Of the roughly 47,000 dairies left in the U.S., 97 percent raise heifers on-site.
Independently of where they are raised, it is critical to know costs associated with raising heifers, said Alvaro Garcia, SDSU Dairy Extension Specialist.
"It can account for 12 to 20 percent of the total cost of milk production," he said. "Heifers represent the future of a dairy and every effort has to be made to fulfill their potential. This has to be done while reducing cost, optimizing efficiency and allowing them to express their potential."
Feed is the single largest expense in raising heifers. Any feed cost reductions that are made cannot sacrifice development and future production to improve net income of the heifer-raising enterprise, explained Garcia.
"Heifers in their first lactation produced the most milk when average daily gains before puberty were 1.8 pounds. In addition, the National Research Council suggests 85 percent of their mature body weight after calving is the optimum compromise between investing in rearing costs and production during first lactation," he said.
Based on this information, Garcia said the ideal weight right after first calving should be not less than roughly 1,200 pounds.
"A farm doing a good job can have heifer raising costs of around $2.5 daily from birth to freshening," he said.
Three things can undermine this figure: 1) deaths during the heifer program, 2) age at first calving, and 3) milking herd culling rate.
Garcia discusses each of these three points in more detail below:
Deaths during the heifer program. Death losses in heifer-growing operations are on average 6% split as: 4.2 percent pre-weaning, 1.6 percent at weaning, and 0.2 percent during pregnancy (APHIS). Losses of 5 percent are achievable and a worthy goal. To maintain stalls full a farm culling 25 percent of its cows needs 50 heifers calving at 24 months per 100 cows every two years. Heifers needed would be 53 and 55 (Table 1) with death losses at 6 percent and 10 percent, respectively. If raising costs are $1,800, two more heifers add $3,600 every two years. A farm with 24,000 pounds rolling herd average adds 8 cents per hundred pounds of milk. This holds true IF heifers calve at 24 months; however, what happens if they do not?
Age at first calving. Heifers calve on average at 25 months of age in the U.S. (APHIS) resulting in 56 heifers needed in the program per 100 cows when losses are 6 percent. If calving at 28 months instead there's a need for 62 heifers (Table 1). Six more heifers (56 to 62) add $10,800 every two years or 23 cents more per hundred pounds of milk.
Milking herd culling rate. Nearly one-third of the cows are replaced from dairies on average yearly in the U.S. If instead of 25 percent culling is at 35 percent, heifer numbers needed rise to 75 per 100 cows every two years. Bear in mind this is with 6 percent death losses and 24 months of calving age. Raising those 22 extra heifers (53 to 75) adds $39,600 over two years or 83 cents more per hundred pounds of milk.
Money can be saved doing a good job at raising heifers on-site. However, optimizing culling rates has a higher economic impact compared to adding other work-demanding chores that may divert the employees' attention from the milking cows.