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Effects of handling aids on calf behavior
Applied Animal Behaviour Science 69 Ž2000. 1–13 www.elsevier.comrlocaterapplanim
Effects of handling aids on calf behavior Candace C. Croney ) , Lowell L. Wilson, Stanley E. Curtis, Erskine H. Cash Dairy and Animal Science Department, The PennsylÕania State UniÕersity 324 William L. Henning Building, UniÕersity park, PA 16802 USA Accepted 17 March 2000
Abstract Effects of three different handling aids on calf behavior were determined. Group 1 calves were intensively-reared intact Holstein males Žmean 180 days old.; Group 2, extensively-reared beef-breed females Žmean 230 days.; Group 3, extensively-reared castrated beef-breed males Žmean 253 days.. Calves in each group were assigned to one of three handling aid treatments Ž n s 5 per treatment subgroup; total n s 45.: electric prod ŽProd., oar with rattles ŽOar., manual urging ŽManual.. Treatments were applied only as needed to encourage forward movement of calves through the length of a solid-sided semicircular chute system. Number of treatment applications, length of time required to move through the entire chute system, and behavior during movement through the chute were recorded. An approach test was conducted 1 day before and 1 day and 1 week after chute tests to evaluate changes in behavior due to handling aid application. During chute tests, Group 1 Prod calves required the fewest treatment applications Ž4.9. vs. 23.5 ŽOar. or 13.5 ŽManual., ran most often Ž1.40 times. vs. 0.20 times ŽManual. or 0.33 times ŽOar., and made contact with chute sides most often Ž1.8 times vs. 0.2 times ŽManual. or 0.7 times ŽOar., respectively Žall P - 0.05.. Similar trends were observed for calves in Groups 2 and 3. There were no significant differences between behaviors observed during the approach tests conducted before and after handling aid treatments had been imposed. Regardless of treatment, intensively-reared Group 1 calves appeared markedly less fearful of handlers during approach tests compared to extensively-reared calves in Groups 2 and 3, which demonstrated overt attempts to escape from the test facilities. One week after chute tests, 13 of 15 Prod calves from all three groups walked, rushed, or backed ) 1 m away from the handler when the prod was buzzed but not applied, suggesting that the buzzing sound alone may have sufficed to encourage movement by calves that
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Corresponding author. Tel.: q1-301-405-0048. E-mail address: [email protected] ŽC.C. Croney..
0168-1591r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 1 5 9 1 Ž 0 0 . 0 0 1 2 1 - 0
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had previously experienced both the sensation and sound associated with electric prodding. q 2000 Elsevier Science B.V. All rights reserved. Keywords: Behavior; Cattle; Electric prod; Handling aids
1. Introduction Handling of cattle is required for routine husbandry procedures such as movement, restraint and transportation. As a practical matter, the use of a handling aid is sometimes required, but it is essential to first identify a suitable aid and then apply it correctly to effectively encourage movement ŽGrandin, 1993.. When handling methods are inappropriate, cattle may exhibit undesirable behavior, or become distressed and even injured. Moreover, a handler may become frustrated by uncooperative cattle and resort to unnecessarily forceful methods of encouraging movement, which may result in injury to handler, animal, or both. Further, rough handling experiences may result in overly excitable, unapproachable cattle, consequently compromising labor efficiency. In fact, Rickenbacker Ž1959. observed that excessive use of handling aids caused cattle to become so confused and excited that the aids actually hindered rather than facilitated movement. Understanding reactions of animals to improper handling can help a handler recognize and respond appropriately to situations in need of improvement. Reducing the distress caused by poor handling presumably, would in turn, decrease the likelihood of chronically activating the sympatho-adrenomedullary system that may result in reduced fertility, decreased milk yield and increased aggression ŽMateo et al., 1990; Willner, 1993.. Few in-depth studies exist relating the behavioral responses of farm animals in general, and cattle in particular, to the use of specific handling aids. Electrical prods, for instance, are frequently used to expedite handling and movement and can be quite effective when applied correctly and in appropriate situations ŽGrandin, 1980.. When used to load pigs, they can produce rapid, relatively orderly movement ŽGuise and Penny, 1989.. Nonetheless, there is evidence that when used inappropriately, electrical prods and other handling aids may have detrimental effects on the behavior and physiological status of some farm animals. Hemsworth et al. Ž1987. found that pigs that were electrically prodded had higher elevations of free corticosteroids when approached by humans than did those that had not been prodded. Also, pigs that were electrically prodded were hesitant to eat when they could see a person in front of their trough and subsequently exhibited aggressive behavior toward handlers ŽBresson, 1982.. Further, when pigs that approached humans were electrically prodded, they subsequently became more hesitant to approach people, and were less inclined to interact with handlers ŽHemsworth et al., 1987.. Consequently, some organizations have recommended abolishing the use of electrical prods for animal handling ŽGuise and Penny, 1989.. Although electrical prods are often used to facilitate handling and movement of cattle, relatively little has been reported about the behavioral responses of cattle to electrical prodding. Lefcourt et al. Ž1985. noted that because cattle have very low electrical resistance, even small neutral to ground voltages Že.g., 0.5–3 V. can cause
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them to respond by lifting their legs, kicking or swaying. Lefcourt et al. Ž1986. also found that cattle behavior was sometimes dramatically affected when they were shocked. When restrained cows were shocked at electrical intensities ranging from 2.5 to 10.0 mA, they responded so violently that their safety and well-being were jeopardized ŽLefcourt et al., 1986.. In fact, cows that were shocked at currents of 12 mA were unapproachable ŽLefcourt et al., 1985.. Because electrical prods and other handling aids are used to facilitate movement of various breeds of calves, an experiment was designed to determine the behavioral responses of different types of calves to the application of one of three kinds of handling aids. Calves’ initial responses to a stationary and approaching handler were recorded and compared with their responses to the same handler after they had experienced one of three different aids. Further, to contrast the efficacies of the aids, the number of applications and length of time required to effect forward movement of calves through a chute Žusing each of the different aids. were recorded.
2. Materials and methods 2.1. Animals and treatments Three groups of calves were used: Group 1 consisted of 15 intact Holstein males 172–187 days old Žmean 180 days., weighing 145–182 kg Žmean 158 kg.; Group 2 consisted of nine Angus and six Simmental intact heifers 205–292 days old Žmean 236 days., 189–348 kg Žmean 290 kg.; Group 3 consisted of seven Angus, three Simmental, and five Hereford castrated males 221–297 days old Žmean 253 days., 246–343 kg Žmean 310 kg.. In addition to breed and gender disparities, several differences existed between groups prior to the study. Group 1 calves had previously been reared indoors and had no prior experience with either restraint or chute. Also, they had been manually handled frequently prior to initiation of the experiment. In contrast, Groups 2 and 3 calves were reared outdoors, and had experienced restraint in a chute system prior to the experiment, but had been only infrequently handled. With the exception of manual handling, none of the calves had previously experienced the handling aids used in the study. Because of the confounding associated with these factors, the effects of group were accounted for in the statistical analyses to be described later. For each group, calves were randomly allotted to five trios Žstratified by body weight.. Each trio was then randomly assigned to one of the three handling-aid treatments: Prod — electric prod ŽModel HS2000, Hotshot Products, Savage, MN; 3.3 kV, 700 mA with 500 V load, alternately on w0.08 msx and off Ž100.00 msx.; Oar — oar with rattles ŽKoehn Marketing, Watertown, SD; 122 cm long.; or Manual — manual urging Žbare-hand slap on calf rump.. For each trio of calves, one additional similar calf was kept with the experimental calves to serve as a companion when an experimental subject was temporarily isolated from its group.
