Isn’t there a small piece in all of us that wishes we could never grow up? To stay young, wild and free just like Peter Pan and his adventures on the island of Neverland? While it’s a whimsical dream we all wish could come true, the reality of growing up is something we all must face, including the heifers on our farm.
According to Gavin Staley, DVM and technical service specialist at Diamond V, dairy farmers across the country are facing a new kind of pandemic – immature heifers entering the milking herd. These animals seem inconspicuous at first but have a way of digging deep into farmer’s pocketbooks later due to lower milk production, increased health issues and their annoying ability to have trouble breeding back.
“There’s been an unfortunate trend over the last number of decades to breed heifers earlier – and there’s a number of valid reasons why farmers want to do that, with high feed prices being one of the main ones,” Staley says. “But if heifers are not mature when they calve, we wind up with a lot of negative, long-lasting side effects along the way.”
He goes on to note that heifers who calve before they are physically ready are never able to reach their full potential. Tina Kohlman, a regional dairy extension educator for the University of Wisconsin-Madison, concurs, adding that heifer maturity should not be determined by the animal’s age.
“Heifers can calve earlier to reduce feed and rearing costs but must calve at the ideal weight,” Kohlman says. “Heifer maturity, or the heifer’s weight at calving, is an important benchmark in heifer management. It is the easiest factor to measure and track. Weight at calving not only determines the performance of first-lactation heifers but also lifetime performance.”
According to Kohlman, heifer maturity is important because the onset of puberty is not age-related, but size- and development-related. Instead, maturity depends on a heifer’s plane of nutrition and average daily gain.
“Growth is the biggest driver for heifer maturity,” Kohlman says. “One needs to focus on optimal growth rates throughout the heifer’s life.” She provides the following growth benchmarks:
- Puberty: 45% of the dairy herd’s mature body weight
- Breeding: 55 to 60% of the dairy herd’s mature body weight
- Pre-calving heifers: 90 to 95% of the dairy herd’s mature body weight
- Post-calving (1st lactation): 80 to 85% of the dairy herd’s mature body weight
Agreeing with Kohlman, Staley notes that producers need to move away from breeding heifers based on size and make the effort to weigh animals instead.
“Size can mask an animal’s maturity,” Staley says. “Just because she’s big doesn’t mean she’s mature. Once a heifer calves, they grow 7x slower. Don’t believe the people who say heifers will catch up when they enter the milking herd. They don’t.”
Kohlman shares similar thoughts, adding, “It is not good practice to subjectively determine if a heifer is mature enough to breed. An investment in a scale can assist greatly in determining the best size to breed heifers, allowing one to analyze their heifer management program. Obtain mature body weights of the 3rd lactation and greater cows at 80 to 120 days in milk to establish the benchmark for the heifer program. Weigh heifers at various stages of growth (birth, weaning, pre-breeding, springing, and freshening) to determine if you are achieving a rate of gain goals.”
According to Staley, weight at calving not only determines first-lactation performance, it pretty much sets in stone lifetime performance and your herd’s overall performance. “First lactation milk production sets the ‘ceiling’ for the whole herd,” he says. “The herd cannot out-perform the production level set by first lactation animals.”
He goes on to note that every pound of “missing” body weight will cost 7 pounds of milk production. So, one month of growth deficit before calving costs 7 months of lactation.
Staley offers six tips to help heifers meet their maturity goals before calving:
- Get mature body weights on your 3rd, 4th and 5th lactation cows at 80 – 120 days in milk.
- Weigh heifers as they freshen.
- Set heifer health and growth goals for all stages of heifer development, from colostrum feeding through calving, and then meet them.
- Weigh calves at various stages of growth to determine if your heifer program is achieving rate of gain goals.
- If you are, you can confidently breed heifers to calve at 22 to 23 months.
- If you are not meeting growth goals, delay breeding so that heifers are reaching their maturity weight goals at calving.
“Mediocrity lives in immaturity,” Staley says. “Mature heifers transition well, peak well and breed back – all things that allow them to last in the herd. Elite herds are the ones who are taking the time to develop elite heifers.”
