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Action thresholds as decision tools for insecticide application were developed and tested against the major insect pests of rice at four sites in the Philippines over a 13-year period. Action threshold treatments were compared to the farmers' practice, prophylactic insecticide usage, and an untreated check. Yield loss data using the insecticide check method partitioned yield losses over three crop growth stages in the same test fields. Chronic pests that exceeded action thresholds in 79% of fields were whorl maggot Hydrellia philippina Ferino (Diptera: Ephydridae), defoliators Naranga aenescens Moore and Rivula atimeta (Swinhoe) (Lepidoptera: Noctuidae), leaffolders Cnaphalocrocis medinalis (Guenée) and Marasmia patnalis Bradley (Lepidoptera: Pyralidae), and stemborers Scirpophaga incertulas (Walker) and S. innotata (Walker) (Lepidoptera: Pyralidae). Minor chronic pests reached threshold levels in only one site each: rice bug Leptocorisa oratorius (F.) (Koronadal), whitebacked planthopper Sogatella furcifera (Horvath) (Zaragoza) and green leafhopper Nephotettix virescens (Distant) (Guimba); brown planthopper Nilaparvata lugens (Stål) did not exceed a threshold in any field. Stemborers were the most important pest group in terms of yield loss. Despite the insecticide check method underestimating losses, a mean crop loss of 0.62 t/ha was measured which showed ample scope for corrective action. But loss was evenly distributed across crop growth stages (0.15?–?0.24 t/ha) reducing the impact of insecticides. Action threshold treatments overall outyielded the untreated check, more so in the two sites with highest pest density. The benefit of thresholds was to reduce insecticide usage, as a cost saving. However all the practices showed poor economic returns including the farmers' practice. Farmers' practice employed low insecticide dosages and timing was not consistent with pest damage, but yields were often similar to threshold treatments. Farmers appear to use insecticide more for risk aversion than for profit. The best threshold characters when evaluated against resulting pest density and yield loss criteria showed accuracies >?90% correct decisions. Future work is needed to improve the insecticide response rather than monitoring tools. Thresholds need to be incorporated into improved crop management, which was often found suboptimal by farmers, to take advantage of the high levels of tolerance in modern high tillering cultivars. Crop husbandry practices which improve yield potential such as selection of longer maturing varieties and nitrogen fertilizer may be a more effective pest management strategy than insecticides. 相似文献
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Objective To determine the effects of the amount of beak removed and cauterisation time on neuroma formation in hens.
Design A pathology study with controls.
Animals Twenty domestic fowl were beak-trimmed. Three non-beak-trimmed domestic fowl were used as controls.
Procedure Beaks of two age groups with two levels of beak removal and either 2 s or 4 s cauterisation, were investigated macroscopically and microscopically for deformities.
Results Scattered trauma-associated neuromas were present in the beaks of pullets 10 weeks after moderate trimming at hatch. Neuromas were not present in beaks of adult hens that had been similarly trimmed. Sensory corpuscles were present 10 and 70 weeks after moderate trimming, though fewer in number than in intact control hens. In contrast, trauma-associated neuromas persisted in beaks of 70-week-old hens that had been severely trimmed at hatch. A range of deformities that were absent in moderately trimmed hens, were observed in hens with severely trimmed beaks. Receptors were not seen in severely trimmed beaks.
Conclusion Beak-trimming at hatch induces the formation of neuromas, regardless of the amount of tissue removed. There is a critical amount of beak tissue that can be removed, beyond which trauma-associated neuromas will not resolve, but will persist in mature hens. 相似文献
Design A pathology study with controls.
Animals Twenty domestic fowl were beak-trimmed. Three non-beak-trimmed domestic fowl were used as controls.
Procedure Beaks of two age groups with two levels of beak removal and either 2 s or 4 s cauterisation, were investigated macroscopically and microscopically for deformities.
Results Scattered trauma-associated neuromas were present in the beaks of pullets 10 weeks after moderate trimming at hatch. Neuromas were not present in beaks of adult hens that had been similarly trimmed. Sensory corpuscles were present 10 and 70 weeks after moderate trimming, though fewer in number than in intact control hens. In contrast, trauma-associated neuromas persisted in beaks of 70-week-old hens that had been severely trimmed at hatch. A range of deformities that were absent in moderately trimmed hens, were observed in hens with severely trimmed beaks. Receptors were not seen in severely trimmed beaks.
