Evaluation of a chlorous acid-chlorine dioxide teat dip under experimental and natural exposure conditions

A postmilking teat dip containing chlorous acid-chlorine dioxide was evaluated by experimental challenge and in two herds under natural exposure. The test product had an efficacy of 78.9% against Staphylococcus aureus and 52.5% against Streptococcus agalactiae in the experimental challenge trial. The product was compared with a 1% iodine product in a 15-mo natural exposure study. Post-dipping with chlorous acid-chlorine dioxide reduced incidence of udder infection by major mastitis pathogens 36.1% when data were combined from the two herds. The 1% iodine and the chlorous acid-chlorine dioxide products were not equivalent for major mastitis pathogens; the test product was more effective. Incidence of udder infection by environmental mastitis pathogens was reduced 36.8% in both herds combined. Efficacy of the two teat dips was equivalent for environmental pathogens.     

Evaluation of nine teat dip formulations under experimental challenge to staphylococcus aureus and streptococcus agalactiae

Nine postmilking teat dips were evaluated by an experimental challenge model against either Staphylococcus aureus, Streptococcus agalactiae, or both. Formulations containing .9 and .6% sodium hypochlorite, 1% sodium dichloro-s-triazene-trione, .55% chlorhexidine gluconate, and .35% povidone iodine reduced incidence of Staphylococcus aureus infections 56.8, 28.3, 75.9, 92.5, and 77.9%. Incidence of infections with Streptococcus agalactiae was reduced 48.1 and 63.2% by 1.7 and 1% sodium dichloro-s-triazene-trione formulations. The 1% chlorhexidine gluconate and .35% povidone iodine products reduced Streptococcus agalactiae infections 71.0 and 67.0%. Three experimental 1% iodophor formulations reduced Streptococcus agalactiae infections 28.9, 44.8, and 50.7%. The experimental challenge model was refined further and provided an efficient method to determine efficacy of postmilking teat dips.     

Hygiene in the prevention of udder infections. V. Efficacy of teat dips under experimental exposure to mastitis pathogens.

Efficacy (reduction of new intramammary infections) was determined against Staphylococcus aureus in 14 trials and against Streptococcus agalactiae in 5 trials. Against Staphylococcus aureus seven 1% iodophor products had an average efficacy of 89.9% while three .5% iodophor products averaged 76.4%. A solution of sodium dichloro-s-triazenetrione reduced infections 79.0% and 2% dodecyl benzene sulfonic acid was 50.4% effective. Efficacies of two quaternary ammonium products at .18 and .5% were 84.8 and 60.9%. A placebo vehicle and .15 M saline as teat dips reduced infections 8.9 and 9.2%. Infection rates with Streptococcus agalactiae were low; efficacy ranged from 50.5 to 100.0%, average 65.6%. The model of experimental exposure provided a better estimate of effectiveness of a teat dip than would be possible under conditions of most commercial dairying.     

Field studies on linear dodecyl benzene sulfonic acid teat dip

A teat dip containing 1.94% linear dodecyl benzene sulfonic acid and 12% glycerine, an anionic detergent formulation, was evaluated in two field trials on a commercial dairy. In Trial 1, the teat dip was compared to an undipped control in a split-herd design. Incidence of infection with Streptococcus agalactiae was reduced 57.8%; infections with presumptively identified Staphylococcus aureus were not reduced. Milking machine function and milking procedures may have affected teat dip effectiveness and incidence of udder infection. Streptococcus agalactiae was eradicated prior to Trial 2 in which the detergent teat dip was compared to a 1% iodophor product of proven efficacy. Incidence of Staphylococcus aureus infection was 40.5% lower in the detergent than in the iodophor group. Taxonomic studies on Staphylococcus species indicated that presumptive microbial identification resulted in erroneous conclusions concerning efficacy of the teat dip products. Importance of speciation of staphylococcal isolates is discussed.     