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2.2. Procedures 2.2.1. Adjustment Each group of 15 experimental and five companion calves was moved to an outdoor pen to adjust for 2 weeks. The adjustment period was granted to accustom the calves to group housing in new facilities, as it was necessary to move them from their previous quarters to new pens near the testing site. The 2-week period was therefore deemed sufficient for the calves to recover from any distress caused by the move and the novel surroundings. All calves were fed the same quantity of the same diet throughout the adjustment and experimental periods. 2.2.2. Initial approach test To assess individual calves’ respective initial reactions to a human in close proximity, an approach test was conducted on the day before the chute tests ŽDay 0.. A handler directed each trio of calves plus a randomly selected companion calf from the outdoor group pen into a small indoor holding pen. After a 15-min rest period, one experimental calf was separated at random and driven approximately 3 m to the test area where it remained in auditory but not visual contact with its conspecifics during the test. This procedure was repeated until all calves in the trio had been approach-tested. All trios were similarly tested. The test area was constructed of pipe gates sheathed with plywood Ž1.22 m high. arranged as an octagon Žminimum radius 3.68 m.. The ground was covered to 8 cm with wood chips. As a calf entered the test area, a handler stood motionless in the center of the area, holding the calf’s assigned handling aid at a 458 angle against his body so that the tip of the aid rested against the handler’s right shoulder. If the calf approached the handler within 1 min, an observer recorded the hesitation time Ždefined as its latency to approach handler., as well as the distance it moved towards the handler. If it did not approach, then for 4 min, the handler continuously walked towards the calf. The distance Žif any. the handler walked before the calf moved away was also recorded. This distance was defined as the calf’s flight zone. The calf’s behavior in response to being approached was also recorded. To verify distances and further evaluate behavior, the test area was video-recorded using a video camera ŽModel WV-BP 100rWV-BP104, Panasonic, Secaucus, NJ., video recorder ŽModel VCR4000, Emerson Radio, Princeton, IN., and wide-angle lens ŽComputar APC 3.6 mm TV lens, Chugai International, Commack, NY.. All behaviors that were observed were recorded. These included: stand, walk, butt, run, circle, sniff groundrhandlerrpen, approach, and escape attempt. A detailed ethogram is presented in Table 1. At the end of the approach test, the calf was returned to the indoor holding pen. 2.2.3. Chute tests Tests of calves’ behavioral reactions to being driven through a solid-sided, semi-circular chute system Ž18.5 m long, Powder River Livestock Handling Equipment, Provo, UT. were conducted the next day ŽDay 1.. In the chute’s crowd pen, a handler randomly chose and separated one calf and allowed it 20 s to investigate its assigned handling aid, which he held. Then, the sliding door at the chute entrance was opened, and the handler applied the handling aid once to the calf’s right rump as he directed it into the chute.
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Table 1 Behavior patterns of calves recorded during approach tests and chute testing Behavior
Definition
Stand Walk Run Turn Circle Jump
Calf motionless, supported on all four legs Slow forward locomotion Rapid forward locomotion Movement of head and forelegs backward or to the side Continuous, regular forward locomotion around perimeter of test area Upward motion with calf supported only by hind legs, forelegs raised and extended towards test pen walls Calf standing or walking, head extended Žtoward handler, movement aid, around or pen walls with nostrils flared. Calf standing with head lowered, followed by forward movement with head directed forcefully at handler, aid or pen walls Calf walking toward handler, then standing within 0.5 m of handler Any visible occurrence of physical contact between calf and handler Calf standing or walking while permitting handler to move within 0.5 m of its body Calf running toward test pen walls, followed by jumping Forward locomotion interrupted by visible buckling of calf’s knees or legs Calf bumping forcefully against walls of chute Sniffing or licking handler, handling aid, test pen walls or ground Standing motionless, refusing to move despite handling aid application
Sniff Butt Approach Physical interaction Allow approach Escape attempt Stumble Side contact Investigate Balk
The prod was applied for no longer than 1 s per occasion, and was used only as necessary to effect the calf’s progress through the chute Že.g., the aid was only applied if the calf stopped moving forward.. Oar calves were lightly struck on the right rump with that aid one time before the sliding door was opened, and again, as needed to effect forward movement. As described for the prod, the oar was applied only when the calves stopped moving. Manual calves were gently slapped once on the right rump with a bare hand prior to entry into the chute system. To the extent that it was possible to do so, the handler used the same amount of force each time a handling aid Žor slap. was administered. The number of prod applications, oar strikes, or hand slaps required to move the calf through the chute was recorded. Additionally, the number of stop, turn, run, walk, investigate, contact side, refuse, and stumble behaviors were recorded. The total handling time and the actual handling time were also recorded. Total handling time was defined as time required to separate the calf from its trio Žincluding the 20-s period of interaction with the aid. to the time the calf exited the scale at the end of the chute system. Actual time was defined as the time taken from the moment the calf entered the sliding door at the chute entry to the time the calf stepped onto the chute’s scale. After the first trio had been tested, the next trio of calves within the assigned handling aid group was tested, and so on, until all had been tested. 2.2.4. Subsequent approach tests To determine the effects of the respective handling aids on the calves subsequent behavior, the approach test Žas described above. was repeated 1 day and 1 week after chute testing.
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Table 2 Frequenciesa of behaviors observed during approach tests for Groups 1, 2 and 3 calves Means in the same row with different superscripts Žb, c, d. differ; ns 5rtreatment Ž P - 0.05.. Means in the same row with different superscripts Že, f, g. differ; ns 5rtreatment Ž P - 0.10.. Item
Treatment Manual
GROUP 1 Before handler approach Stand 2.60 Sniff Žpen. 0.87 e Sniff Žground. 0.27 Sniff Žhandler. 0.47 Walk 1.87 Run 0.00 Circle 0.00 Approach 0.53 Escape attempt 0.00 After handler approach Stand 7.33 bc Sniff Žpen. 3.13 Sniff Žground. 1.80 e Sniff Žhandler. 0.73 b Walk 7.27 bc Run 0.00 Circle 0.00 Approach 3.80 Escape attempt 0.00 GROUP 2 Before handler approach Stand 4.32 Sniff Žpen. 2.40 Sniff Žground. 0.79 b Sniff Žhandler. 0.22 Walk 2.52 Run 0.40 b Circle 1.45 b Approach 0.42 Escape attempt 0.01 After handler approach Stand 15.03 Sniff Žpen. 10.21 Sniff Žground. 2.55 Sniff Žhandler. 1.11 Walk 10.35 Run 1.88 Circle 5.85 Approach 6.21 Escape attempt 0.76 b
Oar
Pooled SEM
Friedman’s P
Prod
2.47 1.00 f 0.60 0.80 2.20 0.00 0.00 0.80 0.00
2.27 0.40 g 0.27 0.60 1.47 0.00 0.00 0.87 0.00
0.31 0.22 0.16 0.22 0.37 0.00 0.00 0.29 0.00
0.98 0.10 0.16 0.82 0.86 0.00 0.00 0.72 0.00
5.47 b 2.93 1.80 f 2.87 c 6.20 b 0.00 0.00 3.73 0.00
9.07 c 3.67 3.40 g 1.20 d 9.20 c 0.00 0.00 4.40 0.00
0.76 0.49 0.50 0.46 0.90 0.00 0.00 1.10 0.00
0.01 0.76 0.07 0.01 0.08 0.00 0.00 0.47 0.00
3.87 1.93 1.33 c 0.33 2 .93 0.00 c 0.50 c 0.27 0.00
3.40 1.80 0.40 d 0.27 2.39 0.20 bc 0.20 d 0.33 0.07
0.46 0.43 0.27 0.15 0.48 0.15 0.37 0.18 0.04
0.67 0.94 0.03 0.76 0.80 0.01 0.00 0.37 0.16
1.59 1.28 0.64 0.49 1.73 0.48 1.20 1.24 0.25
0.69 0.40 0.87 0.39 0.68 0.14 0.24 0.72 0.05
15.33 9.27 1.93 1.40 10.87 1.33 4.27 6.33 0.27 c
16.13 7.87 2.27 2.40 12.73 0.53 4.33 5.80 0.33 c
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Table 2 Ž continued . Item
Treatment Manual
GROUP 3 Before handler approach Stand 2.79 b Ž . Sniff pen 1.71 Sniff Žground. 1.29 b Sniff Žhandler. 0.14 Walk 2.29 b Run 0.07 Circle 0.29 Approach 0.14 Escape attempt 0.00 After handler approach Stand 14.47 b Sniff Žpen. 5.53 Sniff Žground. 2.13 Sniff Žhandler. 4.87 b Walk 13.87 b Run 1.27 Circle 1.00 Approach 13.67 Escape attempt 0.07 a
Oar
Pooled SEM
Friedman’s P
Prod
4.00 c 2.00 1.43 b 0.07 3.50 c 0.36 0.29 0.21 0.00
2.79 b 1.50 0.29 c 0.00 2.21b 0.07 0.21 0.00 0.00
0.24 0.35 0.50 0.07 0.33 0.13 0.15 0.09 –
0.01 0.62 0.01 0.61 0.02 0.52 0.96 0.37 –
18.79 c 6.29 3.93 2.43 c 17.07 c 0.71 1.00 12.13 0.36
18.80 c 4.73 1.93 2.33 c 19.67 c 0.60 0.27 11.93 0.00
1.44 0.99 0.70 0.65 1.53 0.53 0.34 0.87 0.18
0.13 0.48 0.18 0.04 0.03 0.81 0.43 0.63 0.17
Frequencies denote the number of times a behavior was observed during a test period.
