Discipline: mastitis; Keywords: dairy cow, mastitis, udder health, prevention, economics, costs.

The impact of mastitis is significant and costly. Mastitis leads to economic losses to both the farmer and processor, welfare implications for the cow and antimicrobial resistance concerns. Describing and analyzing the measures used to prevent this disease and to minimize the losses is important from an economic perspective. In evaluating the economics of managing mastitis, farmers need to take into account losses incurred subsequent to the disease (failure cost, FC) and those invested to prevent the disease (preventive cost, PC). The authors cited below estimated these costs at the herd level with data as reported by South African dairy farmers in 2016.

The average herd size was 514, with a reported milk production of 19 litres per cow per day. The incidence of mastitis was 32% and the cull rate due to mastitis was 6%. The average total cost (TC) of mastitis was R1982 per cow, with FC contributing R1604 and PC R378. Milk lost due to subclinical mastitis was the most significant, accounting for 73% of FC and 59% of TC. Other FC estimated, as a proportion of FC, were mastitis-related culling (14%), milk discard (12%) and clinical mastitis treatment (1%). Contributing to PC were post-milking teat disinfection (36%), blanket dry cow treatment (16%), liner replacement (15%), pre-milking teat disinfection (12%), routine whole herd milk testing programs (SCC portion alone, 12%), followed by vaccination for mastitis, veterinary consulting limited to udder health, milker gloves and udder health consultants, all less than 2.5%. Between herd variation was marked with FC ranging from R744 to R2992, PC from R55 to R940 and TC from R1002 to R3728.

Farmers who reported themselves as high input, higher milk production managers had, on average, smaller herds (491 versus 593 cows), produced less milk (16 versus 23 litres per cow per day), had fewer mastitis cases (25% versus 39%) and a higher bulk tank somatic cell count (BTSCC, 319,000 versus 281,000). Interestingly, 63% of pasture based producers considered themselves as high input, high production managers versus 35% in the latter group. In turn, ten-fold more managers of TMR herds considered themselves as low input, lower production managers (35 versus 3%). The total costs for high and low management herds were similar at R1938 and R2084, high versus low, respectively. High input managers spent more money on post-milking teat disinfection (36% versus 30%) and lost more consequent to subclinical mastitis (77% versus 68%). Low input managers lost more money because of milk discarded (18% versus 8%). Irrespective the group, losses consequent to subclinical mastitis remain significant, contributing 59%, 64% and 55% to TC for all, high and low input herds, respectively.

It was recommended that, given the differences in adoption of measures on any one farm, their costs and the losses incurred, farmers should assess their udder health management taking into account their specific circumstances, targeting reduction in subclinical mastitis. Already adopted measures, with known benefit, should have their execution re-examined.


M. L. van der Leek, L. Leenaerts, N. Schlimmer, H. Hogeveen & M. Nielen, 2021. Farmer-reported Costs of Mastitis in South African Dairy Herds. Part of PhD study at Wageningen University, The Netherlands.