Later Stages Of Incubation Research Articles

High renesting rates in Arctic-breeding Dunlin (Calidris alpina)

ABSTRACT. The propensity to replace a clutch is a complex component of avian reproduction and poorly understood. We experimentally removed clutches from an Arctic-breeding shorebird, the Dunlin (Calidris alpina arcticola), during early and late stages of incubation to investigate replacement clutch rates, renesting interval, and mate and site fidelity between nesting attempts. In contrast to other Arctic studies, we documented renesting by radiotracking individuals to find replacement clutches. We also examined clutch size and mean egg volume to document changes in individual females' investment in initial and replacement clutches. Finally, we examined the influence of adult body mass, clutch volume, dates of clutch initiation and nest loss, and year on the propensity to renest. We found high (82–95%) and moderate (35–50%) rates of renesting for early and late incubation treatments. Renesting intervals averaged 4.7–6.8 days and were not different for clutches removed early or late in incubation. Most pair...

Energetic constraints and parental care: Is corticosterone indicative of energetic costs of incubation in a precocial bird?

Suppression of the adrenocortical response (e.g., corticosterone release) to an acute stressor is a physiological adjustment thought to decrease the likelihood of avian parents abandoning their nests. However, some periods of parental care, like incubation, are energetically costly, thus corticosterone could increase during these stages to allow incubating parents to utilize energy reserves. Wood ducks (Aix sponsa) have ~30day incubation periods and only the female incubates the eggs. We hypothesized that corticosterone would be important in regulating energy availability during incubation in this species. Because resources invested in reproduction increase with clutch size, we also hypothesized that clutch size would influence plasma corticosterone during incubation. We measured baseline and stress-induced corticosterone in incubating females during early and late stages of incubation. At both stages of incubation all hens had low baseline corticosterone levels. However, we found that stress-induced corticosterone was 105% greater late in incubation than early in incubation. We also detected a significant negative correlation between female body mass and stress-induced corticosterone late in incubation, but not during the early stages of incubation. Furthermore, we found a significant positive relationship between stress-induced corticosterone and clutch size. These lines of evidence support the hypothesis that incubation in wood ducks is energetically costly and corticosterone is important in supporting the energetic demands of incubating hens. Our findings suggest that corticosterone's role in supporting parental care behaviors are dynamic and are influenced by several factors and that there is a greater physiological cost associated with incubating larger clutches.

Sex-biased mortality analysis in chick embryos during the entire period of incubation

SUMMARY From 50,129 fertile eggs, a total of 1,712 dead chick embryos were collected from 5 different strains of chickens: ai-Jiao (233), Xing-Xing (143), HuBei-local (894), Hy-line (212), and Zhu-Si (230). the embryos were collected during the early (1 to 7 d), middle (8 to 14 d), and late (15 to 21 d) stages of incubation. Sex-biased embryonic mortality was analyzed during the different stages. We found that the overall mortality of female embryos was significantly higher than that of males in different stages of incubation (P < 0.05). We then analyzed the data by strain. In Hy-line, HuBei-local, and Zhu-Si chickens, female mortality was significantly higher (P < 0.05) during the early stage. During the middle stage, female mortality in HuBeilocal chickens was significantly greater than that of males (P < 0.005). During the late stage, female mortality was significantly lower (P < 0.05) in ai-Jiao chickens but was significantly higher (P < 0.01) in HuBei-local chickens. thus, more females died during the entire period of incubation, especially in the early and middle stages. Mortality was variable among strains during the late stage of incubation. In strains with smaller egg sizes, more females died, whereas in strains with larger egg sizes, more males died.

Soil N Dynamics Related to Soil C and Microbial Changes During Long-Term Incubation