2.2.5. Reactions to sound of handling aid alone Prior to each calf’s release at the end of the Day 7 test, the handler returned to the center of the test area and resumed holding the handling aids against his body as previously described. For 30 s, the handler buzzed the prod or rattled the oar in the presence of each Prod or Oar calf, respectively, while observers recorded the calves’ responses. To avoid differences in responses due to different handlers, the same handler and observers were used for the entire test procedure for each group of calves. 2.3. Statistics Continuous data were analyzed using one-way analysis of variance ŽMinitab, 1996.. Because there were numerous pre-existing group differences Že.g., gender, age, housing and breed. between the three groups of calves, preliminary data analyses of the approach test data were conducted. These analyses indicated significant interactions between main effects ŽGroup X Treatment. which precluded combining all data. Therefore, each group’s approach test and chute test data set were analyzed separately. Data sets, which were not normally distributed, were transformed by deriving their square roots prior to analysis of variance ŽSteel and Torrie, 1980.. Pearson’s correlation procedure ŽSteel and Torrie, 1980. was used to determine relationships within each trial among the total time
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spent handling the calf in the chute area, actual time required to move the calf through the chute, and number of handling-aid applications required to move the calf through the chute.
3. Results 3.1. Approach tests Frequencies of behavior patterns observed during the approach tests conducted after treatments were imposed are presented in Table 2. No significant differences were observed between approach test behaviors observed before and after administration of handling aids for any of the groups Žall P ) 0.10.. There were also no significant differences between behaviors observed during approach tests conducted 1 day and 1 week after chute testing Žall P ) 0.10.. Therefore, the means of the three approach test results are presented ŽTable 2.. In response to a stationary handler, Group 1 Manual and Oar calves sniffed the pen more often than did Prod calves Ž P - 0.10.. In response to an approaching handler, Prod calves stood Ž P - 0.05. and walked Ž P - 0.05. more often than did Manual or Oar calves. Oar calves sniffed at the approaching handler more frequently than Manual or Prod calves Ž P - 0.05.. In response to a stationary handler, Group 2 Manual calves ran Ž P - 0.05. and circled the test area Ž P - 0.01. more often than did Prod or Oar calves. Oar calves sniffed the ground more frequently than did Manual or Prod calves Ž P - 0.05.. In response to handler approach, Manual calves in this group attempted to escape from the test arena more often than Oar or Prod calves Ž P - 0.05.. In Group 3, Oar calves stood Ž P - 0.01., walked Ž P - 0.05. and sniffed the ground Ž P - 0.05. before the handler approached, more often than did Prod or Manual calves. In response to an approaching handler, Manual calves walked Ž P - 0.05. less often than Oar or Prod calves but Manual calves also sniffed at the handler more often than Oar or Prod calves Ž P - 0.03.. 3.2. Chute tests Frequencies of behavior patterns during chute tests have been categorized by treatments within the three animal groups in Table 3. In Group 1, Prod calves turned, ran, and made contact with the sides of the chute more often than did Manual or Oar calves Žall P - 0.01.. Prod calves also balked and attempted to investigate the chute area less often than Manual or Oar Calves Žboth P - 0.05.. In Group 2, Prod calves stumbled and made contact with the sides of the chute more often than Oar or Manual calves Žboth P - 0.05.. In Group 3, Prod calves ran, made contact with chute sides, and stumbled more often than Manual or Oar calves Žall P - 0.01.. The duration of chute-test trials is summarized in Table 4. In Group 1, the actual time Žtime taken to travel the length of the chute. was less for Prod calves Ž46.27 s. than Manual Ž58.90 s. or Oar calves Ž70.10 s.. No differences were observed for Groups 2 or
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Table 3 Frequenciesa of behavior patterns observed during chute testing for Groups 1, 2 and 3 calves Means with different superscripts Žb, c, d. differ; ns 5rtreatment Ž P - 0.05.. Item
Treatment
Pooled SEM
Friedman’s P
Manual
Oar
Prod
GROUP 1 Turn Run Side contact Walk Balk Stumble Investigate
0.00 b 0.20 b 0.20 b 3.00 b 0.47 b 0.13 2.13 b
0.27 bc 0.33 b 0.73 c 3.07 b 1.47 c 0.13 2.07 b
0.73 d 1.40 c 1.80 d 2.00 c 0.33 b 0.53 0.80 c
0.12 0.19 0.27 0.39 0.29 0.14 0.42
0.01 0.01 0.01 0.04 0.01 0.32 0.02
GROUP 2 Turn Run Side contact Walk Balk Stumble Investigate
0.00 0.47 1.07 b 1.47 0.00 0.13 b 0.00
0.00 0.80 0.53 c 1.60 0.00 0.40 c 0.00
0.00 0.80 1.40 d 1.40 0.00 0.73 d 0.00
– 0.21 0.23 0.15 – 0.14 –
– 0.28 0.02 0.50 – 0.03 –
GROUP 3 Turn Run Side contact Walk Balk Stumble Investigate
0.00 0.33 b 0.47 b 1.33 b 0.07 0.27 b 0.00
0.00 0.33 b 0.33 c 1.47 b 0.00 0.13 b 0.00
0.00 1.47 c 3.33 d 0.47 d 0.07 0.73 c 0.00
– 0.16 0.25 0.14 0.05 0.15 –
– 0.01 0.01 0.01 0.61 0.01 –
a
Frequencies denote the number of times a behavior was observed during a test.
3 for actual time in the chute. Differences in total time Žtime required to move calves from the crowd pen into the chute and to travel through and exit the chute area. were observed for Group 1. Prod calves required least total time Ž84.10 s. vs. 102.3 s ŽManual. and 103.8 s ŽOar.. No differences were observed for Groups 2 or 3 calves for this category. The number of treatment the applications required to effect forward progress through the chute are also summarized in Table 4. Group 1 Prod calves required the fewest treatment applications ŽManual: 13.53; Oar: 23.53; Prod: 4.93; P - 0.01.. Group 2 Prod and Oar calves required fewer treatment applications Ž1.27 and 1.13, respectively. than Manual calves Ž1.60.. No differences were observed in this category for Group 3 calves. There was positive correlation Ž r s 0.95; P - 0.05. between the number of handlingaid applications and actual time spent in the chute for all groups. Similarly, total handling time and actual time spent in the chute were positively correlated Ž r s 0.94; P - 0.05. for all groups.
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Table 4 Number of treatment applications and amount of time required to move calves through the chute system Means in the same row with different superscripts Ža, b, c. differ Ž P - 0.05.. Means in the same row with different superscripts Žd, e, f. differ Ž P - 0.10.. Parameter
Treatment Manual Ž N s 5.
Pooled SEM Oar Ž N s 5.
P
Prod Ž N s 5.
Treatment applications (number) Group 1 13.53 ab Group 2 1.60 d Group 3 2.67
23.53 b 1.13 e 2.60
4.93 a 1.27 e 2.47
4.27 0.15 0.35
0.01 0.09 ) 0.10
Actual time in chute (s) Group 1 58.90 ab Group 2 13.93 Group 3 13.47
70.10 b 14.93 13.53
46.27 a 15.80 14.40
15.10 0.77 0.71
0.05 ) 0.10 ) 0.10
103.80 a 40.50 38.60
84.10 b 39.27 37.90
20.18 0.71 0.98
0.05 ) 0.10 ) 0.10
Total time in chute area (s) Group 1 102.30 a Group 2 37.07 Group 3 36.73
3.3. Reactions to sound of handling aid alone On Day 7 Ž1 week after handling-aid application in chute tests., most Prod and Oar calves appeared to respond behaviorally to the respective sounds of these handling aids alone. 13 of 15 Prod calves moved away ) 1 m Žand eight of them, ) 2 m. from the handler when the electric prod was buzzed in their vicinity. Two responded to the sound of the prod by bucking and running around the test area. Similar responses were observed in 11 of 15 Oar calves when the oar was shaken but not applied on Day 7. One Oar calf attempted to mount the handler, and two others butted the handler in response to the shaking sound of the Oar.
