Fig. 1From: Genotype-by-environment interaction in Holstein heifer fertility traits using single-step genomic reaction norm modelsReproductive events and the definition of critical period in heifers. The red rectangle represents the critical period, defined as the time period for which heifers are likely to suffer from heat stress. AFC = age at first calving, IFL = interval from first to last service, CR = conception rate of first serviceBack to article page