Page 82 - The Welfare of Cattle

bIoteChnoLoGY and anIMaL WeLfare 59

line, was maintained for comparison and housed in single-bird cages. After six generations, annual
mortality of the selected line in multiple-bird cages decreased from 68% to 8.8%. Mortality of
the selected line in multiple-bird cages was similar to that of the unselected control in single-bird
cages. Annual survival improved from 169 to 348 days, eggs per hen per day rose from 52 to 68%,
total eggs per hen from 91 to 237 eggs, and total egg mass from 5.1 to 13.4 kg, while average egg
weight remained unchanged. The author concluded that these data suggested group selection could
eliminate the need to beak-trim to avoid cannibalism by breeding hens to better suit multiple-bird
cage production systems. These outcomes from group selection would seem to align with several
sustainability goals, including decreased cannibalism and a resultant improvement in animal wel-
fare, better production efficiency, reduced need for beak trimming, and group housing rather than
single-bird cages.
In reality, it is likely that moving to alternative production systems (e.g., free range) in the inter-
ests of animal welfare will necessitate an associated “reselecting” for animals that are better suited
to the new production environment. With too much territory birds become territorial and it is not
uncommon to have much greater mortality in floor pens than cages due to the increased area.

CONCLUSION

Biotechnology is a broad term that encompasses many technologies that are routinely used in
animal agriculture. Emerging biotechnologies offer great potential, especially in the area of animal
breeding. Breeding can contribute to improved animal welfare in two ways. First, welfare traits
can be included in breeding objectives to select for improved animal welfare and decreased dis-
ease incidence. Second, modern molecular tools offer the opportunity to introduce novel genetic
variation into animal genomes to address both welfare concerns like dehorning and castration, in
addition to correcting diseases and disorders that have a genetic basis. Developing livestock that are
more resilient and less susceptible to disease is an important component of the development of more
productive and sustainable animal agricultural systems globally.

aCKNOWLeDGMeNtS

The author acknowledges research support from the USDA for grants 2015–67015-23316 and 2015–
33522-24106 that involve genome editing in livestock.