Association of pre-treatment somatic cell counts with bacteriological cure following diagnosis of intramammary infection.

Antibiotic administration is crucial to ensure the health and productivity of dairy cattle. Mastitis is a disease that is typically a result of an intramammary infection (IMI), and antibiotic regimens are implemented to aid in curing IMI. Diagnosis is usually by detection of elevated milk somatic cell counts (SCC) and/or presence of culturable pathogens in the milk. Antibiotic treatment success is associated with the SCC at the time of treatment, though this correlation is still poorly understood. The objective of this project was to evaluate pre-treatment SCC and its association with IMI cure incidence following a standard antibiotic treatment. We hypothesized that pre-treatment SCC would be significantly lower in cases where the IMI ultimately cured compared to cases where the IMI failed to cure. Milk samples were collected aseptically from lactating cow quarters experiencing clinical or subclinical mastitis (n = 52). Clinical mastitis was diagnosed by a trained milking technician and subclinical mastitis was diagnosed at the quarter level as a SCC > 200,000 cells/mL and presence of bacterical growth in milk at time of treatment. After collection of the day 0 (D0) milk samples, the SCC was enumerated, and the milk sample cultured. Intramammary antibiotic therapy Cetftiofur hydrochloride (Spectramast® LC) was administered once/day for 5 days. Post-treatment samples were collected 14 d (D14) and 28 d (D28) later. A bacteriological cure was confirmed when both the D14 and D28 samples were free of culturable pathogens. The overall cure rate was 46.2%. Interestingly, the cure rates of antibiotic therapy decreased as pre-treatment SCC increased. Quarters that experienced bacteriological cure demonstrated a lower pre-treatment SCC (507,041 cells/mL ± 127.86 SEM, P = 0.01) compared to cows that did not cure, which had high pre-treatment SCC (1,640,392 cells/mL ± 333.28 SEM). Quarters that failed to cure had higher SCC values 28 days post-treatment in comparison to quarters that cured (P < 0.001). Future studies should investigate whether we can develop unique SCC-dependent mastitis treatment protocols which increase mastitis cure rates and enhance overall mammary health.

Evaluation of mare endometrial cytology using the novel cytotape technique.

The cytobrush is considered the method of choice to obtain endometrial samples. Rigid brush fibers, however, may induce endometrial irritation and bleeding, or cell fragmentation, decreasing quality and diagnostic value of the samples. It was hypothesized that samples collected using a novel cytotape would provide sample smears of greater quality and less blood contamination than the cytobrush. Endometrial samples were collected with a cytotape and a cytobrush from ten mares without endometritis. Endometritis was then induced with artificial insemination, and samples were again collected 6 h after insemination. A cytology smear and bacterial culture were prepared from each sample. The collection methods and times were compared in terms of number and integrity of endometrial cells; number, integrity, and percentage of neutrophils; number of red blood cells, and number of colony-forming units. Frequency of positive cytology and culture was compared when there was use of each technique. The sensitivity, specificity, positive predictive value, and negative predictive value of cytology and culture for each technique was calculated using endometrial biopsy as the gold standard. While all samples had adequate and comparable cellularity and cell integrity, cytotape samples had less red blood cell contamination compared to cytobrush samples (P < 0.05). The number and percentage of PMNs, frequency of positive cytology diagnosis, number of colony-forming units and frequency of positive cultures did not differ between collection methods. In conclusion, the cytotape is a rapid, easy, and practical technique that can provide endometrial samples with similar diagnostic value to the cytobrush, but with less blood contamination.

Serum, uterine, and vaginal mucosal IgG antibody responses against Tritrichomonas foetus after administration of a commercial killed whole T foetus vaccine in beef cows.

