Heat stress during mid-pregnancy in sheep and the consequences for placental and fetal growth

1993 ◽  
Vol 120 (2) ◽  
pp. 265-271 ◽  
Author(s):  
G. J. McCrabb ◽  
B. J. McDonald ◽  
L. M. Hennoste
Keyword(s):  
Heat Treatment ◽  
Heat Stress ◽  
Fetal Growth ◽  
Rectal Temperature ◽  
Late Pregnancy ◽  
Fetal Weight ◽  
Research Station ◽  
Hot Climate ◽  
Heat Treated ◽  
The Relationship

SUMMARYAn experiment was conducted at Toorak Research Station, Julia Creek, in semi-arid northern Australia (141° E, 21° S) during 1990 to determine the relationship between placental and fetal weight in sheep after placental growth had been restricted by chronic heat stress during mid-pregnancy. Placental and fetal weight were measured in single bearing ewes housed either in a thermoneutral environment throughout pregnancy, or in a heated room between the 30th and 80th days of pregnancy followed by a thermoneutral environment until the 140th day of pregnancy. The placental weight of the heat-treated ewes was lower than that of the control ewes at the 80th (P< 0·05) and 140th (P< 0·01) days of pregnancy. Fetal weight and dimensions did not differ significantly between control and heat-treated ewes at the 80th day of pregnancy, although fetal weight (P< 0·01) and fetal dimensions (P< 0·05) for the previously heat-treated ewes were lower than those for the control ewes at the 140th day of pregnancy. Placental and fetal weight at the 140th day of pregnancy were correlated (P< 0·05) with the rectal temperature of ewes measured at 08.00 and 16.30 h during the period of heat-treatment, but not with the change in rectal temperature between 08.00 and 16.30 h. It was concluded that restricted placental growth in heat-treated ewes retarded fetal growth during late pregnancy even in the absence of heat treatment, and it is suggested that selection of ewes which can maintain normal rectal temperatures during periods of heat stress would produce lambs of normal birthweight in a hot climate.

Structural Defects and Changes in Al-Pd-Fe Crystalline Approximant

2007 ◽  
Vol 26-28 ◽  
pp. 687-690 ◽  
Author(s):  
J.P. Wang ◽  
Wei Sun ◽  
Z. Zhang
Keyword(s):  
Heat Treatment ◽  
High Resolution Electron Microscopy ◽  
Structural Defects ◽  
Decagonal Quasicrystal ◽  
High Temperature Heat Treatment ◽  
Atom Clusters ◽  
Heat Treated ◽  
Resolution Electron ◽  
The Relationship ◽  
Temperature Heat Treatment

Crystalline approximants structurally related to decagonal quasicrystal in the as-cast and heat-treated Al75Pd15Fe10 alloys and defect structures in them have been studied by means of high-resolution electron microscopy (HREM). Structural defects of linear and planar types were found to exist extensively in the orthorhombic ε16-phase formed in the as-cast Al75Pd15Fe10 alloy. In contrast with the distribution and configuration of the defects in the as-cast ε16-phase, we found that high-temperature heat treatment promotes the formation of a kind of regular network of structural defects in the ε16-phase. This suggests that rearrangements of atom clusters and as well as defects occurred due to the heat treatment. The relationship between the distribution of atom clusters and the configuration of defects will be discussed.

Physiological and growth parameters of fattening lambs after shearing under heat-stress conditions

2017 ◽  
Vol 57 (3) ◽  
pp. 569 ◽  
Author(s):  
F. Moslemipur ◽  
S. Golzar-Adabi
Keyword(s):  
Heat Stress ◽  
Rectal Temperature ◽  
Feed Intake ◽  
Growth Parameters ◽  
Underlying Mechanism ◽  
Stress Conditions ◽  
Free Access ◽  
Research Station ◽  
Feed Conversion ◽  
Protein Levels

