The Last 60 to 90 Days before Calving
John B. Hall, Extension Animal Scientist, Beef, Virginia Tech
Precalving Period
The most critical period in the production year is the last 60 to 90 days before calving. Not only are dramatic changes occurring in the cow, but this period also sets the stage for reproductive success or failure in the months that follow. A sound understanding of this period is important to proper management of the cowherd.
Tremendous Change
Considerable tissue growth and change occur during the precalving period. As a result, nutrient needs of the cow are greatly increased. A majority of fetal (calf) growth occurs during these last 90 days. At the start of this period, the calf weighs less than 50% of its final weight. In addition to rapid fetal growth the uterus, placenta and surrounding fetal fluids must also increase in size during this time.
Mammary development in preparation for lactation is also occurring. Proper nutrition and hormonal support is essential during this period for adequate milk production after calving. Recently, we have seen some herds in which milk production was greatly decreased due to grazing highly endophyte infected fescue during the precalving period.
