Serum Canine Trypsin-Like Immunoreactivity, Folate, and Cobalamin Concentrations in German Shepherd and White Shepherd Dogs
N. Grützner; J.S. Suchodolski; R.M. Heilmann; J.M. Steiner
A high prevalence of exocrine pancreatic insufficiency (EPI) has been reported in German Shepherd dogs (GSD). This condition is diagnosed by a severely decreased serum canine trypsin-like immunoreactivity (cTLI) concentration. Serum cobalamin and folate concentrations are reported to be frequently altered in dogs with EPI. However, studies comparing serum cTLI, cobalamin, and folate concentrations between male and female GSD or between GSD and White Shepherd dogs (WSD), a breed that is considered to be a direct descendent of the GSD, are currently lacking. The aim of this study was to evaluate serum cTLI, cobalamin, and folate concentrations in a large group of GSD and WSD.
Serum samples, submitted for an unrelated research project, were collected from 109 GSD and 56 WSD. Owners were asked to fill out a questionnaire regarding the current health status for each dog. Serum cTLI (reference range (RR): 5.7-45.2 µg/L), cobalamin (RR: 251-908 ng/L), and folate (RR: 7.7-24.4 µg/L) concentrations were measured in each dog. A Mann-Whitney test was used to compare the median concentrations of these 3 parameters between GSD and WSD, and between sexes. A Fisher's exact test was used to compare the proportion of dogs with serum cTLI concentrations within the RR to the dogs with a cTLI below the RR (<5.7 µg/L) or to the dogs with a cTLI below the cut-off value for EPI (<2.5 µg/L). Statistical significance was set at p<0.05.
Serum cTLI was subnormal in 24 of 109 GSD (22.0%) and in 5 of 56 WSD (8.9%). Median serum cTLI was significantly lower in GSD (7.9 µg/L) than in WSD (10.0 µg/L; p=0.0004). Median serum cTLI was also significantly lower in male GSD (6.8 µg/L) than in female GSD (8.1 µg/L; p=0.0262). Median serum cTLI was not significantly different between sex groups (p=0.9867) in WSD. The proportion of dogs with a serum cTLI diagnostic for EPI or a cTLI < 5.7 µg/L was not significantly different between both breeds (p=0.2252 and 0.0506, respectively). Serum folate was subnormal in 7 of 109 GSD (6.4%) and in 12 of 56 WSD (21.4%), and above normal in 12 of 109 GSD (11.0%) and in 3 of 56 WSD (5.4%). Median serum folate was significantly lower in GSD (12.5 µg/L) than WSD (11.0 µg/L; p=0.0073). In both GSD and WSD, median serum folate was not significantly different between sex groups (p=0.7226 and 0.6529, respectively). Serum cobalamin was subnormal in 14 of 109 GSD (12.8%) and in 10 of 56 WSD (17.9%), and above normal in 4 of 109 GSD (3.7%) and in 5 of 56 WSD (8.9%). Median serum cobalamin was not significantly different between GSD and WSD (p=0.0705) or between sexes in GSD or WSD (p=0.1763 and 0.2436, respectively).
In conclusion, in this study, GSD had significantly lower median serum cTLI and significantly higher median serum folate concentrations than WSD. However, EPI was not significantly more common in GSD than in WSD.