Comparison of four methods of calf confinement. II. Behavior

Holstein bull calves (N = 46) were blocked by birth order and randomly assigned to be individually reared in stalls, pens or hutches (trials I and II) or as a group in a 3.6 X 7.9 m yard (trial II only). Treatments differed by the degree of restraint and social isolation imposed, with stalls the most restrictive and yard the least. Stalls and pens had wooden slatted floors; hutches and yard were on ground. Calves were placed on treatment within 24 h of birth and remained on treatment 6.5 wk. Total time standing or lying per 24 h in situ at 5 wk was not affected by treatment (P greater than .05), but hutch calves changed position between standing and lying more often than others (P less than .05), in order to remain in sun or shade. At 6.5 wk, calves (N = 24) in trial II were individually open-field tested for 20 min in the presence of alien calves. Stall and pen calves performed more actions utilized in locomotion and defense and engaged in more social behavior than hutch or yard calves (P less than .05). Only stall and pen calves stumbled and fell, but observations were insufficient to allow statistical analysis of these incidents. Treatment effects were found with respect to vocalizations: stall and pen calves emitted more "baaocks," while yard calves emitted more "moos." Results of this study and of a companion physiological study of the calves suggest that the intensification of drives induced by chronic suppression of their release may be accompanied by physiological responses associated with chronic stress.     

Comparison of four methods of estimating glomerular filtration rate in cats

Four methods of evaluating renal function were performed in 6 cats anesthetized with halothane in oxygen. Glomerular filtration rate (GFR) was measured simultaneously in each cat by exogenous creatinine clearance (ECC), bolus inulin clearance, and 99mTc(Sn)-diethylene-triaminepentaacetic acid (DTPA) clearance determined by 2 different methods. In the first DTPA clearance method (DTPA-1), we measured radioactivity in serial blood specimens to construct plasma disappearance curves for calculation of GFR. In the second DTPA clearance method (DTPA-2), we used serial external head counts of radioactivity and a single blood specimen to construct plasma disappearance curves for calculation of GFR. Bolus inulin clearance was calculated from plasma disappearance curves using a 1-compartment open pharmacokinetic model (IN-1) and a 2-compartment open pharmacokinetic model (IN-2). Glomerular filtration rates were measured over 3 hours, for creatinine and DTPA methods, and over 4 hours for the inulin methods. The GFR obtained with the reference method (ECC) was 2.56 +/- 0.61 ml/min/kg of body weight (mean +/- SD). Values for GFR determined by ECC and DTPA-1 were significantly correlated (r = 0.852; P less than or equal to 0.05). Correlation between ECC and DTPA 2 was not as good (r = 0.783; P less than or equal to 0.10), but the 2 DTPA methods significantly correlated with one another (r = 0.897; P less than or equal to 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of four methods of extracting DNA from D. gallinae (Acari: Dermanyssidae)

Dermanyssus gallinae is one of the most serious ectoparasites of poultry and it has been implicated as a vector of several major pathogenic diseases. Molecular detection of such pathogens in mites is crucial and therefore, an important step is the extraction of their DNA from mites. So, we compared four DNA extraction protocols from engorged and unfed individual mites: a conventional method using a Cethyl Trimethyl Ammonium Bromide buffer (CTAB), a Chelex resin, a Qiamp DNA extraction kit and a more recent one filter-based technology (FTA). The DNA samples have been tested for their ability to be amplified by an amplification of a D. gallinae 16S rRNA gene region. The best results were obtained using CTAB and Qiagen methods at the same time with unfed and engorged mites (96% and 100% of amplified samples). FTA produced similar results when using unfed mites but not when processing engorged ones (96% and 70%). Finally, the Chelex method was the least efficient in terms of DNA amplification, especially when applied on engorged individuals (50%). The possible inhibitor role of these Chelex extracted DNA was demonstrated by the means of a PCR control on PUC plasmid. No difference was observed with CTAB, Qiamp DNA extraction kit or FTA methods using DNA extracted one year before.     

