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Introduction
Developments in the area of
cloning over the last years indicate that this technology is ready for
commercial practicability in the field of animal reproduction and transgenesis. We demonstrated through our
consultation service that the production of transgenic cloned cattle from
both fetal and adult sources is possible at
large scale.
Cloning can be used to
increase the intensity of genetic selection, by multiplying genotypes
that are above the population average for traits of value. Clones
of highly productive animals are very probably to be superior to the
population average.
Cloning is useful in improving the accuracy of genetic
selection. However animals within a clonal
line will be not necessarily phenotypically
identical, because every animal’s phenotype is a combination of genetic
and environmental influences. Measurement of traits of
animals within a clonal line will permit the
randomization of environmental influences and offer a better estimate of
the genetic influences.
Cloning technology,
through the production of genetically identical and genetically modified
animals, will increase overall production efficiency, increase the
uniformity and quality of meat products, allow the development of
speciality meat and dairy products.
The technical main barrier to commercializing cloning is the
efficiency of the method. The blastocyst
production is about 20-30% of nuclear transfer units. In bovine,
when two embryos are transferred per recipient 40 to 50% will produce
pregnancies. However, 40 to 50% of the calves are lost near term or
soon after birth. From a cost analysis basis, the cloning procedure
can be divided into two components; the cost of producing the embryo and
the cost of producing the calf. The cost of producing the
embryo is due, primarily, to labor. One
pair of technicians can produce about 100 to 150 nuclear transfers per
day or about one to two calves. Although the cost of supplies and
materials is relatively small per embryo the low development rate makes
the cost significant.
The major cost of producing
cloned calves is the transfer to recipients and development to
term. Recipient costs for large animals are high because many
embryos develop to near term or are born before death of the calf
occurs. In some cases recipients are lost and all the calves must
be taken by caesarian section. In
Argentina this cost are remarkably lower
The use of cloning could also
be critical for the development of brand name and specialty
products. Specialty products may be extra lean beef or highly
marbled beef. A criteria for producing these products is
consistency in the product. Development of brand name and specialty
products could increase the total market for beef products.
Information
Laboratorio Biotecnología de la Reproducción - Facultad de
Agronomía - UBA. Av. San Martín 4453 - CD1417DSE - Buenos Aires
Tel.: 4524-8000/ Int
8196 - E-mail: salamone@agro.uba.ar
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