Well-Grown Heifers Bring More Value
When it comes to raising ideal replacement dairy heifers, it’s a delicate dance between cost and quality, according to two presenters at the recent 2023 Dairy Calf and Heifer Association Annual Conference.
“Custom heifer growers don’t go out of business because they’re too expensive,” declared Paul Dyk, nutritionist with GPS Dairy Consulting. Rather, he said dairy owners leave custom growers when they deliver poor-quality animals at freshening. In short, rearing costs aren’t everything when it comes to raising high-quality replacements.
Dyk’s sentiments were echoed by Dr. Michael Overton, technical services veterinarian for Zoetis. Overton said previous industry trends of trying to shave heifer-rearing expenses via both cheap feedstuffs and early calving age now are being called into question.
“We’ve been focusing too much on cost reduction in the rearing phase, while ignoring future lost opportunity potential when we bring low-quality, poorly grown heifers into the milking string,” Overton stated. “Those animals are being deprived of their genetic potential to perform, and may never hit their full production performance stride because they are forever playing catch-up, especially during their first and second lactations.”
Overton recommends a goal of freshening first-calf heifers at 22-24 months of age. He said at that age, they should be at 82-85% of projected mature bodyweight, 95% of mature height, and free of lingering health issues – like permanent lung damage – that could negatively impact future productivity.
Knowing the actual mature bodyweight and height in the herd are critical pieces in achieving that standard. Dyk said many dairies either do not know their mature weights at all, or dramatically underestimate their cow size and weights.
He recommends weighing heifer calves at birth and freshening on the dairy, using the same scale both times. That data should be recorded into a herd management software like Dairy Comp 305. Then, weighing every cow at calving, regardless of lactation number, should become a standard practice so dairies can track their animal weight trends over time.
Retrospective data has shown that cows continue to gain weight until about 7 years of age. Dyk said monitoring cull weights is another way to assess average mature weight in the herd, as well as standard deviation between animals. For consistent size, the goal should be less than 50 pounds of variance between animals of the same age.
One of Dyk’s client herds of several thousand Holsteins found their 4th-lacation (55 months of age) average freshening weight was 1,760 pounds – meaning a goal of 85% of mature body weight at first freshening would be about 1,500 pounds.
Hitting those heavier weights early is worth it, as Dyk shared data showing first-calf heifers that were 100 pounds heavier at first calving produced 5 pounds more milk per day in their first lactations.
“Heifers that are undersized at calving will partition a greater percentage of nutrients toward growth and away from production, compared to well-grown heifers,” stated Overton. His exhaustive examination of data on herd survival versus bodyweight has borne out two critical findings:
- The primary driver for early culling was not body weight, per se, but rather the milk production differences that resulted from calving at a lighter weight than targeted.
- When adjustments for Age at First Calving were removed and 305-day milk remained, older heifers had a significantly higher risk of being culled.
The second point is an important indicator that not only do heifers need to be well-grown before they have their first calf, but that their pre-calving growth and development must come in an efficient timeframe.
Dyk said raising a heifer to 1,500 pounds by 22 months of age is more costly than calving them out smaller, but also worth the investment in the long view. “We’ve become very specific in developing the type and number of replacement heifers needed in the herd,” he stated. “We don’t have room for any duds.”
