Effect of housing conditions and owner’s schedule on daily total locomotor activity in dogs (Canis familiaris)

Chronophysiology of domestic animals

This review highlights recent findings on biological rhythms and discusses their implications for the management and production of domestic animals. Biological rhythms provide temporal coordination between organs and tissues in order to anticipate environmental changes, orchestrating biochemical, physiological and behavioural processes as the right process may occur at the right time. This allows animals to adapt their internal physiological functions, such as sleep-wake cycles, body temperature, hormone secretion, food intake and regulation of physical performance to environmental stimuli that constantly change. The study and evaluation of biological rhythms of various physiological parameters allows the assessment of the welfare status of animals. Alteration of biological rhythms represents an imbalance of the state of homeostasis that can be found in different management conditions.

Beacon-based sleep-wake monitoring in dogs

The sleep-wake cycle represents a crucial physiological process essential for maintaining homeostasis and promoting individual growth. In dogs, alterations in sleep patterns associated with age and dog's correlation with temperament factors, such as nervousness, have been reported, and there is an increasing demand for precise monitoring of sleep and physical activity in dogs. The present study aims to develop an analysis method for measuring sleep-wake patterns and physical activity in dogs by utilizing an accelerometer and a smartphone. By analyzing time series data collected from the accelerometer attached to the dog's collar, a comprehensive sleep and activity analysis model was constructed. This model classified the activity level into seven classes and effectively highlighted the variations in sleep-activity patterns. Two classes with lower activity levels were considered as sleep, while other five levels were regarded as wake based on the rate of occurrence. This protocol of data acquisition and analysis provides a methodology that enables accurate and extended evaluation of both sleep and physical activity in dogs.

Persistence of clock gene expression in peripheral blood in dogs maintained under different photoperiod schedules

Dogs are the common pets adopted by humans, and their circadian behavior and physiology are influenced by human habits. In many families, there is a change of lifestyle with respect to the natural daylight (NDL) cycle. Exposure to constant light disrupts some central and peripheral circadian rhythms. The aim of the present study was to improve the knowledge about the circadian changes of clock components in the peripheral blood in dogs housed under NDL and constant light (LL) conditions. Blood samples were collected on five female Beagle dogs (2 years old, 14 ± 0.5 kg) every 4 hours for a 24-hour period during an NDL (Sunrise 05:05 h - Sunset 20:55  h) and 24-hour period of constant light (LL). Blood samples were stored in a PAX gene Blood RNA Tube, real-time RT-quantitative polymerase chain reaction was performed to determine Clock, Per1-3, and Cry1-2 gene expression. During the NDL, all genes investigated showed robust diurnal daily rhythmicity. During the constant light, only Clock maintained its daily rhythmicity. Clock acrophase was observed close to sunrise (ZT 0) and was statistically different from the other clock genes except for Per3. Per3 daily oscillations were not statistically significant. No differences were observed among the clock genes tested in the amplitude and robustness values. Our results can be considered preliminary data to provide new insights into the adaptation mechanism of the canine peripheral circadian clock. The persistence of Clock gene expression during the LL indicated the presence of an endogenously generated signal in blood. Because peripheral blood is an easily accessible sample in dogs, the analysis of clock gene expression in this tissue could be useful to investigate the adaptive capacity of this species housed in different environmental conditions linked to the owner's lifestyle.

An In-Depth Look at Fonni's Dog Behavior under Different Outdoor Conditions

This study aimed to investigate the common social and communicative behaviors of the Fonni's Dog under different outdoor conditions. For this study, 70 adult dogs (3-7 years; 32 intact males, 38 intact females) belonging to the Fonni's breed were used. A total of 35 dogs were kept in kennels and 35 were free-ranging dogs in their sheep/goat livestock units. A behavioral repertoire was adapted from the literature and an ethogram was filled in for each dog. All dogs were evaluated in the presence of the owner. Fisher's exact test, following Bonferroni's correction, was used to test possible differences in the categorical variables (presence or absence of the behavior) between free-ranging dogs and dogs kept in kennels. The study revealed that several categories of the dogs' body language were associated with the management condition. However, the breed motivations (guarding and defense of the territory) were satisfied both in kennel and in the animals who were free in the property. The current study suggests a good behavioral balance of the Fonni's Dogs which could be attributed to correct communication between dogs and owners.

Hospitalization disrupts the daily rhythm of tear production in cats

OBJECTIVE

The exposure to constant light during the hospitalization was investigated to verify its influence on the daily rhythmicity of Schirmer tear test I (STT I) in the Felis catus.

ANIMAL STUDIED

One group (HG-hospitalized group) was consisted of 10 owned-cats hospitalized to perform a sterilization procedure and was exposed to a 24/0 light/dark (L/D) cycle; the cat control group (CG) was consisted of 10 staff-owned cats living in an indoor environment (12/12 L/D cycle).

