Comparison of genomic and traditional BLUP-estimated breeding value accuracy and selection response under alternative trait and genomic parameters

Accuracy of prediction of estimated breeding values based on genome-wide markers (GEBV) and selection based on GEBV as compared with traditional Best Linear Unbiased Prediction (BLUP) was examined for a number of alternatives, including low heritability, number of generations of training, marker density, initial distributions, and effective population size (Ne). Results show that the more the generations of data in which both genotypes and phenotypes were collected, termed training generations (TG), the better the accuracy and persistency of accuracy based on GEBV. GEBV excelled for traits of low heritability regardless of initial equilibrium conditions, as opposed to traditional marker-assisted selection, which is not useful for traits of low heritability. Effective population size is critical for populations starting in Hardy-Weinberg equilibrium but not for populations started from mutation-drift equilibrium. In comparison with traditional BLUP, GEBV can exceed the accuracy of BLUP provided enough TG are included. Unfortunately selection rapidly reduces the accuracy of GEBV. In all cases examined, classic BLUP selection exceeds what was possible for GEBV selection. Even still, GEBV could have an advantage over traditional BLUP in cases such as sex-limited traits, traits that are expensive to measure, or can only be measured on relatives. A combined approach, utilizing a mixed model with a second random effect to account for quantitative trait loci in linkage equilibrium (the polygenic effect) was suggested as a way to capitalize on both methodologies.     

含莫纳可林K红曲降低鸡蛋胆固醇效果的研究

48只68周龄的海兰褐蛋鸡分成三组，按0.5％和10％比例分别添加含0．4％莫纳可林K红曲于各组日粮内，饲喂22d，观测其对鸡蛋胆固醇变化的影响。结果表明，投药后5—6d，10％添加组和5％添加组蛋黄胆固醇开始下降；15—22d的胆固醇含量与1～5d相比，10％添加组和5％添加组分别下降了9．02％和5．10％，而对照组升高了5．22％。     

Hemolytic potential of guaifenesin in cattle

The hemolytic effect on bovine red blood cells of 5%, 10%, and 15% guaifenesin solutions in 5% dextrose, 0.9% saline (NaCl), or distilled water was determined in vitro at 2 plasma concentrations (250 micrograms/ml, 500 micrograms/ml). A solution of 5% guaifenesin in a 5% dextrose solution or 5% guaifenesin in 0.9% saline produced minimal hemolysis in vitro. The amount of hemolysis of bovine red blood cells in vitro was related to the concentration of guaifenesin, diluent (5% dextrose, 0.9% NaCl, distilled water) and the plasma concentration of guaifenesin. In addition, plasma hemoglobin was determined in 4 adult dairy cows following the IV administration of 5% and 10% guaifenesin. These studies suggest that a solution of 5% guaifenesin in 5% dextrose is the most suitable solution for clinical use in cattle.     

Serum Biomarkers of Clinical and Cytologic Response in Dogs with Idiopathic Immune‐Mediated Polyarthropathy

Background

Immune‐mediated polyarthopathy (IMPA) is common in dogs, and is monitored by serial arthrocenteses.

Hypothesis/Objectives

Plasma C‐reactive protein (CRP), interleukin‐6 (IL‐6), and CXCL8 (interleukin‐8) would serve as noninvasive markers of joint inflammation in IMPA.

Animals

Nine client‐owned dogs with idiopathic IMPA; 6 healthy controls.

Methods

Prospective study. Plasma CRP, IL‐6, and CXCL8 were measured by ELISA at baseline, 2, and 4 weeks during treatment with prednisone at 50 mg/m²/day. Arthrocenteses, the canine brief pain inventory (CBPI), and accelerometry collars were used to assess joint inflammation, lameness, and mobility at all 3 time points.

Results

C‐reactive protein concentrations were higher in IMPA dogs (median 91.1 μg/mL, range 76.7–195.0) compared with controls (median <6.3 μg/mL, <6.3–13.7; P = .0035), and were significantly lower at week 2 (10.6 μg/mL, <6.3–48.8) and week 4 (<6.3 μg/mL, <6.3–24.4; P < .001).C‐reactive protein was correlated with median CBPI scores (r = 0.68; P = .0004), joint cellularity (r = 0.49, P = .011), and mobility by accelerometry (r = −0.42, P = .048). Plasma IL‐6 concentrations were also higher in IMPA dogs (median 45.9 pg/mL), compared with controls (median <15.7 pg/mL; P = .0008). IL‐6 was lower in IMPA dogs by week 4 (<15.7 pg/mL; P = .0099), and was modestly correlated with CBPI scores (r = 0.47, P = .023). CXCL8 did not differ significantly between IMPA and healthy dogs.

Conclusions

Plasma CRP and IL‐6 might be useful surrogate markers of synovial inflammation and disease activity in dogs with IMPA.     

