High Incidence Of Damage Research Articles

Effect of light and stocking density on performance, breast muscle yield and potential damage caused by feather pecking in two strains of commercial Pekin ducks

Context Minimal information is available as to the optimal stocking density and light intensity for best performance of commercial ducks. Aims To investigate the effects of stocking density and light intensity on commercial Pekin duck production. Methods Cherry Valley and Grimaud Freres Pekin ducks were housed at stocking densities of 4.4 (low), 5.2 (medium) and 6 (high) birds/m2 and from 8 to 41 days of age at 6 lux (low) and 45 lux (moderate) light intensities. On Days 14, 28, and 41 of age all ducks were individually weighed, and pen feed and water intakes recorded. On Day 41, one male and female from each pen was euthanised and breast muscle weight determined. At Weeks 3 and 4 all birds were individually examined, for extent of feather and skin damage. Key results In all weeks, the Grimaud Freres birds had higher liveweight than Cherry Valley birds. Only at Week 4, birds under low light had higher liveweight than those at moderate light intensity. At Week 4, birds at low densities had higher liveweight, while at Week 6 birds at low and medium stocking densities had higher liveweight than those at high stocking densities. At Week 4, the feed to gain ratio was poorer when birds were housed in moderate light intensity. The stocking density had no effect on the feed to gain ratio. Light and stocking density had no effect on any of the breast muscle measures. In Week 4, the birds housed at medium density had a higher feather and skin damage. At Week 3, more damage was directed to the wings than the thigh regions. There was a higher incidence of damage in some pens irrespective of treatments. Conclusions The medium stocking density supported performance equivalent to that at low density and better than at the high density. Ideally the density recommendation should be based on ‘weight density’ (kg/m2) and the current results indicate this was between 16.49 and 19.0 kg/m2. The birds performed similarly under both light intensities. Implications The suitable stocking density for efficient production is 16.5–19.0 kg/m2 and housing at 6 or 45 lux had no influence on performance. Best performance and breast muscle yield was from the Grimaud Freres strain.

Viability assessment using fluorescent markers and ultrastructure of human biopsied embryos vitrified in open and closed systems

Research questionAre there any differences in viability and ultrastructure amongst embryos biopsied on Day 5 versus Day 3 following vitrification in open and closed systems and compared to fresh embryos? DesignOne hundred human embryos (40 blastocysts biopsied on Day 5 and subsequently vitrified in open or closed systems and 60 Day 3 biopsied embryos that developed to blastocysts but were rejected for transfer following preimplantation genetic testing for monogenic/single gene defects and for aneuploidies were either treated fresh [n = 20] or vitrified [n = 40] in open or closed systems) and following warming and culture for 4 h were subjected to viability staining with carboxyfluorescein-diacetate succinimidylester/propidium iodide or processed for transmission electron microscopy. ResultsNo statistically significant differences were observed in the viability of human biopsied embryos following vitrification in open and closed systems. Compared to fresh embryos, vitrified ones had a higher incidence of damage (propidium iodide-stained cells) irrespective of the vitrification method (P = 0.005). These damaged cells were more prominent in Day 5 biopsied blastocysts and mainly located at the position of cutting. Characteristic lipofuscin droplets (representative of apoptosis) and a higher number of vacuoles and distension of mitochondria were also more evident in vitrified embryos, although this was not statistically assessed. ConclusionsVitrification in open and closed systems does not adversely affect the viability and ultrastructure of Day 5 and Day 3 biopsied embryos as revealed by the minimal yet statistically significant cell damage observed. This damage may be compensated by the embryos, which in their attempt to fully recover following vitrification, potentially enable ‘rescue’ processes to eliminate it.

Identification of Soybean Host Plant Resistance to Brown Marmorated Stink Bugs in Maturity Group III Plant Introductions.