PROCEDURE

The STT I values was performed at 4 h intervals over a 48 h period (starting at 8:00 a.m. on Day 1 and finishing at 8:00 a.m. on Day 3) on the left (LE) and right (RE) eyes into two cat groups. A 35 x 5 mm commercial tear test strip was used to record tear production in millimeters wetting per minute (mm/min).

RESULTS

Multivariate for repeated measure analysis of variance (ANOVA) showed a statistically significant effect of time. No difference was found between LE and RE tear production, and between the two experimental conditions. Robust daily rhythmicity was exhibited by the STT I in both eyes during the entire monitoring period in control cats and only during the Day 1 in hospitalized cats.

CONCLUSIONS

These data are a starting point for evaluating the imbalance of ocular physiology observed in hospitalized cats. Further studies on larger sample size and exposing the animals to various hospitalization procedures are needed to establish whether these alterations are caused by hospitalization procedures or by the light/dark schedules.

Amplitude of the daily pattern of rest – activity in different species of Leopardus kept in captivity

Closer examination of the diurnal or nocturnal nature of wildlife species improves the knowledge necessary for landscape identity and biodiversity preservation. The aim of this study was to evaluate the daily rhythmicity of total locomotor activity in wild felids of several species of Leopardus of similar body weight housed in captivity: Geoffroy’s cat (Leopardus geoffroyi), ocelot (Leopardus pardalis), oncilla (Leopardus tigrinus) and margay (Leopardus wiedii). Twenty-four felids, six animals for each species, were housed under a natural light/dark cycle. The activity was recorded for thirteen consecutive days by means of an actimeter attached to a neck collar. Using cosinor rhythmometry, circadian rhythmic parameters (mesor, amplitude and acrophase) were assessed and compared among the several species. The daily and individual chronobiological variations of rest and activity showed a well-defined pattern. A nocturnal daily rhythmicity of locomotor activity was observed in Geoffroy’s cat, ocelot, oncilla and margay. The acrophase was observed shortly after midnight in margay and Geoffroy’s cat, and early at night in oncilla and ocelot. Our results improve the knowledge about the circadian system in wild animals. They can be a contribution to understanding the adaptive behaviour of wild felid species kept in zoological parks and rehabilitation agencies in providing the proper care for these animals

A functional linear modeling approach to sleep-wake cycles in dogs

The study of companion (pet) dogs is an area of great translational potential, as they share a risk for many conditions that afflict humans. Among these are conditions that affect sleep, including chronic pain and cognitive dysfunction. Significant advancements have occurred in the ability to study sleep in dogs, including development of non-invasive polysomnography; however, basic understanding of dog sleep patterns remains poorly characterized. The purpose of this study was to establish baseline sleep-wake cycle and activity patterns using actigraphy and functional linear modeling (FLM), for healthy, adult companion dogs. Forty-two dogs were enrolled and wore activity monitors for 14 days. FLM demonstrated a bimodal pattern of activity with significant effects of sex, body mass, and age; the effect of age was particularly evident during the times of peak activity. This study demonstrated that FLM can be used to describe normal sleep-wake cycles of healthy adult dogs and the effects of physiologic traits on these patterns of activity. This foundation makes it possible to characterize deviations from normal patterns, including those associated with chronic pain and cognitive dysfunction syndrome. This can improve detection of these conditions in dogs, benefitting them and their potential as models for human disease.

Validation of locomotion scoring as a new and inexpensive technique to record circadian locomotor activity in large mammals

Background

The locomotor activity (LA) rhythm, widely studied in rodents, has not been fully investigated in large mammals. This is due to the high cost and the brittleness of the required devices. Alternatively, the locomotion scoring method (SM), consisting of attribution of a score to various levels of activity would be a consistent method to assess the circadian LA rhythm in such species.

New method

To test this, a SM with a score ranging from 0 to 5 has been developed and used in two domestic large mammals, the camel and the goat. One minute interval scoring was performed using visual screening and monitoring of infra-red camera recording videos and carried out by two evaluators.

Results

The SM provides a clear daily LA rhythm that has been validated using an automate device, the Actiwatch-Mini. The obtained curves and actograms were indeed highly similar to those acquired from the Actiwatch-Mini. Moreover, there were no statistical differences in the period and acrophase. The period was exactly of 24.0h and the acrophases occurred at 12h05 ± 00h03 and 12h14 ± 00h07 for the camel and at 13h13 ± 00h09 and 12h57 ± 00h09 for the goat using SM and Actiwatch-Mini respectively.

Comparison with existing methods

Compared to the automatic system, the SM is inexpensive and has the advantage of describing all types of performed movements.

Conclusions

The new developed SM is highly reliable and sufficiently accurate to assess conveniently the LA rhythm and specific behaviors in large mammals. This opens new perspectives to study chronobiology in animal models of desert, tropical and equatorial zones.