1. DeLaval Manufacturing
Hygiene Technology Center ● 11100 N. Congress Ave.. ● Kansas City, Missouri ● 64153
Telephone: 816-891-7700 ● Telefax: 816-891-6990
Sustainable Teat Disinfection for the Prevention of Mastitis
Thomas C. Hemling. Ph. D., DeLaval tom.hemling@delaval.com
Teat disinfection has been widely used across the globe for 30-40 years as a tool to aid in the
prevention of mastitis in dairy farm. The use of post milking teat disinfectants is included as a
key component in local and global programs for mastitis management: 5 Point Plan, 12 Golden
Rules, Countdown Downunder, SAMM Plan to name a few.
5 Point Plan
1. Disinfect all teats after every milking
2. Treat all cases of mastitis promptly and record data
3. Use dry cow treatment on all cows
4. Cull all cows with 3 or more cases
5. Maintain milking machine properly
Post milking teat disinfection programs were implemented initially to control contagious mastitis
at a time when Staphylococcus aureus and Streptococcus agalactiae were major causes of
mastitis. At that time bulk tank SCC levels were often in excess of 500k, and mastitis infection
rates were in the order of 150% per year. Through implementation of mastitis control programs
we now see SCC averages in many countries at or below 200k, along with dramatic reductions in
infections rates to as low as 2 -3% per month.(NMC 2013) Also because the control programs
successfully address contagious mastitis we see environmental mastitis pathogens predominant
in many herds.
Since the initial implementation of posting milking teat disinfection, the dairy industry has been
constantly evolving. There have been: 1) substantial growth in farm size; 2) increase in daily
milk production per cow; 3) increase in prevalence of confinement dairies; 4) pressure by milk
processors and authorities to reduce the use of antibiotic to treat mastitis during lactation; 5) bans
on prophylactic use of antibiotics during the dry period; 6) wide implementation of robotic
milking; and 7) increased availability of on-farm diagnostics to provide point of use information
on mastitis and other animal health parameters. Most recently as a result of the elimination of
quota in Europe and other market factors, more milk is entering international trade. As a
consequence, authorities, dairies and consumers are increasing pressure on milk producers to
reduce milk residues from teat disinfection, antibiotic treatment or even equipment cleaning
chemicals.
Sustainable Options
For the past 30 years numerous active substances have been considered, tested and marketed as
teat disinfectants. Many are included in the annually published NMC bibliography of peer-
reviewed studies on teat disinfectant products.(NMC 2015a) Iodine is the most widely studied
germicide for both pre- and post- milking teat disinfection, with over 30 clinical studies reported
in the NMC bibliography, and commercial market shares ranging from 55 to 95%. Other
germicides tested and marketed include hydrogen peroxide, lactic acid, sodium hypochlorite,
chlorhexidine, chlorine dioxide, dodecylbenzene sulfonic acid, various alcohols, and in some
instances combinations of these materials. Iodine has been shown to be especially effective,

2. particularly in formulations with elevated free iodine. With ever increasing concern over
antimicrobials or biocide residues in milk the choice of suitable actives substances is becoming
more restricted. It is likely that market demands will limit the antimicrobial substance to those
naturally present in food or specifically in milk. Of all the materials listed iodine, hydrogen
peroxide and lactic/organic acids would be preferred over synthetic materials such as
chlorhexidine or dodecylbenzene sulfonic acid. Iodine is an essential animal and human nutrient
and converts to the non-germicidal iodide when contacted with milk. Hydrogen peroxide
likewise decomposes to oxygen and water. Lactic acid is naturally present in milk and residue
contribution from teat disinfection is not detectable versus the natural lactic acid milk
concentration variation. In contrast, use of chlorinating materials such as sodium hypo chlorite,
sodium dichloroisocyanurate or tosylchloramide will likely be restricted because of risk of
formation of the carcinogen chloroform, and because of issues with skin safety.
Contagious Mastitis
Contagious mastitis can be successful managed with proper use of post milking teat
disinfectants: low viscosity dippable/sprayable products or high viscosity barrier products. As
noted above the efficacy of low viscosity products has been widely proven in clinical studies and
is a core component of mastitis control programs. Iodine products are the most widely studied
and used, and products with low iodine content of 1000 to 2500 ppm are shown to be effective
when they are formulated to have elevated and stable free iodine levels. Iodine has been
effectively formulated in a diverse range of product formats, and concentrations. Studies have
also shown good efficacy for formulated hydrogen peroxide, lactic acid, chlorine dioxide and
chlorhexidine. However, efficacy of each of these germicidal substances is formulation
dependent. Hydrogen peroxide for example shows broad spectrum only at concentrations about
3%, but when properly formulated shows efficacy in 30 seconds with only 0.5% peroxide (Lopez
2012). These products are available as ready to use or concentrated products with the exception
of chlorine dioxide, which must be mixed on site, and has a limited shelf life after mixing. All
concentrated products or products requiring mixing introduce a risk factor of improper mixing or
water incompatibility and many farms would be advised to avoid this added complexity to their
processes. Chlorhexidine concentrates are especially risky as chlorhexidine can precipitate with
certain anions typically present in potable water. In addition it has limited activity against certain
organism such as Serratia and certain MRSA are cross resistant to it.