Halyomorpha halys (Stål; Hemiptera: Pentatomidae), brown marmorated stink bug (BMSB), is a polyphagous nonnative insect first found in the United States in 1996. As of 2017, BMSB has been detected in 43 states and is a severe agricultural pest in mid-Atlantic states. On soybean, Glycine max (L.) Merr (Fabales: Fabaceae), damage from BMSB infestation ranges from puncture marks with seed discoloration and deformities to seed and pod abortion. Host plant resistance has been used for managing pest populations and mitigating soybean yield losses caused by neotropical stink bugs (Eushistus heros, Nezara viridula, and Piezodorus guildinii) in Brazil and on the U.S. Gulf Coast. We evaluated maturity group III plant introductions (PIs) for resistance to BMSB damage. In 2014, field cage choice tests of 106 PIs revealed a range of both BMSB damage incidence and severity. In field choice tests, PIs 085665 and 097139 showed the lowest incidence of BMSB damage and seed weight loss due to BMSB, while PIs 243532, 243540, and 567252 had the highest. In whole plant no-choice tests, PIs 085665 and 097139 also had high levels of resistance. However, PI 085665 had a higher incidence of damage but lower seed weight loss than PI 097139, which may suggest bimodal resistance. Moreover, PIs 085665 and 097139 are from Japan and North Korea, respectively, two geographically isolated countries where BMSB is native. Thus, further characterization of host plant resistance to BMSB in each of these lines may elucidate distinct mechanisms that could be synergistic if stacked in breeding lines.

Impatto degli ungulati selvatici sui boschi cedui della Val di Bisenzio (Prato)

Similar to other Apennine areas, a considerable increase of wild ungulate density has been observed in the past decades in the Bisenzio valley (province of Prato), leading to a strong impact on coppice regeneration. In some felling areas, the prolonged browsing on young suckers turned the stumps into low and dense bushes, thus threatening the survival of the forest stand and triggering a loss of environmental stability. The aim of this work was to study the impact of deer on sprout regeneration after cutting in mixed coppices felled in the period 2007-2010 and characterized by the dominance of chestnut, hornbeam, Turkey oak, and beech. Some 36 plots were established in four municipal districts of the Prato province (Cantagallo, Vernio, Montemurlo, Vaiano). Damage and browsing intensity on each stump were evaluated using an index that allowed the comparison among different areas and fores stand types. Regardless of the species, over 90% of the sprouts revealed a very strong damage, whereas only 6% did not exhibit any damage. A significant difference in the sprout height was detected between browsed and non-browsed areas. Despite a high incidence of damage in all the studied areas, chestnut showed a greater resilience against browsing. In summary, overgrazing by wild game may determine severe contraints to the evolutionary dynamics of forest stands, frustrating the effects of silvicultural practices. The possible benefits of the implementation of a large-scale integrated wildlife plan, including hunting and forest-evironmental management are discussed.

Non-Predatory Shell Damage in Neogene Western Atlantic Deep-Burrowing Bivalves

AbstractFew shell-crushing predators can excavate prey living deep within the sediment. Despite this infaunal refuge from predators, many deep-burrowing bivalves display a strikingly high incidence of shell damage when compared with species living at shallower depths. A non-predatory origin is necessary to explain this high incidence of injury. To evaluate the generality of this hypothesis, repair frequency (number of repairs per shell), along with position and geometry, were determined for 68 Neogene bivalve species from the US Atlantic and Gulf Coastal Plain, seven of which are classified as deep burrowers (>20 cm depth of sediment penetration). Panopea bitruncata, Panopea floridana, Panopea reflexa, and Panopea americana, which are among the deepest burrowers (up to 100 cm), have repair frequencies (2.8– 6.2) that are higher than any other species, while the value for Cyrtopleura costata (0.76) is exceeded only by semi-infaunal Atrina species (1.12). However, not all deep-burrowing species had such high incidences of damage. Two moderately deep-burrowing species (Anodontia alba and Tagelus plebeius; 20–50 cm) showed repair frequencies (0.04–0.30) that overlapped the range (0.001–0.52) for shallow-burrowing, semi-infaunal, and epifaunal species. Therefore, any generalizations about the relationship between depth of sediment penetrated and frequency of shell damage are inadvisable. Most scars on deep burrowers were not attributable to the direct activity of shell-crushing predators because: (1) injury occurred late in life when individuals were positioned in the safety of a deep burrow; (2) scar types consistent with a predatory origin were rare; and (3) scars frequently occurred on the anterior of the shell, which is least accessible to digging predators.

