The refractometers, including a nontemperature-compensating instrument, performed similarly in detection of FPT. Serum protein concentration test endpoints of 5.0 and 5.2 g/dL yielded accurate results in the assessment of adequacy of passive transfer; lower or higher test endpoints misclassified larger numbers of calves.

BackgroundSubclinical mastitis is of concern in veterinary hospitals because contagious mastitis pathogens might be unknowingly transmitted to susceptible cows and then back to their farm of origin.ObjectivesTo evaluate the California mastitis test (CMT) as an indicator of intramammary infection (IMI) in lactating dairy cows admitted to a veterinary hospital.AnimalsA total of 139 admissions of 128 lactating dairy cows admitted to the University of Illinois Veterinary Teaching Hospital over a 2‐year period.MethodsA retrospective study with a convenience sample was conducted. Medical records of cows with CMT results and milk culture results for the day of admission were reviewed. Breed, age, season, maximum CMT score for the 4 quarters, maximum CMT score difference, and clinical diagnosis were evaluated as predictors of IMI by the chi‐square test and stepwise logistic regression.ResultsAn IMI was identified in 51% of quarters. For cows admitted without evidence of clinical mastitis, the sensitivity of a CMT score ≥trace in predicting an IMI on a quarter or cow basis was 0.45 and 0.68, respectively. The distributions of maximal quarter CMT score and the maximum difference in quarter CMT score for cows without evidence of clinical mastitis did not differ (P = 0.28, P = 0.84, respectively) for cows with and without IMI. Stepwise logistic regression did not identify significant predictors of IMI in cows without clinical mastitis.ConclusionsLactating dairy cattle admitted to a veterinary hospital should be managed as if they have an IMI, even in the absence of clinical mastitis.

No abstract

Passive transfer of Mycoplasma bovis-specific antibodies in calves born to vaccinated dams Mycoplasma bovis is a bacterial pathogen that has been shown to cause respiratory disease, mastitis, polyarthritis, keratoconjunctivitis, and other diseases in cattle worldwide. High costs associated with these diseases are attributed to treatment, culling, deaths, and purchase of replacement animals. Prevention of M. bovis associated diseases include sound management practices similar to those used by beef and dairy cattle managers to prevent other causes of respiratory disease and mastitis. Commercially available vaccinations are also available to producers and veterinarians to be used as an added preventative measure. Efficacies of these vaccines are still being evaluated.

Intramammary infections acquired during the dry period are difficult to diagnosis and tend to lead to decreased production in the subsequent lactation. In addition, the use of dry cow therapies (DCT) have virtually eliminated major pathogens, such as Streptococcus agalactiae. However, use of dry cow therapy or teat sealants may have questionable efficacy against other pathogens. Selective dry cow therapy, based on farm- or cow-specific pathogen profiles, tend to decrease usage of antimicrobial products. However, to generate farm-specific pathogen profiles, knowledge of incidence of intramammary pathogens is needed. The objectives of this observational study were to determine the incidence of new intramammary infections (NIMI) in dairy cattle during the dry period and risk factors associated with NIMI incidence risk.