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Heat stress, coupled with water deprivation, is widely acknowledged as one of the most potent stressors capable of impairing the production performance of small ruminants; therefore, comprehending and mitigating this stressor is of paramount importance. This experiment aimed to investigate the physiochemical adaptability of heat-stressed goats to periods of water deprivation and subsequent rehydration, focusing on determining the minimum time interval required to fully eliminate the carryover effects. Nine healthy Aardi bucks, aged 10 months and weighing 29.14±1.06 kg, underwent three experimental stages: euhydration (EU), dehydration (DE), and rehydration (RE). The EU and DE stages lasted 72 hours each, while the RE stage extended to 10 days. Physiochemical responses, including daily feed intake (DFI), rectal temperature (RT), respiratory rate (RR), hematology, biochemistry, and hemogasometry, were all monitored. Exposure of heat-stressed goats (as evidenced herein by the temperature-humidity index values) to complete water deprivation during the DE stage had manifested significant modulation in their physiological responses (DFI, RT, and RR), which thereby led to notable changes in their hematological, biochemical, and hemogasometric profiles. Surprisingly, blood pH remained unchanged throughout the experiment, underscoring goats’ remarkable adaptive mechanisms to tolerate infrequent liquid intake in their natural hot and arid environment. Notably, all measured variables completely returned to EU levels after 10 days of commencing the RE stage. Based on the obtained findings, a minimum recovery period of 10 days post-rehydration is recommended to eliminate carryover impacts of water deprivation for 72 hours before conducting any further experiments on heat-stressed and water-deprived goats. This research contributes to enhancing goat welfare under harsh environmental conditions. [ABSTRACT FROM AUTHOR]

In light of the escalating global concern regarding adaptation and resilience to elevated temperatures due to climate change, this experiment was designed to assess the thermo-physiological attributes of two native sheep breeds (Najdi and Naimi) and to delineate potential genetic factors conferring heat tolerance amidst acute exposure to elevated ambient temperatures. Meteorological and thermo-physiological parameters were scrutinized at distinct intervals (0 min, 30 min, 120 min, 24 hr, and 48 hr), alongside the analysis of heat-responsive gene expression at 0 min, 30 min, and 120 min, following the exposure of nine healthy male lambs from each breed (mean body weight: 25 kg; age: 4 months) to a bio-meteorologically-simulated environment, maintaining an average ambient temperature of 45 °C (approximately 93 units in the temperature-humidity index). In addition, blood samples were collected from each lamb, with total RNA isolated and purity assessed, followed by qRTPCR analysis of 16 heat stress candidate genes using validated primers and standardized thermocycling protocols, including controls to ensure accuracy. Data were analyzed using statistical methods, including PROC GLM and PROC MEANS in SAS, one-way ANOVA, and pairwise differences with the LSD test for significance, while gene expression differences were calculated using the comparative Ct method and 2 (-Ct) for relative quantification. The findings elucidate that the Najdi breed manifests heightened thermotolerance relative to the Naimi breed, as evidenced by diminished indicators of heat stress, encompassing skin temperature, respiratory rate, packed cell volume, adaptability coefficient, serum total protein, glucose levels, and triiodothyronine concentration. Moreover, analysis of gene expression patterns revealed widespread activation of heat stress-responsive genes in both breeds under thermal stress conditions; however, Najdi lambs consistently exhibited elevated expression levels of these genes compared to their Naimi counterparts. Notably, genes including HSP90AB1, HSPB6, HSF1, STIP1, HSP60, HSP90, and HSPB1 demonstrated particularly pronounced upregulation in Najdi lambs. In conclusion, the integrative thermo-physiological and molecular profiling highlights the superior thermotolerance and evolutionary adaptation of the Najdi breed to the hot climate of the KSA, in contrast to the Naimi breed. [ABSTRACT FROM AUTHOR]

Some basic questions regarding sheep's ability to tolerate different levels of water intake (WI), especially when fed on a pelleted-complete diet (PCD) and reared under comfortable climatic conditions, are still open. To investigate the direct influence of different levels of WI in sheep fed PCD and reared under such conditions on the lambs' physiological (performance, thermal, blood and urine) status, 24 healthy male growing Najdi lambs were exposed under thermo-neutral conditions to three levels of WI (100%, 67%, and 33% of their ad libitum WI or water requirement) for 6 weeks. Meteorological, production performance, thermo-physiological, as well as blood and urine biochemical measurements, were all determined. The obtained findings clearly substantiate that reducing the level of water intake (p<0.05) produced tangible effects in both 67-WI and 33-WI lamb groups. However, 67-WI lambs showed resilience to limited water availability by inducing proportional physiological responses in their production performances, body temperatures, blood metabolites, and renal function but within the homeostatic ranges similar (p>0.05) to 100-WI lambs. Results collectively signify that diminishing WI up to 33% in lambs (fed on PCD and reared under comfortable conditions) would ensure that water is adequately conserved under prevailing water scarcity and can be implemented without compromising their homeostatic functions. Such applied approaches can consequently have a pragmatic aspect through improving water management approaches required for PCD-based sheep production under water scarcity conditions, which is crucial to economical animal production and responsible animal stewardship. Feasibility studies are thereby highly recommended. [ABSTRACT FROM AUTHOR]