Knowledge of the pools and fluxes of C and N soil components is required to interpret ecosystem functioning and improve biogeochemical models. Two former grassland soils, where wheat or corn are currently growing, were studied by kinetic analysis of microbial biomass C and N changes, C and N mineralization rates, acid hydrolysis, and pyrolysis. Nearly twice as much C as N was mineralized during incubation. Modeling of changes during incubation demonstrated that two-pool first-order kinetics effectively described losses of microbial biomass C and N and concurrent N mineralization. Loss of microbial biomass N during incubation accounted for a significant portion of the N mineralized. Microbial biomass N content and soil N mineralization rates were strongly affected by soil type and soil management. Nitrification, but not N mineralization, was inhibited during the latter stages of incubation in one of the soils. We believe nitrifier populations had dropped below effective levels. Nonacid hydrolysable C was increased in both amount and mean residence time by cultivation and incubation. Hydrolysis removed a larger amount of N than incubation. Data after pyrolysis of soils, in argon at 550°C, closely reflected results for both C and N found after cultivation and incubation. This technique should be further investigated to identify the recalcitrant forms of C and N in soils. The dynamics of soil C and soil N, although related, are not identical; thus, management can be targeted to soil C or N cycling in ecosystem functioning or to soil organic matter dynamics in global change.

Effect of neighbour visibility on nest attendance patterns of Barn Swallows Hirundo rustica in loose colonies

To assess the benefits of nesting at a site hidden from neighbours in a loosely colonial species, the Barn Swallow Hirundo rustica, we carried out two field experiments, obstruction removal and mirror placement, both replicating a situation in which a nest is made visible from another nest. Under manipulated conditions in both experiments, females increased the length of time they stayed at their nests during the egg‐laying and late incubation stages, while males extended their duration of stay during the egg‐laying and early nestling stages in mirror placement experiments only. The results suggest that Barn Swallows conceal their nests to reduce fitness costs imposed by neighbours nesting in view and that hiding the nest can reduce the amount of time spent guarding the nest during certain stages of the breeding period.

Bacterial Loads on Eggshells of the Pied Flycatcher: Environmental and Maternal Factors

Abstract. We studied environmental and maternal factors explaining bacterial loads on eggshells in a population of a hole-nesting passerine, the Pied Flycatcher (Ficedula hypoleuca) and the possible effects of bacteria on hatching success. We collected bacteria from eggshells at early and late stages of incubation and from females' feces, as a surrogate for cloacal samples, at intermediate stages of incubation. Higher environmental temperatures during laying promoted bacterial loads on the eggshells during early incubation, supporting the fact that bacterial growth is generally favored by increasing ambient temperature. Bacterial loads on the eggshells at late stages of incubation were correlated positively with bacterial loads in the female's cloaca, suggesting possible vertical transmission of bacteria. We detected no significant differences between bacterial loads of the eggshells at early and late stages of incubation. Possible bacteriostatic effects of incubation and/or other alternative mechanisms n...

The Role of Python Eggshell Permeability Dynamics in a Respiration‐Hydration Trade‐Off

Parental care is taxonomically widespread because it improves developmental conditions and thus fitness of offspring. Although relatively simplistic compared with parental behaviors of other taxa, python egg-brooding behavior exemplifies parental care because it mediates a trade-off between embryonic respiration and hydration. However, because egg brooding increases gas-exchange resistance between embryonic and nest environments and because female pythons do not adjust their brooding behavior in response to the increasing metabolic requirements of developing offspring, python egg brooding imposes hypoxic costs on embryos during the late stages of incubation. We conducted a series of experiments to determine whether eggshells coadapted with brooding behavior to minimize the negative effects of developmental hypoxia. We tested the hypotheses that python eggshells (1) increase permeability over time to accommodate increasing embryonic respiration and (2) exhibit permeability plasticity in response to chronic hypoxia. Over incubation, we serially measured the atomic and structural components of Children's python (Antaresia childreni) eggshells as well as in vivo and in vitro gas exchange across eggshells. In support of our first hypothesis, A. childreni eggshells exhibited a reduced fibrous layer, became more permeable, and facilitated greater gas exchange as incubation progressed. Our second hypothesis was not supported, as incubation O(2) concentration did not affect the shells' permeabilities to O(2) and H(2)O vapor. Our results suggest that python eggshell permeability changes during incubation but that the alterations over time are fixed and independent of environmental conditions. These findings are of broad evolutionary interest because they demonstrate that, even in relatively simple parental-care models, successful parent-offspring relationships depend on adjustments made by both the parent (i.e., egg-brooding behavioral shifts) and the offspring (i.e., changes in eggshell permeability).

Isolation of a new heterolobosean amoeba from a rice field soil: Vrihiamoeba italica gen. nov., sp. nov.

