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The ecological adaptability of cloned sheep to free-grazing in the Tengger Desert of Inner Mongolia, China

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Abstract

Since the birth of the first cloned sheep, somatic cell nuclear transfer technology has been successfully used to clone a variety of mammals. Cloned livestock have no apparent health risks, and the quality and safety of the cloned animal products are similar to non-cloned animals. The social behavior and environmental adaptability of postnatal cloned animals, especially when used for grassland farm production purposes, is unknown. In the present study, the cloned Dorper sheep equipped with GPS location devices were free-grazed in a harsh natural environment similar to conditions commonly experienced by Mongolian sheep. The main findings of this research were as follows. (1) Under free-grazing conditions, the cloned sheep showed excellent climatic and ecological adaptability. In extreme temperature conditions ranging from -30 to 40°C, the cloned sheep maintained acceptable body condition and behaved as other sheep. (2) The cloned sheep quickly adapted from a herd feeding strategy to the harsh environment and quickly exhibited a grazing regimen as other free-grazing sheep. (3) The cloned sheep exhibited free-grazing patterns and social behavior as other sheep. (4) The cloned sheep in the harsh environment thrived and produced healthy lambs. Overall, the cloned Dorper sheep exhibited excellent ecological adaptation, which is an important consideration for breeding meat sheep by cloning. The Dorper sheep readily adapted to the free-grazing conditions on the Mongolian plateau grassland, which attests to their ability to withstand harsh environmental conditions.

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The history of the Dorper sheep.

(2000)
This short history of the Dorper sheep traces its background and the steps taken to develop that breed in South Africa. The most important traits considered for the developing of the Dorper are listed and the breeding system outlined. The development of the White Dorper is also detailed and the breed improvement programs are indicated.
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Somatic cell nuclear transfer cloning: practical applications and current legislation.

Somatic cloning is emerging as a new biotechnology by which the opportunities arising from the advances in molecular genetics and genome analysis can be implemented in animal breeding. Significant improvements have been made in SCNT protocols in the past years which now allow to embarking on practical applications. The main areas of application of SCNT are: Reproductive cloning, therapeutic cloning and basic research. A great application potential of SCNT based cloning is the production of genetically modified (transgenic) animals. Somatic cell nuclear transfer based transgenic animal production has significant advances over the previously employed microinjection of foreign DNA into pronuclei of zygotes. This cell based transgenesis is compatible with gene targeting and allows both, the addition of a specific gene and the deletion of an endogenous gene. Efficient transgenic animal production provides numerous opportunities for agriculture and biomedicine. Regulatory agencies around the world have agreed that food derived from cloned animals and their offspring is safe and there is no scientific basis for questioning this. Commercial application of somatic cloning within the EU is via the Novel Food regulation EC No. 258/97. Somatic cloning raises novel questions regarding the ethical and moral status of animals and their welfare which has prompted a controversial discussion in Europe which has not yet been resolved. © 2012 Blackwell Verlag GmbH.
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Frequency and occurrence of late-gestation losses from cattle cloned embryos.

Nuclear transfer from somatic cells still has limited efficiency in terms of live calves born due to high fetal loss after transfer. In this study, we addressed the type of donor cells used for cloning in in vivo development. We used a combination of repeated ultrasonography and maternal pregnancy serum protein (PSP60) assays to monitor the evolution of pregnancy after somatic cloning in order to detect the occurrence of late-gestation losses and their frequency, compared with embryo cloning or in vitro fertilization (IVF). Incidence of loss between Day 90 of gestation and calving was 43.7% for adult somatic clones and 33.3% for fetal somatic clones, compared with 4.3% after embryo cloning and 0% in the control IVF group. Using PSP60 levels in maternal blood as a criterion for placental function, we observed that after somatic cloning, recipients that lost their pregnancy before Day 100 showed significantly higher PSP60 levels by Day 50 than those that maintained pregnancy (7.77 +/- 3.3 ng/ml vs. 2.45 +/- 0.27 ng/ml for normal pregnancies, P < 0.05). At later stages of gestation, between 4 mo and calving, mean PSP60 concentrations were significantly increased in pathologic pregnancy after somatic cloning compared with other groups (P < 0.05 by Day 150, P < 0.001 by Day 180, and P < 0.01 by Day 210). In those situations, and confirmed by ultrasonographic measurements, recipients developed severe hydroallantois together with larger placentome size. Our findings suggest that assessing placental development with PSP60 and ultrasonography will lead to better care of recipient animals in bovine somatic cloning.

Author and article information

Affiliations
1. The Key Laboratory of National Education Ministry for Mammalian Reproductive Biology and Biotechnology, Key Laboratory of Herbivore Reproductive Biotechnology and Breeding of Ministry of Agriculture, Inner Mongolia University, Hohhot 010070, China
2. The Inner Mongolia Rangeland Ecology Institute, Alashan 750306, China
Author notes
xurg@cae.cn
gpengli@imu.edu.cn
Contributors
Journal
Front. Agr. Sci. Eng.
FASE
CN10-1204/S
Frontiers of Agricultural Science and Engineering
Higher Education Press (4 Huixin Dongjie, Chaoyang District, Beijing 100029, China)
2095-7505
2014
: 1
: 3
: 191-200

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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RESEARCH ARTICLE
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