Mare colostrum quality and relationship with foal serum immunoglobulin G concentrations and average daily weight gains.

Background: Foals suffer from total failure to transfer passive immunity (TFTPI) when serum immunoglobulin (IgG) is <4 g/L, and partial failure to transfer passive immunity (PFTPI) when serum IgG is 4-8 g/L.

Objectives: To explore risk factors for poor serum IgG concentration.

Study Design: Retrospective observational study.