Physiology & behavior
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Physiology & behavior · Feb 2015
Heart rate and heart rate variability in multiparous dairy cows with unassisted calvings in the periparturient period.
Behavioural changes before calving can be monitored on farms; however, predicting the onset of calving is sometimes difficult based only on clinical signs. Heart rate (HR) and heart rate variability (HRV) as non-invasive measures of autonomic nervous system (ANS) activity were investigated in Holstein-Friesian cows (N=20) with unassisted calvings in the periparturient period to predict the onset of calving and assess the stress associated with calving. R-R-intervals were analysed in 5-min time windows during the following three main periods of measurement: 1) between 0 and 96 h before the onset of calving restlessness (prepartum period); 2) during four stages of calving: (I) early first stage; between the onset of calving restlessness and the first abdominal contractions; (II) late first stage (between the first abdominal contractions and the appearance of the amniotic sac); (III) early second stage (between the appearance of the amniotic sac and the appearance of the foetal hooves); (IV) late second stage (between the appearance of the foetal hooves and delivery of the calf), and 3) over 48 h following calving (postpartum period). ⋯ Our results indicate that ANS activity measured by HRV indices is a more immediate indicator of the onset of calving than behaviour or HR, as it changed earlier than when restlessness or elevation in HR could be observed. However, because of the possible effects of other physiological mechanisms (e.g. oxytocin release) on ANS activity it seems to be difficult to measure stress associated with calving by means of HRV between the onset of calving restlessness and delivery. Further research is needed to enable more precise interpretation of the prepartum changes in HR and HRV in dairy cattle.
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Physiology & behavior · Feb 2015
Chronic psychological stress in high-anxiety rats induces sustained bladder hyperalgesia.
To evaluate whether anxiety-prone rats exposed to chronic water avoidance stress (WAS) develop visceral bladder hyperalgesia in addition to increased voiding frequency and anxiety-related behaviors. ⋯ Chronic WAS induces sustained bladder hyperalgesia, lasting over a month after exposure to stress. The urinary frequency demonstrated previously in anxiety-prone rats exposed to chronic WAS seems to be associated with bladder hyperalgesia, suggesting that this is a potential model for future studies of bladder hypersensitivity syndromes such as interstitial cystitis/painful bladder syndrome (IC/PBS).
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Physiology & behavior · Jan 2015
Cortisol and pain-related behavior in disbudded goat kids with and without cornual nerve block.
Plasma cortisol and behavior were measured in disbudded goat kids with and without the use of cornual nerve block. A total of 45 kids were used in 5 experimental groups (n=9, males and females). Group LidoD was infiltrated with 1 mL of 2% lidocaine locally at the cornual branches of lacrimal and infratrochlear nerves, 15 min before thermal disbudding. ⋯ Struggles tended to be higher in SD (16.5 ± 2.5), CD (17.8 ± 2.5) and LidoD (15.6 ± 2.5) than Sim (10.6 ± 2.5; p=0.1). The total behavioral response was different between groups (CD, 59.6 ± 6.8; LidoD, 52 ± 6.8; SD, 62.6 ± 6.8; Sim, 36.8 ± 6.8; p=0.05), and disbudded animals showed the strongest reactions (disbudded, 58.1 ± 3.9 vs non-disbudded, 36.8 ± 6.8; p=0.01). It was concluded that cornual nerve block (lacrimal and infratrochlear) using 2% lidocaine did not prevent pain during thermal disbudding of goat kids.
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Physiology & behavior · Jan 2015
Comparative StudyBehavioral study of non-evoked orofacial pain following different types of infraorbital nerve injury in rats.
Directed isolated face grooming following unilateral chronic constriction injury to the infraorbital nerve (IoN-CCI) is a unique measure of spontaneous neuropathic pain. Variability between rats and the limited duration of the increased face grooming behavior has hampered its usefulness. We studied three possible sources of variability: variations in surgery, pre-existing differences in nocifensive behavior between the rats and variation in time. ⋯ It is therefore unclear if pre-existing behavioral differences between animals are a major cause of variability in the IoN-CCI model. Finally, repeated testing showed significant variability in time. It is concluded that tight ligation of the IoN nerve has long-lasting effects on face grooming behavior and that part of the variability in face grooming behavior may be reduced by performing repeated testing.
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Physiology & behavior · Jan 2015
A mouse model for binge-like sucrose overconsumption: Contribution of enhanced motivation for sweetener consumption.
Behavioral and neural features of binge-like sugar overconsumption have been studied using rat models. However, few mouse models are available to examine the interaction between neural and genetic underpinnings of bingeing. In the present study, we first aim to establish a simple mouse model of binge-like sucrose overconsumption using daytime limited access training in food-restricted male mice. ⋯ Our results suggest that even when caloric consumption is not necessarily required, limited access training shapes and triggers binge-like overconsumption of sweetened solution in trained mice. The binge-like behavior in trained mice may be mainly due to enhanced hedonic motivation for the sweetener's taste. The present study suggests that our mouse model for binge-like sugar overconsumption may mimic some human features of binge eating and can be used to investigate the roles of neural and genetic mechanisms in binge-like overconsumption of sweetened substances in the absence of physical hunger.