Page 120 - The Welfare of Cattle

breedInG and WeLfare 97

2009), understanding how quickly, and what types of bacteria are effective in facilitating a positive
welfare state are critical pieces of knowledge needed for the development of this biotechnology.
Improving cattle temperament during common stressors (e.g., transportation and handling) may
provide economic and animal welfare benefits. Temperament in cattle is a behavioral characteris-
tic that impacts profitability and worker safety. Cattle with excitable temperaments have reduced
growth rates (Voisinet et al., 1997), decreased carcass quality (King et al., 2006), reduced immune
function (Burdick et al., 2011), and higher cortisol levels during handling (Curley et al., 2006), yet
more aggressive maternal behavior can be associated with increased calf survival (Sandelin et al.,
2005). From an animal management perspective, cattle with excitable temperaments are more dif-
ficult to handle, present greater risk to animal managers, and may influence the behavior of herd-
mates. Cattle temperament has been observed to be consistent over time and context and influences
animal responsivity to stress and human handling (Curley et al., 2006). Cattle temperament is mod-
erately to highly heritable in many breeds (Stricklin et al., 1980; Gauly et al., 2001; Riley et al. 2014),
indicating selection potential to alter it. Most studies have also shown worse temperament scores for
females than males (Shrode and Hammack, 1971; Stricklin et al., 1980; Voisinet et al., 1997 Gauly
et al., 2001; Riley et al., 2014). It is also known that genetics influences feed efficiency (Archer et al.,
1997; Arthur et al., 2001; Robinson and Oddy, 2004; Nkrumah et al., 2007) indicating the potential
to alter nutrient utilization in cattle, and there are interrelationships between cattle temperament,
feed efficiency, and feeding behaviors. Whether the gut microbiome can influence temperament in
cattle or the plasticity of the relationships with other traits remains unexplored. Therefore, we need
to understand production- and behavioral-based aspects of the brain–gut axis in cattle to identify
biotechnologies designed to promote animal welfare.

Biotechnologies

Many of the biotechnologies developed for cattle have the capacity to enhance productivity and
profitability in both the beef and dairy industries. The type of commodity being produced (e.g., milk
or meat) will dictate what types of technologies are applied, when during the production cycle in
which they are implemented, and how management practices are altered to accommodate the imple-
mentation of these biotechnologies. The following sections identify management practices that may
be implemented to enhance the well-being of cattle.
Dehorning (including disbudding). Cattle are dehorned in order to reduce injuries to themselves
and conspecifics, minimize hide damage, improve human safety, reduce damage to facilities, and
facilitate safe transport and handling. Genetically selecting for polled cattle is a viable option, but
this is a long-term process. When polled genes or seed stock are not readily available, dehorning
(disbudding) is achieved by removal of the horn buds with a knife, thermal cautery of the horn buds,
or the application of chemical paste to cauterize the horn. It is recommended that producers use
analgesia or anesthesia for dehorning of beef cattle, particularly for older cattle with more advanced
horn development. However, it is also recommended that dehorning be performed in cattle at the
earliest age possible. Biotechnology offers a better path to increasing the frequency of the polled
gene in cattle. In cattle, the poll allele (P) is dominant to the horn allele (p). If a calf inherits a single
polled allele from either parent then it will be born without horns. Animals with two polled alleles
are homozygous polled. Animals with single polled allele and single horn allele are heterozygous
and carry the horn gene. Therefore, 25% of offspring from matings between heterozygous animals
will be horned.
In the United States, about 80% of all dairy calves (4.8 million per year) and 25% (8.75 million
animals) of beef cattle are dehorned yearly (Spurlock et al., 2014). Dairy cattle are less likely to be
born polled because the dominant POLLED gene exists at a much lower frequency in dairy cattle
(e.g., Holsteins), while it is well fixed in beef cattle such as the Angus breed. This is partly due to