The daily rhythm of body temperature, heart and respiratory rate in newborn dogs.
We asked whether, during the postnatal period, the daily patterns of body temperature (Tb), heart rate (HR) and breathing frequency (f) begin and develop in synchrony. To this end, measurements of HR, f and Tb were performed weekly, on two consecutive days, for the first two postnatal months on puppies of three breeds of dogs (Rottweiler, Cocker Spaniel and Carlino dogs) with very different birth weights and postnatal growth patterns. Ambient conditions and feeding habits were constant for all puppies. The results indicated that (1) the 24-h average Tb increased and average HR and f decreased with growth, (2) the daily rhythms in Tb were apparent by 4 weeks, irrespective of the puppy's growth pattern, (3) the daily rhythm of Tb in the puppy was not necessarily following that of the mother; in fact, it could anticipate it. (4) The daily rhythms in HR and f were not apparent for the whole study period. We conclude that in neonatal dogs the onset of the daily rhythms of Tb has no obvious relationship with body size or rate of growth and is not cued by the maternal Tb rhythm. The daily rhythms of HR and f do not appear before 2 months of age. Hence, they are not in synchrony with those of Tb.
Laboratorio di Cronofisiologia Veterinaria, Dipartimento di Scienze Sperimentali e Biotecnologie Applicate, Facoltà di Medicina Veterinaria, Università degli Studi di Messina, Polo Universitario dell'Annunziata, 98168, Messina, Italy. giuseppe.piccione@unime.it
Giuseppe
G
Piccione
Elisabetta
E
Giudice
Francesco
F
Fazio
Jacopo P
JP
Mortola
D000375:Aging / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000502:physiology*; D049628:Body Size / Q000502:physiology; D001831:Body Temperature / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D004285:Dogs / Q000145:classification / Q000254:growth & development / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D008297:Male; D015656:Respiratory Mechanics / Q000502:physiology*