Comparison of four methods to assess colostral IgG concentration in dairy cows

OBJECTIVE: To determine sensitivity and specificity of 4 methods to assess colostral IgG concentration in dairy cows and determine the optimal cutpoint for each method. DESIGN: Cross-sectional study. ANIMALS: 160 Holstein dairy cows. PROCEDURES: 171 composite colostrum samples collected within 2 hours after parturition were used in the study. Test methods used to estimate colostral IgG concentration consisted of weight of the first milking, 2 hydrometers, and an electronic refractometer. Results of the test methods were compared with colostral IgG concentration determined by means of radial immunodiffusion. For each method, sensitivity and specificity for detecting colostral IgG concentration < 50 g/L were calculated across a range of potential cutpoints, and the optimal cutpoint for each test was selected to maximize sensitivity and specificity. RESULTS: At the optimal cutpoint for each method, sensitivity for weight of the first milking (0.42) was significantly lower than sensitivity for each of the other 3 methods (hydrometer 1, 0.75; hydrometer 2, 0.76; refractometer, 0.75), but no significant differences were identified among the other 3 methods with regard to sensitivity. Specificities at the optimal cutpoint were similar for all 4 methods. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that use of either hydrometer or the electronic refractometer was an acceptable method of screening colostrum for low IgG concentration; however, the manufacturer-defined scale for both hydrometers overestimated colostral IgG concentration. Use of weight of the first milking as a screening test to identify bovine colostrum with inadequate IgG concentration could not be justified because of the low sensitivity.     

Comparison of behavior, physical condition and performance of laying hens in four molting methods

The objective of the present study was to evaluate the welfare level of hens in four molting methods by comparing their behavior, physical condition and performance. In total, 96 White Leghorn layers (72 weeks of age) were used. The four molting methods consisted of 10 days of feeding and the first 3 days of water withdrawal WFW); 10 day feed withdrawal (WF) followed by ad libitum access to a layer diet from day 11, 28 days of restricted feeding (RF) and 28 days without withdrawing their feed (NW). The RF and NW hens were fed a low energy diet. The WFW and WF hens showed two clear phases of behavior during the 10‐day fasting period. Explorative and stereotyped behavior increased for WFW and WF hens just after their fast. Standing‐resting then increased for WFW and WF hens while lying‐resting decreased. In contrast, RF and NW hens did not show clear behavioral changes during the 28‐day molt period. The weight loss of the NW hens was more gradual compared with the other three methods. No significant differences were seen in any productive trait among the four methods during the postmolt period. In conclusion, the welfare level of RF and NW, especially NW, was higher compared with WFW and WF.     

Comparison of four staining methods for detection of mast cells in equine bronchoalveolar lavage fluid

Mast cells normally are present in equine bronchoalveolar lavage fluid (BALF), but usually represent <2% of all cells in healthy horses. An increased percentage of mast cells has been associated with airway hyperactivity and inflammatory airway diseases, but marked differences are reported between studies in normal and diseased horses. Because an abnormal mast cell count may be of clinical relevance, we compared the ability of a fast Romanowsky method to stain mast cell granules with that of 3 metachromatic stains: automated Romanowsky, May-Grünwald Giemsa, and toluidine blue stains. The BALF cells from 24 horses were studied. A differential cell count was performed blindly on 400 cells. The percentages of mast cells obtained were analyzed by means of repeated-measures analysis of variance and Fischer's PLSD test. The Bland and Altman method was used to assess agreement among stains. The mean percentage of mast cells in BALF was significantly lower with the fast Romanowsky than with the automated Romanowsky, May-Grünwald Giemsa, and toluidine blue stains. With the fast Romanowsky stain, the metachromatic granules of mast cells were not stained, and their identification was based on morphologic criteria. Toluidine blue staining allowed detection of the highest mean percentage of mast cells, but was inadequate for performing a differential cell count on other cell types. In conclusion, fast Romanosky stain may be inadequate for detection of mast cells in equine BALF, whereas automated Romanowsky, May-Grünwald Giemsa, and toluidine blue stains provide metachromatic staining of mast cell granules.     

