scholarly journals Physiological and Genetic Adaptation of Desert Sheep and Goats to Heat Stress in the Arid Areas of Egypt

2021 ◽  
pp. 106499
Author(s):  
A.M Aboul Naga ◽  
T.M. Abdel Khalek ◽  
Mona Osman ◽  
A.R. Elbeltagy ◽  
E.S. Abdel-Aal ◽  
...  
Keyword(s):  
Heat Stress ◽  
Genetic Adaptation ◽  
Arid Areas ◽  
Sheep And Goats

Resting and field metabolic rates of Awassi sheep and Baladi goats raised by Negev bedouin

2020 ◽  
Vol 158 (5) ◽  
pp. 431-437
Author(s):  
Michael Kam ◽  
Shaher El-Meccawi ◽  
Arieh Brosh ◽  
A. Allan Degen
Keyword(s):  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
Arid Areas ◽  
Metabolic Rates ◽  
Herbaceous Vegetation ◽  
Sheep And Goats ◽  
Awassi Sheep ◽  
Natural Pasture ◽  
Field Metabolic Rates ◽  
The Cost

AbstractSheep are grazers and goats are intermediate feeders. By employing O2 consumption and heart rate measurements, resting metabolic rate (RMR) and field metabolic rate (FMR) were determined in four male fat-tailed Awassi sheep (44.0 ± 3.94) and four male Baladi goats (35.5 ± 5.42 kg) that were co-grazing natural pasture in the Negev Desert. There were 67.7 ± 3.75 g DM/m2 of herbaceous vegetation biomass, which was rapidly becoming senescent and more fibrous. We hypothesized that FMR of these desert-adapted ruminants would be relatively low when compared to other sheep and goat breeds, as animals in arid areas tend to have low metabolic rates. Both sheep (n = 6) and goats (n = 6) foraged 71% of the allotted 11 h free-pasture period; however, sheep grazed more than goats (P < 0.001); whereas goats browsed more than sheep (P < 0.001). RMR was higher (P = 0.007) in sheep than in goats (529 ± 23.5 v. 474 ± 25.4 kJ/kg0.75 BW/d), but FMR did not differ between species (618 ± 55.7 v. 613 ± 115.2 kJ/kg0.75 BW/d). In addition, the cost of activities, as a proportion of FMR, did not differ between sheep and goats; FMR increased by 89 kJ/kg0.75 BW/d or 17% in sheep and by 138 kJ/kg0.75 BW/d or 29% in goats. In comparing FMRs of sheep and goats in this study with these species in other studies, differences were inconsistent and, therefore, our hypothesis was not supported.

scholarly journals Towards Heat Stress Management in Small Ruminants – A Review

2017 ◽  
Vol 17 (1) ◽  
pp. 59-88 ◽  
Author(s):  
Amani Al-Dawood
Keyword(s):  
Heat Stress ◽  
Small Ruminants ◽  
Well Being ◽  
Economic Losses ◽  
Natural Immunity ◽  
Animal Products ◽  
Sheep And Goats ◽  
Agriculture Sector ◽  
Hot Climate ◽  
The Impact

Abstract Small ruminants (sheep and goats) play a predominant role in the economy of million people, and have provided meat, milk, skin, wool and fiber for centuries. Animals undergo various kinds of stressors, i.e. physical, nutritional, chemical, psychological and heat stress (HS). Among all, HS is the most concerning at present in the ever-changing climatic scenario. Climate change is the most serious long-term challenge faced by small ruminants’ owners worldwide. HS results in decreased growth, reproduction, production, milk quantity and quality, as well as natural immunity, making animals more vulnerable to diseases, and even death. Thus, HS results in great economic losses, emphasizing the necessity to objectively assess animal welfare. The increasing demand for animal products paralleled by the frequent hot climate is a serious threat for the agriculture sector. The ability of sheep and goats to cope with HS without harming their welfare and productive performance has been often overrated. To date, little attention has been paid to comprehensive detailed data on the adverse effect of HS on sheep and goats. Therefore, this review discusses in detail the sheep and goats’ behavioral, physiological, molecular/cellular, hematological, biochemical and immunological responses under HS conditions. In addition, this review also presents the adverse effects of HS on reproduction and fertility, milk quantity and quality, feed intake, and water consumption of sheep and goats. Finally, this review suggests various methods for HS alleviation. In conclusion, HS impairs productivity and well-being in sheep and goats. The improved understanding of the impact of HS on small ruminants will help in developing management techniques to alleviate HS and highlighting the need for future researches on HS in sheep and goats.

