Color Doppler flow imaging for the early detection of nonpregnant cattle at 20 days after timed artificial insemination.

The objective was to determine the accuracy of a pregnancy test for predicting nonpregnant cattle based on the evaluation of corpus luteum (CL) blood flow at 20 d (CLBF-d20) after timed artificial insemination (TAI). Crossbred Holstein-Gir dairy heifers (n=209) and lactating cows (n=317) were synchronized for TAI using the following protocol: intravaginal implant (1.0 g of progesterone) and 2mg of estradiol benzoate i.m. on d -10, implant removal and 0.526 mg of sodium cloprostenol i.m. on d -2, 1mg of estradiol benzoate i.m. on d -1, and TAI on d 0. On d 20, animals underwent grayscale ultrasonography (US) to locate the CL and color flow Doppler to evaluate CLBF-d20 using a portable ultrasound equipped with a 7.5-MHz rectal transducer. Based only on a visual, subjective CLBF evaluation, the animals were classified as pregnant or not pregnant. On d 30 to 35, blinded from results of the previous diagnosis, the same operator performed a final pregnancy diagnosis using US to visualize the fetal heartbeat (gold standard; US-d30). A second evaluator also analyzed the CLBF-d20 in the same animals by watching 7-s recorded videos. Blood samples were collected from a subset of 171 females to determine, by RIA, plasma progesterone (P4) concentrations, which indicate CL function. The final pregnancy outcome (US-d30) was retrospectively compared with the CLBF-d20 diagnoses and then classified either as correct or incorrect. The number of true positive, true negative, false positive, and false negative decisions were inserted into a 2 × 2 decision matrix. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the CLBF-d20 test were calculated using specific equations. Binomial variables (pregnancy rate and proportions) were analyzed using Fisher's exact test for the effect of parity and to compare between evaluators and tests (CLBF-d20 vs. plasma P4). The kappa values were calculated to quantify the agreement between CLBF-d20 and the gold standard (US-d30) and between evaluators. The performance parameters of CLBF-d20 test were as follows: sensitivity=99.0%, specificity=53.7%, positive predictive value=65.1%, negative predictive value=98.5%, and accuracy=74.8%. False negatives represented only 0.4% of the exams. No differences existed in these parameters between evaluators (no. 1 vs. no. 2) and tests (CLBF-d20 vs. plasma P4). Moreover, a high level of agreement was observed between evaluators (0.91). In conclusion, visual evaluation of CLBF-d20 represents a quick, reliable, and consistent diagnostic test that enables the early detection of nonpregnant cattle.

[The stability of antibiotics administered in "and" with a parenteral nutrition mixture enriched with branched-chain amino acids. II. The cephalosporins]. / Estabilidad de antibióticos administrados en "Y" con una mezcla de nutrición parenteral enriquecida en aminoácidos de cadena ramificada. Parte II. Cefalosporinas.

Part I of these stability studies commented on the benefits, in terms of care and therapy, of the Y administration of antibiotics and parenteral nutrition. The aim of this study is to determine the stability of the cephalosporins ceftazidime, ceftriaxone, ceftizosime and cefotaxime in vitro, at therapeutic concentrations, infused together with a parenteral nutrition mixture with polyols, enriched in branched chained amino acids, and without lipids. A microbiological stability analysis was carried out on the antibiotics in the parenteral nutrition, and an HPLC aminogram was done to determine the concentration of amino acids in the infusion together with the antibiotic. As well, pH, osmolarity and colour change were measured in the antibiotics, in the parenteral nutrition used and in the joint infusion mixtures. It is concluded that parenteral nutrition can be jointly infused with cefotaxime and ceftazidime, at the concentrations studied, given the stability results obtained both with HPLC (antibiotics and amino acids) and microbiologically (antibiotics). At the same time, the microbiological analysis of ceftriaxone with the nutrition showed its stability in the study conditions. Its joint infusion with parenteral nutrition, studied by HPLC, confirmed the stability of the amino acids. The ceftizoxime analysed by HPLC remained stable during joint infusion with the parenteral nutrition.