Shearing is a common practice for lamb hygiene and health, which can also influence the animal survival and productivity in stressful environments. This study was conducted to investigate the effects of shearing on performance and some metabolic and physiological parameters of fattening lambs exposed to ambient heat stress. Thirty -two male Dalagh fattening lambs (32.4 ± 5.7 kg), 3.5 ± 0.5 months of age, were selected from a herd existing at the research station of the University of Gonbad Kavoos (temperate mild-latitude zone of Iran). Lambs were divided into two groups, maintained individually and fed with a mixture of alfalfa hay and concentrate with free access to drinking water. One group was completely shorn while the other group was left unshorn, and both groups were reared for 10 weeks (July–Sept.) with mean ambient temperature of 29.3°C. Feed intake and liveweight changes were recorded weekly whereas metabolic parameters were measured daily. Fasting blood samples were collected three times a week and used for blood metabolites and hormone assays. Results showed that shearing has no effects on feed intake and weight gain over the study. Feed conversion ratio was improved (P < 0.05) by shearing (10.70 vs 13.26 kg/kg). Shearing also caused a decline in lamb rectal temperature (P < 0.05), whereas heart rate remained unchanged. Respiratory rate was lower in shorn lambs (P < 0.001), whereas blood glucose, urea and total protein levels were not affected. Serum concentrations of thyroxine declined in shorn lambs compared with unshorn lambs (P < 0.05), but cortisol level was unchanged between groups. In conclusion, the study showed that when lambs are kept sheltered under heat stress conditions, shearing appears to induce energy retention via reducing some vital activities such as respiration and heat loss leading to enhanced feed efficiency. The decrease in thyroxine level can be considered as the possible underlying mechanism for the decline observed in rectal temperature.

scholarly journals Changes in Colour, Strength and Chemical Properties of Oil Heat Treated 18-Years Old Planted Acacia mangium

2017 ◽  
Vol 9 (3) ◽  
pp. 12
Author(s):  
Razak Wahab ◽  
Ros Syazmini M. Ghani ◽  
Hashim W. Samsi ◽  
Mohd Sukhairi M. Rasat
Keyword(s):  
Heat Treatment ◽  
Chemical Properties ◽  
Treated Wood ◽  
Acacia Mangium ◽  
Chemical Compositions ◽  
Bending Tests ◽  
Colour Strength ◽  
Heat Treated ◽  
The Relationship ◽  
And Chemical Properties

This study was carried to investigate changes in the oil heat treated 18-years old of planted Acacia mangium. Harvested trees segregated into bottom, middle and top portions containing heartwood and sapwood were oil heat treated in stainless tank with palm crude oil as heating medium at temperatures of 180oC, 200oC and 220oC for 30, 60 and 90 minutes respectively. The evaluation of the changes in the wood were performed by standards using a Minolta Chroma Meter, TAPPI Standard T204 om-88, TAPPI Standard T203 cm-99, TAPPI Standard T222 cm-02, and BS EN 310:1993 static bending tests. The relationship between the changes in the colour, mechanical and chemical composition, were made using correlation analysis. The result showed oil-heat treatment reduced the lightness of the wood and darkened the both parts of the wood. The strength of the wood reduced slightly after the oil-heat treatment. In the chemical compositions, the percentages of the holocellulose, α-cellulose, hemicellulose and extractive contents decrease with the increase in treatment duration and temperature. The oil heat treatment process at 200°C for duration 60 minutes is recommended for acacia mangium wood as it improved the colour of Acacia mangium and standardized the colour of sapwood and heartwood. The loss in strength at this temperature and duration is acceptable as the treated wood only loss up to 15% strength in MOR and 10.7% in MOE.

scholarly journals The Effect of Cooling Rate on Mechanical Properties of Carbon Steel (St 35)

2014 ◽  
Vol 7 (1) ◽  
pp. 109-118
Author(s):  
Jenan Mohammed Nagie
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Carbon Steel ◽  
Cooling Rate ◽  
Experimental Results ◽  
Heat Treated ◽  
Before And After ◽  
Water Media ◽  
The Relationship

