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Evaluation of a Novel Persistent Barrier Teat Dip For Preventing Mastitis During The Dry Period Leo Timms, Andrea Steffens, Stacia Piggot
and Leah Allen Mastitis research has shown that 40-50% of intramammary infections (IMI) are contracted during the dry or non-lactating period with the greatest percentages of these occurring during the first and last two weeks of the dry period. At these times, the mammary gland is in a transitional state. Immunological factors are preoccupied or suppressed, milk is no longer being flushed from the gland, and increased mammary pressure distends the teat, thus allowing for easier bacterial penetration through the streak canal. The primary goal for mastitis control during the dry period is to minimize bacterial exposure on teat ends. The overall objective of this research is to develop or find a barrier type teat dip product which could 1) persist for 3-7 days on teat ends of dry cows; 2) prevent IMI; and 3) not harm teat tissue. The objective of this presented research was to evaluate a novel barrier teat dip for preventing IMI under natural exposure conditions. Materials and Methods A natural exposure field trial was conducted from November, 1995-November, 1996 using an experimental persistent barrier teat dip that was shown to persist >3 days on 98% of dipped quarters of dry cows in preliminary studies. All dry cows and freshening heifers at the Iowa State University Dairy Farm were included in the trial. The trial was a randomized half udder design with either right or left quarters dipped while the others served as controls. All cows were dry treated. Cows were only dipped once at dry off following dry cow treatment administration. Cows and heifers were dipped starting approximately 10 days prepartum and were redipped as needed until parturition. Dip persistency was evaluated daily on all cows. Duplicate aseptic quarter milk samples were taken at 3 days pre-dry off, dry off, calving and 3 days postpartum and frozen until subsequent bacteriological analysis. All samples were initially cultured on blood agar for 24-48 hrs at 37° C. Isolates were differentiated using gram staining, catalase and coagulase testings, and CAMP and EMB agar plates. Results New IMI at calving are shown in Table 1. A total of 190 cows and 756 quarters completed the trial (66 heifers, 264 quarters; 124 cows, 492 quarters). Dipped quarters of heifers show a 20, 40, and 50% reduction in total, major pathogen, and environmental streptococcal (ES) IMI, with no significant reduction in coagulase negative staphylococcal (CNS) or gram negative IMI. Dipped quarters of cows showed a 47, 52, 68, and 43% reduction in total, major pathogen, ES, and CNS IMI with no reduction in gram negative IMI. Combining data from both groups shows an overall reduction of 37, 48, 63, and 28% of total, major pathogen, ES, and CNS IMI in dipped quarters as compared to controls. Two problems during the late spring-summer including switching of transition cow and heifer lots (May-June, 15/18 gram negatives occurred; dip unable to dry before exposed to moisture) and decreased product viscosity (persistency) above 65° F were encountered and may explain the limited reduction in gram negative IMI and lower reductions in IMI in heifers as compared to cows. Table 1. New intramammary infections at calving in quarters dipped
with a novel persistent barrier teat dip and undipped control quarters. Summary and Implications Dipping of cows at dry off and cows and heifers 10 day prepartum until calving with an experimental barrier teat dip product resulted in a 20, 40, and 50% reduction of total, major pathogen, and environmental streptococcal IMI at calving in heifers and a 47, 52, 68, and 43% reduction in total, major pathogen, environmental streptococcal, and coagulase negative staphylococcal IMI at calving in cows. This novel persistent barrier teat dip significantly reduced dry period and calving IMI, and had no effect on teat tissue. This dip may provide an alternative to dry cow therapy in low SCC cows at dry off. Field trials are currently being conducted at LSU (natural exposure) and Guelph, Canada (experimental challenge). Current enhancements to the dip including inclusion of a germicide, coloring agent(s), and adjustments to maintain optimum viscosity across all temperatures are underway. National Mastitis Council Annual Meeting Proceedings (1997) |
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Prevent Mastitis During The Dry Period Roger Mellenberger New infections of a mammary gland can occur at almost
any time. However, the new infection rate is much higher during the
first 10 days of a dry period and during a few days either side of calving.
