Randomized equivalence study comparing the efficacy of 2 commercial internal teat sealants in dairy cows

Abstract

The use of an internal teat sealant (ITS) at dry-off has been repeatedly shown to improve udder health in the subsequent lactation. However, almost all ITS research conducted in North America has evaluated one product (Orbeseal, Zoetis, Parsippany, NJ). The objective of this study was to evaluate a new ITS product (Lockout, Boehringer-Ingelheim Animal Health, Duluth, GA), by comparing it directly to Orbeseal in a multi-site, randomized, positively controlled equivalence trial for health indicators during the dry period [quarter-level new intramammary infection (IMI) risk, IMI cure risk, and IMI risk at 1 to 13 d in milk, DIM] and during the first 100 DIM [clinical mastitis and culling or death risk and test-day milk somatic cell count (SCC) and milk yield]. At dry-off, cows were randomly allocated to be treated with Orbeseal or Lockout after blanket administration of a cloxacillin dry cow therapy product. Cows were then followed from dry-off until 100 DIM. Intramammary infection status at enrollment and at 1 to 13 DIM was determined using standard bacteriological methods, allowing for the measurement of IMI dynamics during the dry period (i.e., IMI cures and new IMI). The effect of ITS group on dry period IMI cure, dry period new IMI, and IMI risk at 1 to 13 DIM was determined using generalized linear mixed models (logistic). Marginal standardization was used to derive risk difference estimates. An equivalence hypothesis test was conducted to compare ITS groups for dry period new IMI risk (margin of equivalence was ±5% units). The effect of ITS group on clinical mastitis and culling or death was determined using Cox proportional hazards regression. The effect of ITS group on testday SCC and milk yield was determined using linear mixed models. Final models indicated that measures of quarter-level IMI dynamics were similar between ITS groups (i.e., risk difference estimates and 95% confidence intervals all close to zero). Furthermore, Lockout was found to be equivalent to Orbeseal for dry period new IMI risk using an equivalence hypothesis test. Hazard ratio estimates for clinical mastitis and culling or death were close to 1 and differences in SCC and milk yield between ITS groups were close to 0, indicating negligible effects of ITS group on test-day SCC and milk yield. In most cases, these effect estimates were relatively precise (i.e., narrow 95% confidence intervals). We conclude that producers using blanket dry cow therapy could consider including Orbeseal or Lockout treatment in their programs.

Randomized controlled trial investigating the effect of 2 selective dry-cow therapy protocols on udder health and performance in the subsequent lactation

“…We believe that our research is relevant to a large proportion of American dairy farmers, because cows were enrolled from 7 herds located in the west, midwest, and northeast dairy farming regions of the United States. Furthermore, study herds used similar management practices and had similar prevalences of IMI at dry-off to other herds recently studied in the United States (Rowe et al, 2019(Rowe et al, , 2020b. However, readers should consider the herd enrollment criteria that were used, which may have favored selection of larger, better-managed herds.…”

An overview on mastitis-associated Escherichia coli: Pathogenicity, host immunity and the use of alternative therapies

“…La idea original fue usarlos después del ordeño para prevenir la entrada de bacterias a la ubre. Posteriormente, se observó la ventaja de su uso en el momento del secado de las vacas al generar una barrera que impide el paso de las bacterias del exterior a la cisterna del pezón y su consiguiente multiplicación para desarrollar la mastitis (44,45).…”

randomized equivalence study evaluating the efficacy of two commercially available teat sealants in dairy cows

“…We assumed that 20% of quarters would develop a NIMI over the dry period 10 and the equivalence margin was selected based on previous work. 11 Based on these assumptions, we estimated that 1,320 quarters (330 cows) would be required for each treatment. These estimates were inflated 1.2 times to account for clustering within the data and to account for some anticipated missed samples, contaminated samples, and loss to follow up post-calving.…”