4. Discussion The finding of no significant differences for any group between approach test behaviors observed before and after handling aid administration suggests that brief exposure to a particular handling aid may be insufficient to alter calves’ behavioral reactions to a handler during subsequent approach tests. These results imply that the use of the aids in the chute test environment did not subsequently cause the calves to behave differently towards a handler that merely held the same aids in a different setting. The finding of no differences in approach test behaviors after treatment administration may have been due to partial masking of the effects of the handling aids by factors such as the differences in breeds and temperaments of the calves, as well as their previous exposure to handlers and handling facilities. For instance, all calves in Group 1,
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which were of dairy breeding and previously had been extensively handled in an indoor setting, appeared relatively undisturbed during approach tests, regardless of the handling aid experienced. In fact, calves that were electrically prodded Žpresumably, the most aversive of the handling treatments. were no less hesitant to approach or interact with a stationary or approaching handler after treatments were imposed, and no overt fear responses Že.g., escape attempts. were observed during any of the approach tests. In contrast, calves in Groups 2 and 3 Žof beef breeding and previously handled less frequently than Group 1 calves. frequently displayed fear responses Že.g., escape attempts, repeated circling of the pen’s perimeter, and running away from the handler. during approach tests. These observations suggest that the previous handling experience of the calves may have influenced their behavior patterns in agreement with the results of Boissy and Bouissou Ž1988., Trunkfield and Broom Ž1990. and Gonyou Ž1993.. However, because the current experiment was not designed to compare the effects of factors, such as breed and previous handling experience, on approach test behavior, but rather, was aimed only at clarifying the effects of the aids Žas a function of breed, experience, etc.. these observations are not based on statistical inference, and perhaps, should be investigated in future studies. Despite their apparent inability to alter the calves’ behavior from one approach test to the next, some effects of handling aids were observed both within and across groups during the approach test conducted 1 day after the treatments were administered. For example, regardless of group, Oar calves engaged in more investigatory behavior Že.g., sniff handling aid or handler. than did Prod or Manual calves. This might have been due to the oar’s rattling sound, which sometimes unintentionally occurred, even when the oar was not applied. Perhaps, the novel rattling sound caused the Oar calves to become curious about the source of the noise, so they investigated it, as suggested by Fraser Ž1974.. In contrast, Prod calves tended to investigate Že.g., sniff handling aid or handler. less often than did Manual or Oar calves. Perhaps, this tendency to avoid the handler and the handling aid occurred because these calves were more fearful of the handler and Žor. the aid than calves handled differently, and they subsequently tried to avoid further contact. This agrees with Fraser’s Ž1974. claim that animals rarely explore when they are fearful. In some instances, Manual calves in Groups 2 and 3 investigated more frequently than Oar or Prod calves, but then, also displayed more fear responses Že.g., running, circling the arena, and attempting to escape.. This finding was unexpected. Evidently, the Manual calves in these groups were disturbed by some aspect of the approach test procedure, and may have investigated their surroundings primarily to find some means of escaping. Similar results have been reported by Stephens and Toner Ž1975. who found elevated heart rates in calves that nonetheless appeared outwardly calm in response to an approaching handler. Although the behavior patterns of the calves remained relatively unchanged when the handler simply held the aids, it was observed that when the same handler buzzed the prod or rattled the oar at the end of the final approach test Žbut did not move toward the calves or attempt to apply the aids., most Prod and Oar calves visibly reacted to the sound of the aid that they had experienced. It is possible that these responses occurred because the calves learned and remembered the association between the buzzing sound
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of the electric prod or the rattling sound of the oar with the Žpresumably. unpleasant sensations that accompanied application of those aids. Learning which occurs under conditions of fear or distress tends to be well retained and may allow an animal to avoid extremely noxious stimuli after even one experience ŽBeilharz, 1985.. The observation that the calves responded to the sound of the aids alone after a week supports Grandin’s Ž1980. theory that once a calf has heard the sound that accompanies an application of an aversive sensation, that sound alone may suffice to encourage movement away from a handler. The results of the chute test demonstrated that electrically prodded calves required fewest treatment applications and the least time to move into and through the length of the chute. However, although the Prod calves moved most rapidly, they also stumbled and contacted the chute sides most often. Rickenbacker Ž1959. similarly reported that when handling aids were applied in a manner that elicited unnecessarily rapid animal movement, increased incidences in the number of contacts with stationary parts of the facility Že.g., the number of potential bruise-causing incidents. resulted. The findings in this study also concur with Gonyou’s Ž1993. belief that animals should not be hurried during movement because of the likelihood of missteps and other accidents occurring. Overall, the results of this experiment suggest that brief exposure to a specific handling aid may not significantly alter calves’ subsequent behavioral responses to stationary or approaching handlers that are not attempting to apply aids. The calves’ responses during such circumstances are perhaps less influenced by the type of handling aid experienced in one instance, than by other aspects of handling, such as isolation, and previous experience with handling procedures and facilities. However, upon hearing the sound of a handling aid that has been experienced, calves may respond by moving away. Thus, there may be instances when the sound of a handling aid alone would suffice to encourage calf movement. This possibility should be investigated further. Despite differences in breed, gender and previous experience, calves in all groups that were electrically prodded in a confined area Ža chute system. tended to rush away from handlers, stumble and make contact with the sides of the chute and other parts of the facilities more frequently than calves that were handled differently. Repeated electrical prodding of calves in a confined area should be avoided altogether, and particularly, immediately prior to slaughter, because consequent injuries to animals can have negative impacts on both their well-being and economic returns ŽGrandin, 1993.. Thus, it is important that handlers select appropriate handling aids and apply them correctly. Correct application procedure includes applying the aid only to calves that have stopped moving and are able to move away from the handler, and terminating that application once the calf has begun to move in the desired direction. Acknowledgements This research was partially supported by funds administered by the Pennsylvania Department of Agriculture. The authors gratefully acknowledge the contributions to this project by Elizabeth Carney, Brenda Coe, Daniel Deaver, Jack Decker, Michelle Hooven, Susan Koessler, Peter LeVan, Donald Nichols, Stephen Spencer, Randall Swope and Melissa Westerman.
