considered, aversion learning techniques are an effective method to determine which handling practices cattle find aversive or rewarding. q 2000 Elsevier Science B.V. All rights reserved.
Keywords: Dairy cattle; Handling; Aversion; Learning; Mazes; Fear
1. Introduction
Cows find certain forms of handling to be aversive and, consequently, can develop a fear of people which can reduce welfare and milk production and increase the risk of
Ž .
injury to both animals and handlers Hemsworth and Coleman, 1998 . Dairy cows and calves learn to avoid a particular handler as a result of aversive treatment by that handler
Ž .
de Passille et al., 1996; Munksgaard et al., 1997; Rushen et al., 1999 . However, we do
´
not yet know which handling treatments cattle find aversive. One approach is to use aversive learning techniques, which are based on the principle that animals learn to
Ž .
avoid treatments that they find aversive for a review, see Rushen, 1996 . These
Ž .
techniques have been used with poultry Rutter and Duncan, 1991, 1992 , cattle
Ž .
Ž .
Schwartzkopf-Genswein et al., 1997 , sheep Grandin et al., 1986; Rushen 1986 and Ž
. deer Grigor et al., 1998 . One promising procedure involves the repeated application of
a treatment at the end of a race and measuring the time and force necessary to return the Ž
. animal through the race to the place where the treatment was done Karsh, 1962 . The
more aversive the treatment, the more the animal will resist returning to that place and the more time and force will be required to move the animal through the race. Aversion
raceways based on this principle have been used to assess the aversiveness of simulated
Ž .
shearing to sheep Hargreaves and Hutson, 1990 , the aversiveness of electroimmobilisa- Ž
. Ž
. tion to both sheep Rushen, 1986 and beef cattle Pascoe and McDonell, 1986 and the
Ž .
relative aversiveness of various management practices to red deer Grigor et al., 1998 . This technique has not been used previously to evaluate the aversiveness of various
handling procedures for dairy cattle. This paper describes the results of three experiments aimed at determining the
aversiveness of dairy cattle handling practices using the aversion race. In the first experiment, we tested the empirical validity of the aversion race by determining how
well it differentiates between treatments known to differ in aversiveness. In the second experiment, we used the aversion race to determine the relative aversiveness of various
techniques used to move cows. In the final experiment, we examined if the aversion race can differentiate between treatments thought to be rewarding, rather than aversive, to
young heifers.
2. General methods
2.1. Animals and housing Experiment 1 used lactating multiparous Holstein cows, which were brought in from
pasture each morning for milking, then moved from the milking parlour to the test barn. After tests were completed, animals were returned to pasture and milked in the evening.
In experiments 2 and 3, non-lactating multiparous Holstein cows and 1–1.5-year-old Ž
. Holstein heifers were housed in pens 5.3 = 9.3 m, maximum of 10 animals per pen in
a room in the same barn as, and adjacent to, the room where experimental procedures were done. Animals were fed at 13:00 h, after experimental procedures were completed.
2.2. Procedures Experimental procedures were approved by the institutional animal care committee at
the Lennoxville Research Centre, itself monitored by the Canadian Council for Animal Ž
. Care. Animals were placed in a pre-test holding pen 5.3 = 9.3 m either immediately
Ž .
before experiment 1 or at least 24 h before experimental procedures were initiated Ž
. experiments 2 and 3 . All experimental procedures were performed between 08:00 and
12:00 h. One animal at a time was moved from the holding pen down an alley to the
beginning of the race. The race was 10 m long = 1 m wide with 2 m high walls made Ž
. from solid wood Fig. 1 . Animals could see the person who applied the treatments
Ž .
Ž .
dressed in red standing sideways not looking at the animal at the end of the race. The race was divided into four equal sections. The animals were placed at the beginning of
the first section and allowed 30 s to move through each section. If the animal had not moved through the section once this time had elapsed, the person moving the animals
approached the animal from behind and applied increasing levels of force until it entered the next section. The force required to move the animal into the next section was scored
Ž .
using a standardised method derived from Schwartzkopf-Genswein et al. 1997 : 0 s nothing, animal moves through section within 30 s on its own; 1 s approach and speak
Ž .
in a gentle voice; 2 s poke side with fingers five times ; 3 s hit rump with open hand Ž
. Ž
. five times ; 4 s hit rump with two open hands five times ; 5 s pencil poke on back
Ž .
three times ; 6 s push and force animal to advance. Near the end of the race, the animals walked up a small ramp into a 2-m long cage where they received assigned
treatments. Ž
. The latency to enter the race after leaving pre-test holding area , the time required to
Ž move through the race from start of race until the animal entered the individual
Fig. 1. Plan of experimental apparatus.
. treatment pen , and the amount of force required to move the animal down the race
Ž .
summed over the four sections of the race were recorded. 2.3. Statistical analysis
For all three experiments, the total amount of time and the summed force taken to move through the race as well as the latency to enter the race were analysed by analyses
Ž .
of variance using the general linear model procedure of SAS 1990 . The model
consisted of two factors: the treatments applied to the animal, which varied between Ž
. experiments experiment 1, df s 3; experiment 2, df s 4; experiment 3, df s 2 and the
Ž trial number, which was treated as a repeated measures factor experiment 1, df s 1,10;
. experiments 2 and 3, df s 3,6 . To correct for initial differences between cows in
moving down the race before treatments were applied, we included the measure on the Ž
. first trial as a covariate df s 1 . We tested for interactions between trial number and the
treatment. Contrast statements were used to compare treatments within each experiment Ž
. each contrast df s 1 . Due to large variation, data were log transformed before
analyses, but untransformed values are presented for clarity. In all experiments, prelimi- nary analyses demonstrated no effect of week, group or any interactions between these
factors and treatment, and these factors were removed from the final analysis.
3. Experiment 1: Validity of the aversion race
