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Comparative Study of Heart Rate Variability Between Holstein Cattle and Mini Cows
by
, , ,
Carlos Javier Lainez Reyes
1,
Simone Biagio Chiacchio
1,
Paola Alejandra Montenegro Cuellar
1,
Lucas Vinícius de Oliveira Ferreira
1
,
Dario Alejandro Cedeño Quevedo
2,
Miriam Harumi Tsunemi
1,
Renata Benedetti Cepinho
1,
Rodrigo Francisco
1 and
Maria Lúcia Gomes Lourenço
1,* 1
Department of Veterinary Clinics, School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Botucatu 18618-970, SP, Brazil
2
Department of Animal Health, Faculty of Animal Sciences, University of Nariño (UDENAR), Pasto 52001, Colombia
*
Author to whom correspondence should be addressed.
Animals 2026, 16(12), 1909; https://doi.org/10.3390/ani16121909 (registering DOI)
Submission received: 4 April 2026
/
Revised: 12 June 2026
/
Accepted: 16 June 2026
/
Published: 19 June 2026
(This article belongs to the Section Cattle)
Simple Summary
Miniature cattle are becoming popular as a sustainable alternative to traditional large dairy breeds, but very little is known about their heart health. In this study, we compared the heart rhythm patterns of miniature cows and Holstein cows to see if their smaller body size affects the way their hearts are regulated. We measured heartbeats using a non-invasive sensor placed on the animals and analyzed the natural variations that occur between beats, which reflect how the body balances stress and relaxation. Our results showed that miniature cows had slower heart rates and stronger natural variation between beats compared to Holstein cows, with differences becoming more noticeable in mature animals. However, because the cows were evaluated on different farms, and only the Holstein cows were actively producing milk, these findings represent preliminary associations rather than direct proof of breed-specific adaptations. Overall, this observational study shows that portable sensors are practical tools for field monitoring and provides a useful baseline for future, more controlled research on the cardiovascular well-being of miniature cattle.
Abstract
Heart rate variability (HRV) is an established biomarker of autonomic nervous system activity, yet its profile in miniature cattle remains poorly understood despite their growing importance in sustainable farming. This study compared HRV parameters between miniature and Holstein cows and assessed the influence of age on these profiles. Eighty clinically healthy female cattle (40 miniature, 40 Holstein), aged 2 to 8 years, were evaluated under field conditions using a Polar H10 heart rate monitor. RR intervals were analyzed using Kubios HRV software to obtain time- and frequency-domain indices. Miniature cows exhibited significantly lower heart rates and higher time-domain measures (RMSSD and SDNN) compared to Holsteins, while frequency-domain analysis revealed significant differences in LF, HF, and LF/HF ratio, suggesting group-associated differences in proportional autonomic balance. Age-stratified analysis revealed that these physiological distinctions were more pronounced in older cows (6–8 years). However, given the observational cross-sectional design of this study, confounding factors—specifically the different farm environments, management systems, and the active lactation status of the Holstein group—preclude attributing these differences solely to breed or body size. Therefore, these results suggest an associative physiological pattern rather than a definitive autonomic adaptation. Despite these limitations, portable HRV monitoring proved feasible under farm conditions, providing valuable preliminary baseline data that can inform future controlled studies on bovine cardiovascular welfare.
