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1.
Haematological and biochemical investigations were performed on 14 koalas with uncomplicated cystitis, 8 with complicated cystitis, 8 with conjunctivitis, 8 with lymphosarcoma, and 14 with miscellaneous diseases. Changes were limited and inconsistent in individual koalas with uncomplicated cystitis and conjunctivitis. In contrast, individual koalas with complicated cystitis were more likely to have anaemia, leukocytosis due to neutrophilia, hypoproteinaemia due to hypoalbuminaemia, and azotaemia due to elevated urea concentration. Although these changes were non-specific they did allow assessment of prognosis for survival and response to treatment. Koalas with lymphosarcoma were invariably anaemic, leukaemic, azotaemic and hypoalbuminaemic. Elevated enzymes (aspartate transaminase [AST]. lactate dehydrogenase [LD] and gamma glutamyl transferase [GGT]) were more common in koalas with lymphosarcoma. Koalas affected by miscellaneous conditions showed variable changes but once again anaemia, leukocytosis, azotaemia, elevated AST and LD, and hypoalbuminaemia were not uncommon. On the basis of these findings a minimal profile is suggested for the investigation of sick koalas and would include haematocrit, total and differential leukocyte counts, urea, total protein and albumin concentrations and AST, GGT and LD activities.  相似文献   
2.
Bovine respiratory disease (BRD) is the most costly feedlot disease in the United States. Selection for disease resistance is one of several possible interventions to prevent or reduce the economic loss associated with animal disease and to improve animal welfare. Undesirable genetic relationships, however, may exist between production and disease resistance traits. The objectives of this study were to estimate the phenotypic, environmental, and genetic correlations of BRD with growth, carcass, and LM palatability traits. Health records on 18,112 feedlot cattle over a 15-yr period and slaughter data on 1,627 steers over a 4-yr period were analyzed with bivariate animal models. Traits included ADG, adjusted carcass fat thickness at the 12th rib, marbling score, LM area, weight of retail cuts, weight of fat trim, bone weight, Warner-Bratzler shear force, tenderness score, and juiciness score. The estimated heritability of BRD incidence was 0.08 +/- 0.01. Phenotypic, environmental, and genetic correlations of the observed traits with BRD ranged from -0.35 to 0.40, -0.36 to 0.55, and -0.42 to 0.20, respectively. Most correlations were low or negligible. The percentage of carcass bone had moderate genetic, phenotypic, and environmental correlations with BRD (-0.42, -0.35, and -0.36, respectively). Hot carcass weight and weight of retail cuts had moderate, undesirable phenotypic correlations with BRD (0.37 and 0.40, respectively). Correlations of BRD with LM palatability and ADG were not detected. Low or near zero estimates of genetic correlations infer that selection to reduce BRD in feedlot cattle would have negligible correlated responses on growth, carcass, and meat palatability traits or that selection for those traits will have little effect on BRD susceptibility or resistance.  相似文献   
3.
Hereford x Angus crossbred steers (n = 36) were stunned, exsanguinated, and infused via the carotid artery either with an aqueous solution containing 98.52% water, 0.97% saccharides, 0.23% sodium chloride, and 0.28% phosphates (MPSC; n = 12) or with 0.3 M CaCl2 (n = 12). The remaining 12 steers served as noninfused controls. At 48 h postmortem, the quadriceps muscles and subcutaneous fat were removed from the carcasses, frozen, and later made into ground beef (18 to 20% fat). The longissimus lumborum (LL), semimembranosus, and psoas major (PM) also were removed, vacuum packaged, aged until 14 d postmortem, and then one steak was sliced from each muscle for visual and instrumental color evaluations. The inside (ISM) and outside (OSM) portions of the SM were evaluated separately. The LL and OSM steaks from MPSC-infused carcasses had a lighter red (P < 0.05) initial appearance than steaks from the other treatments. The LL steaks from noninfused carcasses had the most (P < 0.05) uniform color; the MPSC treatment was intermediate, and the CaCl2 treatment was the most two-toned. Steaks from both infusion treatments had higher (P < 0.05) L* values for the LL, ISM, and OSM muscles compared with noninfused carcasses. In general, the LL from CaCl2-infused carcasses had lower (P < 0.05) a* values, saturation indices, and 630 nm to 580 nm reflectance values, and had larger (P < 0.05) hue angles. Infusion with MPSC increased (P < 0.05) hue angles in the LL and OSM. Display color stability was lowest (P < 0.05) for LL steaks from CaCl2-infused carcasses, whereas steaks from MPSC-infused carcasses were lighter red in initial color, but otherwise had display color stability similar to those from noninfused carcasses. No differences (P > 0.05) due to infusion were found for any color traits for the PM muscle and ground beef. Carotid artery vascular infusion of carcasses with CaCl2 resulted in undesirable meat colors, whereas the MPSC solution lightened loin and inside round color in a desirable way, but the color stability was slightly less compared to muscle from noninfused carcasses. Infusion effects were not consistent among muscles, and further research will be needed to determine what caused these differences.  相似文献   
4.