Testing the resource concentration hypothesis with tarnished plant bug on strawberry: density of hosts and patch size influence the interaction between abundance of nymphs and incidence of damage

Abstract. 1. Attributes of patches with strawberry plants were manipulated experimentally to assess the impact of patch size and host density on the abundance of tarnished plant bug (Hemiptera: Miridae) and incidence of fruit damage.2. The density of nymphs per inflorescence increased with patch size and host density for some but not all generations of plant bug, providing partial support for the resource concentration hypothesis, while emphasising the importance of replicating experiments across several generations of herbivore.3. Increasing density of nymphs with increasing patch size and host density did not translate into a high incidence of damage, which may be due to the relatively low feeding impact of nymphs in patches with numerous fruits and to the relatively high perimeter‐to‐area ratio in small patches resulting in a relatively high proportion of damaged fruits.4. The decreasing proportion of damaged fruits with increasing density of fruits per patch suggests that nymphs exhibit a saturating functional response to density of strawberry fruits. Functional responses of herbivores may be a critical yet overlooked component that influences interactions between insects and their host plant. In particular, concentrated plant resources may result in increased numbers of herbivores yet sill have a negligible influence on plant damage and/or fitness.

Variation in abundance and feeding impact of tarnished plant bug (Hemiptera: Miridae) for different cultivars of strawberry: role of flowering phenology and yield attributes.

The current study evaluated whether flowering phenology and yield attributes of different strawberry cultivars affect the abundance and feeding impact of tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), as well as behavioral decisions made by feeding nymphs and ovipositing adults. The distribution of emerged nymphs in cage experiments involving nine different cultivars of June-bearing strawberry cultivars suggests that females lay more eggs on plants with numerous flower receptacles, while cultivar per se did not influence their oviposition behavior. A large number of nymphs emerged from receptacles of strawberry plants, while the distribution of emerged nymphs among receptacles, petioles, leaves, and stems varied for different cultivars. These results suggest that the relative intensity of damage caused by ovipositing females may vary for different cultivars. Foraging nymphs did not exhibit a preference for any strawberry cultivar per se, although the abundance of nymphs increased with the weight of receptacles, especially for late instars. Evaluating the density and feeding impact of L. lineolaris for different cultivars under field conditions revealed that some host plant attributes affect the abundance of plant bugs, such as early flowering season and high productivity. Decreasing number of emerged nymphs per flower per plant with increasing density of receptacles per plant suggests that females lay relatively more eggs per receptacle on plants with few receptacles; this pattern of oviposition may explain, in part, why patches with low density of plants typically have high incidence of damage. Planting a high yielding early season cultivar such as 'Cavendish' may contribute to reduce the incidence of damage by L. lineolaris.

Effectiveness of Teflon and Sevin Sprays in Controlling Caterpillar Damage to Microsprinkler Supply Tubing

Larvae of Selenisa sueroides (Guenee) can cause failure of the supply tubing used on microsprinkler assemblies in Florida citrus groves. The S. sueroides caterpillars use the microsprinkler supply tubing as alternate hosts to native plant species with hollow stems. They bore holes in the tubing, enter the hollow interior, and pupate. This experiment was conducted to determine if Sevin or Teflon sprays were effective at preventing damage to microsprinkler assemblies from S. sueroides. Microsprinkler assemblies made from either polyethylene or vinyl were placed in a field of Aeschynomene americana (American jointvetch), a known host to S. sueroides. Prior to placement in the field, assemblies were left untreated or were subjected to sprays by either liquid Sevin or liquid Teflon. Assemblies with polyethylene tubing had a higher incidence of damage than those with vinyl tubing. Assemblies sprayed with Teflon had about 40% of the damage of the untreated assemblies. Sevin was an ineffective treatment.