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References Beilharz, R.G., 1985. Learned behaviour. In: Fraser, A.F. ŽEd.., World Animal Science, Ethology of Farm Animals. Elsevier, New York, pp. 93–102. Boissy, A., Bouissou, M.F., 1988. Effects of early handling on heifers’ subsequent reactivity to humans and to unfamiliar situations. Appl. Anim. Behav. Sci. 20, 259–273. Bresson, S., 1982. Influence of long term psychical stress Žnoise, fighting and electrical stimulation. on the physiology and productivity of growing-finishing pigs. In: Livestock Environment II: Proceedings of the Second International Livestock Environment Symposium. American Society of Agricultural Engineers, St. Joseph, pp. 449–456. Fraser, A.F., 1974. Farm Animal Behaviour. Balliere Tindall, New York. Gonyou, H., 1993. Behavioural principles of animal handling and transport. In: Grandin, T. ŽEd.., Livestock Handling and Transport. CAB International, Wallingford, Oxon, UK, pp. 11–20. Grandin, T., 1980. Livestock behavior as related to handling facilities design. Int. J. Stud. Anim. Prod. 1, 33–52. Grandin, T., 1993. Behavioural principles of cattle handling under extensive conditions. In: Grandin, T. ŽEd.., Livestock Handling and Transport. CAB International, Wallingford, Oxon, UK, pp. 43–57. Guise, H.J., Penny, R.H.C., 1989. Factors influencing the welfare and carcass and meat quality of pigs. Anim. Prod. 49, 511–515. Hemsworth, P.H., Barnett, J.L., Hansen, C., 1987. The influence of inconsistent handling by humans on the behaviour, growth and corticosteroids of young pigs. Appl. Anim. Behav. Sci. 17, 245–252. Lefcourt, A.M., Akers, R.M., Miller, R.H., Weinland, B., 1985. Effects of intermittent electrical shock on responses related to milk ejection. J. Dairy Sci. 68, 391–401. Lefcourt, A.M., Stanislaw, K., Akers, R.M., 1986. Correlation of indices of stress with intensity of electrical shock for cows. J. Dairy Sci. 69, 833–842. Mateo, J.M., Estep, D.Q., McCann, J.S., 1990. Effects of differential handling on the behaviour of domestic ewes Ž OÕis aries .. Appl. Anim. Behav. Sci. 32, 45–54. Minitab, 1996. Minitab Reference Manual, Release 11 for Windows. Minitab, State College, PA. Rickenbacker, J.E., 1959. Handling conditions and practices causing bruises in cattle. Marketing Res. Rep. 346, Farmer Cooperative Service, US Department of Agriculture, Washington, DC. Steel, R.G.D., Torrie, J.H., 1980. In: Principles and Procedures of Statistics, A Biometrical Approach. Mc-Graw Hill, New York, pp. 546–547. Stephens, D.B., Toner, J.N., 1975. Husbandry influences on some physiological parameters of emotional responses in calves. Appl. Anim. Ethol. 1, 233–243. Trunkfield, H.R, Broom, D.M., 1990. The welfare of calves during handling and transport. Appl. Anim. Behav. Sci. 28, 135–152. Willner, P., 1993. Animal models of stress: an overview. In: Stanford, S.C., Salmon, P. ŽEds.., Stress, From Synapse to Syndrome. Academic Press, New York, pp. 145–165.
Effects of handling aids on calf behavior Candace C. Croney ) , Lowell L. Wilson, Stanley E. Curtis, Erskine H. Cash Dairy and Animal Science Department, The PennsylÕania State UniÕersity 324 William L. Henning Building, UniÕersity park, PA 16802 USA Accepted 17 March 2000
Abstract Effects of three different handling aids on calf behavior were determined. Group 1 calves were intensively-reared intact Holstein males Žmean 180 days old.; Group 2, extensively-reared beef-breed females Žmean 230 days.; Group 3, extensively-reared castrated beef-breed males Žmean 253 days.. Calves in each group were assigned to one of three handling aid treatments Ž n s 5 per treatment subgroup; total n s 45.: electric prod ŽProd., oar with rattles ŽOar., manual urging ŽManual.. Treatments were applied only as needed to encourage forward movement of calves through the length of a solid-sided semicircular chute system. Number of treatment applications, length of time required to move through the entire chute system, and behavior during movement through the chute were recorded. An approach test was conducted 1 day before and 1 day and 1 week after chute tests to evaluate changes in behavior due to handling aid application. During chute tests, Group 1 Prod calves required the fewest treatment applications Ž4.9. vs. 23.5 ŽOar. or 13.5 ŽManual., ran most often Ž1.40 times. vs. 0.20 times ŽManual. or 0.33 times ŽOar., and made contact with chute sides most often Ž1.8 times vs. 0.2 times ŽManual. or 0.7 times ŽOar., respectively Žall P - 0.05.. Similar trends were observed for calves in Groups 2 and 3. There were no significant differences between behaviors observed during the approach tests conducted before and after handling aid treatments had been imposed. Regardless of treatment, intensively-reared Group 1 calves appeared markedly less fearful of handlers during approach tests compared to extensively-reared calves in Groups 2 and 3, which demonstrated overt attempts to escape from the test facilities. One week after chute tests, 13 of 15 Prod calves from all three groups walked, rushed, or backed ) 1 m away from the handler when the prod was buzzed but not applied, suggesting that the buzzing sound alone may have sufficed to encourage movement by calves that
)
Corresponding author. Tel.: q1-301-405-0048. E-mail address: [email protected] ŽC.C. Croney..
0168-1591r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 1 5 9 1 Ž 0 0 . 0 0 1 2 1 - 0
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had previously experienced both the sensation and sound associated with electric prodding. q 2000 Elsevier Science B.V. All rights reserved. Keywords: Behavior; Cattle; Electric prod; Handling aids
1. Introduction Handling of cattle is required for routine husbandry procedures such as movement, restraint and transportation. As a practical matter, the use of a handling aid is sometimes required, but it is essential to first identify a suitable aid and then apply it correctly to effectively encourage movement ŽGrandin, 1993.. When handling methods are inappropriate, cattle may exhibit undesirable behavior, or become distressed and even injured. Moreover, a handler may become frustrated by uncooperative cattle and resort to unnecessarily forceful methods of encouraging movement, which may result in injury to handler, animal, or both. Further, rough handling experiences may result in overly excitable, unapproachable cattle, consequently compromising labor efficiency. In fact, Rickenbacker Ž1959. observed that excessive use of handling aids caused cattle to become so confused and excited that the aids actually hindered rather than facilitated movement. Understanding reactions of animals to improper handling can help a handler recognize and respond appropriately to situations in need of improvement. Reducing the distress caused by poor handling presumably, would in turn, decrease the likelihood of chronically activating the sympatho-adrenomedullary system that may result in reduced fertility, decreased milk yield and increased aggression ŽMateo et al., 1990; Willner, 1993.. Few in-depth studies exist relating the behavioral responses of farm animals in general, and cattle in particular, to the use of specific handling aids. Electrical prods, for instance, are frequently used to expedite handling and movement and can be quite effective when applied correctly and in appropriate situations ŽGrandin, 1980.. When used to load pigs, they can produce rapid, relatively orderly movement ŽGuise and Penny, 1989.. Nonetheless, there is evidence that when used inappropriately, electrical prods and other handling aids may have detrimental effects on the behavior and physiological status of some farm animals. Hemsworth et al. Ž1987. found that pigs that were electrically prodded had higher elevations of free corticosteroids when approached by humans than did those that had not been prodded. Also, pigs that were electrically prodded were hesitant to eat when they could see a person in front of their trough and subsequently exhibited aggressive behavior toward handlers ŽBresson, 1982.. Further, when pigs that approached humans were electrically prodded, they subsequently became more hesitant to approach people, and were less inclined to interact with handlers ŽHemsworth et al., 1987.. Consequently, some organizations have recommended abolishing the use of electrical prods for animal handling ŽGuise and Penny, 1989.. Although electrical prods are often used to facilitate handling and movement of cattle, relatively little has been reported about the behavioral responses of cattle to electrical prodding. Lefcourt et al. Ž1985. noted that because cattle have very low electrical resistance, even small neutral to ground voltages Že.g., 0.5–3 V. can cause
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them to respond by lifting their legs, kicking or swaying. Lefcourt et al. Ž1986. also found that cattle behavior was sometimes dramatically affected when they were shocked. When restrained cows were shocked at electrical intensities ranging from 2.5 to 10.0 mA, they responded so violently that their safety and well-being were jeopardized ŽLefcourt et al., 1986.. In fact, cows that were shocked at currents of 12 mA were unapproachable ŽLefcourt et al., 1985.. Because electrical prods and other handling aids are used to facilitate movement of various breeds of calves, an experiment was designed to determine the behavioral responses of different types of calves to the application of one of three kinds of handling aids. Calves’ initial responses to a stationary and approaching handler were recorded and compared with their responses to the same handler after they had experienced one of three different aids. Further, to contrast the efficacies of the aids, the number of applications and length of time required to effect forward movement of calves through a chute Žusing each of the different aids. were recorded.
