mastitis represents a major economic cost to dairy farmers with losses of up to  190 per case depending on severity   and  60 per cow for the average milk supplier .
the losses associated with mastitis include discarded milk , increased number of culled cows , cost of antibiotic treatment and reduced milk quality and price .
even though , it has been shown that factors such as genetic characteristics , impaired immune - function , feeding regimes   and machine milking   are related to mastitis , poor milking hygiene has been associated with increased somatic cell count ( scc ) , reduced milk production and inferior milk quality .
machine milking may also be considered as a major cause of bacterial cross contamination from cow to cow .
however , a good premilking hygiene routine can decrease the cow infection ratio by not only reducing udder bacterial contamination from the environment , but also reducing bacterial contamination from other infected animals .
newbould . showed a positive relationship between bacteria presence on teats and new intramammary infection .
staphylococcus aureus is one of the major and more virulent pathogens that can cause mastitis infection and lactating cows can be considered one of the main reservoirs of this species .
moreover , staphylococcus aureus colonisation of teat skin increases the risk of staphylococcus aureus intrammmary infection .
the aim of any teat cleaning routine is not only to reduce mastitis infection risk , but also to enhance milk quality .
. also showed that spore concentration in milk was highly correlated with spore concentration on teats ; hence milk bacterial spores most likely originated from dirt and faeces attached to the teats at the time of milking . many methods of pre - milking udder preparation are practiced by producers and overall , one of the most important aspects of pre - milking udder hygiene is udder dryness at the time of machine attachment ( visser et al .
bacteria contaminated water can also increase milk bacterial counts   ( visser et al . 2007 ) .
a commonly used pre - milking teat preparation method involves washing teats by hand with water and drying teats with a paper towel just before the machine is attached .
there is strong evidence that among all pre - milking procedures , wet cleaning treatment , followed by paper towel manual drying will result in the lowest bacterial counts : this practice is particularly effective in reducing milk bacterial contamination during the winter housing period .
similar seasonal bacterial infection trends linked to the pasturing / housing routine have been observed by hutchison et al . .
as an alternative to washing and drying teats , many producers now dip teats pre - milking with various disinfectant products such as iodophor solution , iodine based gel , sodium hypoclorate , dodecyl benzene sulfonic acid ( ddbsa ) , chlorine , chlorhexidine , phenolics and alcohol .
showed that both iodine based gel and 0.5% iodophor solution significantly reduced milk bacterial count and clinical mastitis occurrence compared to teat washing and drying with paper towels .
however ,   showed that pre - milking disinfection with 0.25% iodine dip or phenolics solution did not reduce the incidence of clinical mastitis when compared to post - milking disinfection only .
however , pankey et al .   reported that predipping reduced the rate of intrammamary infection with major mastitis pathogens such as staphylococcus aureus , streptococcus agalactiae and coliforms .
in addition to iodine products , chorhexidine when used as a pre - dip , significantly decreased scc values in herds infected with mastitis . furthermore , gibson et al
.   concluded that a chlorine based dip followed by a dry wipe was an effective pre - milking treatment for controlling cow mastitis .
the benefit of using some disinfectant products pre - milking in reducing new mastitis infection has been demonstrated . a study by roberson et al
.   demonstrated that teat orifices colonised with staphylococcus aureus were 3.3 times more likely to have intramammary infection .
therefore , reducing the microbial count on teats prior to milking is an important step in the prevention of mastitis .
the type of disinfectant product used as a pre - dip may have varying degrees of success in reducing the microbial count on teats .
however , there is no knowledge on the effect of pre - milking disinfection using a range of newly - formulated teat disinfectants in reducing the microbial counts on teats .
thus , the objective of this study was to investigate the effectiveness of six different pre - milking teat preparation procedures on lowering the staphylococcal , streptococcal and coliform bacterial count on teat skin .
six pre - milking teat preparations were applied to spring calving holstein friesian cows during two herd management periods , while cows were housed ( indoors ) and while cows were grazed on pastures ( outdoors ) . during the indoor period and for the previous three months
, cows were housed in an easy - feed slatted house with matted cubicle beds and dressed with lime daily to maintain a dry bed . during the outdoor period and for the previous three months
, cows were grazed under a rotational grazing system and moved every 24 hours to new pasture .
ten cows which were free from clinical mastitis infection were randomly chosen for each pre - milking preparation for a period of five days per treatment .
the six pre - milking applications applied are identified as ' washing and drying ' , ' iodine ' , ' chlorhexidine ' , ' chlorine ' , ' wipes ' and ' no preparation ' .