Post milking products are applied by dipping, spraying or foaming immediately after take off of
the milking cluster. Speed of application and speed of kill are important as the negative pressure
gradient in the udder at the end of milking can pull milk contaminated with bacteria into the
gland. The importance of speed of kill is demonstrated by Foret (2005), who showed a 50%
reduction in mastitis between two 2500 ppm iodine products that differed only by the superior
product having faster speed of kill resulting from an elevated stable free iodine. Application by
dipping is preferred and full coverage of the teat apex and barrel is easier to guarantee. Spray
application is often used although coverage is often compromised. Robotic spray application has
the potential to provide consistent teat coverage compared to manual spray.
Post milking teat disinfectants can be formulated as barrier products that provide a residual
physical or germicidal barrier during the inter-milking period. Barrier products can help reduce
contagious mastitis by inhibiting skin colonization by S. aureus and by promoting good teat skin
and end conditioning. Iodine, lactic acid, and chlorine dioxide are widely used in barrier

3. products. Persistent iodine barrier products are shown to provide improved control of mastitis,
and are desirable as iodine is shown to be re-activated if the barrier film comes in contact with
water from bedding or manure. Iodine is also visible on teats so that it can be efficiently removed
at the next milking. Lactic acid combined with the appropriate excipients can be formulated into
broad spectrum, persistent barrier teat dips. As barrier formulations need to be easily removed
from the teat at the next milking with aqueous teat preparation routine, there is a trade off in
persistency versus easy of removal. The user can select products based on their needs for highly
persistent products or ones that are less persistent but more easily removed.
In addition to low viscosity and barrier products, high viscosity, non-barrier teat dips are an
option for certain situations. These products are typically formulated to contain high emollient
levels and are recommended for use under conditions that are challenging to teat health such as
cool dry air, or wet, damp muddy conditions.(Cameron 2015) They are applied by dipping only,
which increases hit rate and coverage success, and are easily washed off at the next milking.
Environment Mastitis
With the successes made in controlling contagious mastitis, focus has switched to improving the
control of environment mastitis through pre-milking teat hygiene, pre-milking teat disinfection
and the use of barrier teat disinfection. Environmental bacteria of concern include E. coli, S.
uberis, coagulase-negative staphylococcus, Klebsiella pneumonia, which can be found in
manure, soil and various bedding materials.
The goal of the pre-milking teat preparation process is to provide a clean, dry, disinfected teat
and to provide stimulation for rapid milk let down. The recommended procedure is to: 1) strip
the teat; 2) disinfect by dipping; 3) wipe; and 4) attach. The procedure should be arranged to
allow 30 seconds contact time for the disinfectant and 90 seconds between stimulation and
attachment to allow effective milk letdown due to oxytocin release.
Pre-milking teat cleaning with or without the inclusion of a germicide is practiced globally. Dirt
and bacteria are removed from the teat by use of a cleaning agent that is applied by dipping,
spraying foaming or a wet towel. Bacterial removal results in both reduced bulk tank bacterial
counts and reduced mastitis rates. Improved results in bulk tank bacterial accounts are seen when
products are formulated to contain a germicidal agent in addition to a cleaning agent. Ideal
products would have excellent cleaning properties and rapid bacteria killing properties, and
would be formulated with germicides naturally present in milk. Iodine pre-milking teat
disinfectants have been proven to reduce bacterial counts and mastitis rates. The 1000 ppm
iodine product, Quarter Mate is widely studied (Galton 1988) and registered in UK, US, Japan,
NZ and AU. Because of the short contact time, typically 15 to 30 seconds, success of pre-
milking teat disinfection in reducing environmental mastitis is highly correlated with speed of
kill. Impact of the use of low iodine products on milk residues has been shown to be minimal.
Other germicides used for pre-milking disinfection include hydrogen peroxide and lactic acid.
Germicides such as quaternary ammonium compounds or chlorhexidine that can remain
germicidal in milk are to be avoided as they potentially inhibit yoghurt or cheese cultures.
Dipping has been shown to be highly effective and spraying carries the same coverage and hit
rate risk discussed for post milking application. Foaming of product pre-milking has proven
successful in many herds. Data shows foaming can provide greater reductions in bulk tank

4. bacteria counts. While the improved efficacy could be the results of small formulation
differences, it is likely that the highly visible foam creates a mental image to perform a more
thorough wiping of the teat. Pre-wetting towels, while proving convenience, must be used with
caution, as care is need to insure adequate transfer of the cleaning or disinfecting liquid to the
critical teat end.