2. Materials and methods 2.1. Animals and treatments Three groups of calves were used: Group 1 consisted of 15 intact Holstein males 172–187 days old Žmean 180 days., weighing 145–182 kg Žmean 158 kg.; Group 2 consisted of nine Angus and six Simmental intact heifers 205–292 days old Žmean 236 days., 189–348 kg Žmean 290 kg.; Group 3 consisted of seven Angus, three Simmental, and five Hereford castrated males 221–297 days old Žmean 253 days., 246–343 kg Žmean 310 kg.. In addition to breed and gender disparities, several differences existed between groups prior to the study. Group 1 calves had previously been reared indoors and had no prior experience with either restraint or chute. Also, they had been manually handled frequently prior to initiation of the experiment. In contrast, Groups 2 and 3 calves were reared outdoors, and had experienced restraint in a chute system prior to the experiment, but had been only infrequently handled. With the exception of manual handling, none of the calves had previously experienced the handling aids used in the study. Because of the confounding associated with these factors, the effects of group were accounted for in the statistical analyses to be described later. For each group, calves were randomly allotted to five trios Žstratified by body weight.. Each trio was then randomly assigned to one of the three handling-aid treatments: Prod — electric prod ŽModel HS2000, Hotshot Products, Savage, MN; 3.3 kV, 700 mA with 500 V load, alternately on w0.08 msx and off Ž100.00 msx.; Oar — oar with rattles ŽKoehn Marketing, Watertown, SD; 122 cm long.; or Manual — manual urging Žbare-hand slap on calf rump.. For each trio of calves, one additional similar calf was kept with the experimental calves to serve as a companion when an experimental subject was temporarily isolated from its group.
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2.2. Procedures 2.2.1. Adjustment Each group of 15 experimental and five companion calves was moved to an outdoor pen to adjust for 2 weeks. The adjustment period was granted to accustom the calves to group housing in new facilities, as it was necessary to move them from their previous quarters to new pens near the testing site. The 2-week period was therefore deemed sufficient for the calves to recover from any distress caused by the move and the novel surroundings. All calves were fed the same quantity of the same diet throughout the adjustment and experimental periods. 2.2.2. Initial approach test To assess individual calves’ respective initial reactions to a human in close proximity, an approach test was conducted on the day before the chute tests ŽDay 0.. A handler directed each trio of calves plus a randomly selected companion calf from the outdoor group pen into a small indoor holding pen. After a 15-min rest period, one experimental calf was separated at random and driven approximately 3 m to the test area where it remained in auditory but not visual contact with its conspecifics during the test. This procedure was repeated until all calves in the trio had been approach-tested. All trios were similarly tested. The test area was constructed of pipe gates sheathed with plywood Ž1.22 m high. arranged as an octagon Žminimum radius 3.68 m.. The ground was covered to 8 cm with wood chips. As a calf entered the test area, a handler stood motionless in the center of the area, holding the calf’s assigned handling aid at a 458 angle against his body so that the tip of the aid rested against the handler’s right shoulder. If the calf approached the handler within 1 min, an observer recorded the hesitation time Ždefined as its latency to approach handler., as well as the distance it moved towards the handler. If it did not approach, then for 4 min, the handler continuously walked towards the calf. The distance Žif any. the handler walked before the calf moved away was also recorded. This distance was defined as the calf’s flight zone. The calf’s behavior in response to being approached was also recorded. To verify distances and further evaluate behavior, the test area was video-recorded using a video camera ŽModel WV-BP 100rWV-BP104, Panasonic, Secaucus, NJ., video recorder ŽModel VCR4000, Emerson Radio, Princeton, IN., and wide-angle lens ŽComputar APC 3.6 mm TV lens, Chugai International, Commack, NY.. All behaviors that were observed were recorded. These included: stand, walk, butt, run, circle, sniff groundrhandlerrpen, approach, and escape attempt. A detailed ethogram is presented in Table 1. At the end of the approach test, the calf was returned to the indoor holding pen. 2.2.3. Chute tests Tests of calves’ behavioral reactions to being driven through a solid-sided, semi-circular chute system Ž18.5 m long, Powder River Livestock Handling Equipment, Provo, UT. were conducted the next day ŽDay 1.. In the chute’s crowd pen, a handler randomly chose and separated one calf and allowed it 20 s to investigate its assigned handling aid, which he held. Then, the sliding door at the chute entrance was opened, and the handler applied the handling aid once to the calf’s right rump as he directed it into the chute.
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Table 1 Behavior patterns of calves recorded during approach tests and chute testing Behavior
Definition
Stand Walk Run Turn Circle Jump
Calf motionless, supported on all four legs Slow forward locomotion Rapid forward locomotion Movement of head and forelegs backward or to the side Continuous, regular forward locomotion around perimeter of test area Upward motion with calf supported only by hind legs, forelegs raised and extended towards test pen walls Calf standing or walking, head extended Žtoward handler, movement aid, around or pen walls with nostrils flared. Calf standing with head lowered, followed by forward movement with head directed forcefully at handler, aid or pen walls Calf walking toward handler, then standing within 0.5 m of handler Any visible occurrence of physical contact between calf and handler Calf standing or walking while permitting handler to move within 0.5 m of its body Calf running toward test pen walls, followed by jumping Forward locomotion interrupted by visible buckling of calf’s knees or legs Calf bumping forcefully against walls of chute Sniffing or licking handler, handling aid, test pen walls or ground Standing motionless, refusing to move despite handling aid application
Sniff Butt Approach Physical interaction Allow approach Escape attempt Stumble Side contact Investigate Balk
The prod was applied for no longer than 1 s per occasion, and was used only as necessary to effect the calf’s progress through the chute Že.g., the aid was only applied if the calf stopped moving forward.. Oar calves were lightly struck on the right rump with that aid one time before the sliding door was opened, and again, as needed to effect forward movement. As described for the prod, the oar was applied only when the calves stopped moving. Manual calves were gently slapped once on the right rump with a bare hand prior to entry into the chute system. To the extent that it was possible to do so, the handler used the same amount of force each time a handling aid Žor slap. was administered. The number of prod applications, oar strikes, or hand slaps required to move the calf through the chute was recorded. Additionally, the number of stop, turn, run, walk, investigate, contact side, refuse, and stumble behaviors were recorded. The total handling time and the actual handling time were also recorded. Total handling time was defined as time required to separate the calf from its trio Žincluding the 20-s period of interaction with the aid. to the time the calf exited the scale at the end of the chute system. Actual time was defined as the time taken from the moment the calf entered the sliding door at the chute entry to the time the calf stepped onto the chute’s scale. After the first trio had been tested, the next trio of calves within the assigned handling aid group was tested, and so on, until all had been tested. 2.2.4. Subsequent approach tests To determine the effects of the respective handling aids on the calves subsequent behavior, the approach test Žas described above. was repeated 1 day and 1 week after chute testing.
