A UW-Madison researcher has developed a program to provide developing countries with quality dairy cows resistant to harsh tropical conditions.
Jack Rutledge, professor of animal science in the College of Agriculture and Life Sciences, created a program that implants hybrid cow embryos into tropical cows in order to produce offspring that are resistant to tropical environments and provide milk efficiently.
Prior research efforts without Rutledge focused on exporting exceptional U.S. dairy cows to developing areas in need of milk. Yet, these cows were ill suited for tropical environments.
'It's not just the heat and humidity it's also the natural environment. There are few good forage plants that naturally grow in the tropics, and most tropical areas have large populations with not a lot of land to devote to crop farming for feeding livestock. Also, external and internal parasites and tick fever present problems,' Rutledge said.
Cows in the tropics live on less foliage than temperate cattle and are heat and tick resistant. Although they can survive in tropical climates, they do not have the same milk capacity as American cows, Rutledge said.
Later research attempted to breed temperate cows with tropical cows in an effort to make a hybrid breed with the positive characteristics of both. Although the first generation was usually a success, all attempts failed to create a sustainable, healthy breed.
The primary obstacle in creating a hybrid breed is that temperate and tropical cows' genes are separated by two million years, according to Rutledge. He said the genes evolved to perform tasks differently, and the genetic instructions do not work well together after the first generation.
Rutledge's new cost-efficient hybrid embryo program makes the development of a new hybrid breed obsolete. By combining South Asian bull semen with the eggs of Wisconsin dairy cattle, he created embryos to be implanted in tropical cattle. Like the cross-breeding strategy, subsequent generations fail, but importation of cheap embryos will maintain an efficient dairy cow population.
Vietnam is the first country to use the program. Approximately 150 embryos have been transplanted resulting in 50 successful dairy cows, according to Rutledge. Possibly within a year, Rutledge would like to see the program grow to other developing countries in need of dairy cows, such as Thailand, China and Mexico.
Wisconsin is qualified to maintain a sufficient dairy cow population in Vietnam for two reasons: 'The ability to make embryos and the ability to put them into cows. We slaughter a lot of Holstein cows in this state, and we have the general ingredients to make embryos by extracting the eggs from the carcasses,' Rutledge said.
The hybrid embryo program also benefits the Wisconsin dairy industry with new technology and provides a 'source of revenue for our state and extra income for cow farmers,' said Kent Weigel, a UW-Madison dairy science professor and extension agent.
At $60 per embryo, the technique is roughly five times cheaper than other methods to introduce dairy cattle to tropical nations. Low prices will help developing nations reliant on milk importation become more self-sufficient milk producers.
However, successful embryo creation and calf births are both suffering from efficiency problems. Only 30 percent of the eggs collected result in embryos and only 40 percent of embryo transfers result in calves.
'We are not as efficient as we would like to be,' Rutledge said.
As the embryo program expands, health standards and trade barriers could also impede the progress of the program, Weigel said.
'One of the challenges is that countries don't have genetic improvement programs.' Rutledge will have to contribute all the necessary research and development, since countries will essentially be starting from scratch, Weigel said.
Despite the challenges Rutledge may face in his research, he said he remains dedicated to the embryo program.
'I never lose sight of what a dairy industry can do for the health and well-being of a population,' he said.
