RESUMO
The aim of this study was to determine the diagnostic accuracy of digital serum total protein (TP) and digital Brix refractometers in estimating different passive immunity levels (<10, <18, <25 mg/mL) in dairy calves. Blood samples were collected from 260 apparently healthy Holstein calves, aged 2-7 days. Serum IgG concentrations were measured using digital Brix and TP refractometers and the radial immunodiffusion (RID) assay, as the gold standard. Data were analyzed by a receiver operating characteristics (ROC) analysis, the area under the ROC curves (AUC) and Cohen's kappa (κ). Optimal thresholds were determined as < 8.4, < 9.0 and < 9.4% for the digital Brix refractometer, and < 5.0, < 5.4 and < 5.8 g/dL for the serum TP refractometer in estimating IgG concentrations of < 10, < 18, < 25 mg/mL, respectively. The sensitivity (Se) and specificity (Sp) of the Brix refractometer were 96.3% and 88.8% for < 8.4% Brix, 97.0% and 83.4% for < 9.0% Brix, and 85.5% and 77.8% for < 9.4% Brix, respectively. The Se and Sp of the serum TP refractometer were 96.3% and 90.1% for < 5.0 g/dL, 91.0% and 89.6% for < 5.4 g/dL, 79.6% and 85.2% for < 5.8 g/dL, respectively. The discriminant ability of the refractometers was moderately accurate in estimating IgG concentrations of < 10 and < 18 mg/mL, and highly accurate in estimating IgG concentrations of < 25 mg/mL. Both refractometers substantially agreed with RID-IgG results and almost perfectly agreed with each other. In conclusion, the digital Brix and digital serum TP refractometers offer a good utility for determining different passive immunity levels in dairy calves.
Assuntos
Imunoglobulina G , Refratometria , Animais , Animais Recém-Nascidos , Bovinos , Colostro , Feminino , Imunidade Materno-Adquirida , Imunodifusão/métodos , Imunodifusão/veterinária , Gravidez , Refratometria/métodos , Refratometria/veterinária , Sensibilidade e EspecificidadeRESUMO
The present study evaluated follicular superstimulatory (FSS) and superovulatory (SOV) responses and in vivo embryo production in lactating Simmental cows treated with FSH starting 1 or 2 days after follicle aspiration (FA). The performance of a lengthened superovulation program, named 6dFSH-P36-hCG60, is described. At random stages of the estrous cycle, cows (nâ¯=â¯52) were subjected to ultrasound-guided transvaginal aspiration of all folliclesâ¯≥â¯5â¯mm. After FA, cows were randomly assigned to one of two groups in which FSH treatments started 1 or 2 days after FA (groups FA-1D and FA-2D, respectively). Cows were superstimulated with a total of 500⯵g pFSH over 6 days on a decreasing dose schedule and were pre-treated with a single dose of 400 IU of eCG 24â¯h before the start of FSH treatments. Follicular superstimulatory (the mean numbers of folliclesâ¯≥â¯8â¯mm on the day of hCG treatment) and SOV responses (the mean numbers of CL and cows with ≥ 3 CL at the time of collection) were similar in FA-1D and FA-2D groups. However, when compared to FA-1D group, the number of unfertilized ova tended to decrease (0.4 vs 1.7; Pâ¯=â¯0.065) and percentage of fertilized ova tended to increase (95.8% vs 84.6%; Pâ¯=â¯0.066) in FA-2D group. Moreover, the mean numbers and percentages of both transferable embryos (8.0 and 77.6% vs 6.4 and 57.7%) and freezable embryos (5.3 and 51.5% vs 3.5 and 31.1%) were numerically higher in FA-2D group than FA-1D group. The results of the study suggest that starting a lengthened superovulation programs in Simmental cows 2 days after FA has potential to increase percentage of fertilized ova and the number of transferable and freezable embryos, although new studies may be needed to confirm this findings.