Correlations Between Serum Copper and Liver Copper Levels in Nondomestic Bovids at the San Diego Zoo Safari Park, 2013–2018
Copper deficiency is a concern in nondomestic bovids at the San Diego Zoo Safari Park (SDZSP) with documented deficiency in individuals noted postmortem.1,2 Adequate antemortem diagnosis remains a challenge as serum copper levels may have inadequate sensitivity/specificity when compared to postmortem liver samples. Medical records were evaluated for bovids that died from 1 Jan 2013 to 15 Jul 2018 to identify those that had postmortem liver copper levels (n=888). This study evaluated the subset of this study population with antemortem serum copper levels collected 0–3 mo (n=130) and 3–6 mo (n=11) prior to death. Censoring animals that received copper boluses (3 mo, n=53; 6 mo, n=57), Spearman rank correlations analyzed the association between paired samples by subfamily and genus. Bovinae females showed positive significant associations between serum/liver copper, 0–3 mo prior to death (r=0.72, n=15, p=0.002). Caprinae of both sexes (r=-0.62, n=23, p=0.002) and Reduncinae females (r=-0.79, n=7, p=0.036) showed negative associations 0–3 mo prior to death. Sensitivity/specificity were still poor with positive correlations but improved with censored neonates. Subfamily variation is noted with more covariable investigation warranted to provide a clearer picture. Continued postmortem sample collection and expanded antemortem testing will better define parameters for diagnosing copper deficiency in nondomestic bovids.
The authors thank the Harter Veterinary Medical Staff for their assistance in collection of data from the electronic and paper medical records.
1. Clancy M, Howard L, Lamberski N. Investigation of population-level effects of copper deficiency on health and reproductive success of hoofstock populations at the San Diego Zoo Safari Park. Proc Am Assoc Zoo Vet; 2018. p. 187.
2. Schlegel ML, Edwards MS. Effective duration of a copper oxide bolus administered orally to bontebok (Damaliscus pygargus dorcas). Proc AZA Nutrition Advisory Group; 2007. p. 223–227.