The effect of levels of concentrate in feedlot diets on the health status of beef calves          下载免费PDF全文

Mwansa PB  Makarechian M  Berg RT 《The Canadian veterinary journal. La revue veterinaire canadienne》1992,33(10):665-668

In this two year study we investigated the effect that the level of concentrate in feedlot diet had on the occurrence of health problems in bull calves belonging to two multibreed groups.

In each of the two years, the 168 day feedlot period was divided into two equal periods of 77 days with an intervening 14 day adjustment period. During the first period, the animals in half of the pens within each breed-group received a high concentrate (85% grain) diet (H) while the rest of the pens received a diet (L) of hay ad libitum and half as much concentrate as the bulls on high concentrate. The L diet contained an average of 48% grain. In the second period, diets of bulls in half of the pens within each breed-group were switched from L to H and vice versa. During the feedlot period, the incidence of sickness among bulls was recorded. Disease incidence was higher in the second year compared to the first. In the second year, 49 out of 56 (87.5%) calves on the high concentrate diet required treatment for respiratory infections compared to only four (7.14%) in bulls on the low concentrate diet. The results suggest that a high concentrate diet for animals in feedlots may be more stressful to calves coming directly to the feedlot following weaning compared to a low concentrate diet, thereby acting as an additional predisposing factor to respiratory infections.

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Protein chemistry     

Borchardt RT 《Science (New York, N.Y.)》1980,209(4454):385-386

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The clinical utility of the right lateral intercostal ultrasound scan technique in dogs     

Brinkman EL  Biller DS  Armbrust LJ  O'Brien RT 《Journal of the American Animal Hospital Association》2007,43(4):179-186

When performing abdominal ultrasonography in dogs, the right aspect of the liver, porta hepatis, right kidney, right adrenal gland, pancreas, and duodenum are often not fully visible from a ventral, or subcostal, approach. The right lateral intercostal plane is an alternative approach that allows evaluation of these structures. This report provides multiple case examples that demonstrate the sonographic anatomy via the right intercostal approach. Other cases are included to demonstrate indications for this approach. Animals in which the right intercostal approach may prove most useful include large- and giant-breed dogs; deep-chested dogs; dogs with gas distention of the stomach, duodenum, and colon; dogs with microhepatia; and those with abdominal effusion and pain.  相似文献   

Validation,use, and disadvantages of enzyme-linked immunosorbent assay kits for detection of cortisol in channel catfish,largemouth bass,red pacu,and golden shiners     

Sink TD  Lochmann RT  Fecteau KA 《Fish physiology and biochemistry》2008,34(1):95-101

Measurement of cortisol response is an important tool to asses stress in fisheries research. Radioimmunoassay (RIA) is a common method for the measure of cortisol in fish. Use of enzyme-linked immunosorbent assays (ELISA) to detect cortisol would eliminate health hazards, costs of handling radioisotopes, and the short stability time associated with RIA. Enzyme-linked immunosorbent assays have been used for the determination of cortisol in several fish species. However, the ELISA method of cortisol determination in fish lacks proper validation testing. We conducted validation procedures for multiple commercial cortisol ELISA kits and compared the results to RIA. The assays were tested for four species: (1) channel catfish Ictalurus punctatus, (2) largemouth bass Micropterus salmoides, (3) red pacu Piaractus brachypomus, and (4) golden shiners Notemigonus crysoleucas. We evaluated the ELISA methods against RIA, and determined that at least one kit is suitable (accuracy: mean recovery of spiked samples, 102.8%; reproducibility: interassay coefficient of variation < 10.5% for all species; precision: intra-assay coefficient of variation < 16.8% for all species; linearity: R ² > 0.96 for all species) for the measurement of cortisol response in fish and comparative determination of stress. All of the ELISA assay results varied by more than 10% from the cortisol concentrations detected by the RIA. The high variability of the kit results indicates that commercial ELISA kits could be utilized for qualitative determination of cortisol in fish, but should be fully validated in each laboratory for each species before being used for research.  相似文献   

