Labor (2) Reproduction (2) Cattle (2) Artificial insemination (2) Animal culture (2) Inseminación artificial (2) Reproducción (2) Ganado vacuno (2) Trabajo (2) Lecheros (2) Evolution (Biology) (1) Minors (1) Plumbing fixtures (1) Vocational education (1) Time (1) Quality of products (1) Production (Economic theory) (1) Pregnancy (1) Ovulation (1) Methodology (1) Livestock (1) Labor (Obstetrics) (1) Jealousy (1) Irrigation (1) Indexes (1) Human behavior (1) Genetics (1) Fertility (1) Education, Primary (1) Dynamics (1)