Page 242 - The Welfare of Cattle

WeLfare Issues In feedLot CattLe 219

stressors imposed at the time of entry which include initial processing, novel environment, and
pen mates likely contribute to increasing stress and susceptibility to disease. The link between
these management factors and reduced animal health and performance has been reported by many
researchers (Ribble et al., 1995; Price et al., 2003; Chirase et al., 2004; Stanger et al., 2005).
The more risk factors associated with a calf, the greater the likelihood that it will succumb
to BRD or to other communicable diseases associated with raising a large number of cattle in a
confined area. Calves that have been exposed to all or most of the previously listed risk factors
are appropriately referred to as “high-risk” calves and feedlot managers need to be proactive in
the prevention, early detection and treatment of these kinds of calves to reduce calf morbidity and
mortality. The greatest incidence of BRD is observed within the first 30 days after calves enter the
feedlot (Duff and Galyean, 2007; Edwards, 2010; Wilson et al., 2017). High-risk calves typically
become ill sooner after arrival than low-risk calves, which is associated with the timing of the
stressors in relationship to the exposure to pathogens. Wilson et al. (2017) concluded that calves
that have spent several days in the marketing chain may develop clinical BRD before or very soon
after they have entered the feedlot while calves spending less time in the marketing chain may get
ill 2–4 weeks after arrival; related to the length of time it takes for BRD to develop. Consequently,
the initial vaccination protocol used on entry to the backgrounding feedlot is determined by the
level of illness risk.

Welfare Issues associated with Feedlot heifers

The most significant welfare issue associated with feedlot heifers is the chance that they may be
pregnant on entry to the feedlot. Feedlot managers have little control over this but can minimize its
occurrence by purchasing heifer calves from reputable and conscientious sources. Pregnancies often
go undetected in heifers due to their small size, making detection and appropriate management
difficult. Unlike cow–calf operations, the feedlot is not well equipped to manage pregnant animals
as they require special facilities such as a calving chute, a sheltered, clean and dry area away from
other cattle and equipment such as a calf jack, chains, etc. Although it is important to have trained
staff to assist calving heifers, typically few feedlot pen riders have this experience. Without the
basic calving facilities and trained staff, the potential for negative welfare outcomes for both the
heifer and the calf are great. Calf survival rates are extremely low because the calf is typically
removed from the heifer shortly after birth with little or no chance to nurse and receive colostrum.
Heifers may also suffer complications following birth such as retained placental or vaginal prolapse
as well as increased death losses and health costs (Habermehl, 1993; Rademacher et al., 2015).
In cases where pregnancies are too advanced for spaying or abortifacients are not used at the
time of arrival, heifers will calve in the feedlot. Calving heifers are at high risk of dystocia because
their pelvis is usually small which decreases the likelihood of calving naturally (Miesner and
Anderson, 2015). If excessive traction with a calf puller is required, this can result in a down heifer
which may become nonambulatory. In this situation, cesarean section is recommended and must be
conducted by an experienced veterinarian with the use of appropriate anesthetics and analgesics to
ensure good welfare outcomes (Miesner and Anderson, 2015).
A common method of managing feedlot pregnancies is to administer abortifacients to heifers
on arrival to the feedlot. Although these agents are effective in eliminating pregnancy, induced
abortions can result in numerous complications including dystocia, retained fetal membranes,
acute toxic metritis, and death (Barth, 1986). An alternative practice to eliminate feedlot pregnan-
cies is spaying (ovariectomy) which could be done as part of a preconditioning program prior to
entering the feedlot or at the time of entry providing the pregnancy is still early. This procedure
may help to improve heifer welfare by eliminating pregnancy as well as estrous/riding behavior
which may make heifers more susceptible to injuries. There are two main methods of spaying;
dropped ovary and flank techniques. The dropped ovary technique is done by inserting a special