Efficacies of chlorine dioxide and lodophor teat dips during experimental challenge with Staphylococcus aureus and Streptococcus agalactiae

We tested two postmilking teat dips for efficacy against Staphylococcus aureus and Streptococcus agalactiae using experimental challenge procedures recommended by the National Mastitis Council. The chlorine dioxide teat dip that contained 0.7% sodium chlorite reduced the number of new intramammary infections (IMI) caused by Staph. aureus by 86.6% and reduced new IMI caused by Strep. agalactiae by 88.4%. The 0.5% iodophor teat dip reduced the number of new IMI caused by Staph. aureus by 92.9% and reduced the number of new IMI caused by Strep. agalactiae by 43.4%. Teat skin and teat end conditions were evaluated before and after the study, and no deleterious effects were noted among dipped quarters compared with undipped control quarters for either teat dip.     

Effects of teat dipping on intramammary infections by staphylococci other than Staphylococcus aureus

Effects of intramammary infections in herds 1) either not teat dipping or postmilking teat dipping with either 2) linear dodecyl benzene sulfonic acid, 3) chlorhexidine, or 4) iodophor containing products were determined. Duplicate quarter foremilk samples were collected once from all lactating cows in 16 herds, four for each practice. Mean percentage of quarters infected with Staphylococcus species other than Staph. aureus was 11.0 in herds not teat dipping and 7.2 in herds teat dipping. Prevalence of Staphylococcus species intramammary infections in herds teat dipping with linear dodecyl benzene sulfonic acid was comparable to herds not teat dipping and greater than in herds using chlorhexidine and iodophor. The predominant Staphylococcus species in herds not teat dipping was Staph. epidermidis (37.1%). Staphylococcus hyicus constituted 48.5% of total Staphylococcus species intramammary infections in herds teat dipping and 12.4% in herds not teat dipping. Differences were not observed among SCC for quarters infected with different Staphylococcus species. Application of germicidal teat dips appeared to have selectively altered both prevalence and distribution of Staphylococcus species intramammary infections.     

Efficacy of two acidified chlorite postmilking teat disinfectants with sodium dodecylbenzene sulfonic acid on prevention of contagious mastitis using an experimental challenge protocol

Two acidified sodium chlorite postmilking teat disinfectants were evaluated for efficacy against Staphylococcus aureus and Streptococcus agalactiae by using National Mastitis Council experimental challenge procedures. The effect of these teat dips on teat skin and teat end condition was also determined. Both dips contained 0.32% sodium chlorite, 1.32% lactic, and 2.5% glycerin. Dips differed in the amount of sodium dodecylbenzene sulfonic acid (0.53 or 0.27%) added as a surfactant. Both dips significantly reduced new intramammary infection (IMI) rates compared with undipped controls. The dip containing 0.53% dodecylbenzene sulfonic acid reduced new IMI by Staph. aureus by 72% and Strep. agalactiae by 75%. The dip containing 0.27% dodecylbenzene sulfonic acid reduced new IMI by Staph. aureus by 100% and by Strep. agalactiae by 88%. Changes in teat skin and teat end condition for treatment and control groups varied in parallel over time. Teats treated with either teat dip had higher mean teat skin and teat end scores than control teats at some weeks. However, teat skin and teat end condition did not tend to change from the start to the completion of the trial. Application of the two new postmilking teat dips was effective in reducing new IMI from contagious mastitis pathogens. (Key words: teat dip, contagious mastitis, chlorous acid)     

Effects of a 1.94% sulfonic acid teat dip and a 1% iodophor teat dip on teat canal infections in lactating dairy cows

Sixty-three cows were used in a natural exposure trial for 1 yr to determine the effects of a 1.94% linear dodecyl benzene sulfonic acid and a 1% iodophor teat dip on teat canal and intramammary infections. Overall, total teat canal infections increased 28.9% and total intramammary infections increased 30% in quarters dipped with the linear dodecyl benzene sulfonic acid compared with a 14.3% increase in teat canal infections and a 17.4% decrease in intramammary infections for the iodophor group. Higher frequencies were observed for teat canal and intramammary infections caused by Staphylococcus epidermidis in the linear dodecyl benzene sulfonic acid group. Staphylococcus hyicus was the predominant organism isolated from teat canal and intramammary infections in the iodophor group. No difference was observed between the two teat dips in the persistence of Staphylococcus aureus teat canal infections. A greater number of S. hyicus teat canal infections persisted in the iodophor group, whereas teat canal infections produced by S. epidermidis and Staphylococcus xylosus persisted longer in the sulfonic acid group. Results of this study indicated that use of a linear dodecyl benzene sulfonic acid teat dip for 1 yr was not associated with increased S. aureus teat canal infections and intramammary infections. However, linear dodecyl benzene sulfonic acid appeared to affect the distribution of coagulase-negative staphylococci isolated from teat canal infections and intramammary infections.     