description of pre - milking teat preparation treatments an iodine ( 2.0% w / v ) teat disinfectant ( 1 - 4 mix ) containing emollients was applied as a post - milking teat disinfectant to the following treatments , ' iodine ' , ' washing and drying ' , ' no preparation ' and disinfectant ' wipes ' using an in - parlour sprayer . ' chlorhexidine ' teat foam and ' chlorine ' teat foam were used for post - milking disinfection , for the respective pre - milking treatments .
the same foam products were used for post - milking disinfection , as it was considered more likely that where the foam products are used on farms as a pre - milking disinfectant , they would also be used for post - milking disinfection .
the possibility of a teat skin reaction if different pre- and post - teat disinfectant products were used was also considered .
analysis of the bacterial counts on teats prior to teat preparation showed no effects of using different post milking disinfectant products .
the ' chlorine ' teat foam product was prepared daily by mixing a foam active base and activator ( 50/50 ) .
the entire circumference of the teat was covered in teat foam by immersing each individual teat in the teat cup . '
iodine ' was applied as a pre - milking disinfectant by spray , as this was considered the most common application method on irish farms .
approximately , 15 mls of iodine was applied to the teats of each cow when used as a pre and post milkinf disinfectant .
teats disinfected pre - milking were dried with individual disposable paper towels approximately 30 seconds after the disinfectant was applied and prior to milking .
cows were milked in a 20-unit , 80-degree side - by - side milking parlour and were milked in the morning at 07:30 h and in the afternoon at 15:30 h. cows were exposed to each pre - milking preparation for a period of five days , for each management period at both the morning and afternoon milking . on day four and five ,
all teats from each cow were swabbed using one sterile swab ( cultiplast , lp italian spa , via carlo reale , 15/4 , 20157 , milano , italy ) per cow before teat preparation and repeated after teat preparation at the morning milking ( table 2 ) .
the sterile swab was rubbed across the teat orifice and down the side of each teat avoiding contact with the udder hair or cows flank at all times . a small number of teats ( < 7% ) that were considered excessively soiled with faeces , and where swabbing of the teat skin was not possible ,
in addition , by omitting these soiled teats , the potential contamination of the agar plates was avoided . in those instances ,
there were no differences in the number of excluded teats between treatments or management periods .
swabbing procedure carried out before and after teat preparation for six pre - milking teat preparation procedures * = one swab per cow , * * = all repeated after teat preparation immediately after teat swabbing was completed , the swabs were placed in individual sterile bottles containing 5 mls of tryptic soy broth ( bd . bbl trypticase soy broth ( soybean - casein digest broth ) .
the broth was manufactured by becton , dickinson and company , sparks , md 21152 usa.38800 le pont - de - claix , france . the broth was prepared in 500 ml amounts and autoclaved at 121c for 15 minutes , and then distributed into 5 ml aliquots in a laminar flow cabinet .
the sterile bottles containing the swabs were frozen ( -20 ) awaiting laboratory analysis for the presence of staphylococcal , streptococcal , and coliforms .
the swabs were subsequently plated on three separate selective agars : baird parker ( staphylococcal ) , edwards ( streptococcal ) , and macconkey ( coliforms ) .
specific bacteria types within each category were not defined . following incubation at 37c for 24 hours , microbial counts ( cfu / ml ) for each pathogen type
were manually counted and assigned to one of six categories depending on the bacterial counts measured .
( 1 = no pathogen present , 2 = 1 to 10 , 3 = 11 to 20 , 4 = > 20 , 5 = numerous , 6 = infinite ) .
the results were analysed by logistic regression using sas . preliminary analysis of the results for before and after treatment was by fitting generalised logits for the multinomial response because , while the response was ordinal in nature , the data did not meet the assumptions of a proportional odds model .
1 = lower category count after treatment and 0 = same or greater category count after treatment .
standard maximum likelihood estimation of the regression could not proceed because of the technical condition of quasicomplete separation for the effects .
an alternative strategy due to heinze and schemper   was implemented using their sas macro code
there were no differences in the levels of staphylococcal , streptococcal and coliform bacterial counts measured on teats ( assigned to different teat preparations ) ' before ' teat preparation .
however , there was a significant reduction ( p < 0.001 ) in the levels of staphylococcal pathogens on teats after teat preparation with all treatments except the ' no preparation ' pre - milking treatment .
the probability of a reduction in the staphylococcal counts tended to be higher ( p < 0.06 ) for cows managed outdoors compared too indoors .
treatment with ' chlorine ' teat foam resulted in a 30% reduction in staphylococcal counts when used on cows at pasture compared to its use on cows indoors , likewise ' iodine ' and ' wipes ' resulted in an increased staphylococcal count reduction of 18% and 20% , respectively , when used on cows at pasture ( table 3 ) . on the other hand ' chlorhexidine ' teat foam had a 20% greater reduction in bacterial counts when used on housed cows , compared to cows at pasture .