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Table 2 Frequenciesa of behaviors observed during approach tests for Groups 1, 2 and 3 calves Means in the same row with different superscripts Žb, c, d. differ; ns 5rtreatment Ž P - 0.05.. Means in the same row with different superscripts Že, f, g. differ; ns 5rtreatment Ž P - 0.10.. Item
Treatment Manual
GROUP 1 Before handler approach Stand 2.60 Sniff Žpen. 0.87 e Sniff Žground. 0.27 Sniff Žhandler. 0.47 Walk 1.87 Run 0.00 Circle 0.00 Approach 0.53 Escape attempt 0.00 After handler approach Stand 7.33 bc Sniff Žpen. 3.13 Sniff Žground. 1.80 e Sniff Žhandler. 0.73 b Walk 7.27 bc Run 0.00 Circle 0.00 Approach 3.80 Escape attempt 0.00 GROUP 2 Before handler approach Stand 4.32 Sniff Žpen. 2.40 Sniff Žground. 0.79 b Sniff Žhandler. 0.22 Walk 2.52 Run 0.40 b Circle 1.45 b Approach 0.42 Escape attempt 0.01 After handler approach Stand 15.03 Sniff Žpen. 10.21 Sniff Žground. 2.55 Sniff Žhandler. 1.11 Walk 10.35 Run 1.88 Circle 5.85 Approach 6.21 Escape attempt 0.76 b
Oar
Pooled SEM
Friedman’s P
Prod
2.47 1.00 f 0.60 0.80 2.20 0.00 0.00 0.80 0.00
2.27 0.40 g 0.27 0.60 1.47 0.00 0.00 0.87 0.00
0.31 0.22 0.16 0.22 0.37 0.00 0.00 0.29 0.00
0.98 0.10 0.16 0.82 0.86 0.00 0.00 0.72 0.00
5.47 b 2.93 1.80 f 2.87 c 6.20 b 0.00 0.00 3.73 0.00
9.07 c 3.67 3.40 g 1.20 d 9.20 c 0.00 0.00 4.40 0.00
0.76 0.49 0.50 0.46 0.90 0.00 0.00 1.10 0.00
0.01 0.76 0.07 0.01 0.08 0.00 0.00 0.47 0.00
3.87 1.93 1.33 c 0.33 2 .93 0.00 c 0.50 c 0.27 0.00
3.40 1.80 0.40 d 0.27 2.39 0.20 bc 0.20 d 0.33 0.07
0.46 0.43 0.27 0.15 0.48 0.15 0.37 0.18 0.04
0.67 0.94 0.03 0.76 0.80 0.01 0.00 0.37 0.16
1.59 1.28 0.64 0.49 1.73 0.48 1.20 1.24 0.25
0.69 0.40 0.87 0.39 0.68 0.14 0.24 0.72 0.05
15.33 9.27 1.93 1.40 10.87 1.33 4.27 6.33 0.27 c
16.13 7.87 2.27 2.40 12.73 0.53 4.33 5.80 0.33 c
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Table 2 Ž continued . Item
Treatment Manual
GROUP 3 Before handler approach Stand 2.79 b Ž . Sniff pen 1.71 Sniff Žground. 1.29 b Sniff Žhandler. 0.14 Walk 2.29 b Run 0.07 Circle 0.29 Approach 0.14 Escape attempt 0.00 After handler approach Stand 14.47 b Sniff Žpen. 5.53 Sniff Žground. 2.13 Sniff Žhandler. 4.87 b Walk 13.87 b Run 1.27 Circle 1.00 Approach 13.67 Escape attempt 0.07 a
Oar
Pooled SEM
Friedman’s P
Prod
4.00 c 2.00 1.43 b 0.07 3.50 c 0.36 0.29 0.21 0.00
2.79 b 1.50 0.29 c 0.00 2.21b 0.07 0.21 0.00 0.00
0.24 0.35 0.50 0.07 0.33 0.13 0.15 0.09 –
0.01 0.62 0.01 0.61 0.02 0.52 0.96 0.37 –
18.79 c 6.29 3.93 2.43 c 17.07 c 0.71 1.00 12.13 0.36
18.80 c 4.73 1.93 2.33 c 19.67 c 0.60 0.27 11.93 0.00
1.44 0.99 0.70 0.65 1.53 0.53 0.34 0.87 0.18
0.13 0.48 0.18 0.04 0.03 0.81 0.43 0.63 0.17
Frequencies denote the number of times a behavior was observed during a test period.
2.2.5. Reactions to sound of handling aid alone Prior to each calf’s release at the end of the Day 7 test, the handler returned to the center of the test area and resumed holding the handling aids against his body as previously described. For 30 s, the handler buzzed the prod or rattled the oar in the presence of each Prod or Oar calf, respectively, while observers recorded the calves’ responses. To avoid differences in responses due to different handlers, the same handler and observers were used for the entire test procedure for each group of calves. 2.3. Statistics Continuous data were analyzed using one-way analysis of variance ŽMinitab, 1996.. Because there were numerous pre-existing group differences Že.g., gender, age, housing and breed. between the three groups of calves, preliminary data analyses of the approach test data were conducted. These analyses indicated significant interactions between main effects ŽGroup X Treatment. which precluded combining all data. Therefore, each group’s approach test and chute test data set were analyzed separately. Data sets, which were not normally distributed, were transformed by deriving their square roots prior to analysis of variance ŽSteel and Torrie, 1980.. Pearson’s correlation procedure ŽSteel and Torrie, 1980. was used to determine relationships within each trial among the total time
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spent handling the calf in the chute area, actual time required to move the calf through the chute, and number of handling-aid applications required to move the calf through the chute.
3. Results 3.1. Approach tests Frequencies of behavior patterns observed during the approach tests conducted after treatments were imposed are presented in Table 2. No significant differences were observed between approach test behaviors observed before and after administration of handling aids for any of the groups Žall P ) 0.10.. There were also no significant differences between behaviors observed during approach tests conducted 1 day and 1 week after chute testing Žall P ) 0.10.. Therefore, the means of the three approach test results are presented ŽTable 2.. In response to a stationary handler, Group 1 Manual and Oar calves sniffed the pen more often than did Prod calves Ž P - 0.10.. In response to an approaching handler, Prod calves stood Ž P - 0.05. and walked Ž P - 0.05. more often than did Manual or Oar calves. Oar calves sniffed at the approaching handler more frequently than Manual or Prod calves Ž P - 0.05.. In response to a stationary handler, Group 2 Manual calves ran Ž P - 0.05. and circled the test area Ž P - 0.01. more often than did Prod or Oar calves. Oar calves sniffed the ground more frequently than did Manual or Prod calves Ž P - 0.05.. In response to handler approach, Manual calves in this group attempted to escape from the test arena more often than Oar or Prod calves Ž P - 0.05.. In Group 3, Oar calves stood Ž P - 0.01., walked Ž P - 0.05. and sniffed the ground Ž P - 0.05. before the handler approached, more often than did Prod or Manual calves. In response to an approaching handler, Manual calves walked Ž P - 0.05. less often than Oar or Prod calves but Manual calves also sniffed at the handler more often than Oar or Prod calves Ž P - 0.03.. 3.2. Chute tests Frequencies of behavior patterns during chute tests have been categorized by treatments within the three animal groups in Table 3. In Group 1, Prod calves turned, ran, and made contact with the sides of the chute more often than did Manual or Oar calves Žall P - 0.01.. Prod calves also balked and attempted to investigate the chute area less often than Manual or Oar Calves Žboth P - 0.05.. In Group 2, Prod calves stumbled and made contact with the sides of the chute more often than Oar or Manual calves Žboth P - 0.05.. In Group 3, Prod calves ran, made contact with chute sides, and stumbled more often than Manual or Oar calves Žall P - 0.01.. The duration of chute-test trials is summarized in Table 4. In Group 1, the actual time Žtime taken to travel the length of the chute. was less for Prod calves Ž46.27 s. than Manual Ž58.90 s. or Oar calves Ž70.10 s.. No differences were observed for Groups 2 or
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Table 3 Frequenciesa of behavior patterns observed during chute testing for Groups 1, 2 and 3 calves Means with different superscripts Žb, c, d. differ; ns 5rtreatment Ž P - 0.05.. Item
Treatment
Pooled SEM
Friedman’s P
Manual
Oar
Prod
GROUP 1 Turn Run Side contact Walk Balk Stumble Investigate
0.00 b 0.20 b 0.20 b 3.00 b 0.47 b 0.13 2.13 b
0.27 bc 0.33 b 0.73 c 3.07 b 1.47 c 0.13 2.07 b
0.73 d 1.40 c 1.80 d 2.00 c 0.33 b 0.53 0.80 c
0.12 0.19 0.27 0.39 0.29 0.14 0.42
0.01 0.01 0.01 0.04 0.01 0.32 0.02
GROUP 2 Turn Run Side contact Walk Balk Stumble Investigate
0.00 0.47 1.07 b 1.47 0.00 0.13 b 0.00
0.00 0.80 0.53 c 1.60 0.00 0.40 c 0.00
0.00 0.80 1.40 d 1.40 0.00 0.73 d 0.00
– 0.21 0.23 0.15 – 0.14 –
– 0.28 0.02 0.50 – 0.03 –
GROUP 3 Turn Run Side contact Walk Balk Stumble Investigate
0.00 0.33 b 0.47 b 1.33 b 0.07 0.27 b 0.00
0.00 0.33 b 0.33 c 1.47 b 0.00 0.13 b 0.00
0.00 1.47 c 3.33 d 0.47 d 0.07 0.73 c 0.00
– 0.16 0.25 0.14 0.05 0.15 –
– 0.01 0.01 0.01 0.61 0.01 –
a
Frequencies denote the number of times a behavior was observed during a test.
3 for actual time in the chute. Differences in total time Žtime required to move calves from the crowd pen into the chute and to travel through and exit the chute area. were observed for Group 1. Prod calves required least total time Ž84.10 s. vs. 102.3 s ŽManual. and 103.8 s ŽOar.. No differences were observed for Groups 2 or 3 calves for this category. The number of treatment the applications required to effect forward progress through the chute are also summarized in Table 4. Group 1 Prod calves required the fewest treatment applications ŽManual: 13.53; Oar: 23.53; Prod: 4.93; P - 0.01.. Group 2 Prod and Oar calves required fewer treatment applications Ž1.27 and 1.13, respectively. than Manual calves Ž1.60.. No differences were observed in this category for Group 3 calves. There was positive correlation Ž r s 0.95; P - 0.05. between the number of handlingaid applications and actual time spent in the chute for all groups. Similarly, total handling time and actual time spent in the chute were positively correlated Ž r s 0.94; P - 0.05. for all groups.