This paper is aimed to study the effect of cooling rate on mechanical properties of Steel 35. Specimens prepared to apply tensile, torsion, impact and hardness tests.Many prepared specimens heat treated at (850ºC) for one hour and subsequently were cooled by three different media [Water-Air-furnace] to show the effect of Medias cooling rate on mechanical properties. Microstructures of all specimens examined before and after heat treatment by an optical microscopy.To figure the phases obtained after heat treatment and its effect on the mechanical properties Experimental results have shown that the microstructure of steel can be changed and significantly improved by varying line cooling rate thus, improving one property will effect on the others because of the relationship between all properties.In water media tensile, torsion and hardness improved while impact results reduced. Air media contributed in improving most of the mechanical properties because of grain size homogeneity. At furnace media ductility and impact improved

Investigation of the Influence of Heat Treatment on the Strength of FGRP Used in Sandwich Constructions

2018 ◽  
Vol 773 ◽  
pp. 72-76 ◽  
Author(s):  
Alexander E. Protsenko ◽  
Daria P. Malysheva ◽  
Victor V. Petrov
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Bending Strength ◽  
Sandwich Structures ◽  
Physical And Mechanical Properties ◽  
Treatment Results ◽  
Heat Treated ◽  
Bend Tests ◽  
Point Bend ◽  
The Relationship

The article presents the data of an experimental study on how heat treatment influences the physical and mechanical properties of cured samples of sandwich structures. The sandwich structures were made using VaRTM method. Heat treatment at 80 °С and 60 °С leads to increase in the bending strength. Three-point bend tests of sandwich structures and FGRP were conducted. Also, hardness and tensile strength were determined. Heat treatment results in increase of bending stress of FGRP by 71%, via the the tensile strength of heat-treated FGRP increased by 78%. The results characterize the relationship between the durability and the temperature and exposure time of the sandwich structures. The results correlate with the data of swelling of the cured binder. As a result of heat treatment at 80 °С for 4 hours, the extent of swelling decreased by 14%. The heat treatment of sandwich structures at a temperature of 80 °С for 4 hours is optimal and leads to increase in the tensile strength by 30.7%.

scholarly journals The study of relation between the gestational age of human fetuses and the diaphyseal length of humerus using ultrasonography

2017 ◽  
Vol 06 (04) ◽  
pp. 266-272
Author(s):  
Chaithra Rao B R ◽  
Sunkeswari Sreepadma ◽  
Keyword(s):  
Fetal Growth ◽  
Gestational Age ◽  
Growth Pattern ◽  
Geographical Area ◽  
Fetal Weight ◽  
Human Fetuses ◽  
Relationship Of ◽  
Maternal Disease ◽  
The Relationship

Abstract Background and Objectives: Ultrasonography is the most effective way to date pregnancy and to estimate the fetal weight in obstetric clinics. Currently, the diaphyseal length of humerus is used as a new parameter to estimate gestational age. The study evaluates the diaphyseal length of humerus as a parameter to estimate the gestational age of the fetus at the time of examination and to assess the growth pattern of humerus with advancing gestational age. Methods: The study was done on 152 antenatal women aged between 20 to 30 years of gestational ages from 15 to 40 weeks from the district of Dharwad, Karnataka, Subjects with maternal disease known to affect normal fetal growth wete excluded. The diaphyseal length of humerus was measured by radiologist in a standardized manner. The study describes the relationship of the diaphyseal length of humerus in centimeters, with the advancing gestational age in weeks. Results: It was observed that the diaphyseal length of humerus gradually increased from 15 weeks to 40 weeks of gestation and that the relationship is linear and direct. Normograms of diaphyseal lengths of humerus can be constructed by the formula derived by this study for this particular geographical area. Conclusion: The relationship between the diaphyseal length of humerus and the gestational age is linear and direct. The measurement of the diaphyseal lengths of humerus [in cm] can be an important additional parametet for estimating gestational age along with other parameters.

