Dairy Cow Production Governed by Annual Rhythms

Penn State University researchers who studied milk production records across the country report that fluctuations in milk yield and composition are mainly driven by photoperiod and not strictly by environmental conditions such as heat stress. “On average, milk yield peaked in April, fat and protein yield peaked in February, fat concentration peaked in January, and protein concentration peaked in December,” said lead researcher Isaac Salfer, doctoral student in animal science. “And the yearly rhythms of milk yield and fat and protein concentration consistently occur, regardless of region.” The findings could help dairy producers develop management strategies that serve them better.