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Table 4 Number of treatment applications and amount of time required to move calves through the chute system Means in the same row with different superscripts Ža, b, c. differ Ž P - 0.05.. Means in the same row with different superscripts Žd, e, f. differ Ž P - 0.10.. Parameter
Treatment Manual Ž N s 5.
Pooled SEM Oar Ž N s 5.
P
Prod Ž N s 5.
Treatment applications (number) Group 1 13.53 ab Group 2 1.60 d Group 3 2.67
23.53 b 1.13 e 2.60
4.93 a 1.27 e 2.47
4.27 0.15 0.35
0.01 0.09 ) 0.10
Actual time in chute (s) Group 1 58.90 ab Group 2 13.93 Group 3 13.47
70.10 b 14.93 13.53
46.27 a 15.80 14.40
15.10 0.77 0.71
0.05 ) 0.10 ) 0.10
103.80 a 40.50 38.60
84.10 b 39.27 37.90
20.18 0.71 0.98
0.05 ) 0.10 ) 0.10
Total time in chute area (s) Group 1 102.30 a Group 2 37.07 Group 3 36.73
3.3. Reactions to sound of handling aid alone On Day 7 Ž1 week after handling-aid application in chute tests., most Prod and Oar calves appeared to respond behaviorally to the respective sounds of these handling aids alone. 13 of 15 Prod calves moved away ) 1 m Žand eight of them, ) 2 m. from the handler when the electric prod was buzzed in their vicinity. Two responded to the sound of the prod by bucking and running around the test area. Similar responses were observed in 11 of 15 Oar calves when the oar was shaken but not applied on Day 7. One Oar calf attempted to mount the handler, and two others butted the handler in response to the shaking sound of the Oar.
4. Discussion The finding of no significant differences for any group between approach test behaviors observed before and after handling aid administration suggests that brief exposure to a particular handling aid may be insufficient to alter calves’ behavioral reactions to a handler during subsequent approach tests. These results imply that the use of the aids in the chute test environment did not subsequently cause the calves to behave differently towards a handler that merely held the same aids in a different setting. The finding of no differences in approach test behaviors after treatment administration may have been due to partial masking of the effects of the handling aids by factors such as the differences in breeds and temperaments of the calves, as well as their previous exposure to handlers and handling facilities. For instance, all calves in Group 1,
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which were of dairy breeding and previously had been extensively handled in an indoor setting, appeared relatively undisturbed during approach tests, regardless of the handling aid experienced. In fact, calves that were electrically prodded Žpresumably, the most aversive of the handling treatments. were no less hesitant to approach or interact with a stationary or approaching handler after treatments were imposed, and no overt fear responses Že.g., escape attempts. were observed during any of the approach tests. In contrast, calves in Groups 2 and 3 Žof beef breeding and previously handled less frequently than Group 1 calves. frequently displayed fear responses Že.g., escape attempts, repeated circling of the pen’s perimeter, and running away from the handler. during approach tests. These observations suggest that the previous handling experience of the calves may have influenced their behavior patterns in agreement with the results of Boissy and Bouissou Ž1988., Trunkfield and Broom Ž1990. and Gonyou Ž1993.. However, because the current experiment was not designed to compare the effects of factors, such as breed and previous handling experience, on approach test behavior, but rather, was aimed only at clarifying the effects of the aids Žas a function of breed, experience, etc.. these observations are not based on statistical inference, and perhaps, should be investigated in future studies. Despite their apparent inability to alter the calves’ behavior from one approach test to the next, some effects of handling aids were observed both within and across groups during the approach test conducted 1 day after the treatments were administered. For example, regardless of group, Oar calves engaged in more investigatory behavior Že.g., sniff handling aid or handler. than did Prod or Manual calves. This might have been due to the oar’s rattling sound, which sometimes unintentionally occurred, even when the oar was not applied. Perhaps, the novel rattling sound caused the Oar calves to become curious about the source of the noise, so they investigated it, as suggested by Fraser Ž1974.. In contrast, Prod calves tended to investigate Že.g., sniff handling aid or handler. less often than did Manual or Oar calves. Perhaps, this tendency to avoid the handler and the handling aid occurred because these calves were more fearful of the handler and Žor. the aid than calves handled differently, and they subsequently tried to avoid further contact. This agrees with Fraser’s Ž1974. claim that animals rarely explore when they are fearful. In some instances, Manual calves in Groups 2 and 3 investigated more frequently than Oar or Prod calves, but then, also displayed more fear responses Že.g., running, circling the arena, and attempting to escape.. This finding was unexpected. Evidently, the Manual calves in these groups were disturbed by some aspect of the approach test procedure, and may have investigated their surroundings primarily to find some means of escaping. Similar results have been reported by Stephens and Toner Ž1975. who found elevated heart rates in calves that nonetheless appeared outwardly calm in response to an approaching handler. Although the behavior patterns of the calves remained relatively unchanged when the handler simply held the aids, it was observed that when the same handler buzzed the prod or rattled the oar at the end of the final approach test Žbut did not move toward the calves or attempt to apply the aids., most Prod and Oar calves visibly reacted to the sound of the aid that they had experienced. It is possible that these responses occurred because the calves learned and remembered the association between the buzzing sound
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of the electric prod or the rattling sound of the oar with the Žpresumably. unpleasant sensations that accompanied application of those aids. Learning which occurs under conditions of fear or distress tends to be well retained and may allow an animal to avoid extremely noxious stimuli after even one experience ŽBeilharz, 1985.. The observation that the calves responded to the sound of the aids alone after a week supports Grandin’s Ž1980. theory that once a calf has heard the sound that accompanies an application of an aversive sensation, that sound alone may suffice to encourage movement away from a handler. The results of the chute test demonstrated that electrically prodded calves required fewest treatment applications and the least time to move into and through the length of the chute. However, although the Prod calves moved most rapidly, they also stumbled and contacted the chute sides most often. Rickenbacker Ž1959. similarly reported that when handling aids were applied in a manner that elicited unnecessarily rapid animal movement, increased incidences in the number of contacts with stationary parts of the facility Že.g., the number of potential bruise-causing incidents. resulted. The findings in this study also concur with Gonyou’s Ž1993. belief that animals should not be hurried during movement because of the likelihood of missteps and other accidents occurring. Overall, the results of this experiment suggest that brief exposure to a specific handling aid may not significantly alter calves’ subsequent behavioral responses to stationary or approaching handlers that are not attempting to apply aids. The calves’ responses during such circumstances are perhaps less influenced by the type of handling aid experienced in one instance, than by other aspects of handling, such as isolation, and previous experience with handling procedures and facilities. However, upon hearing the sound of a handling aid that has been experienced, calves may respond by moving away. Thus, there may be instances when the sound of a handling aid alone would suffice to encourage calf movement. This possibility should be investigated further. Despite differences in breed, gender and previous experience, calves in all groups that were electrically prodded in a confined area Ža chute system. tended to rush away from handlers, stumble and make contact with the sides of the chute and other parts of the facilities more frequently than calves that were handled differently. Repeated electrical prodding of calves in a confined area should be avoided altogether, and particularly, immediately prior to slaughter, because consequent injuries to animals can have negative impacts on both their well-being and economic returns ŽGrandin, 1993.. Thus, it is important that handlers select appropriate handling aids and apply them correctly. Correct application procedure includes applying the aid only to calves that have stopped moving and are able to move away from the handler, and terminating that application once the calf has begun to move in the desired direction. Acknowledgements This research was partially supported by funds administered by the Pennsylvania Department of Agriculture. The authors gratefully acknowledge the contributions to this project by Elizabeth Carney, Brenda Coe, Daniel Deaver, Jack Decker, Michelle Hooven, Susan Koessler, Peter LeVan, Donald Nichols, Stephen Spencer, Randall Swope and Melissa Westerman.
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