A heterolobosean amoeba strain 6_5F was isolated from an Italian rice field soil. Although 18S rRNA gene sequence analysis demonstrated that the new isolate was closely related to Stachyamoeba sp. ATCC 50324, further molecular analysis and morphological observation showed distinct differences amongst the two. The 5.8S rRNA gene was successfully amplified and sequenced for strain 6_5F but not for strain ATCC 50324. Trophozoites of strain ATCC 50324 transform into flagellate forms in the late stage of incubation before encystment, while strain 6_5F do not show flagellate forms under different conditions of the flagellation test. Light and electron microscopic observation showed the structural difference of cysts of strain 6_5F from strain ATCC 50324 and also from the type strain Stachyamoeba lipophora. The results show that the strain 6_5F is distinct from Stachyamoeba spp. and we propose a new genus and species for this isolate, Vrihiamoeba italica gen. nov., sp. nov.

Chick &lt;em&gt;ex ovo&lt;/em&gt; Culture and &lt;em&gt;ex ovo&lt;/em&gt; CAM Assay: How it Really Works

Chicken eggs in the early phase of breeding are between in vitro and in vivo systems and provide a vascular test environment not only to study angiogenesis but also to study tumorigenesis. After the chick chorioallantoic membrane (CAM) has developed, its blood vessel network can be easily accessed, manipulated and observed and therefore provides an optimal setting for angiogenesis assays. Since the lymphoid system is not fully developed until late stages of incubation, the chick embryo serves as a naturally immunodeficient host capable of sustaining grafted tissues and cells without species-specific restrictions. In addition to nurturing developing allo- and xenografts, the CAM blood vessel network provides a uniquely supportive environment for tumor cell intravasation, dissemination, and vascular arrest and a repository where arrested cells extravasate to form micro metastatic foci. For experimental purposes, in most of the recent studies the CAM was exposed by cutting a window through the egg shell and experiments were carried out in ovo, resulting in significant limitations in the accessibility of the CAM and possibilities for observation and photo documentation of effects. When shell-less cultures of the chick embryo were used(1-4), no experimental details were provided and, if published at all, the survival rates of these cultures were low. We refined the method of ex ovo culture of chick embryos significantly by introducing a rationally controlled extrusion of the egg content. These ex ovo cultures enhance the accessibility of the CAM and chick embryo, enabling easy in vivo documentation of effects and facilitating experimental manipulation of the embryo. This allows the successful application to a large number of scientific questions: (1) As an improved angiogenesis assay(5,6), (2) an experimental set up for facilitated injections in the vitreous of the chick embryo eye(7-9), (3) as a test environment for dissemination and intravasation of dispersed tumor cells from established cell lines inoculated on the CAM(10-12), (4) as an improved sustaining system for successful transplantation and culture of limb buds of chicken and mice(13) as well as (5) for grafting, propagation, and re-grafting of solid primary tumor tissue obtained from biopsies on the surface of the CAM(14). In this video article we describe the establishment of a refined chick ex ovo culture and CAM assay with survival rates over 50%. Besides we provide a step by step demonstration of the successful application of the ex ovo culture for a large number of scientific applications.

Chick &lt;em&gt;ex ovo&lt;/em&gt; Culture and &lt;em&gt;ex ovo&lt;/em&gt; CAM Assay: How it Really Works

Chicken eggs in the early phase of breeding are between in vitro and in vivo systems and provide a vascular test environment not only to study angiogenesis but also to study tumorigenesis. After the chick chorioallantoic membrane (CAM) has developed, its blood vessel network can be easily accessed, manipulated and observed and therefore provides an optimal setting for angiogenesis assays. Since the lymphoid system is not fully developed until late stages of incubation, the chick embryo serves as a naturally immunodeficient host capable of sustaining grafted tissues and cells without species-specific restrictions. In addition to nurturing developing allo- and xenografts, the CAM blood vessel network provides a uniquely supportive environment for tumor cell intravasation, dissemination, and vascular arrest and a repository where arrested cells extravasate to form micro metastatic foci. For experimental purposes, in most of the recent studies the CAM was exposed by cutting a window through the egg shell and experiments were carried out in ovo, resulting in significant limitations in the accessibility of the CAM and possibilities for observation and photo documentation of effects. When shell-less cultures of the chick embryo were used1-4, no experimental details were provided and, if published at all, the survival rates of these cultures were low. We refined the method of ex ovo culture of chick embryos significantly by introducing a rationally controlled extrusion of the egg content. These ex ovo cultures enhance the accessibility of the CAM and chick embryo, enabling easy in vivo documentation of effects and facilitating experimental manipulation of the embryo. This allows the successful application to a large number of scientific questions: (1) As an improved angiogenesis assay5,6, (2) an experimental set up for facilitated injections in the vitreous of the chick embryo eye7-9, (3) as a test environment for dissemination and intravasation of dispersed tumor cells from established cell lines inoculated on the CAM10-12, (4) as an improved sustaining system for successful transplantation and culture of limb buds of chicken and mice13 as well as (5) for grafting, propagation, and re-grafting of solid primary tumor tissue obtained from biopsies on the surface of the CAM14. In this video article we describe the establishment of a refined chick ex ovo culture and CAM assay with survival rates over 50%. Besides we provide a step by step demonstration of the successful application of the ex ovo culture for a large number of scientific applications. Daniel S. Dohle, Susanne D. Pasa, and Sebastian Gustmann contributed equally to this study.

