Here’s the assignment: Find the lost milk. Where are you going to look? When Cornell students focused on this task, helping a New York dairy producer – one who had an exemplary calf program and whose cows should have been producing 6 kilograms or more milk per day than they were – they found it.
The lost milk was in the heifer barn.
The lesson? Even when your herd is of the highest genetic merit, selected for milk production, and the calf program is top notch, things often go off track in the heifer barn.
Raising a quality heifer means not detracting from her optimized milk output. The challenge is in raising heifers in a cost-effective manner without compromising future milk production.
While the lost milk may be found in the heifer barn, optimizing lifetime production begins at birth.
“Growth is always going to be a priority over lactation,” said Mike Van Amburgh, department of animal science, Cornell University. “Growth rate and milk output are analogous.”
The key is to “manage them for their genetic potential starting at birth,” Van Amburgh emphasized in his presentation at the 2015 Cornell Calf and Heifer Conference.
“A quality heifer is an animal carrying no limitation – nothing that detracts from her ability to produce milk under the farm’s management system.”
Calf program goals
Any deficit in early calf nutrition makes it much more difficult to meet future benchmarks for productivity, and the animal’s milk production will be “always somewhat compromised,” he said.
“The effect of that early life nutrition and management is as significant in the second lactation as it was in the first.”
The goal is to capture feed efficiency of early life, with a minimum goal of doubling the birth rate at 56 days. Feeding calves to meet this goal has an impact on long-term productivity.
Preweaning average daily gain has been shown to impact first-lactation milk yield. The increased average daily gain is achieved by feeding adequately to meet energy needs under given conditions. Simply feeding more isn’t the answer. There is a management effect, too.
If conditions are optimal, feed efficiency is maximized, as is return on investment. A farm with a high feed cost per animal but stress-free conditions can achieve a lower cost per kilogram of gain than one with a lower feed per animal cost.
But where the intake above maintenance is inadequate, so the cost per unit of gain is much higher. Under heat stress, in crowded conditions or other less-than-optimal scenarios, feed efficiency will decrease, as will performance, which causes a higher feed cost per animal.
As a result, target weights for breeding may be missed, possibly costing unrealized milk.
For animals with lower genetic merit, feeding above maintenance can enhance their lifetime production, while high-merit cows can have production negatively impacted if maintenance energy needs are not met. In other words, the nutrition program influences genetic potential, either positively or negatively.
A good nutrition program can optimize the herd’s overall productivity, no matter the genetics.
Optimizing calf nutrition can also achieve breeding weight sooner.
Age at first calving has been shown to impact lifetime milk production. Analyzing this within the herd – so that the effect of management, environment and genetics are neutralized – shows animals that calve at younger ages have both more productive days and greater lifetime milk yield.
Economically, lower age at first calving is advantageous, with less of a need for replacement heifers to maintain herd size.
“First-lactation animals are going to redirect these nutrients toward growth,” not milk production, Van Amburgh said. “Animals are always going to grow until maturity.”
Even if the benchmarks are met for calf growth and bodyweight at breeding, missing growth targets in the heifer barn reduces that lifetime milk production potential.
Calving at a low bodyweight percentage causes lost milk during the first lactation and makes it much more difficult to achieve benchmarks for the subsequent lactations as well.
“Many dairies have great calf programs and get them pregnant at the right time and bodyweight,” but then overcrowd and don’t pay enough attention – and therefore fail to get to the right bodyweight at calving, in the heifer barn, Van Amburgh said.
“You’re actually hurting yourself,” by not monitoring heifer growth.
The goal is to calve at 82 percent of mature bodyweight. While increasing this is possible, anything above the 82 percent point begins to detract from the payback.
Producers would put more time and money into achieving any higher a bodyweight percentage, yet receive little gain in productivity over the 82 percent mark.
The benchmark for maximum productivity is 92 percent mature bodyweight at second lactation, 96 percent at the third and 100 percent by the fourth.
Income over feed cost calculations show the value of reaching expected peak production and finding your lost milk. Calculating the income over feed cost for feeding cows for peak production, comparative to the value of the milk lost if this doesn’t happen, can help demonstrate the importance of achieving benchmarks for first-lactation heifers.
For herds with a large percentage of first-lactation animals, not achieving superior growth can result in a lot of unrealized milk money.
Whether in the calf or the heifer barn, quantitative thinking can go a long way to optimizing future milk production. Not many producers weigh cows, but estimating weight – particularly since most significantly underestimate bodyweight – makes it difficulty to optimize nutrition.
“For high-lactating cows, we want to balance to grams of amino acid, but we are 200 to 300 pounds (90 to 136 kilograms) off in bodyweight,” Van Amburgh said, making it impossible to properly balance the diet. As a result, the nutrition program can be way off target. “People don’t know, and we’re losing milk.”
In the calf barn, it’s been all “bottles and buckets” rather than measurable units. To develop an optimal nutrition program, “we have to behave like we do with the grown-up cows and think in terms of how many Mcals of energy and grams of protein are required for this calf.”
While optimizing herd genetics is ideal, maximizing that genetic potential and achieving maximum productivity involves hands-on, quantitative monitoring through every stage of growth.
Meeting maintenance needs and meeting growth benchmarks in calf and heifer programs can prevent unrealized milk and can economically make sense.
“We all select for milk” and to have the highest-genetic-merit cows, “but then we don’t always treat them like the animals we selected,” Van Amburgh said.
“Obtaining the highest-quality heifer at the lowest possible cost usually in the least amount of time” is the overall goal of achieving superior growth and requires genetics, optimizing calf and heifer growth, understanding future productivity and a solid grasp of herd economics.
Tamara Scully, a freelance writer based in northwestern New Jersey, specializes in agricultural and food system topics.
Before commenting on our articles, please note our Terms for Commenting.