Comparison of four methods for detection of oestrus in dairy cows with resynchronised oestrous cycles

OBJECTIVE: To compare the sensitivity and positive predictive value of four methods for detection of oestrus in dairy cows with resynchronised oestrous cycles. PROCEDURE: Oestrous cycles in cows in three herds were synchronised for a first round of artificial insemination (AI) and then resynchronised for a second round of AI. Sensitivity and positive predictive value of four aids (pedometers, radiotelemetric transmitters [HeatWatch; HW], tail-paint and heatmount detectors) that were used to detect the resynchronised oestrus were compared. Milk progesterone concentration and pregnancy testing at 12 weeks were used as the reference standard for cows being in oestrus. RESULTS: The mean sensitivity and positive predictive value for detecting the resynchronised oestrus, for each aid that was used, was > 80%. Tail-paint was significantly more sensitive at detecting oestrus compared to heatmount detectors (P = 0.002), but not significantly more sensitive than pedometers (P = 0.07) or HW (P = 0.55) for detecting oestrus (91.3, 85.7; 81.4 and 88.4%, respectively). Positive predictive value of HW for detecting oestrus was greater than tail-paint (P = 0.014) and heatmount detectors (P = 0.024) but not pedometers (P = 0.25; 100, 91.7, 92.9 and 87.5%, respectively). Positive predictive value of heatmount detectors was greater than pedometers in herd C (93.4% vs 73.3%; P = 0.035) but not in herds A (95.0% vs 90.0%; P = 0.56) or B (90.8% vs 100%; P = 0.10). No other significant differences in sensitivity or positive predictive value of detection of oestrus were found between aids. CONCLUSION: Tail-paint, heatmount detectors, pedometers and HW provide a high sensitivity (> 80%) and positive predictive value (> 85%) of detecting oestrus in dairy cows with resynchronized oestrous cycles.     

Comparison of four methods for early detection of experimental Trichinella spiralis infections in pigs

Four methods employed in the diagnosis of experimental porcine trichinellosis (trichinoscopy, digestion method, immunofluorescence and enzyme linked immunosorbent assay (ELISA)) were compared by eleven laboratories in the countries of the European Economic Community and Sweden. The aim of this study was to test the reliability of ELISA during the onset of T. spiralis infection. Material from conventionally raised pigs infected with 1500 or 10000 larvae was compared to uninfected controls at Day 17 and Day 21 post infection.The serological techniques gave higher percentages of positive results than the direct techniques. Specific antobodies could be demonstrated with ELISA at an earlier stage and at higher percentages than with the other methods. ELISA micro-assay was the most sensitive procedure.     

新生犊牛皱胃平滑肌细胞的原代培养——组织块培养法和胶原酶消化法的比较研究

通过组织块培养法和胶原酶消化法分离培养犊奶牛皱胃平滑肌细胞,采用免疫细胞化学方法和免疫荧光化学方法对其进行鉴定,并将鉴定结果、细胞生长曲线进行比较。结果,两种方法培养出的细胞生长曲线基本相同,细胞纯度免疫细胞化学鉴定结果为：组织块培养法为95％以上,胶原酶消化法为90％;免疫荧光鉴定结果为：组织块培养法为96％,酶消化法为89％。组织块培养法操作简单、经济,但耗时较长;胶原酶消化法快速、获得细胞较多,但价格昂贵,故在实际操作中可将两种方法联合应用。     

Dairy calf management,morbidity and mortality in Ontario Holstein herds. I. The data

