Heat Stress Effects on Fetal Development during Late Gestation in the Ewe

1977 ◽  
Vol 44 (3) ◽  
pp. 442-446 ◽  
Author(s):  
D. E. Brown ◽  
P. C. Harrison ◽  
F. C. Hinds ◽  
J. A. Lewis ◽  
M. H. Wallace
Keyword(s):  
Heat Stress ◽  
Fetal Development ◽  
Late Gestation ◽  
Stress Effects

Heat Stress Effects of a Navy/USMC vs. Army Aviator Ensemble in a UH-6O Helicopter Simulator

1998 ◽  
Author(s):  
Matthew J. Reardon ◽  
E. B. Fraser ◽  
Lawrence Katz ◽  
Patricia LeDuc ◽  
Pooria Morovati
Keyword(s):  
Heat Stress ◽  
Stress Effects

scholarly journals 216 Thermoregulatory and physiological responses of sows at different reproductive stages exposed to increasing ambient temperature

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 7-7
Author(s):  
Betty R McConn ◽  
Alan W Duttlinger ◽  
Kouassi R Kpodo ◽  
Jacob M Maskal ◽  
Brianna N Gaskill ◽  
...  
Keyword(s):  
Heat Stress ◽  
Ambient Temperature ◽  
Physiological Responses ◽  
Blood Gases ◽  
Respiratory Alkalosis ◽  
Stress Sensitivity ◽  
Late Gestation ◽  
Acid Base Balance ◽  
Study Objective ◽  
Cell Counts

Abstract Pregnant sows, especially during late-gestation, may be susceptible to heat stress due to increased metabolic heat production and body mass. Therefore, the study objective was to determine the thermoregulatory and physiological responses of sows exposed to increasing ambient temperature (TA) at 3 reproductive stages. In 3 repetitions, 27 multiparous sows (parity 3.22±0.89) were individually housed and had jugular catheters placed 5.0±1.0 d prior to the experiment. To differentiate between reproductive stages, sows were categorized as open (not pregnant, n=9), mid-gestation (59.7±9.6 days pregnant, n=9), or late-gestation (99.0±4.8 days pregnant, n=9). During the experiment, sows were exposed to 6 consecutive 1 h periods of increasing TA (period 1, 14.39±2.14°C; period 2, 16.20±1.39°C; period 3, 22.09±1.87°C; period 4, 26.34±1.39°C; period 5, 30.56±0.81°C; period 6, 35.07±0.96°C), with 1 h transition phases in between each period. Respiration rate (RR), heart rate (HR), skin temperature, and vaginal temperature (TV) were measured every 20 min and the mean was calculated for each period. At the end of each period, blood gases, leukocytes, and red blood cell counts were measured. Overall, RR and HR were greater (P≤0.04; 45.6% and 12.9%, respectively) in late-gestation versus mid-gestation sows. Compared to mid-gestation and open sows, TV tended to be greater (P=0.06) during period 4 (0.18°C and 0.29°C, respectively) and period 5 (0.14°C and 0.18°C, respectively) in late-gestation sows. Blood O2 increased (P< 0.01; 18.1%) for all sows with advancing period, regardless of reproductive stage. Late-gestation sows had reduced (P=0.02; 16.1%) blood CO2 compared to mid-gestation sows, regardless of period. In summary, late-gestation sows appear to be more sensitive to increasing TA as indicated by increased RR, HR, TV, and blood O2, and reduced blood CO2 when compared to mid-gestation or open sows. This change in O2 and CO2, due to increasing RR and heat stress sensitivity of late-gestation sows, may suggest an alteration to the acid-base balance, leading to respiratory alkalosis.

Effects of Maternal Nutrient Restriction During Gestation on LH Production in the Female Bovine Fetus

2021 ◽  
Vol 99 (Supplement_2) ◽  
pp. 25-26
Author(s):  
Sterling H Fahey ◽  
Sarah West ◽  
John M Long ◽  
Carey Satterfield ◽  
Rodolfo C Cardoso
Keyword(s):  
Protein Content ◽  
Fetal Development ◽  
Monozygotic Twins ◽  
Late Gestation ◽  
Nutrient Restriction ◽  
Western Blots ◽  
Physiological Processes ◽  
Individual Potential ◽  
The Individual