Conclusion Beak-trimming at hatch induces the formation of neuromas, regardless of the amount of tissue removed. There is a critical amount of beak tissue that can be removed, beyond which trauma-associated neuromas will not resolve, but will persist in mature hens. 相似文献
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PC Rodriguez LB Valdez T Zaobornyj A Boveris MT Beconi 《Reproduction in domestic animals》2011,46(1):74-81
The aim of this work was to quantify NO, O2? and ONOO? production during heparin‐induced capacitation of cryopreserved bovine spermatozoa. A time dependent hyperbolic increase was observed for heparin‐dependent capacitation, O2 uptake, and NO production. Conversely, O2? production was increased during the first 15 min of incubation, showing a decrease from this time until 45 min. At 15 min of heparin incubation, a threefold increase in O2 consumption (5.9 ± 0.6 nmol/min × 107 cells), an enhancement in NO release (1.1 ± 0.2 nmol/min × 107 cells), and a five‐fold increase in O2? production (1.3 ± 0.07 nmol/min × 107 cells), were observed. Peroxynitrite production rate was estimated taking into account NO and O2? generation and the second‐order rate constant of the reaction between these species. To conclude, heparin‐induced capacitation of cryopreserved bovine spermatozoa activates (i) mitochondrial O2 uptake by high ADP levels due to increased energy requirements, (ii) NO production by a constitutive NOS and (iii) O2? production by a membrane‐bound NAD(P)H oxidase. The products of both enzymes are released to the extracellular space and could be involved in the process of sperm capacitation. 相似文献
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近几十年来,肉鸡的生产性能得到了大幅度的改善。因此,营养模式也发生了变化。基于肉鸡的遗传进展,正确的维生素添加水平是需要的。最佳维生素营养（Optimum Vitamin Nutrition,OVN）理念对于在肉鸡日粮中补充正确数量的维生素是一个非常有用的工具。 相似文献
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Keysuke Muramatsu Alex Maiorka Isabel Cristina Mores Vaccari Renata Nuernberg Reis Fabiano Dahlke Adelar Almeida Pinto Uislei Antonio Dias Orlando Marcelo Bueno Momca Imagawa 《农业科学与技术》2013,(12):1017-1028
The present study evaluated the effect of feed particle size, thermal processing, several levels of fat inclusion and moisture addition on pellet quality and protein solubility in potassium hydroxide （KOH） in a corn, soybean meal and animal by products based broiler diets. The different processing factors were combined in a 2 x 4 x 4 x 2 factorial arrangement in an eight randomized block consisting of eight production series： two particle sizes （coarse： 1,041 microns and medium： 743 microns）, four fat inclusion levels at the mixer （15, 25, 35 and 45 g/kg of feed）, four moisture addition levels in the conditioner （0, 7, 14 and 21 g/kg of feed） and two thermal processing treatments （conditioner-pellet press treatment or conditioner-expander-pellet treatment） which resulted in 64 different processed feeds. For the determination of the pellet durability index （PDI）, the amount of intact pellets and protein solubility determinations, eight feed samples （replicates） were collected for each treatment. The data were transformed using a variation of Box-Cox transformation in order to fit a normal distribution （p 〉 0.05）. Adding moisture up to 21 g/kg of feed in the conditioner improved pellet quality of the diets （p 〈 0.05）. Expansion of diets before pelleting improved （P 〈 0.05） PDI and amount of intact pellets by 26% and 31%, respectively, as compared to a simple conditioning-pelleting feed processing. Expander treatment （at 110 ℃） decreased （p 〈 0.05） protein solubility in KOH from 686 g/kg to 643 g/kg total protein as compared to pelleting process （at 80-82 ℃）. The amount of intact pellets reduced from 773 g/kg to 746 g/kg of feed （/7 〈 0.05） as particle size increased from medium to coarse grinding. Pellet quality was significantly reduced with fat inclusion levels higher than 35 g/kg of diet. 相似文献
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Félix AP Gabeloni LR Brito CB Oliveira SG Silva AV Maiorka A 《Journal of animal science》2012,90(9):3060-3067