Examination the effect of post-hatch heat-treatment and heat-stress in Transylvanian Naked Neck chicken

2020 ◽  
Author(s):  
Roland Tóth ◽  
Nikolett Tokodyné Szabadi ◽  
Bence Lázár ◽  
Kitti Buda ◽  
Barbara Végi ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Egg Production ◽  
Sperm Quality ◽  
Heat Shock Factors ◽  
Expression Levels ◽  
Heat Treated ◽  
Shock Proteins

Abstract Background One of the most critical global problem nowadays is the increased environmental temperature. Agriculture is very susceptible to this adverse effect because the productivity of animals and poultry decreased. Although several studies reported the effects of heat-stress in chicken, the expression profile of heat-shock proteins and heat shock factors was not investigated in the gonads and germ cells of Transylvanian Naked Neck chickens. Methods In the first experiment, 24 hours after hatching 80 chicks were heat treated on 38.5oC ambient temperature with 60% humidity for 12 hours. After maturation, their primary productivity parameters, such as egg production, abnormalities in embryo development, sperm quantity, concentration, and motility were studied following two weeks of heat-stress on 30 °C room temperature. In the second experiment, the thermal manipulation of 60 chicks was the same but 15 treated and 15 control chicks were sacrificed immediately after the treatment. The other 15–15 chickens were raised to maturity. Expression levels for two heat-shock proteins and four heat shock factors were determined by real-time PCR in the gonads of heat-treated and heat-stressed chickens. Results We found that the heat-treated layers had significantly higher egg production than the control group in heat-stressed conditions. In cockerels, the sperm quality did not differ significantly between the heat-treated and heat-stressed group and the heat-stressed but not heat-treated group. We examined the expression pattern of HSPs and HSFs in the gonads. We found that the expression of HSP90 and HSF4 increased significantly (p < 0.05) in heat-treated female chick gonads but in adult females the expression of HSF2 and HSF3 were significantly lower compared to the control. In case of adult heat-treated males, the HSP70, HSF1 and HSF3 expression levels showed a significant increase in both gonads, compared to the control expression levels (P < 0.05). Conclusion Heat shock proteins and heat-shock factors protect cells against different stressors, including heat stress. Our findings show a significant effect on egg production but not on the sperm quality after post-hatch heat treatment in heat stress condition. The presented significant differences might be related to the increased expression level of HSP90 and HSF4 in heat-treated chickens.

Short-Term Responses of Photosystem II to Heat Stress in Cold-Acclimated Atrazine-Resistant and Susceptible Biotypes of Erigeron canadensis (L.)

1999 ◽  
Vol 54 (9-10) ◽  
pp. 665-670 ◽  
Author(s):  
Sándor Dulai ◽  
István Molnár ◽  
Evelin Péli ◽  
Endre Lehoczki
Keyword(s):  
Heat Treatment ◽  
Heat Stress ◽  
Elevated Temperature ◽  
Photosystem Ii ◽  
Significant Shift ◽  
Short Term ◽  
Erigeron Canadensis ◽  
Heat Treated ◽  
Temperature Dependences

When leaves of atrazine-resistant (AR) and atrazine-sensitive (S) Erigeron canadensis (L.) plants grown at 5 °C were exposed to an elevated temperature (35 °C) for 30 min, the critical (Tc) and peak temperatures (Tp) of the F0 vs. T curves were considerably higher for the leaves of the S biotype, but not for those of the AR biotype. The temperature dependences of Fv/Fm and ΔF/Fm′ were not greatly different for the heat-treated cold-acclimated AR biotype, in contrast with the situation for the S plants. This short-term heat treatment resulted in a more significant shift in the optimal thermal interval of CO2 fixation for the S than for the AR biotypes

scholarly journals Maternal undernutrition during mid-pregnancy in sheep. Placental size and its relationship to calcium transfer during late pregnancy