scholarly journals Effects of Heat Stress on Heart Rate Variability in Free-Moving Sheep and Goats Assessed With Correction for Physical Activity

2021 ◽  
Vol 8 ◽  
Author(s):  
Kaho Kitajima ◽  
Kazato Oishi ◽  
Masafumi Miwa ◽  
Hiroki Anzai ◽  
Akira Setoguchi ◽  
...  
Keyword(s):  
Physical Activity ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Heat Stress ◽  
Small Ruminants ◽  
Cardiac Activity ◽  
Heart Beat ◽  
Invasive Technique ◽  
Sheep And Goats ◽  
Non Linear

Heart rate variability (HRV) is the heart beat-to-beat variation under control of the cardiovascular function of animals. Under stressed conditions, cardiac activity is generally regulated with an upregulated sympathetic tone and withdrawal of vagal tone; thus, HRV monitoring can be a non-invasive technique to assess stress level in animals especially related to animal welfare. Among several stress-induced factors, heat stress is one of the most serious causes of physiological damage to animals. The aim of this study was to assess the effects of heat stress on HRV in small ruminants under free-moving conditions. In three experimental periods (June, August, and October), inter-beat intervals in sheep and goats (three for each) in two consecutive days were measured. HRV parameters were calculated from the inter-beat interval data by three types of analyses: time domain, frequency domain, and non-linear analyses. The temperature–humidity index (THI) was used as an indicator of heat stress, and vectorial dynamic body acceleration (VeDBA) was calculated to quantify the physical activity of the animals tested. First, we investigated correlations of THI and VeDBA with HRV parameters; subsequently, THI was divided into five categories according to the values obtained (≤ 65, 65–70, 70–75, 75–80, and &gt;80), and the effects of the THI categories on HRV parameters were investigated with and without correcting for the effects of physical activity based on the VeDBA. The results indicated that HRV significantly decreased with increasing THI and VeDBA. For non-linear HRV parameters that were corrected for the effects of physical activity, it was suggested that there would be a threshold of THI around 80 that strongly affected HRV; high heat stress can affect the autonomic balance of animals non-linearly by inducing the sympathetic nervous system. In conclusion, to assess psychophysiological conditions of unrestrained animals by HRV analysis, the confounding effect of physical activity on HRV should be minimized for a more precise interpretation of the results.

scholarly journals Adaptive Capacity of Saidi Sheep and Goats to Heat Stress and Diurnal Variation under the Hot Dry Conditions of Upper Egypt

2021 ◽  
Vol 58 (3) ◽  
pp. 123-129
Author(s):  
Adel Aboulnaga ◽  
Mohmed Hayder ◽  
Mohmed Abdelkhalek ◽  
Mohmed Shafie ◽  
Taha AbdelSabour ◽  
...  
Keyword(s):  
Heat Stress ◽  
Diurnal Variation ◽  
Adaptive Capacity ◽  
Upper Egypt ◽  
Sheep And Goats ◽  
Dry Conditions

scholarly journals Influence of heat stress on milk production and its financial implications in semi-arid areas of South Africa

Heliyon ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. e06202
Author(s):  
Abiodun A. Ogundeji ◽  
Hermela Lakew ◽  
Weldemichael Tesfuhuney ◽  
Willem Lombard
Keyword(s):  
South Africa ◽  
Heat Stress ◽  
Milk Production ◽  
Arid Areas ◽  
Semi Arid

scholarly journals Heat-induced maternal effects shapes avian eggshell traits and embryo response to high temperatures

2021 ◽  
Author(s):  
Alexander Hoffman ◽  
Leslie Dees ◽  
Haruka Wada
Keyword(s):  
Heat Stress ◽  
Thermal Stress ◽  
Phenotypic Plasticity ◽  
Thermal Environment ◽  
Genetic Adaptation ◽  
Pore Density ◽  
Transgenerational Plasticity ◽  
The Face ◽  
Incubation Temperatures ◽  
Rapid Environmental Change

Abstract Populations without a sufficient rate of genetic adaptation may risk extinction in the face of rapid environmental change, however, phenotypic plasticity can facilitate their persistence. For example, mothers can prepare offspring for the thermal environment young will experience through transgenerational plasticity. In oviparous species, whether mothers can prepare offspring to cope with thermal stress experienced as embryos is largely unknown. We demonstrate that when zebra finch mothers are exposed to a heat stress, their offspring show altered heart rates as embryos in response to high incubation temperatures, as well as an increase in eggshell pore density that was positively correlated with survival. These results are the first to show that temperature induced transgenerational plasticity may promote embryonic survival in an oviparous species.

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