Global losses due to dairy cattle diseases: A comorbidity-adjusted economic analysis

Abstract

An economic simulation was carried out over 183 milk-producing countries to estimate the global economic impacts of 12 dairy cattle diseases and health conditions: mastitis (subclinical and clinical), lameness, paratuberculosis (Johne's disease), displaced abomasum, dystocia, metritis, milk fever, ovarian cysts, retained placenta, and ketosis (subclinical and clinical). Estimates of disease impacts on milk yield, fertility, and culling were collected from the literature, standardized, meta-analyzed using a variety of methods ranging from simple averaging to random-effects models, and adjusted for comorbidities to prevent overestimation. These comorbidity-adjusted disease impacts were then combined with a set of country-level estimates for lactational incidence or prevalence or both, herd characteristics, and price estimates within a series of Monte Carlo simulations that estimated and valued the economic losses due to these diseases. It was estimated that total annual global losses are US$65 billion (B). Subclinical ketosis, clinical mastitis, and subclinical mastitis were the costliest diseases modeled, resulting in mean annual global losses of approximately US$18B, US$13B, and US$9B, respectively. Estimated global annual losses due to clinical ketosis, displaced abomasum, dystocia, lameness, metritis, milk fever, ovarian cysts, paratuberculosis, and retained placenta were estimated to be US$0.2B, US$0.6B, US$0.6B, US$6B, US$5B, US$0.6B, US$4B, US$4B, and US$3B, respectively. Without adjustment for comorbidities, when statistical associations between diseases were disregarded, mean aggregate global losses would have been overestimated by 45%. Although annual losses were greatest in India (US$12B), the United States (US$8B), and China (US$5B), depending on the measure of losses used (losses as a percentage of gross domestic product, losses per capita, losses as a percentage of gross milk revenue), the relative economic burden of these dairy cattle diseases across countries varied markedly.

Keywords: dairy; disease; economic; impact.

Figure 1

Global milk production and the availability of farm production data. (A) Global milk production (metric tonnes of cow's milk) in 2021 (FAOSTAT, 2023b). (B) Availability of International Farm Comparison Network data (IFCN, 2023) and the resulting degree of confidence in the production values used as inputs in the estimation of economic losses.

Figure 2

Graphical representation of disease associations used in the comorbidity adjustment of disease impact estimates. Wider connections represent stronger statistical associations between disease pairs. CK = clinical ketosis; CM = clinical mastitis; DA = displaced abomasum; DYS = dystocia; LAM = lameness; MET = metritis; MF = milk fever; PTB = paratuberculosis; RP = retained placenta; OC = ovarian cyst; SCK = subclinical ketosis; SCM = subclinical mastitis.

Figure 3

Estimated global losses due to dairy cattle diseases across regions and diseases. (A) Total annual losses across regions. (B) Total annual losses across diseases. See Supplemental File S5 for details. CK = clinical ketosis; CM = clinical mastitis; DA = displaced abomasum; DYS = dystocia; LAM = lameness; MET = metritis; MF = milk fever; PTB = paratuberculosis; RP = retained placenta; OC = ovarian cyst; SCK = subclinical ketosis; SCM = subclinical mastitis.

Figure 4

Proportion of total losses attributed to diseases across regions and loss types (reduced milk yield, reduced fertility, and increased culling). (A) Diseases across regions. (B) Loss types across diseases. See Supplemental Files S6 and S7 for details. CK = clinical ketosis; CM = clinical mastitis; DA = displaced abomasum; DYS = dystocia; LAM = lameness; MET = metritis; MF = milk fever; PTB = paratuberculosis; RP = retained placenta; OC = ovarian cyst; SCK = Subclinical ketosis; SCM = Subclinical mastitis.

Figure 5

Total comorbidity-adjusted annual losses per cow due to mastitis (subclinical and clinical), lameness, paratuberculosis (Johne's disease), displaced abomasum, dystocia, metritis, milk fever, ovarian cysts, retained placenta, and ketosis (subclinical and clinical). See Supplemental File S8 for details.

Figure 6

Mean estimated comorbidity-adjusted losses due to mastitis (subclinical and clinical), lameness, paratuberculosis (Johne's disease), displaced abomasum, dystocia, metritis, milk fever, ovarian cysts, retained placenta, and ketosis (subclinical and clinical) among global dairy cattle. (A) Annual national losses. See Supplemental File S9 for details. (B) Annual losses per capita. Population data obtained FAO (FAOSTAT, 2023a). See Supplemental File S10 for details.

Figure 7

Sensitivity of total estimated annual losses per cow in an average country to variations in the model's input values. (A) Variations in disease prevalence (paratuberculosis) and incidence (all other diseases modeled). (B) Variations in disease impacts. Y = yield impact; F = fertility impact; C = culling impact. (C) Variations in the magnitude of interdisease odds ratios (OR) that were captured in the literature search (i.e., mean OR ≠ 1). (D) Variations in the magnitude of interdisease odds ratios that were not captured in the literature search (i.e., mean OR = 1). CK = clinical ketosis; CM = clinical mastitis; DA = displaced abomasum; DYS = dystocia; LAM = lameness; MET = metritis; MF = milk fever; PTB = paratuberculosis; RP = retained placenta; OC = ovarian cyst; SCK = subclinical ketosis; SCM = subclinical mastitis.