Outward appearance (phenotype) is an expression of genetic and environmental factors and should be taken seriously by everyone in the cattle business. The appearance of a cow can be a strong indicator of fertility. In general, an absence of masculinity in heifers and cows suggests fertility. No coarse curly hair, no short/humped neck, no broad shoulders, etc. Those traits are tied to androgen (male hormones) and tend to present in females with incorrect hormonal balance. Cows lacking masculine traits will see more success with AI, earlier sexual maturity, and an overall shorter interval between calving and breeding back. That said, it's far easier and more effective to select for bulls with good fertility. Bulls that exhibit healthy masculine traits tend to produce fertile, feminine daughters.
As an aside, fertility is only partly heritable. In order to significantly improve or worsen fertility, it takes consistent breeding choices and multiple generations. Failure to select for fertility will only reveal itself in future generations and will be extremely challenging to correct. This is different from traits like birth weights and frame sizes, which can change significantly over a couple of generations.
Jan Bonsma has rightly been mentioned, but for more information I would recommend James Drayson and Gearld Fry, who have excellent books on the subject.