To keep up with modern growth demands, today’s dairy heifers under 6 months of age have approximately the same nutritional needs as a cow giving 90 pounds of milk, according to Tom Tlyutki, consultant with Ag Modeling and Training Systems.
Tlyutki told the audience of the 2024 Dairy Calf and Heifer Association Annual Conference: “Feed those little girls the high-cow TMR. Do a couple-week transition from calf starter to TMR by top-dressing a fixed amount of starter.”
He added that heifer raisers without a lactating herd can do the same, simply by formulating a diet that simulates a high-group ration.
According to Tlyutki, a big Holstein cow today weighs about 1,900 pounds. As cow size increases, so, too, does the need to achieve a good share of that growth prior to lactation. He shared data that showed a 1,500-pound mature cow would need to weigh about 225 pounds at 90 days of age, and 825 pounds at breeding.
But a 1,900-pound cow would need to weigh 285 pounds at 90 days and 1,045 pounds at breeding. Along these lines, Tlyutki advised that a goal of tripling birth weight by 90 days of age is now realistic and advised.
If growth is not maximized early in life, the downside is that heifers may never reach their full potential as cows. “On any given day, a cow should be giving 12-13% of her weight in milk,” he stated. So, a 1,900-pound cow should realistically be giving 228-247 pounds per day.
“We should not ask how cows that are actually doing that are so special. We should ask why more of them aren’t doing it,” Tlyutki declared.
He also noted that the earlier growth can be achieved, the better, because it’s challenging for heifers to grow much once they become pregnant. In fact, they will barely grow at all in the last 4-6 weeks of pregnancy, so they should reach their target calving weight by 4-6 weeks prepartum.
While the prospect of such intense nutrition for heifers may sound costly, Tlyutki said feeding for high levels of correct growth early in life is actually the lowest cost per pound of gain. He’s not a fan limit/target feeding, because he believes it trains heifers to slug feed, a habit that will stay with them through life. Instead, he prefers to provide heifers with plenty of low-nutrient-dense roughage for fill.
Tlyutki also is critical of cheap calf starters, which typically contain a lot of corn, and can lead to acidosis. “If you want to make fat heifers, feed a lot of bypass starch,” he added, noting that lactic acid levels from 5-6% will make heifers fat in as little as 1 month. He advises a goal of 4% lactic acid or less, citing triticale silage as an example of terrific heifer feed that can be fed in large quantities at about 60-62% NDF and low lactic acid levels.
He added that growing heifers “right” actually can be cheaper and increase rearing capacity, because heifers move through the system faster. “The first few months of life are the period of highest growth efficiency, when calves are able to maximize frame and muscle development if fed properly,” he advised. “Take advantage of the efficiency of young animals.”
