A Complex Interrelationship between Rectal Temperature and Dairy Cows’ Performance under Heat Stress Conditions

Upper limit of thermal stability and subsequent rise of thermoregulatory functions are affected by body temperature. This study was designed to determine the effects of rectal temperature (RT) on dairy cows’ performance (heart rates (HR), respiratory rates (RR), milk yield (MY), dry matter intake (DMI), digestibility, plasma concentration of vitamin C under hot climate. This study was carried out in 2009, in north-west of Tunisia using 30 Holstein cows in mid lactation. The experiment was performed in spring (15th of February-15th of March: P1) and summer (1st-30th of August: P2). On each test day, temperature-humidity index (THI), RT, HR, RR, MY, DMI, digestibility and plasma VC concentration were determined. All this parameters were affected (P < 0.001) when the THI increased from 65.62 (P1) to 83.27 (P2). Regression analyses were carried out between THI index and some parameters (HR, RR, MY, DMI, digestibility, plasma concentration of vitamin C) and between RT and same parameters (HR, RR, MY, DMI, digestibility, plasma concentration of vitamin C). Characteristics of regression analyses in the two modes were different as also were R2 and r (correlation coefficient) of the regressions. R2 in regressions on RT (R2 (RT, DMI) = 0.92 (P < 0.01);R2 (RT, MY) = 0.91 (P < 0.001)) was markedly higher relative to R2 in regressions on THI (R2 (THI, DMI) = 0.76 (P < 0.001);R2 (THI, MY) = 0.63 (P < 0.001)). The two regressions modes suggest that increasing R2 in regressions on RT confirms that rectal temperature constitutes a larger component of total variance of responses in dairy cows to hot environmental temperature.

Emergency department rectal temperatures in over 10 years:A retrospective observational study

BACKGROUND:Fever in patients can provide an important clue to the etiology of a patient's symptoms.Non-invasive temperature sites(oral,axillary,temporal) may be insensitive due to a variety of factors.This has not been well studied in adult emergency department patients.To determine whether emergency department triage temperatures detected fever adequately when compared to a rectal temperature.METHODS:A retrospective chart review was made of 27 130 adult patients in a high volume,urban emergency department over an eight-year period who received first a non-rectal triage temperature and then a subsequent rectal temperature.RESULTS:The mean difference in temperatures between the initial temperature and the rectal temperature was 1.3 °F(P<0.001),with 25.9%of the patients having higher rectal temperatures >2°F,and 5.0%having higher rectal temperatures >4 °F.The mean difference among the patients who received oral,axillary,and temporal temperatures was 1.2 °F(PO.001),1.8 °F(PO.001),and 1.2 °F(P<0.001) respectively.About 18.1%of the patients were initially afebrile and found to be febrile by rectal temperature,with an average difference of 2.5 °F(P<0.001).These patients had a higher rate of admission(61.4%,P<0.005),and were more likely to be admitted to the hospital for a higher level of care,such as an intensive care unit,when compared with the full cohort(12.5%vs.5.8%,P<0.005).CONCLUSIONS:There are significant differences between rectal temperatures and noninvasive triage temperatures in this emergency department cohort.In almost one in five patients,fever was missed by triage temperature.

Comparison of the effects of cold water and ice ingestion on endurance cycling capacity in the heat

Purpose: The purpose of this study was to examine the effects of pre-cooling and fluid replacement with either crushed ice or cold water.Methods: On 2 separate occasions, in a counterbalanced order, 9 recreationally-trained males ingested 1.25 g/kg(80–100 g) of either crushed ice(0.5℃)or cold water(4℃) every 5 min for 30 min before exercise. They also ingested 2.0 g/kg(130–160 g) of the same treatment drink at 15 min, 30 min, and45 min after the commencement of cycling to exhaustion at 60%VO_(2max) until voluntary exhaustion in a hot environment(35℃ and 30% relative humidity).Results: The cycling time to exhaustion in the crushed ice trial(50.0 ± 12.2 min) was longer than the cold water trial(42.2 ± 10.1 min; p = 0.02).Although the rectal temperature fell by 0.37℃± 0.03℃(p = 0.01) at the end of the resting period after the crushed ice ingestion, the rates of rise in rectal temperature during the exercise period were not significantly different between these 2 conditions(crushed ice: 0.23℃± 0.07℃, 5 min;cold water: 0.22℃± 0.07℃, 5 min; p = 0.94).Conclusion: Crushed ice ingestion before and during exercise in a hot environment may be a preferred and effective approach for minimizing thermal strain, and for improving endurance performance as compared with cold water ingestion.

Evaluation of the diuretic effects of crude stem bark extraction of Zanthoxylum heitzii(Rutaceae) in Wistar rats

OBJECTIVE： Zanthoxylum heitzii is a medicinal plant widely used in central Africa for the treatment of many diseases, especially cardiovascular diseases and hypertension. The diuretic effects of crude stern bark extraction were determined and its safety in rats was evaluated. METHODS： The diuretic effects of crude stem bark extraction of Z. heitzii were investigated in Wistar rats （250 g ＋ 10 g） of both sexes. The crude stem bark extraction of Z. heitzii at the doses of 225, 300 and 375 mg/kg was administered to rats at 5 mL/kg body weight. Urine volume was determined 1, 2, 3, 4, 5, 6 and 24 h after administration of the extract. Kinetics of electrolyte elimination in response to a single oral administration dose of acute treatment was measured. The experiments were performed under the same conditions with two synthetic pharmacological diuretics considered as reference （furosemide and hydrochlorothiazide）. Urinary and plasma concentrations of sodium and potassium ions were determined using flame photometry. Concentrations of creatinine, urea, glucose, albumin and electrolytes in the plasma and urine samples were evaluated using a two-way digital bidirectional spectrophotometer. The osmolarity of plasma and urine samples was measured by cytometry using an osmometer. Aldosterone was measured by radioimmunoassay. RESULTS： The plant extract accelerated the elimination of overloaded fluid and increased urine volume and the excretion of Na＋, K＋ and CI 24 h after administration （P〈0.05）. The increase in elimination of Na＋, K＋, and Cl- induced by the extract caused alkalinization of the urine, and showed a strong inhibitory effect on carbonic anhydrase and saluretic. These effects were mainly observed at the dose of 375 mg/kg. At the maximum diuretic response, urinary osmolarity decreased significantly （P 〈 0.05） when compared to controls. The stability of aldosterone level, the absence of correlation with the plasma levels of Na＋, and increased clearance of free water in the animals treated with extract indicated that increased diuresis and natriuresis were tubular in origin. No significant （P 〉 0.05） changes were observed in the body temperature of the animals. CONCLUSION： The significant increase in urine volume 24 h after treatment followed a doseresponse pattern. The excretion of Na＋, K＋ and Cl- caused a decrease in urine osmolarity. The stability of aldosterone, the absence of correlation with the plasma levels of sodium, and increased clearanceof free water in animals treated with aqueous extract suggest that increased diuresis and moderate natriuresis elevation were of tubular origin.