Abbas Ahmadi

Relationships of milk culture status at calving with somatic cell counts and milk production of dairy heifers during early lactation on a Californian dairy

Abstract Four-quarter, composite milk samples were collected from 339 heifers calving for the first time in a large Californian dairy which consistently had low herd somatic cell counts and low prevalence of major mastitis pathogens. The milk samples were collected on average at 6.4 days post partum (range 1–17). Thirty-nine percent of the heifers were subclinically infected with coagulase-negative Staphylococcus spp. Other results were: no growth, 29%; coliform only, 16%; Streptococcus spp. only, 11%; Streptococcus spp. and coagulase-negative Staphylococcus spp. only, 4%; others, 1%. The somatic cell counts and milk production were not significantly different ( P > 0.05) between culture groups over the first five monthly Dairy Herd Improvement test periods. Somatic cell counts decreased significantly after the first test period within the Streptococcus spp. group ( P Staphylococcus spp. group ( P P Staphylococcus spp.) had no significant effect on average somatic cell counts or milk production during early to middle lactation.

Mosquito‐mediated attraction of female mosquitoes to a host

ABSTRACT. Female mosquitoes seeking blood respond primarily to kairomones emitted by potential hosts. We now confirm, in the laboratory, field evidence showing that the presence of other female mosquitoes at the host significantly enhances the host‐seeking response. Olfactometry strongly suggests that a chemical of mosquito origin is responsible. The adaptive value of this behaviour is discussed.

Cumulative trauma disorders among California veterinarians

BACKGROUND The prevalence of cumulative trauma disorders (CTDs) in veterinarians has not been adequately studied. METHODS A questionnaire was sent to 2,000 California veterinarians in 1997; the return rate was 73% (n = 1,415). RESULTS Ninety-six percent (1,353) of the respondents were professionally active and were included in the analyses. Sixty-four percent were male and 90% were working full-time. One-fourth of the respondents reported a CTD during their career that required treatment or restricted usual activities. Two-thirds of those reporting CTDs reported chronic or residual problems. In a multivariate regression analysis female sex, working full-time, rectal palpations, and large animal practice were significant risk factors for CTDs. CONCLUSIONS Being in large animal practice increased the CTD risk for both women and men whether they worked full or part-time. CTD risk was highest in women working full-time and doing 80% rectal palpations. Preventive methods to attenuate the risk of CTDs especially in large animal practice should be investigated.

AQUARIUS: A Decision Support System for Aquaculture

The United States shellfish industry is regulated under the National Shellfish Sanitation Program, administered federally by the U.S Food and Drug Administration, and at the state level by departments of health or agriculture. Shellfish authorities are empowered to close shellfish harvest if water quality drops below food safety levels. Because monitoring for all human pathogens in growing areas is not feasible, fecal coliform bacteria are used as indicator organisms for the potential presence of pathogens from fecal contamination. Every decade, sanitary surveys are conducted during adverse pollution conditions to establish equations and rules for conditionally approved growing areas to predict rainfall levels when fecal coliform levels might exceed the “NSSP 14/43” safety standard. Modifying these rules requires an extensive sampling programs and analyses. As watersheds change, there is pressure to reclassify growing sites and to modify closure rules. The AQUARIUS program is the first tool developed to directly evaluate closure rules for the shellfish industry, and to perform a series of “what-if” scenarios for selected variables. AQUARIUS uses the actual rainfall data to simulate the open/close status of a given growing site for any length of time under two closure rules: one the current rule and the other proposed new rule. AQUARIUS then uses the actual fecal coliform data from the site to compare the fecal coliform level of “site open under current rule” versus “site open under new rule. Based on the results of SSP 14/43” standards and T-Tests, the new closure rule is either accepted or rejected.