The evaluation of exposure risks for natural transmission of scrapie within an infected flock

BackgroundAlthough the epidemiology of scrapie has been broadly understood for many years, attempts to introduce voluntary or compulsory controls to eradicate the disease have frequently failed. Lack of precision in defining the risk factors on farm has been one of the challenges to designing control strategies. This study attempted to define which parts of the annual flock management cycle represented the greatest risk of infection to naive lambs exposed to the farm environment at different times.ResultsIn VRQ/VRQ lambs exposed to infected sheep at pasture or during lambing, and exposed to the buildings in which lambing took place, the attack rate was high and survival times were short. Where exposure was to pasture alone the number of sheep affected in each experimental group was reduced, and survival times were longer and related to length of exposure.ConclusionAt the flock level, eradication and control strategies for scrapie must take into account the need to decontaminate buildings used for lambing, and to reduce (or prevent) the exposure of lambs to infected sheep, especially in the later stages of incubation, and at lambing. The potential for environmental contamination from pasture should also be considered. Genotype selection may still prove to be the only viable tool to prevent infection from contaminated pasture, reduce environmental contamination and limit direct transmission from sheep to sheep.

Nest site selection of the Kelp gull (Larus dominicanus) in the Beagle Channel, Tierra del Fuego, Argentina

Nest site selection of Kelp gulls Larus dominicanus breeding in Conejo and Bridges islands, Tierra del Fuego, Argentina, was assessed between 14 and 30 December 2005 to describe variability in nest site features and determine variables affecting nest choice. Fourteen microhabitat variables were quantified at 40 nest sites and at 40 random points in each island during the late incubation stage. Nests at the two colonies were placed on different kinds of substrates across areas with varying degrees of cover provided either by rocks or vegetation. Despite the variability observed in nest site features, rock cover and rocky substrates were the main factors determining nest site selection. At Conejo Island, nest sites presented more rock cover, less percentage of vegetation cover and of vegetation debris substrate, and were placed further from the nearest vegetation in comparison to random points. Similarly, gulls at Bridges Island selected nest sites with more rock cover which were placed mainly on rocky and vegetation substrates. This contrasts with results previously obtained in Argentina, which indicated that vegetation is a key factor influencing Kelp gull nest site selection. Over 80% of the nests at both study colonies were placed on the northern slopes of the islands, relatively more protected from the strong prevailing southwest winds, and nests at both colonies tended to be more protected on their southern side either by rocks or vegetation. Results obtained at Tierra del Fuego confirm the plasticity of microhabitat use by Kelp gulls, and their ability to take advantage of nesting sites according to availability and local environmental factors.

Androgens during development in a bird species with extremely sexually dimorphic growth, the brown songlark, Cinclorhamphus cruralis

In birds, early exposure to androgens has been shown to influence offspring growth and begging behaviour, and has been proposed as a mechanism for the development of sexual size dimorphism (SSD). Sex specific effects during development can occur due to sex-specific allocation of maternal androgens, sensitivity to, or synthesis of, androgens. In addition, maternal hormones have been suggested as a mechanism to skew brood sex ratio. This study uses one of the world’s most extreme SSD species, the brown songlark Cinclorhamphus cruralis, to investigate (1) sex-specific differences of androgens in yolk and chick plasma and (2) the relationship between androgens and sex ratio bias. The study reveals no indication of sex-specific maternal allocation, but a modest sex effect during the later stages of incubation when the embryo starts to produce its own androgens. Moreover, there was a strong seasonal sex ratio bias: female-biased early and male-biased later in the season, but yolk testosterone (T) did not show a seasonal trend. Taken together these results suggest that if androgens, from any source, have a significant role in development of SSD in this species it is most likely via sex-specific sensitivity or synthesis rather than differential maternal transfer to the egg.