Barrier products discussed above are primarily employed as an aid to reduce mastitis caused by
environmental pathogens. The persistent physical or germicidal barrier protects the teat from
environmental bacteria it may come in contact with during the inter-milking period. The physical
barrier blocks bacteria from entering the teat canal and when the barrier contains a persistent
germicide it will also inactivate the environmental bacteria. The NMC guideline for clinical
efficacy trials requires that barrier products provide increased reduction of mastitis from
environmental bacteria compared with non-barrier control products. The effectiveness of iodine
barrier products in reducing mastitis caused by environmental bacteria is proven in large herd
clinical trials. The functionality of the barrier film itself is shown in a trial of two 2500 ppm
iodine barrier products, differing in the degree of persistence during the inter-milking period.
The product with the more persistent film showed better reduction of mastitis. (Lago 2014a)
Lactic acid barrier products are shown effective in clinical trials under a range of conditions.
(Lago 2014b): Lactic acid barrier: 68 new IMI, 2.4% incidence; Iodine barrier control: 95 new
IMI, 3.4% incidence.
Teat Conditioning and animal safety
Teat Conditioning is a second important property of teat disinfectants. For pre-milking products,
contact time is typically only 15 to 60 seconds, and the product is wiped off the teat so there is
limited opportunity to improve teat condition. Products should however “cause no harm”. Most
pre-milking teat disinfectants and cleaners meet this requirements, except for products that
include strong oxidants like sodium hypochlorite, are of very low pH (<2.5 or >9) or contain
harsh surfactants..
Post milking products, especially barrier and high viscosity non-barrier products remain on the
teat for extended contact times and can provide skin condition benefits. Improvement of teat skin
and teat end condition has been shown to reduce mastitis risk, reduce milking time, increase milk
yield (McKinzie 1995) and reduce skin colonization by S. aureus. Management of teat end
hyperkeratosis (thickness and roughness) is important and can be facilitated by the use of
appropriate teat disinfectants. Neijenhuis et al.2001, showed that teat end hyperkeratosis is
directly correlated with increased mastitis risk. The thickness of teat end hyperkeratosis is mainly
affected by the milking process, especially unit on time with low milk flow, stage of lactation,
and low temperatures. Research shows that teat dip selection can have an impact on teat end
roughness but limited impact on teat end thickness. Teat condition benefits are provided by
formulating to skin friendly pH (3 to 9), use of mild surfactants, and inclusion of skin hydrating
ingredients (glycerin, sorbitol) or moisture barriers (lanoline derivatives).
Product Registration and Testing
Teat disinfectants, whether pre- or post-milking are used to kill pathogenic bacteria as an aid to
prevent mastitis. Globally products are regulated under various registration schemes that treat

5. these products as either biocides or as veterinary animal drugs. When registered as biocides,
product claims are made for killing bacteria rather than preventing mastitis. Product efficacy is
shown according to standard testing (EN 1656) with a milk soil challenge. Products can meet the
requirements by demonstrating a 5 log reduction of common mastitis pathogens (S. aureus, E.
coli and S. uberis) in 5 minutes. Many products on the market can demonstrate this germicidal
effect in 30 seconds, and some products in as little as 15 seconds. When registered as veterinary
animal drugs, teat disinfectants must prove efficacy in clinical trials versus a negative or positive
control. Because of animal welfare issues, positive control trials are most common. The NMC
(2015) has developed and published guidelines for clinical efficacy for post milking teat
disinfectants, barrier post-milking teat disinfectants, and pre-milking teat disinfectants. These
guidelines are accepted by regulatory officials in most countries. In addition to efficacy tests,
product registrants are required to demonstrate animal safety especially with regards to teat skin
condition. Standard protocols for teat skin conditioning have been developed by industry
researchers and are available from NMC (2015).
References
Cameron, M. et al. 2015 Efficacy of Two Iodine-Based Post Milking Teat Disinfectants for
Prevention of Intramammary Infection. 54th
NMC Annu. Meet. Proc. p 225-226.
Foret, C. , et al. 2005. Efficacy of Two Iodine Teat Dips Based on Reduction of Naturally
Occurring New Intramammary Infections J. Dairy Sci. 88:426-432.
Galton, D. et al. 1988. Evaluation of Udder Preparations on Intramammary Infections. J. Dairy
Sci. 71:1417-1421.
Laga, A. et al. 2014a. Longer Iodine Persistence on Teats Improves Prevention of New
Intramammary Infections under Natural Exposure Conditions. . NMC 53rd
Annu. Proc. p 255-
256
Lago, A., et al. 2014b Efficacy and Safety of a Lactic Acid Based Post-milking Teat Dip. NMC
53rd
Annu. Proc. p 253-254.
McKinzie, M. et al. 1995. The Effect of Teat Skin Condition on Milk Yield and Milk-out Time.
NMC 34th
Annu. Meet. Proc. p 160-162.
Lopez-Benavides, M. et al. 2012. In Vitro Efficacy of Non-Iodine Teat Disinfectants, NMC 51st
Annual Meeting, , p 195-6.
NMC 2013 National Mastitis Council 52rd
Annu. Meet. Proc. , General Session 3: Milk Quality
Around the World p 34-54.
NMC 2015 http://www.nmconline.org
Neijenhuis et al.2001 Relationship Between Teat-End Callosity and Occurrence of Clinical
Mastitis. J. Dairy Sci. 84:2664-2672.