Journal Articles
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Item Comparison of the cardiovascular effects of immobilization with three different drug combinations in free-ranging African lions(Oxford University Press on behalf of The Society for Experimental Biology, 2023-01-12) Donaldson AC; Meyer LCR; Fuller A; Buss PE; Seebacher FThirty-six free-ranging lions (12 per group) were immobilized with tiletamine-zolazepam (Zoletil 0.6 mg/kg i.m.) plus medetomidine (0.036 mg/kg i.m.) (TZM), ketamine (3.0 mg/kg i.m.) plus medetomidine (0.036 mg/kg i.m.) (KM) or ketamine (1.2 mg/kg i.m.) plus butorphanol (0.24 mg/kg i.m.) plus medetomidine (0.036 mg/kg i.m.) (KBM). During immobilization cardiovascular variables were monitored at 5-minute intervals for a period of 30 minutes. Lions immobilized with all three drug combinations were severely hypertensive. Systolic arterial pressure was higher at initial sampling in lions immobilized with KM (237.3 ± 24.8 mmHg) than in those immobilized with TZM (221.0 ± 18.1 mmHg) or KBM (226.0 ± 20.6 mmHg) and decreased to 205.8 ± 19.4, 197.7 ± 23.7 and 196.3 ± 17.7 mmHg, respectively. Heart rates were within normal ranges for healthy, awake lions and decreased throughout the immobilization regardless of drug combination used. Lions immobilized with TZM had a higher occurrence (66%) of skipped heart beats than those immobilized with KBM (25%). The three drug combinations all caused negative cardiovascular effects, which were less when KBM was used, but adverse enough to warrant further investigations to determine if these effects can be reversed or prevented when these three combinations are used to immobilize free-living lions.Item Effect of cocoa consumption on postprandial blood pressure in older adults with untreated hypertension: A randomized crossover clinical trial(Nanchang University, Northwest University, Jiangsu University, Zhejiang University, Fujian Agriculture and Forestry University and John Wiley and Sons Australia, Ltd, 2024-07-15) Osei EO; Amoah I; Lim JJ; Tawiah P; Aduama-Larbi MS; Oduro IN; Cobbinah JC; Dare AP; Diako CCocoa powder is an important dietary source of flavanols that modulate elevated blood pressure (BP). This study aimed to investigate the acute effects of cocoa beverage co-consumption with a high-fat-high-salt meal (HFHSM) on postprandial systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate in older adults living with uncontrolled hypertension. The study was a randomized crossover trial and involved older adults (aged 52.50 ± 9.36 years) (n = 28) living with hypertension. Participants, following an overnight fast, consumed either an HFHSM and cocoa beverage comprising 15 g cocoa powder in 250 mL water (HFHSM + CB; intervention) or HFHSM and 250 mL water (HFHSM + W; control). Resting SBP, DBP, and the heart rate of participants were measured at baseline (−5 min and 0 min) and 15, 30, 45, 60, 90, and 120 min following the consumption of either HFHSM + CB or HFHSM + W using an automated BP monitor. Repeated measures linear mixed model was used to compare the effect of cocoa beverage and water on postprandial outcomes over a 2-h period. A significant reduction (−3.8 ± 0.6 mmHg, p <.05) in resting SBP was observed postprandially following the intake of the HFHSM + CB over the 120-min period compared to the HFHSM + W. The effect was more prominent during the 90- and 120-min time points of the trial duration. No significant change in the DBP and heart rate following the consumption of HFHSM + CB compared to the HFHSM + W was observed. Cocoa beverage co-consumption with HFHSM improved postprandial SBP in older adults living with hypertension.Item Effects of yard weaning and human contact compared to paddock weaning on the liveweight gain and stress reactivity of beef cattle(Taylor and Francis Group, 2023-09-03) Cranston LM; Ramsay BA; Schoorl J-AAJ; Stayton KM; Greaves A; Shanks RD; van Kampen CJ; Cockrem JF; Beausoleil NJ; Morris ST; Sneddon NW; Hickson REIn New Zealand beef herds, calves undergo ‘paddock weaning’ by separating calves and cows into different paddocks. Anecdotal evidence indicates ‘yard weaning’ whereby calves are yarded and receive regular human contact during weaning may improve long-term stress reactivity and growth rates. Calves were allocated to one of three treatments for seven days post-separation from dams: paddock weaned with minimal human interaction (PN), paddock weaned with daily human interaction (PV), yard weaned with daily human interaction (YV). Calf liveweight, behavioural and physiological measures of stress reactivity and faecal corticosterone concentration were measured. Until day seven, YV calves lost less liveweight than PV or PN calves (0.5 kg vs. 3.5 and 4.8 kg P < 0.05). On day seven, PN calves had a 23% greater heart rate compared to YV calves and a greater faecal corticosterone concentration than PV and YV calves (in cohort 2 only) (P < 0.05). This indicates, regular non-aversive human contact during weaning may reduce stress associated with the weaning process itself and reduced stress reactivity to subsequent handling and restraint. However, this effect was transient with no consistent longer-term benefits over traditional paddock weaning, in terms of growth or stress reactivity to human handling.Item Heart Rate and Heart Rate Variability Change with Sleep Stage in Dairy