The objective of this study was to determine the level and duration of IgG antibodies induced against killed whole Tritrichomonas foetus and T foetus-purified surface antigen (TF1.17) in serum, vaginal, and uterine secretions after systemic immunization of beef cows with a vaccine containing killed whole T foetus. Twenty nonpregnant beef cows were randomly assigned to vaccine or control groups as follows: Vaccine (n = 10): cows received 2 mL of a commercial vaccine containing killed whole T foetus subcutaneously and a 2-mL booster 2 weeks later. Control (n = 10): cows received 2 mL of sterile saline on the same schedule. Vaginal secretions and blood samples were collected on Days 0, 8, 15, 22, 29, 36, 43, 50, 60, 75, 89, 110, 146, and 182 relative to day of primary vaccination. Uterine flush fluid was collected on Days 0, 15, 29, and 43 after the day of primary vaccination. Samples were assayed for IgG antibodies to the killed whole T foetus and surface antigen TF1.17 using enzyme-linked immunosorbent assay. Serum whole T foetus-specific IgG levels were significantly increased (between Days 15 and 182) following vaccination with T foetus or with saline. No differences between vaccinates and controls in uterine responses to whole-cell antigen were detected. Serum anti-TF1.17 IgG responses to vaccination were significantly higher than Day 0 throughout the immunization period (P < 0.001) and were higher than responses in control animals on each day post immunization through Day 146 (P < 0.001). A significant rise in TF1.17-specific IgG levels was observed in vaginal and uterine fluids from Day 15 post vaccination compared to the Day 0 levels. These levels remained significantly elevated in vaginal and uterine fluids through Days 75 (P < 0.05) and 43 (P < 0.001) after primary vaccination, respectively. Antibody levels in serum, vaginal, and uterine secretions against TF1.17 remained low in the control group throughout the study. In conclusion, vaccination of beef cows with a commercial vaccine containing T foetus induced significant increase in the levels of IgG to the T foetus TF1.17 surface antigen in serum, vaginal secretions, and uterine fluid, which remained elevated through Days 43, 75, and 182 in uterine fluids, vaginal secretions, and serum, respectively. Since purified TF1.17 antigen has been shown to protect against experimental T foetus infection in heifers, the vaccine-induced TF1.17-specific IgG response is likely to be important in the prevention of trichomoniasis in beef cattle.

The cost of clinical mastitis in the first 30 days of lactation: An economic modeling tool.

Clinical mastitis results in considerable economic losses for dairy producers and is most commonly diagnosed in early lactation. The objective of this research was to estimate the economic impact of clinical mastitis occurring during the first 30 days of lactation for a representative US dairy. A deterministic partial budget model was created to estimate direct and indirect costs per case of clinical mastitis occurring during the first 30 days of lactation. Model inputs were selected from the available literature, or when none were available, from herd data. The average case of clinical mastitis resulted in a total economic cost of $444, including $128 in direct costs and $316 in indirect costs. Direct costs included diagnostics ($10), therapeutics ($36), non-saleable milk ($25), veterinary service ($4), labor ($21), and death loss ($32). Indirect costs included future milk production loss ($125), premature culling and replacement loss ($182), and future reproductive loss ($9). Accurate decision making regarding mastitis control relies on understanding the economic impacts of clinical mastitis, especially the longer term indirect costs that represent 71% of the total cost per case of mastitis. Future milk production loss represents 28% of total cost, and future culling and replacement loss represents 41% of the total cost of a case of clinical mastitis. In contrast to older estimates, these values represent the current dairy economic climate, including milk price ($0.461/kg), feed price ($0.279/kg DM (dry matter)), and replacement costs ($2,094/head), along with the latest published estimates on the production and culling effects of clinical mastitis. This economic model is designed to be customized for specific dairy producers and their herd characteristics to better aid them in developing mastitis control strategies.

Measuring lanthanide concentrations in molten salt using laser-induced breakdown spectroscopy (LIBS).

The versatility of laser-induced breakdown spectroscopy (LIBS) as an analytical method for high-temperature applications was demonstrated through measurement of the concentrations of the lanthanide elements europium (Eu) and praseodymium (Pr) in molten eutectic lithium chloride-potassium chloride (LiCl-KCl) salts at a temperature of 500 °C. Laser pulses (1064 nm, 7 ns, 120 mJ/pulse) were focused on the top surface of the molten salt samples in a laboratory furnace under an argon atmosphere, and the resulting LIBS signals were collected using a broadband Echelle-type spectrometer. Partial least squares (PLS) regression using leave-one-sample-out cross-validation was used to quantify the concentrations of Eu and Pr in the samples. The root mean square error of prediction (RMSEP) for Eu was 0.13% (absolute) over a concentration range of 0-3.01%, and for Pr was 0.13% (absolute) over a concentration range of 0-1.04%.

