Page 123 - The Welfare of Cattle

100 the WeLfare of CattLe

selection of genotypes that favor the desired phenotype (health status or production traits) avoids
controversy associated with cloning and transgenic animals. Genome marker-assisted selection
can be applied to large populations of animals used in food production enterprises. This approach
benefits the animal as well as the social acceptability of animal agriculture.

alternative Interpretations of Biotechnologies: exploiting the Microbiome in Cattle

Bioactive molecules in colostrum and the gut microbiome: effects on health of the neonate.
Calves acquire passive immunity and resistance to diseases through the first milk or colostrum
that is consumed within 24–48 hours after birth. The volume and quality of colostrum ingested
is important during the first 36–48 hours after birth to promote passive immunity and to affect
maturation of the gut. Adequate colostrum intake will decrease morbidity and mortality, as well as
increase gut maturation and development of reproductive organs. This is due to the establishment
of a population of bacteria in the gut referred to as the gut mass microbiome and those bacteria are
favorable for the health of calves.
The gut microbiome contributes to the nutritional status, immune function, and psychological
well-being of the newborn calf, for example, because the bacteria metabolize dietary nutrients,
inhibit pathogen colonization, regulate immune processes, and produce neural signals (see Hinde
and Lewis, 2015). Microbes present in breast milk affect development of the neonatal gut and those
derived from surface skin of the mother’s mammary gland are taken into the gut while the neonate
is suckling. Human milk, for example, has a great diversity of sugars that are preferred nutrients
for a species of bacteria known to promote a healthy gut in infants. These sugars are metabolized
to fatty acids and other molecules used as energy by bacteria in the neonatal gut to aid the infant’s
immune system and create an environment that is hostile to some pathogens.
Maternal effects mediated via colostrum also influence development and phenotype of animals
(see Bartol et al. 2017). For example, bioactive molecules in colostrum have significant long-term
effects on the infants even though they are only transferred from mother to neonate during the
first 24–36 hours after birth. In pigs, sheep, cows, and mice, for example, disruption of colostrum-
dependent development during neonatal life can have lasting effects on uterine growth and repro-
ductive performance as adults. Maturation of the male reproductive tract of pigs is also stimulated
by the intake of colostrum as is gut maturation in both sexes of mammals.
Weaning refers to the transfer of the calf to a solid and more fibrous diet consumed by either
self-feeding or grazing. Weaning is more stressful for beef than dairy calves, but should be done
in beef and dairy calves being shifted to a solid or fibrous diet only when the ruminant digestive
system has developed sufficiently to enable the calf to maintain growth and health from a solid
feed or forage based diet. Weaning may be accomplished by abrupt separation of cow and calf,
fence-line separation of cow and calf or placement of a device on the nose of the calf to discour-
age suckling. Abrupt weaning is especially stressful and often associated with additional stressors
including transportation, vaccination, dietary changes, and social mixing—all of which increase
the risk of morbidity and mortality. Ranchers and dairy managers should consider these factors
when implementing best practices as to the time and method of weaning for their type of cattle and
production system. Sound management decisions will decrease morbidity and mortality rates for
calves, promote calm and safe cattle movement, physical appearance, and reduce adverse effects on
health and productivity.

PUBLIC PerCePtIONS aND ethICS OF aNIMaL BIOteChNOLOGY

Animal biotechnology is not a new concept, nor is it a new tool in our quest to feed the future and
create a sustainable food system. Precision breeding is commonplace and the capacity to generate