Efficacy of two iodine teat dips during experimental challenge with Staphylococcus aureus and Streptococcus agalactiae

An experimental challenge trial was performed against Staphylococcus aureus and Streptococcus agalactiae following the procedures recommended by the National Mastitis Council. The efficacy of two teat dips, product 1 (Bovadine with I-Tech II) and product 2 (Bovadine with I-Tech, used as a positive control), was determined. Both teat dips contain 1% iodine and 10% glycerin. Product 1 established an 89.7% reduction in infections against Staph. aureus and 73.1% reduction in infections against Strep. agalactiae. Product 2 demonstrated an 86.2% reduction in infections against Staph. aureus and 78.4% reduction in infections against Strep. agalactiae. Teat skin and teat ends were evaluated before and after the trial. No significant change in teat condition was observed for either product.     

Effect of postmilking teat antisepsis on teat canal infections in lactating dairy cows

Effects of a .18% iodophor teat dip and a fatty acid plus lactic acid teat dip on teat canal infections were studied in two separate trials under experimental challenge procedures using Staphylococcus aureus and Streptococcus agalactiae. The iodophor teat dip was 90% effective in preventing new S. aureus teat canal infections and 95.6% effective in reducing progression of S. aureus teat canal infections to intramammary infections. The dip also reduced persistence of S. aureus teat canal colonizations from week to week by 94.4%. The fatty acid plus lactic acid dip had no effect on preventing S. aureus teat canal infections but reduced progression of S. aureus teat canal infections to intramammary infections by 43.8%. The fatty acid plus lactic acid dip also reduced the persistence of S. aureus teat canal infections by 39%. An insufficient number of Strep. agalactiae teat canal infections was detected in both trials for valid analyses. Neither dip had any effect on prevalence of naturally occurring, coagulase-negative staphylococcal teat canal infections or on teat canal infections by other organisms.     

Germicidal teat dip in a herd with low prevalence of Streptococcus agalactiae and Staphylococcus aureus mastitis

Effectiveness of an iodophor teat dip in reducing new intramammary infection and clinical mastitis was tested in a herd free of Streptococcus agalactiae and with a low prevalence of Staphylococcus aureus infections. In this 6-mo study with an average of 152 lactating cows on trial on sampling dates, right rear and left front teats were dipped after each milking while right front and left rear teats were undipped controls. Teat dipping significantly reduced new infections by Staphylococcus aureus, streptococci (other than Streptococcus agalactiae), coagulase-negative staphylococci, and Corynebacterium bovis and reduced clinical cases caused by infections established during the trial. However, the dip did not reduce new infections or clinical mastitis caused by coliform bacteria. Therefore, use of a germicidal dip is recommended for herds with a low prevalence of Streptococcus agalactiae and Staphylococcus aureus, but the practice should not be expected to control coliform mastitis.     

Efficacy of two iodophor postmilking teat germicides against Streptococcus agalactiae

Two iodophor teat germicides containing .1% and .5% titratable iodine were subjected to experimental challenge with Streptococci agalactiae in a 131-cow research herd. Both germicides reduced the number of new infections with challenge organisms during a 5-wk study. The .1% iodophor reduced the new infection rate 60.7%, and the .5% iodophor reduced the new infection rate 61.5%. Teat skin irritation and other teat abnormalities were not observed.     