Heifer calf management practices and clinical outcomes were studied on 104 randomly selected Holstein dairy farms in southwestern Ontario between October 1980 and July 1983. Data were collected at both the farm level (all farms) and the individual calf level (1968 calves, 35 farms).Farm-level management data were collected by means of questionnaires and farm visits. Calf-level management data were recorded by farmers on forms provided. Treatments for disease and mortality data were recorded by the farmers on the calves up to the age of weaning, the age at which calves were no longer fed milk or milk substitutes on a regular basis.Farm size ranged from 23 to 154 calvings per year. Farm-level mortality rates per six-month season (winter/summer) were skewed, with a mean of about 6%, a median of zero, and a range of 67%. Morbidity rates were similarly skewed. Four percent of liveborn heifer calves died, 20% were treated for scours, and 15% were treated for pneumonia before the age of weaning.Stated farm policies on calf rearing were implemented to varying degrees on different farms, as estimated from individual calf data. This posed particular problems for interpreting farm-level data, since the danger of committing an ecologic fallacy was high. The data set described in this paper formed the basis for an observational study of the interlationships of heifer calf management and clinical outcomes.     

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Comparison of four test kits for feline leukemia virus antigen.

The sensitivity and specificity of 4 commercial FeLV ELISA kits, using blood, were compared with results of virus isolation from blood and immunofluorescent antibody (IFA) testing on blood. Significant differences were not found among the 4 ELISA kits. Marked decrease in sensitivity of the ELISA kits was detected when virus isolation was used as the standard of positivity rather than the IFA test. Virus isolation was a more sensitive indicator of early infection, with marked discrepancy among results obtained by virus isolation, ELISA, and the IFA test. Results became progressively more concordant as infection became fully established. Cats FeLV-positive by virus isolation alone were more likely to eliminate viremia. All cats FeLV-positive by IFA testing remained persistently viremic. Virus isolation, ELISA, and IFA testing appear to differ in their prognostic value. The use of blood rather than serum for the ELISA resulted in several discordant results. Six cats were FeLV-positive by ELISA when blood was tested but were FeLV-negative when serum was tested. Positive ELISA results were obtained for 4 of these cats when serum was tested, using extended incubation to increase sensitivity. It is possible that blood may actually be more sensitive than serum for use of the ELISA method.     

Comparison of four methods for determination of total protein concentrations in pleural and peritoneal fluid from dogs

OBJECTIVE: To compare 4 techniques for determination of total protein concentrations in peritoneal and pleural effusions from dogs. SAMPLE POPULATION: 23 peritoneal and 12 pleural fluid samples from 35 dogs with various abnormalities. PROCEDURE: Samples were collected into tubes containing EDTA, centrifuged, and stored at -20 C until total protein concentrations were assessed. Protein concentration in each sample was determined by use of urine test strips, refractometry, and Bradford and biuret techniques. Accuracy of each method was determined, using dilutions of human control sera. RESULTS: There was good correlation among results of all quantitative procedures. Results of the biuret technique were more accurate than results of the Bradford assay. Refractometry underestimated protein concentration in samples with < 20 g of protein/L. Results of urine test strips correctly classified effusion samples into 2 groups on the basis of total protein concentrations less than or greater than 20 g/L. CONCLUSIONS AND CLINICAL RELEVANCE: Results of any of these 4 techniques can be used to rapidly and efficiently differentiate peritoneal and pleural fluid from dogs into transudates and exudates on the basis of total protein concentration less than or greater than 20 g/L, respectively.     

四个抗草甘膦基因的抗性比较

草甘膦抗性是当代农业重要的农艺性状。为了选择最佳的抗性基因用于植物筛选标记,通过选取cp4-epsps、GR79-epsps、gat4621和GAT四个草甘膦抗性基因进行比较,在拟南芥中验证各基因对草甘膦的抗性。4个基因的转化苗经4个浓度的草甘膦喷施检测,结果显示,GAT类基因的抗性明显高于epsps类基因,基因间的差异达到了极显著水平。gat4621基因对草甘膦的抗性最好,在各浓度下存活率均表现为最高值,且抗性稳定。国内发掘的GAT基因对草甘膦也表现出良好的抗性。GAT类基因的拟南芥转化苗在喷施高浓度草甘膦条件下出现严重抽苔抑制;但在停施草甘膦后抑制解除,且可以开花结实。转epsps类基因可以获得高抗草甘膦植株,但在花期喷施草甘膦将造成败育。从基因大小及抗性强弱考虑,GAT类基因作为筛选标记基因应该更为适合。