Page 127 - The Welfare of Cattle

104 the WeLfare of CattLe

(fetal overgrowth) syndrome and extreme variation was also possible within clone-mates (Wilson
et al., 1995; Young et al., 1998). This phenomenon was also reported for calves produced through in
vitro fertilization. More recently, variability in methylation patterns has been associated with fetal
overgrowth syndrome in cattle (Hiendleder et al., 2004), and wide discrepancies in methylation
patterns of genes have been shown among cattle clones (Bourc’his et al., 2001; de Montera et al.,
2010). Development of in vitro cultured embryos has also resulted in “Large Offspring Syndrome”
calves where gestation lengths are longer. Thus, the offspring grow to a size that makes calving
difficult, and many of the offspring possess congenital abnormalities. The implementation of this
biotechnology before its components were understood presented welfare risks to both the offspring
and the dam. Animals that are developed for disease modeling may become intentionally sick which
is contrary to “Freedom from disease and injury.” Furthermore, if the concept of animal welfare
is moving toward providing a “life worth living,” then breeding animals to be chronically ill or
to knowingly undergo a difficult pregnancy is in direct contradiction to efforts to enhance animal
welfare.
We are just beginning to understand factors such as epigenetics and modification of DNA that
influence both animal production and animal health. Genetic modification can result in a wide
variety of phenotypic consequences. While scientists can intentionally alter genetic material, they
have limited control on how genetic material is altered and when the alteration goes into effect.
This unpredictability of when and how genetic modifications will be presented phenotypically can
have implications for animal managers, the efficacy of the technology, and the impact of the genetic
modification on future generations. This lack of knowledge regarding when and if welfare problems
will manifest provides animal managers additional challenges.
Animals modified by biotechnology may require different management, may have different
capacities to cope with stress and may have to work harder to cope with stressors. Conversely, they
may be able to cope better with stressors, may respond less severely to these stressors, and may
subsequently have better welfare. The unknown consequences of genetic manipulation or biotech-
nology implementation on the sensory functioning, bone or muscle structure, hormone produc-
tion, and neural control presents a scenario in which animal managers must evaluate these animals
objectively and be willing to make management changes as needed. Therefore, animal managers
must evaluate animals that are either GM or treated with biotechnology differently than those that
are not—as their biological systems may be operating differently. When necessary, management
practices, human behavior toward animals, and resource provision should be altered to accommo-
date any observed changes so that these animals can experience a welfare state comparable to or
better than their unmodified counterparts.

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