Page 62 - The Welfare of Cattle

ChaPter 6

Cattle ectoparasites in extensive
and Intensive Cattle Systems

Alec C. Gerry
University of California

CONteNtS

Extensive vs. Intensive Systems: Ectoparasite Presence and Abundance ........................................40
Ectoparasite Life History Characteristics ........................................................................................43
Permanent Ectoparasites .............................................................................................................44
Intermittent Ectoparasites............................................................................................................44
Temporary Ectoparasites .............................................................................................................46
Extensive vs. Intensive Systems: Ectoparasite Management ...........................................................47
References ........................................................................................................................................49

University of California, Riverside Ectoparasites can negatively affect cattle health, welfare,
and productivity in many ways, ranging from reductions in cattle weight gain or milk production, to
severe health consequences and even death of parasitized animals. These negative impacts can be
categorized as (1) physical damage to cattle caused by the feeding of ectoparasites on blood, skin,
or hair, (2) irritation and disturbance of cattle resulting in unproductive pest avoidance behaviors
in response to the painful or irritating bites of ectoparasites, (3) transmission of disease agents
to cattle by ectoparasites, and (4) nuisance to facility employees and neighbors by the activity of
some ectoparasites even when these ectoparasites have no measureable impact on cattle (Table 6.1).
Furthermore, ectoparasites can reduce feed conversion efficiency thereby impacting production
even when no obvious damage to cattle has occurred.
The presence and abundance of ectoparasites at any individual cattle facility is driven primarily
by the local environment and by the operational characteristics of the facility. Most ectoparasites
exhibit seasonal activity that is relatively consistent among years and across cattle production sys-
tems within a geographic area, with the timing of peak activity often predictable by temperature
and rainfall during the preceding months. But while environmental characteristics determine the
timing of peak ectoparasite activity, it is the operational characteristics of the facility, particularly
facility design and herd management, that often determine the abundance of ectoparasites and the
severity of their impacts to cattle health and production.

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