however , the median reduction in the staphylococcal count for all treatments was 21% better for cows on pasture compared to its use on housed cows .
the probability of a reduction in streptococcal bacterial counts in response to overall teat preparation was not significantly different between indoor and outdoor management periods . however , some pre - milking treatments resulted in greater reductions in counts when used on cows housed compared to when used on cows at pasture and vice versa .
the treatment containing ' iodine ' resulted in a 26% greater reduction in streptococcal counts when used on cows indoors compared to when used on cows at pasture ( table 3 ) .
similarly , the ' chlorhexidine ' teat foam treatment had a 20% greater reduction when used indoors , compared to when used on cows outdoors .
however , both the ' chlorine ' and disinfectant ' wipes ' teat preparation treatments resulted in a 30% greater reduction when used outdoors compared to when used on cows indoors .
the reduction observed for ' coliform ' counts was low for both indoor and outdoor management periods ( table 3 ) .
however , the probability of a greater response to teat preparation for ' coliform ' bacteria is more likely outdoors ( or = 0.27 ; p < 0.05 ) compared to indoors ( table 4 )
. effect of pre - milking teat preparation treatment in reducing staphylococcal , streptococcal and coliform bacteria counts on teats at two time periods ( indoor and outdoor ) ( % reduction ) estimated odds ratios ( or ) and their 95% confidence intervals ( ci ) for the effect of pre - milking teat preparation and management period on staphylococcus spp .
( str ) and coliform ( col ) counts table 4 shows the association between pre - milking teat preparation procedure and management period on the probability of a reduction in the microbial levels of staphylococcal , streptococcal and coliform pathogens . '
washing and drying ' had a higher probability ( p < 0.001 ) of reducing both the staphylococcal and streptococcal counts on teats compared to ' no preparation ' , as would be expected .
both ' chlorhexidine ' ( or = 4.46 ) and ' wipe ' treatments ( or = 4.46 ) had an increased probability ( p < 0.01 ) of reducing the staphylococcal count on teats compared to ' washing and drying ' .
treatments with ' chlorine ' ( or = 3.45 ) and ' wipes ' ( 3.45 ) had the highest probability ( p < 0.01 ) of reducing the streptococcal count compared to ' washing and drying ' .
both ' iodine ' ( or = 1.24 ) and ' chlorhexidine ' ( or = 1.65 ) also tended to have greater probability of reducing streptococcal counts compared to ' washing and drying ' . ' washing and drying ' had a higher probability ( p < 0.05 ) of reducing the coliform count on teats compared to ' no preparation ' .
any of the remaining treatments did not enhance reduction in coliform numbers ( p>0.05 ) compared to ' washing and drying ' .
no differences in the microbial counts were observed on teats , regardless of the post - milking disinfectant products used at the previous milking .
therefore , using different products as a post disinfectant in this study did not influence the outcome of the study . in this study ,
the use of some disinfectant products for pre - milking teat preparation had beneficial effects on reducing the levels of staphylococcal and streptococcal pathogens on teat skin compared to ' washing and drying ' and ' no preparation ' . where teat preparation is omitted , increased teat colonisation could be expected and this may result in new intramammary infection .
this would concur with the findings of pankey et al .   who reported that pre - dipping can reduce the rate of intrammamary infection with major mastitis pathogens .
furthermore , gibson et al .   concluded that most pre - milking teat cleaning treatments reduce the teat total bacterial count , but that cleaning effectiveness was influenced by the type of disinfectant and the application methods .
while commercially available disinfectant products may appear to use similar ingredients , the levels and strength of ingredients with additional emollients may influence the success of a product in reducing somatic cell count and improving teat condition over a longer period . when ' iodine ' was used as a pre - milking disinfectant , while it did not significantly reduce bacterial numbers , it was 2.3 times more likely to reduce staphylococcal and 1.24 times more likely to reduce streptococcal counts on teats compared to ' washing and drying ' or no preparation treatments .
this result tends to agree with the findings of ingawa et al .   who demonstrated that iodine reduced the bacterial count on teats compared to washing and drying .
the use of a 0.25% iodine solution pre - milking has also been shown by oliver et al .   to reduce major pathogen intramammary infections resulting from streptooccus uberis and dysgalactiae by as much as 49% . however , including ' iodine ' as a pre - milking teat preparation treatment may have implications for milk residues as pre or post dipping with an iodine product can increase iodine levels in milk .
therefore , correct disinfectant concentration and drying after application with paper towels must be advised to reduce milk residues . '
chlorhexidine ' teat foam which is a new product sold on the irish market was 4.46 times more likely to reduce the staphylococcal count on teats prior to milking when compared to washing and drying .
this is of particular signifance to irish dairy farmers as staphylococcus aureus pathogens are to be found in 51% of irish bulk milk samples .
