Economic comparison of systemic antimicrobial therapies for metritis in dairy cows

Abstract

Metritis is a prevalent disease with effects on production, reproduction, and survival, thereby affecting dairy farm profitability. A component of the cost of metritis is antimicrobial therapy. Some antimicrobials result in milk withhold that adds to the cost of disease. The objectives were (1) to determine cost of metritis for 2 antimicrobial treatments using a herd budget that includes costs associated with incidence of concurrent diseases, milk production and reproduction losses, and removal from the herd and (2) to apply sensitivity analysis to determine the cost of different scenarios. Cows with metritis from a previous study assigned randomly to receive ampicillin (AMP, n = 259), an antimicrobial that requires milk withhold, or ceftiofur (CEFT, n = 269), an antimicrobial with no milk withhold, were used for the economic analysis. A group of cows with no metritis (NOMET, n = 268), matched by parity and calving day, served as the baseline for comparison. The incidence of other diseases in the first 60 d postpartum, culling and death, reproductive performance, discarded milk, milk yield, total milk sold per cow, and residual cow value were used as responses. The economic analysis considered the costs associated with therapy, reproductive management, discarded milk, estimated DM consumed, income from saleable milk, and the residual cow value at 300 d postpartum or earlier if the cow was removed from the herd. Sensitivity analyses were performed considering 3 scenarios for milk and feed prices. The incidence of diseases other than metritis (NOMET, 30.4%; AMP, 45.4%; CEFT, 34.0%) and days in the hospital (NOMET, 2.7 d; AMP, 8.6 d; CEFT, 3.5 d) were greater for cows treated with AMP than CEFT. Treatment did not affect the risk of leaving the herd (NOMET, 15.5%; AMP, 15.0%; CEFT, 19.1%). The 21-d pregnancy rate was lower for cows with metritis but did not differ between AMP and CEFT (NOMET, 24.9%; AMP, 18.9%; CEFT, 17.0%). Milk yield was greater for cows without metritis than those with metritis and greater for AMP than CEFT (NOMET, 33.7 kg/d; AMP, 32.5 kg/d; CEFT, 31.2 kg/d). Cost of metritis did not differ with choice of therapy, but it increased as milk price increased. When both milk and feed prices were the average values considered ($0.44/kg and $0.26/kg, respectively), the costs of a case of metritis for AMP and CEFT were, respectively, $344 and $410 when milk was discarded and $267 and $406 when milk was fed to calves. Cost of therapy for AMP and CEFT represented 16.6 and 24.6% of the total cost of metritis when milk was discarded and 21.5 and 24.8% of the total cost of metritis when milk was fed to calves. The largest component of cost of metritis for both therapies was the reduced income from milk minus feed cost, ranging from 40.0 to 56.7%. Collectively, metritis is an expensive disease, and choice of antimicrobial therapy did not influence survival, reproduction, or cost of the disease.