Plasma aldosterone, vasopressin and atrial natriuretic peptide in hypovolaemia: a preliminary comparative study of neonatal and mature horses.
BACKGROUND
Neonatal foals succumb rapidly to hypovolaemic shock in comparison to mature horses; they do not consistently increase their heart rate in response to hypotension and respond differently to fluid administration. The hormonal responses to hypovolaemia in the horse and foal require investigation.


OBJECTIVE
The hormonal responses to hypovolaemia and fluid administration differ between mature and neonatal horses.


METHODS
Five mature horses and 5 neonatal foals fulfilling predetermined criteria for hypovolaemia, were included in the study. A blood sample was taken at admission and after normalisation of fluid balance. These were analysed for plasma aldosterone, vasopressin (AVP) and atrial natriuretic peptide (ANP). Normally distributed variables were compared using the Student's t test and nonparametric data using the Mann-Whitney U test.


RESULTS
ANP, AVP and aldosterone were higher before fluid resuscitation than after fluid resuscitation in mature horses. Aldosterone was higher before than after fluid resuscitation in foals, and was higher in foals both before and after fluid resuscitation than in mature horses. ANP was lower in mature horses after fluid resuscitation than in foals. No other comparisons were significantly different.


CONCLUSIONS
The hormonal responses of the mature and neonatal horses are different during hypovolaemia and following fluid resuscitation.


CONCLUSIONS
The differences in the hormonal responses to hypovolaemia and fluid resuscitation may be important when considering fluid resuscitation of hypovolaemic horses and foals, and warrants further investigation.
Hollis
A R
AR
New Bolton Center, 382 West Street Road, Kennett Square, PA 19348, USA.
Boston
R C
RC
Corley
K T T
KT
D000375:Aging / Q000097:blood*; D000450:Aldosterone / Q000097:blood*; D000818:Animals; D000831:Animals, Newborn; D009320:Atrial Natriuretic Factor / Q000097:blood*; D001826:Body Fluids / Q000378:metabolism; D005260:Female; D005440:Fluid Therapy / Q000662:veterinary; D006734:Horse Diseases / Q000097:blood* / Q000628:therapy; D006736:Horses; D020896:Hypovolemia / Q000097:blood / Q000628:therapy / Q000662:veterinary*; D008297:Male; D018709:Statistics, Nonparametric; D016896:Treatment Outcome; D014667:Vasopressins / Q000097:blood*
D014667:Vasopressins; D000450:Aldosterone; D009320:Atrial Natriuretic Factor