Canis domesticus
The effect of neutering on tear production in dogs
R Ofri1, R
Ckalifa1, T Bdolah-Abram1, L Shore2
Koret School
of Veterinary Medicine, Hebrew University
of Jerusalem, Israel1;
Department of
Endocrinology, Kimron Veterinary Institute, Ministry of Agriculture, Israel2.
Purpose: There are conflicting reports
regarding gender predisposition to keratoconjunctivitis sicca (KCS), with some
authors demonstrating the disease to be more prevalent in female dogs. While
this finding is disputed by others, there appears to be a consensus that
neutered dogs, of either gender, are predisposed to KCS, probably due to
decline of sex hormones regulating tear production. Our aim was to evaluate
tear production in dogs prior to, and following, neutering and to correlate it
with levels of sex hormones. Methods: Study animals included 25 healthy
dogs (14 females, 11 males) presented for elective neutering. Schirmer Tear Test
I (STT) was performed, and blood samples for progesterone, estrogen and
testosterone assays were withdrawn, on days 0 and 14. Fourteen dogs (8 females,
6 males) were re-evaluated 6 months later. Results: Mean±sd STT results on
days 0, 14 and 180 were 19.7±4.4, 19.0±3.6 and 20.3±6.9
mm/min, respectively. There were no significant differences between the three
readings (P=0.65), or between males and females (P=0.40). Nor was there a
significant decrease in STT over time in either neutered males or females
(P=0.99). No significant correlation was found between STT and any of the three
hormones assayed (P>0.10). Conclusions. We believe this small scale,
pilot study is the first one to measure STT over time in the same dog, prior to
and following neutering. While the study needs to be repeated with a larger
sample, it seems that in dogs, unlike other species, neutering has an
insignificant effect on tear production.
European College of Veterinary Ophthalmologists (2011)
Capra nubiana (pictures courtesy of Ron Ofri)
Ibex Intraocular pressure
Panthera leo
Ofri, R., Shore, L.S., Kass, P.H. and Horowitz, L.H. (1999). The effect of elevated progesterone levels on intraocular pressure in lions (Panthera leo). Research in Veterinary Science 67:121-123
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