Diversity of Flavobacterium psychrophilum and the potential use of its phages for protection against bacterial cold water disease in salmonids     

Castillo D  Higuera G  Villa M  Middelboe M  Dalsgaard I  Madsen L  Espejo RT 《Journal of fish diseases》2012,35(3):193-201

Flavobacterium psychrophilum causes rainbow trout fry syndrome (RTFS) and cold water disease (CWD) in salmonid aquaculture. We report characterization of F. psychrophilum strains and their bacteriophages isolated in Chilean salmonid aquaculture. Results suggest that under laboratory conditions phages can decrease mortality of salmonids from infection by their F. psychrophilum host strain. Twelve F. psychrophilum isolates were characterized, with DNA restriction patterns showing low diversity between strains despite their being obtained from different salmonid production sites and from different tissues. We isolated 15 bacteriophages able to infect some of the F. psychrophilum isolates and characterized six of them in detail. DNA genome sizes were close to 50 Kbp and corresponded to the Siphoviridae and Podoviridae families. One isolate, 6H, probably contains lipids as an essential virion component, based on its chloroform sensitivity and low buoyant density in CsCl. Each phage isolate rarely infected F. psychrophilum strains other than the strain used for its enrichment and isolation. Some bacteriophages could decrease mortality from intraperitoneal injection of its host strain when added together with the bacteria in a ratio of 10 plaque-forming units per colony-forming unit. While we recognize the artificial laboratory conditions used for these protection assays, this work is the first to demonstrate that phages might be able protect salmonids from RTFS or CWD.  相似文献   

Effect of harvesting and drying conditions on chlorophyll levels of soybean (Glycine max L. Merr)     

Gomes MS  Sinnecker P  Tanaka RT  Lanfer-Marquez UM 《Journal of agricultural and food chemistry》2003,51(6):1634-1639

Chlorophyll in soybean represents a downgrading factor for the crops. Five Brazilian cultivars were harvested between R(6) and R(8) stage of development (Fehr & Caviness scale) and dried at 25 degrees and 40 degrees C. The effect of maturity stages and two drying conditions after harvest were studied to achieve reduction of moisture and chlorophylls to acceptable levels. When seeds were dried at 25 degrees C, even harvesting at early stages of development such as R(6), the green pigments were almost degraded, and 16 ppm of chlorophyll were found at maximum, accompanied by loss of moisture. Moisture and chlorophyll declines as seed matures, but at intermediary stages (R(6)-R(7)), chlorophyll degrades first, so the rate of moisture loss should not be used to predict chlorophyll contents. At 40 degrees C, complete degradation of chlorophyll pigments is only achieved when seeds are swathed from R(7) stage up, otherwise the seed quality could be compromised. Slow drying allows almost complete removal of green pigments, even when seeds are swathed a few days before the physiological maturity stage.  相似文献   

Crop productivity and photoassimilate partitioning     

Gifford RM  Thorne JH  Hitz WD  Giaquinta RT 《Science (New York, N.Y.)》1984,225(4664):801-808

The photosynthetic basis for increasing the yield of major field crops is examined in terms of improving the interception of seasonal solar radiation by crop foliage, the efficiency of conversion of intercepted light to photosynthetic assimilates, and the partitioning of photoassimilates to organs of economic interest. It is concluded that, in practice, genetic and chemical manipulation of light interception over the season and of partitioning offer the most potential for achieving further increases in yield. During the history of improvement of genetic yield potential of crops, increase in the partitioning of photoassimilates to harvested organs has been of primary importance.  相似文献   

HPLC法同时测定葛根中葛根素·大豆苷及大豆苷元含量     

魏锐  王建南  谢朝阳  何侃  郑群怡 《安徽农业科学》2013,41(9):4047-4047,4064

[目的]建立HPLC同时测定葛根中葛根素、大豆苷、大豆苷元含量的检测方法。[方法]HPLC色谱条件为:C18柱,流动相为甲醇-1%醋酸水溶液梯度洗脱,检测波长250 nm,流速1.0 ml/min,柱温30℃,进样量10μl。[结果]在测定范围内,葛根中葛根素、大豆苷、大豆苷元混合对照品的线性关系良好。[结论]该方法可为葛根的质量控制及综合开发提供参考。  相似文献   