Determination of teat dip germicidal activity using the excised teat model

Fifteen postmilking teat antiseptics were evaluated in seven trials using the excised teat model. All products were tested against Staphylococcus aureus Newbould 305 and Streptococcus agalactiae Cornell 48. Eight of nine iodophor products provided log reductions greater than 3 against Staph. aureus and Strep. agalactiae. A .045% iodophor product was ineffective. A .5% chlorhexidine product yielded a log reduction of 3.22 against Staph. aureus but only 2.92 against Strep. agalactiae. Two products containing fermented milk emulsified in detergent were tested upon receipt and after 1 yr storage. Fresh product provided log reductions greater than 3 against both pathogens. Storage for 1 yr resulted in minimal loss of germicidal activity. Three products containing 1, .5, and .2% dodecylaminoalkyl glycine provided log reductions greater than 3.5 against Staph. aureus and greater than 4 log reduction against Strep. agalactiae.     

Hygiene in the prevention of udder infections. IV. Evaluation of teat dips with excised cows' teats.

Suspensions of Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli, and Pseudomonas aeruginosa were used to contaminate teats excised from cows. Commercially available teat dips were applied for evaluation of comparative germicidal activity. Iodophors, sodium hypochlorite, and sodium dichloro-s-triazenetrione were highly effective against all four test organisms. Quarternary ammonium, chlorhexidine, and cetylpyridinium chloride were effective against Staphylococcus aureus, and Streptococcus agalactiae but not Escherichia coli and Pseudomonas aeruginosa. Bronopol and 8-hydroxyquinoline sulfate were marginally effective on the two Gram positive organisms and ineffective on the two Gram negatives. Three of the dips were ineffective against all four pathogens; two were in nonaqueous bases, and the other was a blend of pine oil and antibodies with udder origin. In other trials, iodophor at .3% titratable iodine was highly effective against Staphylococcus aureus and Streptococcus agalactiae. Products containing .5 and 1% iodophor maintained effectiveness after each was used to dip 140 teats under conditions of commercial dairying. Logarithmic reduction in the geometric mean number of organisms recovered from teats was more meaningful for evaluating data than percent reduction.     

Evaluation of 1.6% phenol as a premilking and postmilking teat dip in preventing new bovine intramammary infections

We evaluated the effectiveness of a 1.6% phenol-based teat dip using both a teat skin assay and natural exposure field trial. A teat skin assay was conducted to ascertain the concentration of phenol + phenate to be used in the field study. One percent and 0.5% iodine, and 0.5, 1.1, and 1.6% phenol + phenate were compared using Escherichia coli and Staphylococcus aureus. Logarithmic reductions for S. aureus were 2.2 and 2.8 for 0.5 and 1% iodine, and 1.3, 2.1, and 2.8 for 0.5, 1.1, and 1.6% phenol + phenate, respectively. Logarithmic reductions for E. coli were 3.3 and 3.8 for 0.5 and 1% iodine, and 1.2, 1.9, and 2.6 for 0.5, 1.1, and 1.6% phenol + phenate, respectively. A concentration of 1.6% phenol + phenate was chosen as experimental teat dip, and 0.5% iodine served as control. The field study was conducted at Beltsville (n = 185) and Clarksville (n = 100) dairy herds using a split herd design. Teat dips were used premilking and postmilking for 12 mo. The number of new intramammary infections (IMI) for the Beltsville herd in iodine and phenol + phenate teat dipped cows were: 29 and 35 for major pathogens, and 81 and 72, for minor pathogens. For the Clarksville herd, number of new intramammary infections in iodine and phenol + phenate teat dipped cows was 9 and 10 for major pathogens, and 50 and 60 for minor pathogens. Rates of IMI per quarter day per lactation were not different for either herd or when herd data were combined. The number of clinical mastitis cases per 100 cows per month were similar in both treatments. The incidences of new IMI and clinical mastitis were similar using both dips.     

Efficacy of dodecylaminoalkyl glycine teat dip against Staphylococcus aureus and Streptococcus agalactiae mastitis

Dodecylaminoalkyl glycine teat dip, diluted to 1.5% active ingredients, was evaluated in a controlled experimental challenge study to determine efficacy for preventing new intramammary infections with Staphylococcus aureus (Newbould 305) and Streptococcus agalactiae (McDonald 44). The dip reduced the incidence of intramammary infection with Staphylococcus aureus by 81.2%. Reduction of Streptococcus agalactiae intramammary infection was 67.5%.     