Abstract Gestational nutrient restriction causes epigenetic and phenotypic changes that affect multiple physiological processes in the offspring. Gonadotropes, the cells in the anterior pituitary that secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH), are particularly sensitive to nutritional changes during fetal development. Our objective herein was to investigate the effects of gestational nutrient restriction on LH protein content and number of gonadotropes in the fetal bovine pituitary. We hypothesized that moderate nutrient restriction during mid to late gestation decreases pituitary LH production, which is associated with a reduced number of gonadotropes. Embryos were produced in vitro with X-bearing semen from a single sire then split to generate monozygotic twins. Each identical twin was transferred to a virgin dam yielding four sets of female twins. At gestational d 158, the dams were randomly assigned into two groups, one fed 100% NRC requirements (control) and the other fed 70% of NRC requirements (restricted) during the last trimester of gestation, ensuring each pair of twins had one twin in each group. At gestational d 265, the fetuses (n = 4/group) were euthanized by barbiturate overdose, and the pituitaries were collected. Western blots were performed using an ovine LH-specific antibody (Dr. A.F. Parlow, NIDDK). The total LH protein content in the pituitary tended to be decreased in the restricted fetuses compared to controls (P < 0.10). However, immunohistochemistry analysis of the pituitary did not reveal any significant changes in the total number of LH-positive cells (control = 460±23 cells/0.5 mm2; restricted = 496±45 cells/0.5 mm2, P = 0.58). In conclusion, while maternal nutrient restriction during gestation resulted in a trend of reduced LH content in the fetal pituitary, immunohistological findings suggest that these changes are likely related to the individual potential of each gonadotrope to produce LH, rather than alterations in cell differentiation during fetal development.

scholarly journals Nutritional strategies to alleviate heat stress effects through feed restrictions and feed additives (vitamins and minerals) in broilers under summer conditions

2019 ◽  
Vol 7 (3) ◽  
pp. 123-131 ◽  
Author(s):  
Mohamed Abdelhameed Salah Abdelhameed ◽  
◽  
Lozovskiy Alexander Robertovich ◽  
Ali Amany Muhammad Ahmed ◽  
◽  
...  
Keyword(s):  
Heat Stress ◽  
Feed Additives ◽  
Stress Effects ◽  
Nutritional Strategies

Alterations in oxytocin prohormone processing during early development in the fetal sheep

1992 ◽  
Vol 263 (3) ◽  
pp. R738-R740 ◽  
Author(s):  
M. Morris ◽  
M. Castro ◽  
J. C. Rose
Keyword(s):  
Fetal Development ◽  
Plasma Levels ◽  
Umbilical Artery ◽  
Umbilical Vein ◽  
Late Gestation ◽  
Developmental Changes ◽  
Fetal Sheep ◽  
Fetal Plasma ◽  
Prohormone Processing ◽  
Specific Antisera

Oxytocin (OT) prohormone processing was studied in fetal sheep. Using specific antisera that recognize the amidated and the COOH-terminal extended forms of OT, we measured arterial and venous levels of the OT peptides in fetal sheep plasma at 94 and 138 days of gestation. Plasma levels of the COOH-terminal extended forms, OT-X, were highest early in development, 35.7 +/- 9.8 vs. 14.3 +/- 5.7 pg/ml (94 vs. 138 days). The ratio of the plasma peptides, OT-X to OT, was higher in the young fetus (35 +/- 11.6 vs. 3.1 +/- 1.3, 94 vs. 138 days). There were also developmental changes in the umbilical artery-umbilical vein differences, with positive values noted in late gestation. These results demonstrate that the changes in the processing of the OT precursor that occur during fetal development are reflected by alterations in the relative amounts of prohormone and amidated hormone found in fetal plasma.

Heat stress effects on source–sink relationships and metabolome dynamics in wheat

2019 ◽  
Vol 71 (2) ◽  
pp. 543-554 ◽  
Author(s):  
Mostafa Abdelrahman ◽  
David J Burritt ◽  
Aarti Gupta ◽  
Hisashi Tsujimoto ◽  
Lam-Son Phan Tran
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Negative Impact ◽  
Grain Filling ◽  
Wheat Breeding ◽  
Wheat Genotypes ◽  
Stress Effects ◽  
Wide Range ◽  
High Yields ◽  
Source Sink

Abstract Crops such as wheat (Triticum spp.) are predicted to face more frequent exposures to heat stress as a result of climate change. Increasing the yield and sustainability of yield under such stressful conditions has long been a major target of wheat breeding, and this goal is becoming increasingly urgent as the global population increases. Exposure of wheat plants in their reproductive or grain-filling stage to high temperature affects the duration and rate of grain filling, and hence has a negative impact on wheat productivity. Therefore, understanding the plasticity of the response to heat stress that exists between wheat genotypes, especially in source–sink relationships at the reproductive and grain-filling stages, is critical for the selection of germplasm that can maintain high yields under heat stress. A broad understanding of metabolic dynamics and the relationships between metabolism and heat tolerance is required in order to achieve this goal. Here, we review the current literature concerning the effects of heat stress on sink–source relationships in a wide range of wheat genotypes, and highlight the current metabolomic approaches that are used to investigate high temperature responses in wheat.

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