Relationships among somatic cell count, California mastitis test, impedance and bacteriological status of milk in goats and sheep in early lactation.

The objectives of this trial were to evaluate and compare the test characteristics of a number of indirect tests of bacteriological status of the milk from goats and sheep and to assess the affect of varying levels of prevalence of infection on the performance of those tests.The somatic cell count, California mastitis test (CMT) score, electrical impedance and the bacteriological status of 220 and 262 milk samples from the glands of lactating dairy goats and sheep, respectively, were determined. The sensitivity and specificity of indirect tests in predicting the bacteriological status were compared by analyzing the areas under the receiver operating characteristic curve and calculating the likelihood ratio at various cut-off values.

Invasion of bovine epithelial cells by verocytotoxin-producing Escherichia coli O157:H7.

The ability of verocytotoxin-producing Escherichia coli (VTEC) O157:H7 to enter selected human (RPMI-4788 and HeLa) and bovine (MAC-T, mammary secretory; MDBK, kidney) epithelial cell lines was evaluated. All VTEC evaluated efficiently entered RPMI-4788 and MAC-T cell lines. VTEC entered MDBK cells at approximately 4% of MAC-T cells.

Effects of freezing on the viability of nine pathogens from quarters with subclinical mastitis.

Milk samples from 45 quarters containing mastitis pathogens were collected from lactating cows to determine the viability of those pathogens after freezing. An initial bacteria count was conducted, and samples were divided into 2-ml portions and frozen. Weekly bacteria counts were conducted for 6 wk.

Winter evaluation of a postmilking powdered teat dip.

A powdered teat dip designed for winter usage was evaluated for bacteriological efficacy and teat conditioning qualities. A positive control, natural exposure field trial was conducted for 3 mo on 509 lactating cows. Two sets of cows, primiparous and multiparous, were used.

Evaluation of a 1% iodophor postmilking teat sanitizer.

A natural exposure field trial a with positive control was conducted to evaluate bacteriological efficacy and teat conditioning qualities of an experimental postmilking teat dip. An experimental 1% iodine postmilking teat sanitizer with a 10% emollient system was compared with a 1% iodine plus 10% glycerin teat sanitizer. Efficacy of the two sanitizers was equivalent for all new IMI, major pathogens, and environmental pathogens.