Broiler incubation. 2. Interaction of incubation and brooding temperatures on broiler chick feed consumption and growth

The effect of either hot or cool brooding litter temperature on feed consumption, BW, and mortality of broiler chicks that had been exposed to either normal or high temperature during latter stages of incubation was studied in 2 experiments. The duration of experiments 1 and 2 was 14 and 21 d, respectively, with BW and feed consumption determined at 2, 5, 7, and 14 d of age in experiment 1 and at 7, 14, and 21 d of age in experiment 2. High incubator temperature after embryonic d 16 decreased chick feed consumption and BW at all ages in both experiments. Hot brooding litter temperature increased feed consumption at 2 and 5 d in experiment 1 and at 7 d in experiment 2 but decreased feed consumption at 14 and 21 d in experiment 2. Feed consumption was also influenced by the incubation temperature x brooding litter temperature interaction. From 0 to 2 d or 0 to 7 d in experiments 1 and 2, respectively, the highest to lowest feed consumption was exhibited by the normal-hot, high-hot, normal-cool, and high-cool interaction groups but the order changed to normal-cool, normal-hot approximately high-cool, and high-hot from 7 to 14 and 14 to 21 d in experiment 2. Significant effects on mortality were observed in experiment 2 only where males exhibited greater mortality that was most evident in the combination of high temperature incubation followed by cool brooding. Excessive (high) eggshell temperature during the latter stages of incubation reduced feed consumption and BW through 21 d of age. However, the results showed that the hot brooding litter temperature supported increased feed consumption during the first few days of brooding even for the chicks that had been subjected to high incubation temperature. Hot brooding also reduced male mortality in experiment 2. Nonetheless, hot brooding litter temperatures should be limited as extending beyond a few days eventually decreased feed consumption.

Findings—Innovations' Origins: When, By Whom, and How Are Radical Innovations Developed?

Innovation research tends to consider only the post-commercialization period or examine a few innovations through case studies. In this study, we examine 29 radical innovations from initial concept to mass-market commercialization. We find that these innovations were developed over an average of at least 50 years and divide this long development period into four distinct stages—conceptualization, gestation, early incubation, and late incubation. We find that the duration of a stage is longer when different firms lead product development at the beginning and end of the stage. These changes in product development leaders happen frequently, e.g., 76% of firms that were first to commercialize an innovation failed to launch it in the broader market. We also find that the time-to-takeoff for a product category is significantly related to the duration of the preceding late incubation stage. In addition, we find four different ways in which radical innovations borrow from prior seemingly unrelated innovations. We report many other findings on when (duration times), by whom (product development leaders), and how (technology borrowing) radical innovations are developed.

Age and clutch size variation in Dusky Flycatcher nest survival

Examination of spatial and temporal factors that influence nest survival can provide insight into habitat selection, reproductive decisions (e.g., clutch size), population dynamics, and conservation requirements for species. We used nest survival data for the Dusky Flycatcher Empidonax oberholseri to examine several factors that may influence nesting success. Our prediction was that the number of nest initiations would be positively associated with period nest survival. We used a model selection framework and found that nesting success was a function of clutch size and a cubic effect of age. Clutches with one, two, three, and four eggs had period survival rates of 0, 0.05, 0.33, and 0.49, respectively. Daily survival rates decreased from the onset of egg-laying and increased during the later stages of incubation before remaining relatively constant through the later portions of the nestling stage. Model-selection criterion provided support for a date effect on daily survival (i.e., daily nest survival declined across the nesting season) although the 95% confidence interval for the estimate included zero. We found that the majority of nest initiations occurred early in the nest season and declined across the season as period nest survival declined. Our prediction concerning nest survival was partially supported. In addition, we found substantial positive associations between clutch size and nest survival. While low daily survival rates for clutches with one or two eggs suggested that individuals may have reduced reproductive effort in response to nest predation risk, we did not find strong evidence that individuals reduced their clutch sizes in subsequent nest attempts. Alternative predictions, including the preferential settlement of higher quality individuals (e.g., those with the ability to lay full clutches to replace depredated nests) into high-quality habitat and differences in behavior patterns (e.g., number of visits to provision nestlings), may provide more consistent explanations for these patterns.