A simple radionuclide-driven single-ion source.

We describe a source capable of producing single barium ions through nuclear recoils in radioactive decay. The source is fabricated by electroplating (148)Gd onto a silicon α-particle detector and vapor depositing a layer of BaF(2) over it. (144)Sm recoils from the alpha decay of (148)Gd are used to dislodge Ba(+) ions from the BaF(2) layer and emit them in the surrounding environment. The simultaneous detection of an α particle in the substrate detector allows for tagging of the nuclear decay and of the Ba(+) emission. The source is simple, durable, and can be manipulated and used in different environments. We discuss the fabrication process, which can be easily adapted to emit most other chemical species, and the performance of the source.

Observations on the nesting and prey of the solitary wasp, Tachysphex inconspicuus, with a review of nesting behavior in the T. obscuripennis species group.

The nesting behaviors of 10 females of Tachysphex inconspicuus (Kirby) (Hymenoptera: Crabronidae) were studied on a sandy, mowed lawn at the La Selva Biological Station in northeastern Costa Rica on 27-29 April 1980. Twenty-four completed nests were observed, excavated, and measured. The nests had oblique, short burrows leading to one or two shallow cells. Prey cockroaches belonging to 11 species of Chorisoneura and Riatia fulgida (Saussure) (Blattaria: Blattellidae), all tropical wet forest canopy indicator species, were removed from the cells, weighed, and identified. The cockroaches consisted mainly of adult females, selectively preyed upon over adult males and nymphs due to their larger sizes. The aggregate prey mass in cells was separable into prospective larger (heavier) female and smaller (lighter) male cells. Wasps usually oviposited on the heaviest cockroach in a cell, in most cases an adult female. Atypical genus behavior included (1) prey being carried to one side of the wasp and perhaps grasped by a hindleg during removal of the temporary entrance closure and nest entry and (2) wasp's egg being laid affixed to a forecoxal corium and extending backward in a longitudinally posteriad position across the prey's ventral thorax. A comparison with the nesting behavior of other species in the Tachysphex obscuripennis species group is made.

The effect of injectable butaphosphan and cyanocobalamin on postpartum serum beta-hydroxybutyrate, calcium, and phosphorus concentrations in dairy cattle.

The objective of this study was to determine the effect of an injection of 10% butaphosphan and cyanocobalamin (Catosal, Bayer, Shawnee Mission, KS) on the day of calving and 1 d later on the prevalence of subclinical ketosis in dairy cattle in the early postpartum period. Cows from 4 herds (n=1,122) were randomized to receive either 25mL of 10% butaphosphan and cyanocobalamin or 25mL of sterile water subcutaneously on both days. Each milliliter of Catosal contained 0.05mg of cyanocobalamin and 100mg of butaphosphan, which provided 17.3mg of P in the form of [1-(butylamino)-1-methylethyl]-phosphonic acid. Serum was sampled for beta-hydroxybutyrate (BHBA) concentration at calving (pretreatment) and again between 3 and 10 d in milk. A subset of samples from mature cows was also evaluated for serum Ca and P concentrations. When cows from all age groups were included in the analysis, there was no difference between the median serum BHBA concentrations of cows in the 2 treatment groups, and no difference in the proportion of hyperketonemic cows (serum BHBA >or=1,200micromol/L) during the first week postpartum. When the analysis was restricted to mature cows (lactation >or=3), both the median BHBA concentration and the proportion of hyperketonemic cows were significantly lower in the treatment group than in the placebo group. Serum Ca and P concentrations did not differ between treatment groups. Our results suggest that injection of butaphosphan and cyanocobalamin on the day of calving and 1 d later may decrease the prevalence of subclinical ketosis during the week after calving in mature dairy cows, but not in first- and second-lactation animals.