2026-09-05T21:22:06Zhttps://gredos.usal.es/oai/requestoai:gredos.usal.es:10366/1620142025-04-30T20:39:47Zcom_10366_137028com_10366_4512com_10366_3823col_10366_137029
Palacios Riocerezo, Carlos
Plaza Martín, Javier
Abecia, José Alfonso
2025-01-20T11:32:55Z
2025-01-20T11:32:55Z
2021-08-13
Palacios, C., Plaza, J., y Abecia, J.-A. (2021). A high cattle-grazing density alters circadian rhythmicity of temperature, heart rate, and activity as measured by implantable bio-loggers. Frontiers in Physiology, 12, 707222. https://doi.org/10.3389/fphys.2021.707222
http://hdl.handle.net/10366/162014
10.3389/FPHYS.2021.707222
1664-042X
Six cows managed under extensive grazing conditions were used to study the effect of
moving the animals to a higher grazing density on the circadian rhythms of temperature
(T), heart rate (HR), and activity (ACT), which were recorded by implantable bio-loggers.
Cows were maintained at a density of 1.5 livestock units per hectare (LSUs/ha; low density,
LD) until they were moved to a grazing area at 128 LSUs/ha (high density, HD). Animals
were implanted subcutaneously with a T, HR, and ACT bio-logger, which was programmed
to record data at 5-min intervals. For each animal, cosinor rhythmometry (the study of
circadian rhythms by fitting a sine wave to a time series) was applied to the data recorded
over 5 days in LD and HD. Mean Midline Estimating Statistic of Rhythm (MESOR; the
average value around which the variable oscillates), amplitude (difference between the
peak and the mean value of a wave), and acrophase (timing of peak activity) were calculated
and evaluated statistically. Differences between mean day and nighttime values, and mean
LD and HD values were calculated. Cows presented cosinor curves that fit a 24-h rhythm
(p < 0.001) in T, HR, and ACT at both densities. MESOR (T: 37.98 vs. 38.02°C; HR: 69.12
vs. 65.91 bpm; ACT: 49.39 vs. 40.41 mg, for LD and HD, respectively) and amplitude (T:
0.28 vs. 0.28°C; HR: 4.12 vs. 3.14 bpm; ACT: 18.14 vs. 11.28 mg, respectively) did not
differ significantly between the two densities; however, significant (p < 0.05) differences
between densities occurred in the acrophase of the three variables; specifically, the T
acrophase was 2 h later at HD (22:45 h) than LD (20:45 h), and HR (LD: 19:51; HD: 16:49 h)
and ACT acrophases 3 and 2 h earlier at HD than LD (LD: 14:47; HD: 12:49 h), respectively.
T and ACT differed significantly (p < 0.01) between daytime (mean ± SE; 37.92 ± 0.19°C,
40.39 ± 4.74 mg) and nighttime (38.14 ± 0.17°C, 29.93 ± 5.66 mg). In conclusion, our
study suggests that a high animal grazing density might exacerbate the social competence
for valuable resources for animals, resulting in shifting the circadian rhythmicity of
temperature, heart rate, and activity of the cows, advancing or delaying their acrophases.
eng
Frontiers
Cattle
Density
Bio-loggers
Circadian rhythm
Temperature
Heart rate
Ganado
Biólogos
Ritmo circadiano
Temperatura
Frecuencia cardiaca
3103 Agronomía
2401 Biología Animal (Zoología)
A High Cattle-Grazing Density Alters Circadian Rhythmicity of Temperature, Heart Rate, and Activity as Measured by Implantable Bio-Loggers
info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
https://doi.org/10.3389/fphys.2021.707222
info:eu-repo/semantics/openAccess
Frontiers in Physiology
12