Characterizing the nutritional strategy of incubating king eiders Somateria spectabilis in northern Alaska

We measured plasma concentrations of variables associated with lipid metabolism (free fatty acids, glycerol, triglyceride, and β‐hydroxybutyrate), protein metabolism (uric acid), and baseline corticosterone to characterize the nutritional state of incubating king eiders Somateria spectabilis and relate this to incubation constancy at two sites, Kuparuk and Teshekpuk, in northern Alaska. King eiders at both sites appeared to employ a partial‐income incubation strategy, relying on both endogenous and exogenous energy resources. Females maintained high invariant levels of free fatty acids, β‐hydroxybutyrate, and glycerol throughout incubation, indicating that fat reserves were a major energy source, and not completely depleted during incubation. Similarly, uric acid did not increase, suggesting effective protein sparing or protein ingestion and adequate lipid reserves throughout incubation. Baseline corticosterone and triglyceride levels increased during incubation, indicative of an increase in foraging during late stages of incubation. Incubating females at Kuparuk had higher triglyceride concentrations but also had higher β‐hydroxybutyrate concentrations than females at Teshekpuk. This dichotomy may reflect a short‐term signal of feeding overlaying the longer‐term signal of reliance on endogenous lipid reserves due to higher food intake yet higher metabolic costs at Kuparuk because of its colder environment. Incubation constancy was not correlated with plasma concentrations of lipid or protein metabolites.

비지박 및 맥주박을 이용한 알코올 발효사료의 반추위내 발효특성 및 건물 분해율에 미치는 영향

본 실험은 비지박 및 맥주박 알코올 발효사료 처리가 반추위내 발효특성 및 건물 분해율에 미치는 영향을 검토하기 위하여 실시하였다. 공시동물은 반추위 cannula가 장착된 한우에 비지박 알코올 발효사료(AFS) 및 맥주박 알코올 발효사료(AFB)를 급여한 후 시간별(0, 2, 4, 6, 8 및 12시간) 반추위내에서 알코올 함량, pH 변화, ammonia 함량, 휘발성지방산 함량 및 건물 분해율을 조사하였다. 시험구 처리는 대조구와 비지박(DM 20%)과 시판중인 배합사료(DM 87%)를 각각 50:50의 비율로 혼합하고 당밀 5%, yeast 0.5%를 첨가한 후 30C에서 24시간 혐기적으로 배양한 AFS구 및 맥주박(DM 25%), 비지박(DM 20%), 옥분 및 시판중인 배합사료를 각각 25:25:25:25의 비율로 혼합하고 당밀 5%, yeast 0.5을 첨가한 후 제조한 AFB로 나누어 실시하였다. 반추위내 ammonia 농도는 배양 2시간에 비지박 및 맥주박 알코올 발효사료 처리구들이 대조구에 비해 현저히 높았으나 배양 6시간에는 비지박 및 맥주박 알코올 발효사료급여구들이 대조구 보다 유의적으로 낮은 결과를 보였다(p<0.05). 반추위내 pH는 비지박 및 맥주박 알코올 발효사료처리구들이 대조구보다 현저하게 낮게 나타났으며(p<0.05), 배양시간이 경과하면서 점차 대조구와 유사한 결과를 보였다. 비지박 및 맥주박 알코올 발효사료 처리구들의 반추위내 알코올 농도는 반추위내 배양 4시간에 대조구에 비해 현저히 높게 나타났으며(p<0.05), 배양 6시간에는 대조구와 알코올 발효사료 처리구간에 유사한 결과를 보였다. 반추위내 총휘발성지방산 함량은 반추위내 배양초기(2시간)에 비지박 및 맥주박 알코올 발효사료처리구와 대조구간에 유사한 경향을 보였으나 배양시간이 경과함에 따라 비지박 및 맥주박 알코올 발효사료처리구들이 대조구보다 유의적으로 감소하는 결과로 나타났다(p<0.05). 비지박 및 맥주박 알코올 발효사료 처리구의 가용성건물 함량은(S) 대조구에 비해 낮은 결과를 보였으나(p<0.05), 반추위내 분해성 부분은(D) 비지박 및 맥주박 알코올 발효사료 처리구가 대조구에 비해 유의적으로 높은 결과를 보였다(p<0.05). 이상의 결과로 볼때 산업부산물인 비지박과 맥주박을 이용하여 알코올 발효사료를 제조하면 가축의 생산성을 향상시킬 수 있는 사료자원의 가능성이 있음을 알 수 있었다. A study was conducted to determine the effect of alcohol-fermented feedstuff formulated with byproducts on the fermentation characteristics and dry matter disappearance in the rumen. Dietary treatments were either a soybean curd-based alcohol-fermented feedstuff(AFS) and brewery grain-based alcohol-fermented feedstuff(AFB). The AFS and AFB are composed of 50% commercial beef cattle feed, 50% soybean curd dreg, 5% molasses and 0.5% yeast, and 25% commercial beef cattle feed, 25% brewery grain, 25% soybean curd dreg, 25% corn grit, 5% molasses and 0.5% yeast, respectively. The ruminally cannualted Korean cattle were utilized to investigate the change of ammonia, pH alcohol, volatile fatty acids, and DM digestibility at 0, 2, 4, 8 and 12 hr after feeding. The rumen ammonia concentrations were significantly lower in AFS and AFB with incubation time, especially at 6 hr incubation(AFS, 0.7 mg/dl; AFB, 1.5 mg/dl; control 2.5 mg/dl). Lower rumen pH was observed in AFS and AFB during the early stage of incubation, but no significant difference was found at late stage of incubation. The total VFA concentrations were not affected by diet treatments at 2 hr incubation time, but the concentration significantly decreased after that. The dry matter disappearance was significantly lower in AFS and AFB during the early stage of incubation. However, the dry matter disappearance of AFS and AFB was similar to that of control during the late stage of incubation. It is concluded that the industrial byproducts such as soybean curd dreg and brewery grain were effective materials to make an alcohol fermented feedstuffs and resulted in better fermentation characteristics in the rumen when both were applied to Hanwoo.

