The Equine Heart
When you first start examining patients as a veterinary student youre very keen to gently poke and prod every animal you come across. Realizing you can assess cardiovascular function by palpating peripheral pulses is very empowering!
Once you find a pulse in a healthy cow you simply hang on and count as the pulse waves come to you in a more or less steady stream 60 to 80 times a minute. You can confidently anticipate when the next one is going to arrive. Then you examine a horse perhaps a mare in her late teens quiet cooperative and relaxed and all of your confidence disappears. One minute you have the pulse the next you dont. One minute the pulse is strong then it disappears and youre sure you didnt move your fingers. The book says the rate should be 28 to 40 beats per minute but in this horse sometimes its 40 and sometimes its 12.
The cardiovascular system of the horse consists of a heart the arteries that convey cardiac output blood to functioning tissues the microcirculation inside those tissues that moderates local distribution of blood flow and the venous system that collects blood from tissues and returns it to the heart. If I were to ask you which part of this system is most important which part is in charge you would probably say the heart but thats not true. Its actually the microcirculation.
