactation does should be grouped together and milked first. Not only does this reduce stress and competition for feed with older does, it also reduces the risk of cross-contamination from an older doe (who is more susceptible to infection) back through the cups to the younger does.

​

Udder and teat health is also important in reducing the risk of mastitis. Over milking (which can cause cracked teats), dirty environments, physical lacerations from the environment or other goats, or extremely hot and dry environmental conditions can all lead to dry, cracked teats which creates entry points for bacteria.  Consistent attention to the environment, removing cups promptly once the goat has finished milking, and udder treatments (udder creams / emollients in teat spray) all aid in the prevention of mastitis infections.  Likewise, a moisturising teat sanitiser keeps keep the udder skin in good condition and reduces the number of bacteria entering the teat canal post milking.

​

Generally, goats milk out fairly fast, so milking efficiently and at a steady pace is important.  It is normal to have one or two slower milkers that have the potential to hold up the row.  In a herringbone system, mark the does so you can get the cups on them early in the row.  They will still likely be the last one ready to remove the cups from but don't be tempted to wait until they are completely milked out. It is better to have one goat slightly under-milked than 39 (in a 40 bale shed) goats over-milked.The only exception to this is if it has not been detected that the goats teat has been mis-aligned, resulting in one side not being milked out at all.   In this instance, we use the guideline of milking them out until the udder is no longer tight, and know that we will get the rest at the next milking with little on-going impact on production or the goats udder health.   In a rotary shed you can leave them on the platform for a second round.

​

​

​

​

​

​

​

​

 

 

 

Treatment of Mastitis

It is best to discuss treatment options with your vet.  Intra-mammary products are generally not well suited nor highly effective in goats. Anti-inflammatory and pain relief medications are advisable for any goats suffering from a mastitis infection and in some cases, the doe will respond to injectable antibiotics. In mild cases, the infection will often resolve itself without treatment as long as you are able to continue milking out the udder well (discarding the milk) each day.  If a does continues to have mastitis in one side that will not clear up with treatment or on its own, you can dry this side off and milk her as single-titter. In severe cases, or if both sides of the udder are infected, culling the doe may be the best option.