staphylococcus aureus colonisation on teat ends has been shown to increase the risk of intrammmary infection .
therefore , a reduction in staphylococcal numbers on teat ends may reduce the new infection rate on irish farms .
additionally , it has previously been demonstrated that a disinfectant product containing chlorhexidine , when used as a post disinfectant   and when used as a pre - milking disinfectant over a long time period , reduced the somatic cell count . the ' chlorine ' teat foam product used in this study was 3.45 times likely to reduce the streptococcal count on teats prior to milking when compared to the ' washing and drying ' treatment .
this is in agreement with gibson et al .   who showed that a similar chlorine based dip followed by a dry wipe was a most effective treatment for controlling cow mastitis and reducing milk contaminants .
the positive effect observed with ' wipes ' in reducing both staphylococcal and streptococcal counts on teats may be due to the physical manipulation of teats combined with the disinfectant .
dry wiping without disinfectant has been shown to reduce the total bacterial count in bulk milk .
however , the use of dry or wet towels by themselves did not have any significant effect on reducing coliform counts in milk . in this study ,
the reduction in the coliform count on teats with any of the teat preparation treatments used was low .
this may be influenced by a low initial level of coliform pathogens present on teats prior to treatment .
teat washing combined with drying with individual paper towels reduced staphylococcal , streptococcal and coliform pathogens compared to ' no preparation ' and was particularly effective in reducing streptococcal counts when used on cows indoors compared to outdoors .
this is in agreement with the findings of mckinnon et al .   who concluded that washing and drying teats prior to milking significantly reduced milk bacterial counts during the winter housing period , compared to the pasture summer period .
however , the results of this study would indicate that the probability of a reduction in staphylococcal and streptococcal counts could be expected to be greater where a disinfectant is used pre - milking compared to ' washing and drying ' or ' no preparation ' treatments .
this study shows that the use of some disinfectant products for pre - milking teat preparation can have beneficial effects on reducing the levels of staphylococcal and streptococcal pathogens on teat skin .
therefore , the possibility of bacterial transfer from cow to cow during milking could be expected to be reduced compared to many farm situations where ' no preparation ' is normally practiced .
the study time period was not sufficient to come to any conclusions on the effect of premilking teat disinfection with regard to teat condition or somatic cell count .
in conclusion , bacterial numbers , specifically staphylococcal and streptococcal numbers on cow teat surfaces , were significantly reduced when disinfection products were applied to teats .
the use of wipes was particularly effective due to the physical wiping action in conjunction with the disinfectant application .
while the practice of washing and drying did reduce bacterial numbers compared to not cleaning teats at all , it could not be considered to be as effective as cleaning with disinfectant products .
given the level of bacterial numbers on non - prepared teats and the reduction observed with chemical disinfectant , it may be advisable to include this process as part of the milking routine .
however , pre - milking teat disinfection must be followed by teat drying using individual paper towels to minimise the possibility of chemical residues in milk .
 a study was carried out to investigate the effect of six pre - milking teat preparation procedures on lowering the staphylococal , streptococcal and coliform microbial count on teat skin prior to cluster application . 
 the teat preparations included ' iodine ' , ' chlorhexidine ' teat foam , ' washing and drying ' with paper , ' no preparation ' , ' chlorine ' teat foam , and disinfectant ' wipes ' . 
 teat preparations were applied for five days to 10 cows for each treatment during two herd management periods ( indoors and outdoors ) . 
 teats were swabbed on day four and five before teat preparation and repeated after teat preparation . 
 the swabs were plated on three selective agars : baird parker ( staphylococcus spp . ) , edwards ( streptococcus spp . ) , and macconkey ( coliform ) . following incubation , microbial counts for each pathogen type 
 were manually counted and assigned to one of six categories depending on the microbial counts measured . 
 the results were analysed by logistic regression using sas [ 28 ] . 
 the main analysis was conducted on binary improvement scores for the swabbing outcomes . 
 there were no differences for staphylococcal , streptococcal and coliform bacterial counts between treatments , measured ' before ' teat preparation . 
 treatments containing ' chlorhexidine ' teat foam ( or = 4.46 ) and ' wipes ' ( or = 4.46 ) resulted in a significant reduction ( p < 0.01 ) in the staphylococcal count on teats compared to ' washing and drying ' or ' no preparation ' . ' 
 chlorine ' teat foam ( or = 3.45 ) and ' wipes ' ( 3.45 ) had the highest probability ( p < 0.01 ) of reducing streptococcal counts compared to ' washing and drying ' or ' no preparation ' . 
 there was no statistical difference between any of the disinfectant treatments applied in reducing coliforms . 
 thus , the use of some disinfectant products for pre - milking teat preparation can have beneficial effects on reducing the levels of staphylococcal and streptococcal pathogens on teat skin . 