Temperature-humidity index and reproductive performance of dairy cattle farms in Lima, Peru.

Background: Heat stress results in a mild reduction in milk production, while long-term heat stress exposure can severely affect the productive and reproductive performance in dairy cattle.

Aim: To quantify the relationship between reproductive performance and temperature-humidity index in dairy cattle farms in Lima, Peru.

Methods: Monthly service, conception, and pregnancy rates were measured from four dairy farms in four different Lima localities as reproductive performance indicators, along with an index of heat stress and maximum daily temperature-humidity index (max THI), during a 3-year period.