**5.1 Low milk yield**

The loss of yield depends on certain factors of great importance like severity of mastitis, nature of causative agent, stage of lactation at the time of mastitis. Losses are severe in primiparous cows due to clinical mastitis caused by *Staph. aureus*, *E. coli* with *Klebsiella*. However, the maximum loss of production in multiparous is caused by *Streptococcus* spp., *Staphylococcus aureus* and others pathogens [46, 47]. The loss of production is higher in multiparous cows than primiparous. Clinical mastitis occurring before peak production stage/yield causes more extensive loss as compared to rest of the lactation and loss of milk yield is persistent throughout the lactation [12, 48]. According to a study, this yield loss for multiparous could be 300-400 kg (4–6% of lactation) while 200-300 kg in primiparous

animals. The magnitude of yield loss in 30% cases of clinical mastitis reached up to 950-1050 kg per lactation. Whereas, in subclinical mastitis the losses incorporated are 80 kg/lactation (1.3%) and 120 kg/lactation (1.7%) in primiparous and multiparous respectively [49, 50].