Caudal epidural analgesia induced by xylazine administration in cows

Xylazine (0.05 mg/kg of body weight diluted to a 5-ml volume, using 0.9% NaCl) or 5 ml of 0.9% NaCl was administered epidurally into the first caudal intervertebral space (Co1-Co2) in 8 cows (mean +/- SD body weight, 583 +/- 150 kg). Cows were observed for responses to deep needle pricking of the caudal dermatomes (S3 to Co), sedation, and ataxia. Heart rate, respiratory rate, body temperature, rate of ruminal contractions, coccygeal arterial blood pressure, pHa, blood gas tension (PaO2, PaCO2), base excess, total solids concentration, and PCV were determined before and after xylazine administration. Epidurally administered xylazine induced sedation and selective (S3 to Co) analgesia for at least 2 hours. Mild ataxia of hind limbs was observed in 6 cows, but all cows remained standing. Heart rate, respiratory rate, rate of ruminal contractions, arterial blood pressure, PaO2, PCV, and total solids concentration were significantly (P less than 0.05) decreased, and PaCO2, base excess, and bicarbonate concentration were significantly (P less than 0.05) increased after xylazine administration. Epidurally administered 0.9% NaCl did not alter sensory perception to needle pricking and did not affect any of the physiologic variables determined. Although epidural administration of xylazine induced analgesia and sedation in healthy cows, it should be avoided for epidural analgesia in cattle with heart disease, lung disease, and/or gastrointestinal disease because of its potent cardiopulmonary and ruminal depressant effects.     

Hemodynamic response of endotoxemic calves to treatment with small-volume hypertonic saline solution

The hemodynamic effects of hypertonic saline solution (HSS) resuscitation on endotoxic shock were examined in pentobarbital-anesthetized calves (8 to 20 days old). Escherichia coli (055:B5) endotoxin was infused IV at dosage of 0.1 microgram/kg of body weight for 30 minutes. Endotoxin induced large decreases in cardiac index, stroke volume, maximal rate of change of left ventricular pressure (+dP/dtmax), femoral and mesenteric arterial blood flow, glomerular filtration rate, urine production, and mean aortic pressure. Severe pulmonary arterial hypertension and increased pulmonary vascular resistance were evident at the end of endotoxin infusion. Treatment with HSS (2,400 mosm of NaCl/L, 4 ml/kg) or an equivalent sodium load of isotonic saline solution (ISS: 300 mosm of NaCl/L, 32 ml/kg) was administered 90 minutes after the end of endotoxin administration. Both solutions were infused IV over a 4- to 6-minute period. Administration of HSS induced immediate and significant (P less than 0.05) increase in stroke volume and central venous pressure, as well as significant decrease in pulmonary vascular resistance. These effects were sustained for 60 minutes, after which all variables returned toward preinfusion values. The hemodynamic response to HSS administration was suggestive of rapid plasma volume expansion and redistribution of cardiac output toward splanchnic circulation. Plasma volume expansion by HSS was minimal 60 minutes after resuscitation. Administration of ISS induced significant increase in cardiac index, stroke volume, femoral arterial blood flow, and urine production. These effects were sustained for 120 minutes, at which time, calves were euthanatized. Compared with HSS, ISS induced sustained increase in mean pulmonary arterial pressure and only a small increase in mesenteric arterial blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)     

Analgesic, hemodynamic, and respiratory effects induced by caudal epidural administration of meperidine hydrochloride in mares.

OBJECTIVE: To determine the analgesic, hemodynamic, and respiratory effects induced by caudal epidural administration of meperidine hydrochloride in mares. ANIMALS: 7 healthy mares. Procedure: Each mare received meperidine (5%; 0.8 mg/kg of body weight) or saline (0.9% NaCl) solution via caudal epidural injection on 2 occasions. At least 2 weeks elapsed between treatments. Degree of analgesia in response to noxious electrical, thermal, and skin and muscle prick stimuli was determined before and for 5 hours after treatment. In addition, cardiovascular and respiratory variables were measured and degree of sedation (head position) and ataxia (pelvic limb position) evaluated. RESULTS: Caudal epidural administration of meperidine induced bilateral analgesia extending from the. coccygeal to S1 dermatomes in standing mares; degree of sedation and ataxia was minimal. Mean (+/- SD) onset of analgesia was 12 +/- 4 minutes after meperidine administration, and duration of analgesia ranged from 240 minutes to the entire 300-minute testing period. Heart and respiratory rates, rectal temperature, arterial blood pressures, Hct, PaO2, PaCO2, pHa, total solids and bicarbonate concentrations, and base excess were not significantly different from baseline values after caudal epidural administration of either meperidine or saline solution. CONCLUSIONS AND CLINICAL RELEVANCE: Caudal epidural administration of meperidine induced prolonged perineal analgesia in healthy mares. Degree of sedation and ataxia was minimal, and adverse cardiorespiratory effects were not detected. Meperidine may be a useful agent for induction of caudal epidural analgesia in mares undergoing prolonged diagnostic, obstetric, or surgical procedures in the anal and perineal regions.     

Visual resolution and experience: acuity deficits in cats following early selective visual deprivation

Cats reared during the first 5 months of life in environments that contain contours of a single orientation show a diminished ability to resolve gratings of the orthogonal orientation in later life. It is argued that these perceptual deficits result from changes in the organization of the visual cortex induced by the selected early visual input.