1991 ◽  
Vol 65 (2) ◽  
pp. 157-168 ◽  
Author(s):  
G. J. Mccrabb ◽  
A. R. Egan ◽  
B. J. Hosking
Keyword(s):  
Fetal Growth ◽  
Placental Transfer ◽  
Live Weight ◽  
Late Pregnancy ◽  
Placental Weight ◽  
Fetal Weight ◽  
Whole Body ◽  
Maternal Undernutrition ◽  
Significant Difference ◽  
Whole Body Metabolism

The aim of the present experiment was to determine the relationship between placental and fetal weight after placental growth had been retarded by maternal undernutrition. Placental weight and fetal weight were measured in single-lamb-bearing ewes which were well-fed throughout pregnancy, or severely undernourished between the 30th and 96th day of pregnancy. Placental transfer of calcium and whole-body metabolism of both glucose and Ca were measured during late pregnancy. The change in fleece-adjusted live weight between the 30th and 96th day of pregnancy was 99 (se 9.8) and – 146 (se 9.6) g/d for the well-fed and undernourished ewes respectively. The condition score of well-fed ewes did not significantly change between the 96th (2.9 (se 0.08)) and 140th (3.0 (se 0.13)) day of pregnancy, while it increased from 1.6 (se 0.15) to 2.3 (se 0.11) for the previously undernourished group. Undernutrition caused an increase (P < 0.01) in placental weight measured on the 96th (21%) and 140th (30%) day of pregnancy. In contrast fetal growth was not significantly affected by maternal undernutrition. While the voluntary dry matter intakes (g/d) of previously undernourished ewes after the 97th day of pregnancy were higher than for their well-fed counterparts, there was no significant difference between whole-body glucose or Ca metabolism, or the placental transfer of Ca measured during late pregnancy. This experiment confirms earlier reports of an increase in placental weight as a result of maternal undernutrition during mid-pregnancy; but the factors causing and the functional significance of this response have not been identified. Contrary to earlier proposals, placental weight per se did not limit fetal growth during late pregnancy. It is hypothesized that a combination of factors originating from maternal, placental and fetal sources act together to regulate growth of the fetus.

scholarly journals Effect of Post-Hatch Heat-Treatment in Heat-Stressed Transylvanian Naked Neck Chicken

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1575
Author(s):  
Roland Tóth ◽  
Nikolett Tokodyné Szabadi ◽  
Bence Lázár ◽  
Kitti Buda ◽  
Barbara Végi ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Stress ◽  
Heat Shock ◽  
Egg Production ◽  
Sperm Quality ◽  
Expression Level ◽  
Heat Shock Factors ◽  
Naked Neck ◽  
Heat Treated ◽  
Shock Proteins

Although numerous studies reported the effects of heat stress in chickens, it was not investigated in the Transylvanian Naked Neck breed. In our research, Transylvanian Naked Neck chickens, 24 hours after hatching, were heat-treated at 38.5 °C for 12 hours. We compared the control and heat-treated adult chickens’ productivity parameters following 12 weeks of heat-stress at 30°C. We found that the heat-treated layers had significantly higher egg production in heat stress, but in cockerels, the sperm quality did not differ significantly between the two groups. To detect the effect of heat-treatment on a molecular level, the expression of two heat-shock proteins and four heat-shock factors were analysed in the gonads of control and heat-treated chickens. We found that the expression level of HSP90 and HSF4 increased significantly in heat-treated female chicken gonads. Still, in adult females, the expression of HSF2 and HSF3 were substantially lower compared to the control. In adult heat-treated males, the HSP70, HSF1 and HSF3 expression levels showed a significant increase in both gonads compared to the control. We think that the presented significant differences in egg production might be related to the increased expression level of HSP90 and HSF4 in heat-treated female gonads.

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