Many dairy operations across the country are embracing the concept of intensive nutrition programs for aggressive calf growth. But those bigger heifers are not always being bred early enough to make that investment pay off, according to Jason Leonard, calf and heifer specialist with Land O’Lakes Purina Feed.

Leonard says delaying breeding of larger heifers can lead to a greater incidence of metabolic problems at calving such as ketosis; lower milk production; and lost profits as a result of feeding open heifers for an unnecessarily long period. He suggests the following benchmarks for determining the appropriate time to inseminate heifers:

  • Start by getting an average weight on the mature (third-plus-lactation) animals in your herd. Heifers can be bred when they weigh 55 percent of the mature herd size
  • Wither height of the heifers should also be at least 49 inches tall (Holsteins) to ensure proper frame
  • Heifers should weigh around 85 percent of mature herd size after they deliver the calf and reach at least 53 to 54 inches tall (Holsteins) at the withers

These breeding benchmark numbers can typically be hit by 13 to 15 months of age on most farms, which would allow the heifers to calve at 22 to 24 months of age when bred by size. Leonard explains that some very well-managed farms may hit these targets earlier, but breeding at less than 13 months of age is something that needs to be given proper thought and management consideration.