To follow the inheritance potential for heat tolerance after a crossing program in goats, 24 kids from four groups of goat kids (6 kids in each) from Aradi (A) and Damascus (D), their crossbred first-generation F1 (½D½A) and second-generation F2 (¾D¼A), were exposed to acute elevated environmental temperature in controlled climatic chambers. Rectal temperature (RT), respiratory rate (RR), heat tolerance coefficient (HTC), adaptability coefficient (AC), and mRNA expression of heat shock proteins 70 and 90 ((HSP70 and HASP90, respectively), using real-time PCR were estimated. Results showed that Aradi breed goats had the highest level of expression for heat shock proteins 70 and 90, followed by F1, F2, and Damascus (P ≤ 0.01). Crossbreeds and Damascus showed the highest RT, while Aradi breed showed the lowest value (P ≤ 0.01). Aradi and crossbreeds showed the highest RR, while Damascus showed the lowest RR (P ≤ 0.05). Aradi and F1 showed the highest HTC (P ≤ 0.05), while there was no significant difference between pure breeds and crossbreeds in AC. A significant positive phenotypic correlation (0.81) was observed between HSP70 and HSP90. In addition, RR showed moderate positive correlation with both HSP70 and HSP90. It could be concluded that Aradi breed had putative heat tolerance in comparison to its crossbred progeny from the Damascus breed. The crossbreeding may result in some loss of heat tolerance potential, but the crossbreeds still better adapted to high environmental temperature than the Damascus breed. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of dietary chromium (Cr) supplementation on the apparent metabolism of some trace elements in camel calves reared under hot summer conditions. The study was conducted on a total of 15 male camel calves (5–6 months old) reared under hot summer conditions for 12 weeks. The animals were housed individually under shelter and divided into three dietary treatment groups (diets supplemented with 0.0, 0.5, or 1.0 mg Cr/kg DM), five animals each. At the end of the study, a metabolic trial was conducted on all camels for the evaluation of trace elements metabolism. Cr excretion, absorption, and retention showed an increasing trend with the increasing level of dietary Cr supplementation. Dietary Cr supplementation at 0.5 mg Cr/kg DM to camel calves resulted in a significant (P < 0.05) increase in Cu and an increasing trend in Zn and Mn excretion via urine and feces. However, Fe retention increased significantly (P < 0.05) in camel calves fed on diet supplemented with Cr. Dietary Cr supplementation to camel calves resulted in an increasing trend of plasma Cr concentration, while plasma concentration of Cu and Zn tended to decrease and without any effect on plasma Fe concentration. The results of the present study suggests that care should be taken for the negative interaction of Cr with the utilization of other trace elements, in cases where Cr is supplemented to the diet as a feed additive to promote growth and immunity under hot climatic conditions. [ABSTRACT FROM AUTHOR]

The physiological response of hemostatic system, assessed by measuring camel's bleeding time, was determined immediately before, after and during the recovery (post 3, 6, 24 and 48 hours) from 2 hours exercise and 72 hours of dehydration in 5 clinically healthy Arabian dromedary camels. It was observed that both conditions resulted in an activation of blood coagulation cascades as demonstrated by a drastic reductions (P<0.05) in the overall means of their bleeding times. Nevertheless, 3 hours post each condition were found sufficient (in exercise: P=0.22, in dehydration: P=0.38) for retrieval of bleeding time to its normal level. Based upon findings, it may be recommended that short periods of exercise and/or dehydration prior to surgical operations can be practiced to minimize bleeding during surgery. However, further investigations are required to clarify the possible role of different intensity and/or duration of these conditions on other hemostatic measurements. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the thermoregulatory and physiological responses of Najdi rams raised under hot summer conditions prevailing in Kingdom Saudi Arabia. The core temperature (Tcore) showed circadian rhythm characterized by biphasic achrophases, which were associated with the feeding times during both seasons. Average daily Tcore was significantly (P<0.05) higher under hot summer conditions. However, the amplitudes of the rhythmic oscillation during winter and summer seasons were 0.85 and 0.56°C, respectively. Rectal (Tre) and skin temperatures (Tsk) were significantly (P<0.05) higher under hot summer conditions and exhibited similar patterns during both seasons concurrent with the pattern of temperature humidity index (THI), reaching the maximum values late in the afternoon and the minimum values early in the morning. Respiratory rate (RR) and heart rate (HR) showed the same pattern of the thermal parameters and were significantly (P<0.05) higher under hot summer conditions. Serum concentrations of total protein, globulin, glucose, sodium and chloride were significantly (P<0.05) increased while those of albumin and calcium were decreased under hot summer conditions. The results obtained from this study indicate that hot summer conditions of Saudi Arabia is thermally stressful to Najdi rams. Therefore, Najdi sheep production under such conditions would require environmental and/or nutritional modification to alleviate the impact of heat stress. [ABSTRACT FROM AUTHOR]