| Title: | Evaluation of cisternal milk sodium, potassium, and calcium concentrations and electrical conductivity for the diagnosis of subclinical mastitis and intramammary infection at dry-off and freshening in dairy cattle. |
| Authors: | SA Kandeel; AA Megahed, PD Constable |
| Year: | 2019 |
| Keywords: | Not Available |
| Journal: | J Vet Intern Med |
| Volume: | 33 |
| Issue: | 5 |
| Pages: | 2343-2353 |
| Publisher: | Not Available |
| Local/International: | International |
| Paper Link: | |
| Full paper | Ameer Ahmed Abd-Elhameed Megahed_jvim.15550.pdf |
| Supplementary materials | Not Available |
| Abstract: |
Background Subclinical mastitis (SCM) and intramammary infection (IMI) increase the sodium (Na) concentration and electrical conductivity (EC) and decrease the potassium (K) and calcium (Ca) concentrations in glandular secretions of lactating dairy cattle. Hypothesis Low‐cost portable Na, K, Ca, and EC meters are clinically useful cow‐side tests for diagnosing SCM and IMI. Animals One hundred fifteen dairy cows at dry off and 92 cows within 4‐7 days postcalving. Methods Quarter foremilk samples were obtained and the somatic cell count (SCC) was measured using a DeLaval cell counter with SCM defined as SCC ≥ 200 000 cells/mL. Microbiological culture of foremilk samples was used to diagnose IMI. Cisternal milk Na, K, and Ca concentrations and EC were measured using portable ion‐selective meters. Logistic regression was used to determine the area under the receiver operating characteristic curve (AUC) and the optimal cut point was determined using Youden's index. Diagnostic test performance was evaluated by comparing the AUC and calculating the sensitivity, specificity, and positive likelihood ratio (+LR) at the optimal cut point for SCM and IMI. Results Diagnostic test performance was much better when the meters were used to diagnose SCM as compared to IMI. Cisternal milk Na concentration provided the most accurate method for identifying quarters with SCM or IMI. However, AUC was |