Effect of energy and lysine intake in gestation on sow performance   总被引：2，自引：0，他引：2  

Cooper DR  Patience JF  Zijlstra RT  Rademacher M 《Journal of animal science》2001,79(9):2367-2377

Nutrient intake during gestation has an impact on gestation parameters and subsequent lactation performance. The objectives of this experiment were to determine the impact of feeding two levels of amino acids in gestation on sow BW changes in gestation and lactation, and litter size, and to evaluate a factorial method for determining daily energy requirements. At mating, 419 sows (Camborough 15; Pig Improvement Canada, Acme, AB) were assigned randomly within Parities 1, 2 or 3+ to a gestation diet containing either 0.44% (low lysine) or 0.55% (high lysine) total lysine and 3,100 kcal DE/kg; other indispensable amino acids were adjusted to lysine based on ideal protein ratios. Feed allowance in gestation was determined factorially using estimated DE requirements for maintenance, maternal gain, and conceptus growth. Sows were allowed free access to the lactation diet. Gestation BW gain from d 0 to 110 was affected by parity (61.2, 60.0, and 42.3 kg for Parity 1, 2, and 3+, respectively; P < 0.05) but not (P > 0.10) by gestation lysine level. Sow BW changes from d 0 of lactation to weaning were affected by parity (0.5, 6.8, and 5.8 kg for Parity 1, 2, and 3+, respectively; P < 0.01) and gestation BW gain (P < 0.01), but not by gestation lysine level (5.0 vs 3.8 kg for low and high lysine, respectively; P > 0.10). Total piglets born was affected by parity (11.5, 12.1, and 12.5, for Parity 1, 2, and 3+, respectively; P < 0.01) and increased with increasing sow BW gain (P < 0.05). Total piglets born alive (mean = 11.2) was increased with increasing sow BW gain (P < 0.05). Total litter weight born alive was affected by parity (15.9, 18.6, and 19.4 kg for Parities 1, 2, and 3+, respectively; P < 0.01) and gestation BW gain (P < 0.05). The model used to determine daily energy intake requirements resulted in an average BW gain of 10.6 kg above the targets set by the model. Total lysine intakes greater than 10.6 g/d in gestation did not improve sow productivity. Setting target weight gains in gestation and feeding to meet these targets may not always provide predictable results due to a number of factors that affect the energy requirement in the sow.  相似文献   

The impact of traditional management on seasonal internal parasite burdens and productivity of indigenous Tswana goats in southern Botswana     

Nsoso SJ  Machete JB  Molatole M  Ndebele RT  Lebani NN  Chabo RG  Kalake AM  Jacyna L  Segadimo BW  Mine OM 《The Onderstepoort journal of veterinary research》2001,68(2):101-104

Data collected monthly over a period of two years were live weight, packed cell volume (PCV), nematode faecal egg counts (FECs) and coccidial oocyst counts from faecal analyses for 100 mixed age (3-7 years) indigenous Tswana does. The aims of this experiment were to determine seasonal FECs and coccidial oocysts in these goats and quantify the relationships of these burdens to liveweight and PCV. FECs significantly (P < 0.05) varied with season, with the warmer seasons viz spring, summer and autumn having higher log (x + 1) parasite burdens than the cooler winter, while seasonal trends for coccidial oocysts were not obvious. PCV was also significantly (P < 0.05) lower in the warmer seasons than winter. FECs and coccidial oocysts in all seasons were less than the mean log (x + 1) of 3.3 inferred to reduce production in small stock. Correlation coefficients were strongly negative: -0.95 for FECs and liveweight and -0.84 for FECS and PCV, indicating that these worms had a negative impact on productivity. A further study should be conducted to quantify the effects of controlling these parasites during the warm seasons on productivity.  相似文献