A heifer calf was born this morning. On the outside, she appears to be nearly identical to any other calf that’s been born — two ears, two eyes, four legs, a tail and a black-and-white coat.
But she’s different on the inside than many of her contemporaries. No, she’s not a clone or genetically modified by external means, nor is there anything unusual about her internal organs. She’s different because she is genetically superior to her dam. And while that should be the goal of every pregnancy, it doesn’t hold true for every calf born.
“There’s a trend among some producers that simply getting cows pregnant is first and foremost for their reproductive program,” says Joel Mergler, vice president of marketing and training for Select Sires. “They are only concerned about the pregnancy; genetic gain is secondary.”
Much of the emphasis on 21-day pregnancy rates was born out of necessity, as average pregnancy rates dipped to 14 percent or below on some dairies. However, there’s no reason why you can’t get cows pregnant and increase your herd’s genetic potential at the same time. Here’s why you should try.
The dairy industry has made great strides in understanding cow biology during the last 50 years. This has led to unprecedented tools and information from which to make genetic selections. And they have been used with great success. For example,
Of course, better management is responsible for a huge part of this gain. Genetics experts note that until the mid-1980s, most of the increase in milk yield was due to improved management, like better nutrition. However, since then, genetics has become the major factor due to effective use of A.I., intense selection using progeny tested bulls and worldwide distribution of semen from bulls with high genetic merit for production.
From 1992 to 2002, research shows that genetics accounted for 55 percent of the phenotypic changes in milk yield per cow per lactation, says Pascal Oltenacu, dairy geneticist at
During that same time frame, research from
Conception rates in
dropped from about 65 percent in 1950 to about 42 percent by 1998. New York
Services per conception for the New England
DHIdata set increased from 1.6 in 1957 to 3.6 by 2002.
Calving interval increased from 12.8 months in 1957 to 15 months in 2002.
With data like these, it’s easy to see why you’d be tempted to concentrate solely on getting cows bred.
You can do better
Don’t succumb to tunnel vision when it comes to pregnancies. Instead, for each mating considered, ask yourself:
Will the resulting pregnancy help your dairy move forward?
Will the calves that result be genetically superior to their dams and be better able to fit intensive production systems?
Are you breeding animals that will breed back more efficiently and maintain health better than their mothers?
In addition, you must have your reproductive and overall herd management in place in order to make genetic progress. You cannot use genetics alone to solve your management problems.
“The genetics are available, and they are available at reasonable prices,” says Scott Bentley, global dairy product manager for
Furthermore, improving the genetics of each pregnancy can have an impact on many of the health and fitness issues that the dairy industry currently faces.
For example, the genetic correlation between high milk yield and functional traits, such as mastitis, lameness, first-service conception rate and a number of other issues that relate to reproduction and cow survivability, is high but also negative, says Oltenacu. So, when you focus selections to improve milk production, you inadvertently impact other factors in a negative way. That, in turn, can make cows less adaptable to today’s dairy environment.
“The modern day dairy cow is more demanding of her environment, which means there is less room for error. We’ve long said that since traits for fertility, health and longevity were of low heritability, they could be controlled through management, but the fact is, we haven’t controlled them through management,” says Oltenacu.
So, instead of simply focusing on pregnancy rate, you must focus on achieving a higher rate of pregnancies that will not only result in genetic improvement for your herd, but also will help in building longer-lasting, healthier cows with good reproductive status.
Profitability is the goal
Some producers have used a team approach and various synch protocols to achieve pregnancy rates of 20 percent and above. But a good pregnancy rate without genetic gain doesn’t necessarily get you where you want to go.
In order to achieve genetically superior pregnancies — as well as more pregnant cows — you must use tools or economic indices like Lifetime Net Merit Dollars, Type-Production Index, Lifetime Fluid Merit Dollars or Lifetime Cheese Merit Dollars. These tools are designed to help you choose a combination of traits that should help improve your profitability. For example, Lifetime Cheese Merit Dollars focuses on the traits that increase the value of milk used to manufacture cheese in addition to an emphasis on productive life and low somatic cell count scores.
When trying to achieve genetic progress, don’t fall into the trap of simply selecting for fertility — or any other single trait — because you’ll accomplish the reverse of what you want.
When choosing a highly fertile bull that is negative in other areas, such as daughter-pregnancy rate, you are solving a short-term issue, points out Nate Zwald, research and development manager for Alta Genetics. But by doing so, you may be creating even more fertility problems in the next generation.
You’ll be better off focusing on sires that will create daughters that are highly fertile than simply selecting highly fertile bulls, Zwald suggests. “In fact, since male fertility has no correlation with female fertility, selecting highly fertile bulls with no regard for other traits may actually take you in the wrong direction — you’ll create cows that are less fertile.”
Follow your vision
Producers today have more tools available than ever before. But they haven’t yet fully realized these tools potential, notes Ole Meland, Accelerated Genetics vice president of genetics. “Previously, we only had productive life and somatic cell count scores (introduced in January 1994), but now we have several additional management traits such as daughter pregnancy rate, maternal calving ease and more. Most of these are lowly heritable, but those that have a huge economic value are worth exploring. We need to be as on-board with these ‘functional’ traits as we are with milk traits.”
So, what are the traits producers should add to their usual genetic criteria of milk production, feet, legs and udders? Change your focus to include more lowly heritable fitness or functional traits as part of a long-term strategy. Although these traits are more difficult to breed into a herd than milk yield and other production traits, a consistent upgrade of these traits will pay dividends long-term. Just don’t go overboard on their emphasis, or you’ll end up with fewer and fewer sires that meet all of your criteria.
What does this all mean? It’s time for you to align your breeding goals with your management goals. Doing so means you can ensure that the next heifer calf born on your dairy will have a higher genetic potential than her dam. And that’s a strategy that will pay off in the long run.
A New Standard
the image of the perfect cow is changing. the traditional dairy cow has been a large, angular, epitome of “dairyness.” However, more functional cows are a bit smaller in stature and carry a little more flesh that previously thought desirable.
It’s a difficult image to change, says Tom Bjelland, Genex vice president of domestic marketing. “We think in pictures, and visual images are more important than what you read or hear about. But you really need to think about what is best for your herd.”
Functional cows generally result in greater profit.
And, recent research at the
“We’re going to have to learn to like what the profitable cow looks like,” says Ole Meland, Accelerated Genetics vice president of genetics.
“We have several different measures of fertility to begin to offset a trend towards lower fertility seen in many dairy herds,” says Bennet Cassell, extension dairy scientist at
Take the fertility tool of Estimated Relative Conception Rate (ERCR) score, for instance. A Virginia Tech study shows that you could pay a premium of $2 per unit of semen per one unit difference in ERCR score and still come out ahead. For example, two bulls that are nearly equal for production,
Meanwhile, the divergence between bulls for daughter pregnancy (DPR) rate, a distinctly different measure of fertility, is smaller than differences in ERCR. That’s because 21-day pregnancy rates are lower than 70-day non-return rates. DPR is based on the probability of a pregnancy in a 21-day cycle in daughters of a bull. And while heritability is about 4 percent, DPR are useful nonetheless, says Cassell. “Producers should begin to discriminate against bulls with low DPR values, as reproductive performance of their future daughters is expected to be poorer than daughters of bulls with better DPR ratings.”
Of course, these tools should be used in conjunction with wider selection criteria, but can be used as a tiebreaker when evaluating two otherwise similar sires.
For more information on the economics and components of selection parameters, link to: http://www.aipl.arsusda.gov/reference/nmcalc.htm