Ventilatory and timing parameters in normal horses at rest up to age one year.
Abstract: The purpose of the study was to document the developmental changes in the ventilatory and timing parameters associated with quiet breathing at rest in awake, standing horses during the first year post partum. Tidal volume (VT), breathing frequency, airflow, mechanical timing intervals and minute ventilation (VE) were measured serially in foals age 24 h-1 year. In the growing foal, VE increased due to a progressive rise in VT, in spite of a pronounced decrease in respiratory frequency. When normalised to body weight (bwt), VE/kg declined with maturation in a curvilinear fashion, from mean +/- s.d. 848 +/- 231 ml/min/kg in the 24 h-old foal, to 155 +/- 15 ml/kg/min in the 1-year-old foal. Tidal volume normalised to bwt remained relatively constant during the study period, with the exception that at age 3 weeks and from 2-6 months, VT/kg was significantly lower than the value recorded at age 1 week. The decrease in frequency resulted from prolongation of both inspiratory (TI) and expiratory (TE) time but there was a disproportionately larger increase in TE compared to TI, which resulted in a significantly lower ratio of TI/TE in older foals. The allometric equation relating VT to bwt suggested that lung growth in the horse is dysanaptic, with increases in overall body size exceeding lung growth in the maturing foal during the first year post partum.
Publication Date: 1995-07-01 PubMed ID: 8536661DOI: 10.1111/j.2042-3306.1995.tb03074.xGoogle Scholar: Lookup
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Summary
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This research investigated the developmental changes associated with quiet breathing in horses during their first year post birth. The study found that overall, despite a decline in respiratory frequency, a horse’s minute ventilation increased due to rising tidal volume, with body size growth surpassing lung growth.
Ventilatory Parameters
- The study focused on a range of ventilatory parameters including tidal volume (VT), breathing frequency, and airflow. Tidal volume refers to the amount of air inhaled or exhaled during a normal breath.
- These parameters were measured in foals ranging from 24 hours old to one year old.
- Despite a significant decrease in respiratory frequency, it was observed that the minute ventilation increased owing to a rise in VT. Here, minute ventilation (VE) is defined as the total volume of air a horse can inhale or exhale in one minute.
Impact of Body Weight
- The study also evaluated the effects of body weight on these parameters. When normalised for body weight, the VE/kg (minute ventilation per kilogram of body weight) showed a curved linear descent with maturation. From 848 ml/min/kg at 24 hours old, it dropped to 155 ml/kg/min when the foal was a year old.
- The tidal volume normalised to body weight remained relatively consistent, but was noticeably lower at the age of 3 weeks and between 2-6 months as compared to the 1-week-old foals. This indicates that body growth isn’t entirely parallel to lung growth, particularly in these developmental stages.
Respiratory Timing Changes
- Changes were also observed in inspiratory (TI) and expiratory (TE) time as the horses matured. Inspiratory time refers to the time taken to inhale and expiratory time to exhale a single breath.
- The declining frequency of breaths was attributed to the prolongation of both TI and TE. However, TE increased disproportionately compared to TI, resulting in a greater TE/TI ratio in older foals. This suggests a altered respiratory rhythm as the horse grows.
Dysanaptic Lung Growth
- The study concluded with evidence of dysanaptic lung growth in horses, where overall body growth outpaces lung growth in the maturing horse during the first year after birth.
- This pattern of slow pulmonary development relative to body size could have implications for understanding respiratory health and diseases in horses, although more research would be needed to explore these potential connections.
Cite This Article
APA
Koterba AM, Wozniak JA, Kosch PC.
(1995).
Ventilatory and timing parameters in normal horses at rest up to age one year.
Equine Vet J, 27(4), 257-264.
https://doi.org/10.1111/j.2042-3306.1995.tb03074.x Publication
Researcher Affiliations
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610, USA.
MeSH Terms
- Aging / physiology
- Animals
- Horses / growth & development
- Horses / physiology
- Lung / physiology
- Respiration / physiology
- Respiratory Function Tests / veterinary
- Respiratory Mechanics / physiology
- Time Factors
Citations
This article has been cited 2 times.- Sacks M, Raidal S, Catanchin CSM, Hosgood G, Mosing M. Impact of sedation, body position change and continuous positive airway pressure on distribution of ventilation in healthy foals.. Front Vet Sci 2022;9:1075791.
- Raidal SL, Catanchin CSM, Burgmeestre L, Quinn CT. Bi-Level Positive Airway Pressure for Non-invasive Respiratory Support of Foals.. Front Vet Sci 2021;8:741720.
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