Ecophysiological simulation models provide a quantitative method to predict the effects of management practices, plant characteristics and environmental factors on crop and weed growth and competition. The INTERCOM interplant competition model was parameterised, calibrated by monoculture data for three cowpea (Vigna unguiculata) genotypes that differed in growth habit, common sunflower (Helianthus annuus) and common purslane (Portulaca oleracea), and used to simulate competition of cowpea cover crops with sunflower or purslane. The simulation results were compared with observations from field competition experiments in 2003 and 2004. INTERCOM more accurately simulated actual field data for the competition of cowpea genotypes and sunflower than companion field experiments for the competition of cowpea and purslane. The validated simulation model of cowpea and sunflower at two densities was used to study the effects of cowpea growth habit on final biomass production of cowpea and sunflower. The model suggested that erect growth habit was more competitive than semi‐erect and prostrate growth habit, when cowpea genotypes were grown with sunflower. Cowpea leaf area distribution was important to higher cowpea biomass production, while cowpea height growth was important to reduce sunflower biomass. Our simulation approach is suggested as a method for crop breeders to gauge the likely success of selection for competitive crops before undertaking expensive long‐term breeding experiments.  相似文献   
5.
6.
The aim of this study was to evaluate the reproductive performance of three parities of gilts treated or not treated with gonadotropin to induce puberty. Sixty gilts received 600 IU of equine chorionic gonadotropin (eCG) followed by 2.5 mg of porcine luteinizing hormone (LH) 72 h later. Fifty‐nine other gilts were exposed only to a mature boar for 15 min twice daily. Artificial insemination (AI) was performed at 0, 12 and 24 h after the detection of oestrus, and gestation was confirmed by ultrasound after 35 days. Sows were inseminated at the first post‐weaning oestrus. The total numbers of piglets born, piglets born alive, stillborn, mummified foetuses, as well as pregnancy and farrowing rates were evaluated for each of the three parities. Culling rates, farrowing intervals and weaning‐to‐oestrous intervals (WEI) were also analysed. Mean age at puberty and oestrous manifestation were not significantly different between treatments (p = 0.0639; 179.20 ± 17.52 compared with 173.96 ± 16.94, 91.66% compared with 94.92%) across the experimental period. However, females that underwent puberty induction showed modest increases both in the number of total pigs born and in the number of piglets born alive. In conclusion, puberty induction through exogenous gonadotropin administration in field conditions did not induce a more concentrated first oestrous manifestation, but trended to a modest increase in the number of pigs born alive in the first parity and a reduced culling rate during the first gestation.  相似文献   
7.
8.
Our objective was to determine the predictive value of various biochemical and histological traits for tenderness of the longissimus muscle. Data collected from 27 crossbred cattle included longissimus pH, temperature, sarcomere length, total and percentage of soluble collagen, muscle-fiber type and area, cathepsin B and B + L activities, calcium-dependent protease (CDP)-I, -II and inhibitor activities, myofibril fragmentation indices (MFI), Warner-Bratzler shear (WBS) force, sensory-panel tenderness (SPT) ratings and carcass traits. Stepwise regression analyses were performed among breeds or pooled within breeds with WBS and SPT as dependent variables. When MFI were included in the analysis, MFI at d 7 explained 50% of the variation in WBS and SPT at d 14. An additional 19% of SPT was accounted for by the addition of CDP inhibitor d 1 activity and percentage-area of alpha R fibers to the model. However, because variation in MFI was not significant within breed subclasses and MFI could be classified more as a dependent variable, it was removed from the model. This resulted in CDP inhibitor d 1 activity explaining 44% of the variation in WBS and SPT at d 14. Also, percentage-area of beta R fibers, 6 h pH and cathepsin B + L d 14 activity appeared in the model. In addition, CDP inhibitor activity was the only variable to be significant within breed groups. These data suggest that d 7 MFI could be used as a single predictor of d 14 longissimus muscle tenderness; however, CDP inhibitor d 1 activity (a biological event) also may be useful in predicting tenderness.  相似文献   
9.
