By Pat Melgares,
& Extension News
She’s nearly two months old, and doesn’t have a name. Even so, she’s not lacking for attention.
The "baby doe" calf at Kansas State University’s purebred beef research unit is the university’s first-ever, successfully-cloned calf, and from all indications, she’s doing well. But it took 18 months and several failed attempts before this one was born, underscoring the common belief that much needs to be learned before cloning is efficient enough to make it economically- viable for cattle producers.
K-State’s struggle is not unique among U.S. groups who have studied cattle cloning. Nationally, statistics indicate that only 10-20 percent of the cloned pregnancies make it to full term (9 1/2 months); the average birth rate for cloned cattle is 5-10 percent, compared to 60 percent for a non-cloned embryo transfer.
"[Cloning] has got to be more efficient before [cattle] producers will consider using it," said K-State Research and Extension animal scientist David Grieger. "Right now, the efficiency of the process is too low for it to be economically feasible for most cattlemen."
But whether cloning can ever be practical for the Kansas beef industry - which includes an estimated 36,000 farms with cattle and calves - is a question Grieger thinks is worth answering. So, he and K-State colleague Duane Davis are working with a Manhattan company, CyAgra, on a project that hopes to determine the function of the placenta and its relationship to successful animal clones.
"The reasons for cloning cattle are different depending on which industry you’re talking about," said Audy Spell, CyAgra’s Director of Operations in Manhattan and a specialist in reproductive physiology.
"In the dairy industry, producers can clone those animals who are higher producers, and gradually raise the level of their lowest-producing cattle. In the beef industry, the issue is more about consistency - raising cattle that produce a more uniform and consistent meat product."
The cow whose genetics spawned the newly-cloned calf at K-State was the "most productive [Hereford] cow in the history of this place," said Troy Marple, an animal scientist and director of K-State’s purebred beef research unit.
"If (the cloned calf) grows like we hope she will, we’ll put her in the breeding program and treat her like any other calf we have here," Marple said.
The calf’s path to life began with a pea-sized biopsy, or tissue sample, from the ear of the genetic mother. Personnel at CyAgra used the biopsy to grow millions of skin-type cells in a laboratory petri dish.
"The nucleus within each of these cells contains DNA that represents the entire genetic makeup of the cow that is being cloned," Grieger said.
CyAgra cloning specialists Poothappillai Kasinathan and Jason Knott transferred the nucleus from one ear cell into an unfertilized cow egg, a process called nuclear transfer. The cloned embryo was sent back to K-State where scientists transferred it into the uterus of a foster cow, who gave birth to the cloned calf on March 28.
On May 14, the cloned calf met his genetic mother for the first time. Though they share the same genetics, they didn’t share any cow-calf bond. In fact, the calf was more comfortable around the half-dozen visitors and K-State workers who have bottle-fed and nurtured her since birth.
"It should be understood that the cloning of individual animals only replicates the [existing] animal’s genetics and, hopefully, its production ability," Grieger said. "It does not alter or enhance the genetic makeup of the cloned animal. The mixing of genes through normal mating is still the only way to generate new and better genetics."
In 1998, scientists at the University of Massachusetts cloned calves for the first time. Since then, scientists at Texas A&M University and other institutions also have cloned cattle.
Grieger said he is particularly interested in a growing amount of evidence
that an alteration in how the foster cow’s placenta develops is the underlying
reason for the inefficiency of cattle cloning. By analyzing blood samples
of cattle who have carried cloned pregnancies - compared to those with
normal pregnancies - K-State researchers may be able to determine if a
difference exists and whether it contributes to the low success of cloned