Genetics and Behavior During Handling, Restraint, and Herding - Genetics and the Behavior of Domestic Animals - page 121

fearfulness and reactivity may be easier to differentiate when the animal is
held loosely in a single animal scale or head gate. Sebastian et al. (2011) sug-
gests replacing these subjective measurements with objective strain gauges
which measure the force exerted against the head gate by the animal. Another
possible objective measurement method would be a computer program used to
analyze shifts in weight to measure sheep movement in a single animal scale
( Horton and Miller, 2011 ). Many smart mobile telephones are equipped with
accelerometers which can also be used to measure how much an animal
shakes a restraint device (John Church, personal communication, 2012). Aps
originally designed for monitoring earthquakes can be easily downloaded
from the internet. A phone with this application could be used to measure
shaking by taping it to the framework of the chute. Tests that measure move-
ment in a squeeze chute or scale may work poorly on purebred Bos indicus
cattle such as Nelore if they have been subjected to a painful procedure, such
as dehorning. Bos indicus may exhibit tonic immobility and freeze when they
become extremely fearful. Tonic immobility is not likely to occur in crosses
between Bos indicus and Bos Taurus, and almost never occurs in the Bos
Taurus (English or European) breeders of cattle.
Exit Speed Tests
Exit speed tests are also called flight speed tests. It is likely that these tests
mainly measure fear. The speed an animal exits a squeeze chute or single ani-
mal scale is measured with either an electronic device ( Burrow and Dillon,
1997 ), or by gaits such as walk, trot, run ( Baszczak et al., 2006; Lanier and
Grandin, 2002 ). In some studies, exit speed tests have been shown to be more
accurate compared to restraint tests ( Caf´ et al., 2010 ). This may be caused by
cattle being too tightly restrained. In other studies where chute scoring was
able to discriminate individual differences, the animals were restrained
loosely. Hydraulic squeeze chutes that hold animals very tightly and restrict
movement reduce the effectiveness of subjective scoring during restraint,
making it difficult to differentiate between differences in behavior. In studies
where restraint tests were effective for differentiating differences in behavior,
researchers usually used looser restraint methods such as a single animal
scale, a head gate or a manually (hand) operated squeeze chute ( Benhajali
et al., 2010; Holl et al., 2010; Voisinet et al., 1997 ). Studies done by Baszczak
et al. (2006) and Vetters et al. (2013) were conducted using hydraulic squeeze
chutes that held cattle very tightly and exit speed scoring was shown to be
more effective. Brazilian studies by Sant-Anna et al. (2012) report that subjec-
tive behavior scores were effective. It may be that the Brazilian restraint
device held cattle more loosely than a hydraulic squeeze.
Exit speed scoring may not be accurate in Nelore or other purebred Bos
indicus cattle if the animals freeze in response to handling stress. This is
most likely to occur in Nelore which have been subjected to rough handling.