This experiment aimed at evaluating the effects of including the enzyme, β-mannanase, in dog (Canis lupus familiaris) diets based on either poultry (Gallus gallus domesticus) by-product meal (PBM) or soybean [Glycine max (L.) Merr.] Meal (SBM). The second objective was to evaluate 3 methods for determining energy and nutrient digestibility values in diets fed to dogs: total fecal collection (TFC) and use of aia or crude fiber (CF) as a marker. Eight dogs were allotted to a replicated latin square (4 by 4) design. There were 2 diets based on PBM as the major protein source and 2 diets based on SBM as the major protein source. Within each protein source, 1 diet contained no β-mannanase and 1 diet contained 0.01% β-mannanase. Diets were fed for an adaptation period of 5 d followed by 5 d of TFC. Fecal score (1 = watery feces to 5 = dry, hard pellets), pH, DM, and fecal volume were determined. The apparent total tract digestibility (ATTD) of DM, OM, CP, ether extract (EE), N-free extract (NFE), and GE, and ME content were calculated using the methods of TFC, AIA, and CF. Data were analyzed as a 2 by 2 by 3 split-split-plot design (β-mannanase, protein source, and digestibility calculation procedure). There were interactions between protein source and β-mannanase (P < 0.05). Supplementation of β-mannanase increased ATTD of nutrients and energy and ME (+ 195.3 kcal/kg) and also reduced fecal production in the diet with SBM, but not in the diet that contained PBM. There was an interaction between digestibility calculation procedure and protein source (P < 0.05). The use of AIA overestimated ATTD of the diets containing PBM, but digestibility values estimated based on TFC and CF were not different. Dogs fed diets containing SBM produced more feces with greater moisture content and lower pH compared with dogs fed the PBM diet (P < 0.05). Addition of 0.01% β-mannanase increased (P < 0.05) the digestibility and ME content of the diets containing SBM, but did not improve (P > 0.05) fecal texture. Results indicated that values for ATTD of energy and nutrients in diets containing sbm are not different if they are calculated based on TFC, AIA, or CF, but use of AIA may result in an overestimation of values for ATTD of energy and nutrients in diets containing PBM. 相似文献
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The availability of cow ovaries from the slaughterhouse has been very limited in Taiwan. To maximize the use of cow ovaries for research purposes, whole ovary dissection was performed and the developmental competence of the oocytes derived from different sizes of follicles was assessed by the rates of in vitro maturation (IVM) and parthenogenetic activation of the oocytes in Experiment 1 (Exp 1). Cumulus-oocyte complexes (COCs) derived from small (1-2 mm) and large (3-8 mm) follicles were subjected to standard IVM culture for 24 h. Mature oocytes were selected and then parthenogenetically activated using A23187 (5 microm, 5 min) or thimerosal (200 microm, 10 min) alone or combined with 6-dimethylaminopurine (2.5 mm and 3.5 h, respectively). Activation rates of the oocytes, neither from the large nor small follicles, were affected by different activation treatments (single or combined stimuli). Whereas maturation rates for the oocytes from large follicles were superior to those from small follicles in both the single (59% vs 45%) and combined treatments (76% vs 40%; p < 0.05). To understand how prolonged heat shock (HS) influences cytoskeletal configurations of mature bovine oocytes, in Experiment 2 (Exp 2), matured oocytes derived from large follicles were randomly allocated to different durations of HS treatments at 41.5 degrees C for 0 (C0h, control, n = 12), 1 (HS1h, n = 28), 2 (HS2h, n = 31), and 4 h (HS4h, n = 30). An additional control group was cultured for 4 h without HS (38.5 degrees C, 4 h, n = 35). Alterations in nuclear structures, microtubules (MTs), and microfilaments (MFs) of the oocytes were examined. Abnormalities in the chromosomes, spindle MTs and the percentages of oocytes with cytoplasmic MTs increased with time of HS treatment. The intensity of the MF distribution in the HS oocytes was also altered. Significant changes in the cytoskeleton after HS may be associated with the reduced development under hyperthermia and, perhaps, with the low pregnancy rates of the animals during hot seasons. 相似文献