Great Britain researchers compared milk production in two adjacent quarters:
for example, left rear with right rear. An infection in one quarter
which persisted through or started during the dry period reduced milk
production by 33 to 36% in the subsequent lactation when compared to
the non-infected adjacent quarter (Table 1). An infection which exists or starts during the dry period probably affects the development of mammary cells prior to the next calving. In contrast, an udder infection that persisted during a complete lactation but was cured during the dry period will decrease a subsequent lactation by only 11% (Table 1). The 11% decrease in production could be a result of permanent udder damage caused by the previous infection. Research at Michigan State University indicates an 80%
cure rate of all infections at dry off if all cows and all quarters
in a herd are dry treated. This compares to a spontaneous cure of 40%
in control cows. In addition, the new infection rate is cut by 50% with
the use of dry cow treatment compared to untreated controls. In Tables
2 and 3 is an estimate of the loss of production on 10 cows infected
in 2 or more quarters during lactation. Production loss is compared
when cows are dry treated or not treated (Table 2). The 10 cows are
given potential productions of 15,000 and 21,000 lbs. of milk (Table
3). The cost of dry treating 10 cows may range from $40 to $60. At 15,000 lbs. potential production a dairyman could save $1,575 on 10 infected cows for $40 to $60 investment in dry treatment. At 21,000 lbs. potential production the savings is $2,205 for that same $40 to $60. Many dairymen stop dry cow treating when cash flow becomes critical or dairymen stop dry cow treating because their herd has a low somatic cell. Dry treatment to them is just one more cost. However, Table 3 clearly shows that the return on investment for dry cow treatment of infected cows can approach 40 to 1. If the use of dry cow treatment could prevent one 21,000 lb. cow from becoming infected during the dry period a dairyman would have 3,675 lbs. of milk or enough money to dry treat 75 to 110 cows. Clearly the investment in dry cow treatment is economically feasible. Four additional comments on dry cow treatment: 1. Dry cow treatment is intended to cure existing infections and prevent new infections only at the start of the dry period. New udder infections that occur at the end of the dry period are mainly the result of poor sanitation in dry cow lot and maternity areas and do not relate directly to dry cow therapy. 2. Dry cow treatment will appear very ineffective in cows with dry periods greater than 80 days. Cows with long dry periods will be more likely to have clinical mastitis at calving because of extended exposure to bacterial populations in the environment during the last half of the dry period. 3. Cows dry less than 30 days or cows that freshen prematurely could have antibiotic residues in their milk beyond 10 milkings. All cow's milk that fits this category needs to be checked for antibiotic residues prior to addition to the bulk tank. 4. Dairymen should use commercially available antibiotics designed for dry cow treatment. Based on available research it would be extremely difficult for a farmer or veterinarian to mix an antibiotic preparation that could improve on cure rates currently obtained with commercially available dry cow antibiotic preparations. Cure rate is already about 100% for Streptococcus agalactiae, about 100% for Non-agalactiae Streptococcus and 70-80% for Staphylococcus aureus or 80% overall. |
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Experimental Models for the Evaluation of the Adherence of Dry Cow Teat Sealants Tom Hemling 1, Mark Henderson1,
Ken Leslie2, Gillian Lim2, Leo Timms3 Dairy cows are susceptible to new intramammary infections (IMI) at the beginning and end of the dry period. Infusion of antibiotics into the udder at drying-off has been the major tool for the prevention of IMI, as well as treatment of IMI persisting from the previous lactation.1 A dry cow teat sealant (StrongholdTM, DryFlexTM) has been developed to provide an external physical barrier for the teat orifice during the dry period. Timms2 has shown that when used in combination with antibiotic infusion, the teat sealant provides an additional reduction in dry period mastitis in comparison to dry cow therapy alone. Duration of adherence of the sealant to the teat, and protection of the teat orifice, are critical factors in the performance of the teat sealant. Two experimental models have been developed for the evaluation of teat sealant adherence. This report documents the results of several studies using the experimental models to evaluate adherence of different teat sealant products. The models use the rating scale shown below. Note that values 2 through 5 provide equal protection to the teat orifice. In reporting adherence results, the progression from 2 to 1 is considered the critical step in which protection is lost. Adherence Rating Scale (click to view in new window) In the first trial, two teat sealant formulations of interest were applied to mid-dry period cows. These two formulations were randomly allocated to teats on each cow to provide within-cow controls. Each teat sealant composition was applied to 58 teats, and adherence was scored every 24 hours. Results are shown below. The improved product formulation provided protection for 70% of teats for 7.6 days compared to 5.0 days for the original formulation. %
Teat ends covered vs. Days Chart 1 (click to view in new window) Persistence during the mid-dry period is higher than would be expected during the recommended use times at dry-off and pre-calving. 3 To test if the mid-dry period could be used as a model for adherence at dry-off or pre-calving, the trial was repeated by applying the original and new formulations to cows 10 days pre-calving. As previously described, application to teats was randomized for each cow. Product adherence was evaluated every 12 hours. Each composition was applied to 24 teats. As expected, the adherence was of considerably shorter duration than during the mid-dry period. However, the difference in days teat-end covered, between the original and new formulation, was similar. Using the pre-calving model, the improved product provided protection for 70% of teats for 3.1 days compared to 2.4 days for the original formulation. % Teat ends covered vs. Days Chart 2 (click to view in new window) In a recent trial, the mid-dry period model was used to compare the adherence of an aqueous latex-based dry cow teat sealant to the solvent-based polymer sealant (Stronghold, DryFlex). Adherence was assessed using 61 cows on four farms. Average days teat-end covered was 4.1 days for the aqueous latex formulation versus 8.5 days for Stronghold. Seventy percent of teat ends were covered at 6.2 days for Stronghold, versus 2.3 days for the latex sealant. This is similar adherence for Stronghold as reported earlier3, and in the other mid-dry period evaluation reported in this paper. % Teat ends covered vs. Days Chart 3 (click to view in new window) Using the mid-dry period model provides the advantage of testing large numbers of cows, which improves the ability to distinguish differences between groups. 1. Leslie, K.E., Kelton, D.F., Day, K.J., Wagter, L., Godkin, A. and Barnum, D. Milking Management in Ontario Dairy Herds. 1999. National Mastitis Council Annual Meeting Proceedings, pp. 126-127. 2. Timms, L.L. 1997. Field trial evaluation of a persistent barrier teat dip for preventing mastitis during the dry period. J. Dairy Sci. 80:Suppl. 1, 225. 3. Leslie, K.E., Day, K.J., TenHag, J., Kelton, D.F., Duffield, T.F. and Kerbler, T.L. 1999. Factors Affecting the Adherence of a Dry Cow Teat Sealant. 1999. National Mastitis Council Annual Meeting Proceedings, pp. 136-137. |
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