Ma. Wild et al., SURGICAL IMPLANTATION AND EVALUATION OF HEART-RATE TRANSMITTERS IN CAPTIVE BIGHORN SHEEP, Journal of wildlife diseases, 34(3), 1998, pp. 547-554
A surgical approach was developed for implantation of transmitters to
monitor heart rate of bighorn sheep (Ovis canadensis) with an objectiv
e of discrete long-term, long-range data collection. We surgically imp
lanted Telonics model HR400 transmitters on the dorsolateral thorax of
15 captive adult bighorn sheep ewes in April-May and October-November
1995. No complications or marked impairment of function were associat
ed with the surgery; however, a transmitter was passively expelled fro
m one ewe 19.5 mo post-implantation. Twelve of 15 transmitters remaine
d functional greater than or equal to 1 yr, while three failed 3.5 to
4.5 mo following implantation. Heart rate data collected from the tran
smitters using a Lotek SRX_400 telemetry receiver/datalogger equipped
with W9 EVENT-LOG accurately reflected heart rate as measured with ele
ctrocardiogram tracings. Line of sight signal range was at least 800 m
in 95% (37/39) of collections made from standing awes, while data cou
ld be collected reliably (74%; 29/39) to 600 m from bedded ewes. When
a reliable long-lasting inconspicuous telemetry system is required, we
believe that this approach holds promise for success in free-ranging
as well as captive ungulates.