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Performance of dairy cattle clones and evaluation of their milk composition. Photo courtesy Infigen. H. Duane Norman * ,1 and Marie K. Walsh 2 1 Animal Improvement Programs Laboratory Agricultural Research Service, USDA Beltsville, MD 20705-2350, USA
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Performance of dairy cattle clones and evaluation of their milk composition Photo courtesy Infigen H. Duane Norman*,1 and Marie K. Walsh2 1Animal Improvement Programs Laboratory Agricultural Research Service, USDA Beltsville, MD 20705-2350, USA 2Utah State University, Logan, UT 84322, USA *dnorman@aipl.arsusda.gov 301-504-8334
Cloning biotechnology • Embryo splitting • Nuclear transfer • Embryo • Somatic cell • Fetal • Adult
Normal performance? • Animal health (developmental issues) • Mitochondrial DNA differences • Genotype identification (bloodtyping) • Genetic merit • Food safety
Research studies • Norman, Lawlor, and Wright (2002). Proceedings of 7th World Congress on Genetics Applied to Livestock Production 33, 699-702. • Norman, Lawlor, and Wright (2003). Journal of Dairy Science (in press). • Walsh, Lucey, Govindasamy-Lucey, et al. (2003). Cloning and Stem Cells 5, 213-219.
Pedigree merit • Mean genetic merit of parents • Mean genetic superiority (p0.01) of parents relative to population for same birth year:
Genetic merit (PTA) – cows *p0.01 **p0.001
Mean standardized performance *p0.01 **p0.001
Deviation from contemporaries *p0.05 **p0.01
Milk composition • Traits analyzed: Solids, fat, fatty acid profile, lactose, protein • Nuclear-transfer clone breeds: Brown Swiss, Holstein, Holstein Jersey • No differences between clones and non-clones for gross chemical composition of milk • Slight difference for palmitic acid • Mineral content most variable component
Conclusions • U.S. dairy cattle selected for cloning slightly superior genetically to population for yield • No obvious differences between cloned and non-cloned cows • Performance • Milk produced • No food safety concerns related to milk from cloned cows
U.S. Food & Drug Administration “Most clones that survive the perinatal period are normal and healthy as determined by physiological measurements, behavior, and veterinary examinations.” “Edible products from normal, healthy clones or their progeny do not appear to pose increased food consumption risks relative to comparable products from conventional animals.” Draft Executive Summary of Animal Cloning: A Risk Assessment(2003)