Biodiversity Conservation and Sustainable Development in Southwest China

University of Wisconsin-Madison NSF IGERT China Program

Proposals developed at the Workshop on Biodiversity Conservation and Sustainable Development in the Northwest of Yunnan, China

Kunming August 8-18, 2002

Proposal I

Biotechnology Applications in Animal Production Systems

W. Ji and J.J. Rutledge



This project will research the use of biotechnology (in vitro embryo production) to add efficiency to a system of production that has been practiced for 1000’s of years in the plateaus surrounding the Himalaya. Namely indigenous people found long ago that the cross of Bos taurus (ordinary cattle) and B. grunniens (yak) was a superior producer than either parental species. This arises from the concept of complementarity, which occurs when each parent transmits to the crossbred something that is lacking or at least very deficient in the other parent. Yak although very hardy and well adapted to high altitude pastures have very low production owing to their late maturity and two-year calving cycle. Although their milk is rich and nutritious, yields are low. Ordinary cattle have relatively earlier onset of puberty, tend towards yearly calving and produce relatively more milk. They are ill adapted to the environment(s) encountered in Northwest Yunnan, namely they suffer from high altitude sickness, which may lead to congestive heart failure. The F1 cross of the two has long been known to be superior.

This project will research the use of biotechnology to add efficiency to the existing system. The primary drag on efficiency of the existing system is that large numbers of purebreds need to be maintained; these purebreds are either unproductive (yak) or unadapted (ordinary cattle). Estimates are that of the entire herd of a village one quarter are pure yak, one quarter are pure ordinary cattle and only one half are the desired F1 crosses. Hundreds of thousands of high quality spent dairy cows are slaughtered each year in Northern China, New Zealand, Australia, and North America. From each cow about 30 oocytes could be collected. These oocytes when joined with sperm from yak yield the desired F1. This is a mature technology that is used in production systems in Holland, Japan and the United States. One-week post fertilization the embryos are at the blastocyst stage and ready for transfer to recipients for gestation.

We propose to use oocytes collected in Wisconsin and fertilized with yak sperm and then transport these to Kunming for growth to blastocyst stage and subsequent transfer to privately owned cooperator cows in both ZhongDian and WeiXi. The resulting heifer calves will be evaluated for usefulness as milk producers under the conditions of Northwest Yunnan. Each heifer born will be paired with a proband heifer from the same herd to use for comparison. At least 50 and perhaps 100 heifers will be evaluated.

Note that once this system reaches equilibrium no purebreds would need to be maintained. There is a ready source of oocytes, both domestic and foreign, and one yak bull could sire several million progeny when used in in vitro embryo production.


The study initially involves embryo production in Madison, Wisconsin. It is our intention to move the production site to Kunming. Cows will be evaluated in producer herds in ZhongDion and WeiXi.


A major motivation for this research is the degraded nature of the pastures of the test regions. This degradation is a natural consequence of overgrazing. We expect that since the F1’s will have a Holstein parent that they will be at least twice as productive as current cattle. This coupled with relaxing the need to have purebred should make the system at least fourfold productive as present. Since more production will be possible with fewer animals considerable reduction in number of grazers should be possible.


Both of the PI’s have laboratories that routinely do work in in vitro embryo production. They have a 5-year collaboration that has demonstrated all of the technical details of the above. The University of Wisconsin, Department of Animal Sciences has a Peace Corps Master of Science degree program that would fit nicely with this kind of development project. In this program students spend one year at Madison and two years in the host country.



Recent DNA clock evidence indicates that these two species have been reproductively isolated for at least 5 million years. During this period co-adapted gene complexes have been built up which upon crossing are subject to destruction at meiosis. Two key studies are needed.

The first will evaluate extent of introgression of “yak” genes into “cow” and vice-versa. To accomplish this 100 pure yak and 100 pure cow (both as judged by cooperating farmers will be sampled for DNA analysis. Ten to 15 informative loci will be scored on each individual. This will permit estimation of gene frequencies and extent of introgression.

The second will evaluate key life history characteristics of cowXyak hybrids to test hybrid dysgenesis. At the time of birth of F1 heifers from the primary project herd owners will be asked to nominate heifers that are pure yak, 7/8 th yak, 3/4 yak, 1/4 yak, 1/8 yak and pure cow. All of these should be born within two months of the F1 heifer. To the extent possible, these groups will be assembled with a single herd and in all cases within the village herd. This group of heifers will constitute a block in the usual statistical sense. All heifers will be evaluated for a suite of performance traits to include: yearling weight, age at puberty, age at first calf, milk production and inter calving interval. Data will be collected from as many blocks as possible and will be analyzed as in Rutledge (2001). Hybrid dysgenesis will be tested as the deviation of crosses, except F1, from their expected value under a genetic model that includes all intra locus effects.


This study will be conducted ZhongDian and WeiXi.


Motivation for the first study comes from the complaint of farmers that their “yak” are “degenerating”. They have sought and Professor Ji has arranged for semen from very pure yak to be used in the test areas. The degeneration observed by farmers is a possible consequence of introgression of “cow” genes into “yak”.

The second study attempts to understand if hybrid dysgenesis or epistatic loss is actually occurring in these crosses. It extends the notions of Dobzhansky and Wright work with Drosophila conducted in the middle part of the last century. Also it is a study of opportunity in that no one has had animals of these types available for study. Close inspection reveals that most of the data need for this theoretical population genetics study would have been collected for the primary project anyway.


Professors Ji and Rutledge will serve as co-PI’s. Both studies outlined would be suitable for an MS student.

Supportive Literature

Gordon, I. 1994. Laboratory Production of Cattle Embryos. CAB, Wallingford.

Rutledge, J.J. 1996. Cattle breeding systems enabled by in vitro embryo production. Embryo Transfer Newsletter. 15: 14-18.

Rutledge, J.J. 1998. Aplications of in vitro methodology in tropical dairying. Proceedings of the 17 th Technical Conference on Artificial Insemination and Reproduction.

Rutledge, J.J. 2001. Greek temples, tropical kine and recombination load. Livestock Production Science. 68: 171-179

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