The selective basis for increased egg retention: early incubation temperature determines hatchling phenotype in wall lizards (Podarcis muralis)

The thermal environment during development influences many aspects of the phenotype of hatchling reptiles. We hypothesized that temperature should differentially affect early incubation stages, in which differentiation dominates over growth, and late incubation stages, characterized by high growth rates. To test this idea, we incubated eggs of wall lizard (Podarcis muralis) under three regimes with the same mean temperature (29 °C), one constant and two variable with opposite sequences: first cold (25 °C) and then hot (32 °C), and vice versa. Hatchlings incubated at high temperature during the initial period had shorter hindlimbs and tails than those incubated under the other two temperature regimes and shorter heads than those incubated initially at low temperature. Thus, temperature experienced by embryos during the early external incubation period produced similar phenotypic responses compared to those reported in previous studies for the same constant temperature applied over the whole incubation period. Because female wall lizards select lower body temperatures during pregnancy, an increase of intrauterine retention would extend the time of exposure of developing embryos to suitable temperatures. Diminution of body temperature during pregnancy is contrary to the expected pattern under the hypothesis that egg retention has evolved to accelerate development, as proposed by the cold-climate model for evolution of viviparity in squamates, and the results of the present study support the alternative hypothesis of developmental optimization as a special case of the broader maternal manipulation view. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 92, 441–447.

Rabies in Vaccinated Raccoons from Ontario, Canada

From 1999 to 2006, 132 cases of raccoon rabies, caused by the raccoon variant of rabies virus, were confirmed in eastern Ontario, Canada. Trap-vaccinate-release (TVR) and point infection control (PIC) programs were implemented to control the disease; 43,014 raccoons (Procyon lotor) were vaccinated against rabies by injection (Imrab3) during that period. Two vaccinated raccoons were diagnosed with rabies at 6 mo and at 2 wk postvaccination. One may have been due to a vaccination failure. The other was likely due to the animal being in the late stages of incubation for rabies at the time of vaccination. This information will be useful to wildlife rehabilitators and agencies that hold raccoons in captivity in that a vaccinated raccoon is not necessarily immune to rabies.