Do not use. Mass selection is phenotype selection. Individual – by genotype. Producers in animals are individuals with a well-defined pedigree i.e. the genotype for the necessary traits is quite well known. Yes, and the characteristics of animals – it takes time to reach puberty, a small number of offspring (compared with plants – now we can consider the solved problem – artificial insemination, surrogate females) and the impossibility of asexual reproduction.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.