Efficacy of .18% iodine teat dip against Staphylococcus aureus and Streptococcus agalactiae

Effective postmilking teat dip products with lower iodine concentrations are being formulated as concern increases about iodine residues in milk. Increased free iodine concentration with greater germicidal activity in teat dip products is also possible with special formulation procedures. Low iodine concentration dips are cheaper and have reduced teat irritation. A concentrated iodine teat dip containing .18% iodine and 8 ppm free iodine upon dilution was evaluated under experimental bacterial challenge to determine efficacy for prevention of new intramammary infections. The undiluted product also contained 15% collagen protein emollient as a teat skin conditioner. Efficacy of the teat dip was 93.6 and 51. 7% for Staphylococcus aureus (Newbould 305) and Streptococcus agalactiae (McDonald 44). No adverse effects of the dip on teat skin were noted.     

Evaluation of a nisin-based germicidal formulation on teat skin of live cows.

A purified preparation of the nontoxic antimicrobial peptide, nisin (AMBICIN N), was used in the formulation of a germicidal sanitizer suitable for use on cow teats. The germicidal activity of the formulation against mastitis pathogens was measured on teat skin of live cows. The nisin-based formulation gave a mean log reduction of 3.90 against Staphylococcus aureus and 4.22 log reduction against Escherichia coli after exposure for 1 min to the germicide. This activity was comparable with that exhibited by a 1% iodophor teat dip but was significantly greater than that exhibited by the .1 and .5% iodophors and by the .5% chlorhexidine digluconate teat dips. The nisin-based formulation showed little or no potential for skin irritation after multiple application to skin, but iodophor and chlorhexidine digluconate teat dips showed significant potential for skin irritation in comparable studies.     

Efficacy evaluation of two new teat dip formulations under experimental challenge

Two new teat dip formulations were evaluated against Streptococcus agalactiae and Staphylococcus aureus in half-udder, experimental challenge studies. The first product contained a combination of 1.9% linear dodecyl benzene sulfonic acid - .55% iodophor. Incidence of infection was reduced 52.7 and 70.7% for Streptococcus agalactiae and Staphylococcus aureus in dipped quarters compared to undipped controls. The second formulation was a barrier-type product consisting of milk protein solubilized with lauryl sulfate, a surface active detergent and 4.8% glycerin. Rates of infection were reduced 60.3 and 67.9% for Streptococcus agalactiae and Staphylococcus aureus.     

Effects of an automatic postmilking teat dipping system on new intramammary infections and iodine in milk

A technology of automatically applying a postmilking teat dip via the milking machine prior to machine detachment was compared to manual postmilking teat dipping with a teat dip cup for effects on new IMI and iodine content in milk. One hundred twenty Holstein cows were experimentally challenged in a 22-wk trial with Streptococcus agalactiae and Staphylococcus aureus and 148 Holstein cows were experimentally challenged with Streptococcus uberis in another 22-wk trial. The bacterial suspensions were applied to teats of all of the cows after premilking udder preparation and immediately prior to milking machine attachment. In both trials, cows were divided among four treatments: no postmilking teat dipping; manual postmilking teat dipping with a proven efficacious iodophor teat dip; manual postmilking teat dipping with an iodophor teat dip formulated for an automatic postmilking teat dipping system; and automatically postmilking teat dipping via milking machines with an iodophor teat dip formulated for the automatic postmilking teat dipping system. The postmilking teat dipping treatments reduced new Staph. aureus IMI by 64.5, 76.5, and 88.2%; new Strep. agalactiae IMI by 61.5, 77.8, and 94.4%; and new Strep. uberis IMI by 63.5, 82.5, and 93.8%, respectively, against the treatment of no postmilking teat dipping. The treatment applying the postmilking teat dip automatically via milking machines had the lowest number of new IMI caused by the three pathogens. Teat end and teat skin condition were characterized as normal at the end of the study with no differences between treatments. There were no differences with regard to iodine content in milk between treatments.