Carcass measurements from 1,664 steers from the Germ Plasm Utilization project at U.S. Meat Animal Research Center were used to estimate heritabilities (h(2)) of, and genetic correlations (r(g)) among, 14 carcass traits adjusted to different endpoints (age, carcass weight, and fat thickness): HCW (kg), dressing percent (DP), adjusted fat thickness (AFT, cm), LM area (LMA, cm(2)), KPH (%), marbling score (MS), yield grade (YG), predicted percentage of retail product (PRP), retail product weight (RPW, kg), fat weight (FW, kg), bone weight (BNW, kg), actual percentage retail product (RPP), fat percent (FP), and bone percent. Fixed effects in the model included breed group, feed energy level, dam age, birth year, significant (P < 0.05) interactions, covariate for days on feed, and the appropriate covariate for endpoint nested (except age) within breed group. Random effects in the model were additive genetic effect of animal and total maternal effect of dam. Parameters were estimated by REML. For some traits, estimates of h(2) and phenotypic variance changed with different endpoints. Estimates of h(2) for HCW, DP, RPW, and BNW at constant age, weight, or fat thickness were 0.27, -, and 0.41; 0.19, 0.26, and 0.18; 0.42, 0.32, and 0.50; and 0.43, 0.32, and 0.48, respectively. Magnitude and/or sign of r(g) also changed across endpoints for 54 of the 91 trait pairs. Estimates for HCW-LMA, AFT-RPW, LMA-YG, LMA-PRP, LMA-FW, LMA-RPP, and LMA-FP at constant age, weight, or fat thickness were 0.32, -, and 0.51; -0.26, -0.77, and -; -0.71, -0.89, and -0.66; 0.68, 0.85, and 0.63; -0.16, -0.51, and 0.22; 0.47, 0.57, and 0.27; and -0.44, -0.43, and -0.18, respectively. Fat thickness was highly correlated with YG (0.86 and 0.85 for common age and weight) and PRP (-0.85 and -0.82 for common age and weight), indicating that selection for decreased fat thickness would improve YG and PRP. Carcass quality, however, would be affected negatively because of moderate r(g) (0.34 and 0.35 for common age and weight) between MS and AFT. Estimates of h(2) and phenotypic variance indicate that enough genetic variation exists to change measures of carcass merit by direct selection. For some carcass traits, however, magnitude of change would depend on effect of endpoint on h(2) and phenotypic variance. Correlated responses to selection would differ depending on endpoint.  相似文献   
10.
Little information is available in the literature on the interrelationships and interactions among pH, aging time, marbling, and maturity on the flavor profile of some beef muscles commonly used for steaks. To investigate these effects on beef flavor, the infraspinatus (top-blade steak) from the chuck clod, the gluteus medius (top-sirloin steak) from the sirloin, and the psoas major (tenderloin steak) from the loin were obtained from A- (n = 80) and B-maturity (n = 60) carcasses with either Slight (n = 68) or Small (n = 72) marbling, and with either normal (< or = 5.7; n = 80) or high (> or = 6.0; n = 60) pH. Muscles were selected from two commercial processing plants at six different sampling times to evaluate factors that affect the flavor profile of cooked beef steaks. Muscles were vacuum-aged for 7, 14, 21, or 35 d, and a highly trained, flavor-profile sensory panel evaluated charbroiled steaks from these muscles. Numerous statistical interactions (P < 0.05) were detected for flavor attributes of the different muscles. In general, muscles from high pH (dark cutting) carcasses had less typical beef flavor identity and less brown-roasted flavor than those from carcasses with normal pH. Aging longer than 21 d generally decreased beef flavor identity. Top-blade steaks generally had less intense beef flavor identity and more intense bloody/serumy flavor than did top-sirloin and tenderloin steaks. Tenderloin and top-sirloin steaks of normal pH generally had the most brown-roasted flavor, especially when aged 21 d or less. Small degree of marbling generally resulted in a more rancid flavor compared with Slight marbling, but marbling had no other appreciable effects on the flavor profile. Aging steaks for 35 d increased (P < 0.05) the metallic flavor compared with aging for only 7 or 14 d. Top-sirloin steaks had a more intense (P < 0.05) sour flavor than did top-blade steaks, and steaks from carcasses with a high pH were more rancid (P < 0.05) than steaks from carcasses with normal pH. Vacuum-aging top-blade, top-sirloin, and tenderloin steaks to 21 or 35 d postmortem generally increased metallic and rancid flavors and increased sour flavor in top-sirloin steaks that were high in pH.  相似文献   
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