Potential for Biological Control of Soil Insects in the Caribbean Basin Using Entomopathogenic Nematodes

The numerous species and geographic isolates of entomopathogenic nematodes have a diversity of biological attributes which make them adaptable to many uses, especially management of soil pests. Entomopathogenic nematodes are viable substitutes for soil insecticides due to wide host range, persistence, mobility, safety, ease of application, and absence of registration restrictions. Efficacy is often comparable to chemical insecticides, which tend not to perform well in soil. Although soil is generally a very suitable habitat for nematodes, abiotic and biotic constraints are serious impediments in some locales. Surveys should be conducted in Caribbean countries to identify pre-adapted strains. Recent advances have made nematodes more economic to produce, and storage life has been extended. Entomopathogenic nematodes are appropriate for the Caribbean Basin environment due to favorable soil, humidity and temperatures, occurrence of hosts throughout most of the year, and a high incidence of damage caused by coleopterans and lepidopterans--pests which are usually quite susceptible to infection. In vitro production methods, which require medium-level technology and low cost labor, may be particularly suitable for the Caribbean.

An ecological study of Caiman crocodilus crocodilus inhabiting savanna lagoons in the Venezuelan Guayana.

Mark and recapture studies were carried out for three and a half years on a population of Caiman c. crocodilus inhabiting a savanna lagoon system in the Venezuelan Guayana. Sub-adult and adult caimans migrated from permanent lagoon refuges to temporary lagoons during the wet season. A distinct homing response by artificially displaced caimans was observed.The wet season was the most significant time of the year for both feeding and growth. It was estimated that caimans take 6 years to reach a size of 97 cm. Thereafter the growth rate was variable. During a dry year there was little growth, but during a wet year a large caiman could increase in length by up to 10 cm.During the first 18 months of life, young caimans remained near the nest site. Older caimans dispersed and competed for territories which resulted in a high incidence of damage, particularly to the tails, as a result of intraspecific fighting.

Fluorosis in dairy cattle.

The investigation of a high incidence of arthritis in 21 dairy herds disclosed elevated fluorine levels in bone samples. In every herd except one, where herbage and water was contaminated by industrial fall-out, the main source of the fluorine was from mineral supplements; In a few herds, purchased cake or grain balancers contributed to the abnormal levels. Over 100 cows with arthritis had fluroine levels in the bone of between 2000 and 8000 ppm, or were in herds whose diet contained excess fluorine. Characteristic tooth lesions often confirmed the link between arthritis and fluorosis. Sixteen out of 31 samples of mineral supplement contained dangerous levels of fluorine (3000 to 13000 ppm). Grain balancers contained up to 400 ppm F, and dairy cake had levels as high as 140 ppm F. There was a statistical correlation between a high incidence of damage to peri-articular structures, resulting in debility and loss of production, and elevated bone fluorine.

Induction of a high incidence of damage to the X chromosomes of Rattus (Mastomys) natalensis by base analogues, viruses, and carcinogens.

Cultured embryonic cells from Rattus (Mastomys) natalensis were treated with the base analogues 5-bromodeoxyuridine and 2-aminopurine, the viruses herpes simplex virus and adenovirus type 12, and the carcinogens 7,12-dimethylbenz(a)anthracene and urethan. Treatment with these agents, except urethan, causes an increase in the incidence of chromosome aberrations. The induced aberrations are not randomly distributed among the chromosomes or within a chromosome. The X chromosome, especially its long arm, is more sensitive to these agents than is any other chromosomes in the complement. — A possible relationship among the high incidence of damage, the positive heteropycnosis, and the late replication in the X chromosome of R. natalensis is discussed.