Cows(MDPI (Basel, Switzerland), 2021-07-14) Hunter LB; Haskell MJ; Langford FM; O'Connor C; Webster JR; Stafford KJ; Van Eerdenburg FJCMChanges to the amount and patterns of sleep stages could be a useful tool to assess the effects of stress or changes to the environment in animal welfare research. However, the gold standard method, polysomnography PSG, is difficult to use with large animals such as dairy cows. Heart rate (HR) and heart rate variability (HRV) can be used to predict sleep stages in humans and could be useful as an easier method to identify sleep stages in cows. We compared the mean HR and HRV and lying posture of dairy cows at pasture and when housed, with sleep stages identified through PSG. HR and HRV were higher when cows were moving their heads or when lying flat on their side. Overall, mean HR decreased with depth of sleep. There was more variability in time between successive heart beats during REM sleep, and more variability in time between heart beats when cows were awake and in REM sleep. These shifts in HR measures between sleep stages followed similar patterns despite differences in mean HR between the groups. Our results show that HR and HRV measures could be a promising alternative method to PSG for assessing sleep in dairy cows.Item Blood Pressure and Heart Rate Responses following Dietary Protein Intake in Older Men(MDPI (Basel, Switzerland), 3/05/2022) Oberoi A; Giezenaar C; Lange K; Jones KL; Horowitz M; Chapman I; Soenen SPostprandial hypotension (PPH) occurs frequently in older people >65 years old. Protein-rich supplements, particularly whey protein (WP), are increasingly used by older people for various health benefits. We have reported that 70 g WP drinks cause significant, and in some cases marked, falls in blood pressure (BP) in older men. The effects of lower, more widely used, doses (~30 g) on systolic (SBP) and diastolic (DBP) blood pressure and heart rate (HR) are not known. In a randomized order, eight older men (age: 72 ± 1 years; body mass index (BMI): 25 ± 1 kg/m2) after overnight fast ingested a drink containing (i) a non-caloric control (~2 kcal), (ii) 30 g of whey protein (120 kcal; ‘WP30’), or (iii) 70 g of whey protein (280 kcal; ‘WP70’). The BP and HR were measured in this pilot study with an automated device before and at 3-min intervals for 180 min following drink ingestion. Drink condition effects were determined by repeated-measures ANOVA. The SBP decreased after both WP drinks compared to the control (p = 0.016), particularly between 120 and 180 min, with no difference in the effects of WP30 and WP70. The SBP decreased by ≥20 mmHg in more than 50% of people after both WP drinks (WP30: 63%; WP70: 75%) compared to 38% after the control. The maximum fall in the SBP occurred during the third hour, with the nadir occurring latest after WP70. The DBP decreased non-significantly by several mmHg more after the WP drinks than after the control. The maximum HR increases occurred during the third hour, with the greatest increase after WP70. The SBP decreased after both WP drinks compared to the control, with the effects most evident between 120 and 180 min. Accordingly, ingestion of even relatively modest protein loads in older men has the potential to cause PPH.Item Effects of age on blood pressure and heart rate responses to whey protein in younger and older men(John Wiley and Sons, Inc on behalf of The American Geriatrics Society, 2021-05) Giezenaar C; Oberoi A; Jones KL; Horowitz M; Chapman I; Soenen SBACKGROUND: Postprandial falls in blood pressure (BP) are more common in older compared to younger individuals. The effects of protein compared to carbohydrates and fat on postprandial BP, and the relation to gastric emptying rates, are poorly studied. OBJECTIVES: To determine the effects of a whey protein compared to a control drink on systolic BP (SBP) and diastolic BP (DBP), and heart rate (HR) in healthy younger and older men, and to relate these effects to gastric emptying. DESIGN: A pooled analyses of two randomized, double-blind, cross-over studies. SETTING: Two acute clinical intervention studies with identical study design. PARTICIPANTS: Nineteen older (age: 74 ± 1 years, body mass index: 26 ± 1 kg/m2 ) and 13 younger (23 ± 1 years, 24 ± 1 kg/m2 ) healthy men. INTERVENTION: A 70 g/280 kcal whey-protein or control (water with diet cordial, ~2 kcal) drink (450 ml). MEASUREMENTS: BP and HR were assessed with an automated device immediately before and at 3-min intervals after drink ingestion (0-180 min). Gastric emptying of the drinks was measured using 3D ultrasonography (0-180 min). RESULTS: Older versus younger men exhibited a greater fall in SBP (-23 ± 2 vs -15 ± 2 mmHg, p = 0.001) after whey-protein versus control, as BP did not change after the two drinks in younger men (p > 0.05). The nadir in SBP occurred later in the older than younger men (114 ± 11 vs 62 ± 14 min; p < 0.001), with SBP still apparently declining 180 min after whey-protein ingestion in the older men. The magnitude of the rise in HR was greater (p < 0.05) in the younger than older men. CONCLUSION: Following ingestion of 70 g whey protein, healthy older men exhibited a sustained fall in BP, despite an increase in HR, whereas in younger men there was no change in BP. BP may need to be monitored after high protein meals in older people at risk of postprandial hypotension.