The Effects of Handling Frequency on 8-Week Body Weight, Feed Conversion, and Mortality*

The Effects of Handling Frequency on 8-Week Body Weight, Feed Conversion, and Mortality*

The Effects of Handling Frequency on 8-Week Body Weight, Feed Conversion, and Mortality* B. N. MCPHERSON, N. R. GYLES AND J. KAN Department of Animal...

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The Effects of Handling Frequency on 8-Week Body Weight, Feed Conversion, and Mortality* B. N. MCPHERSON, N. R. GYLES AND J. KAN Department

of Animal Industry and Veterinary Science, University of Arkansas,

Fayetteville

(Received far publication January 11. 1961)

I

N EXPERIMENTAL work with chickens, it is often required to handle birds more frequently than in commercial flocks. This raises the question whether such frequent handling would affect certain measures of broiler performance. In the fall of 1960, an experiment was designed to study the effects of handling frequency on 8-week weight, feed conversion, and mortality in broilers. The experiment, covering a period of eight weeks, involved four handling frequencies: (1) Birds were handled and weighed once at eight weeks of age; (2) Birds were handled and weighed twice at seven and eight weeks of age; (3) Birds were handled and weighed four times, once every two weeks; and (4) Birds were handled and weighed eight times, once each week. At eight weeks of age individual body weights were taken and handling consisted of penning in birds with a crowding wire and catching each bird for the purpose of weighing. At all other ages the birds were caught individually and placed in chicken coops. When all birds in the pen were caught, the bulk weight of each pen was recorded. Each treatment was replicated in two pens of 64 male and 59 female chicks in each pen. The birds came from six commercial broiler strains and were distributed in the same proportionate numbers to each pen. Each bird was provided one sq. ft. of floor space and fed a ration containing 973 productive Calories per lb. of feed. Management was rendered similar * Published with the approval of the Director of the Arkansas Agricultural Experiment Station.

in all pens with the exception of handling differences. RESULTS AND DISCUSSION Results of 8-week weight and feed conversion are presented in Table 1 with the appropriate analysis of variance in Tables 2 and 3. It is noted in Table 1 that there is very little difference between the four handling frequencies in average 8-week weight and feed conversion. The analysis oi variance in Tables 2 and 3 indicates that the four handling frequencies have no effect on either 8-week weight or feed conversion. The coefficients of variability are given in Table 1 which are 13%, 13%, 12%, and 13% for the four groups handled once, twice, four times, and eight times, respectively. It is clear that handling does not in any way affect the uniformity of 8-week weight. Mortality, which ranges from 1.6% to 2.4%, is generally low in all treatments. There is no evidence that handling influences the level of mortality. It is interesting to note that the group handled each week actually gave the highest 8-week weight and the best feed conversion among all treatments. This difference, however, was not statistically significant. The measures of performance in Table 1 are economically important. It should be mentioned, however, that these measures are complex traits which are influenced by various genetic and environmental variables. Indicators of stress as such were not investigated in this experiment. Thus, it still remains to be determined whether excessive handling constitutes a stressor to the or-

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EFFECTS OF HANDLING TABLE 1.—Average broiler performance of four handling frequencies p

Treatment

Av. 8-wk. weight1

C.V.2 of 8-wk. wt.

Feed Conversion3

Mortality

2.05 2.07 2.06

0.81 4.06 2.44

(%)

Handled once

North South Both

3.22 3.26 3.24

.1260 .1325 .1292

Handled twice

North South Both

3.21 3.23 3.22

.1405 .1185 .1295

2.01 2.02 2.02

2.44 1.63 2.04

Handled four times

North South Both

3.18 3.31 3.24

.1220 .1230 .1225

1.99 2.05 2.02

0.81 2.44 1.62

Handled eight times

North South Both

3.25 3.28 3.26

.1340 .1305 .1322

2.01 2.00 2.00

1.63 1.63 1.63

All Pens

3.24

.1284

2.02

1.93

1,2 3

Unweighted average of the two sexes, lbs. feed Feed conversion = • lbs. live weight

TABLE 2.—The analysis of variance of 8-week weight of four handling frequencies Source of Variation

D.F.

S.S.

Replicates 1 .36 Sex 1 124.72 Treatments 3 .10 Remainder (Error) 10 2.09 Within Subclass 949 172.70

Source of Variation

M.S. .36 124.72 .03

TABLE 3.—The analysis of variance of feed conversion of four handling frequencies

1.71 593.90** .14

.21 .18

** Significant at the 1% level.

ganism. This is important in view of the concept of adaptation energy (Selye, 1952) where the resistance of the animal to a second stressor may be diminished while the animal adapts itself to the first stressor.

Treatments Replicates Error

D.F.

S.S.

M.S.

.0034 .0028 .0014

.0011 .0028 .0005

2.20 5.60

were subjected to four different handling frequencies during a period from day-old to 8 weeks of age. Each handling frequency was replicated in two pens of 123 chicks each. No significant differences between handling frequencies were observed in 8week weight, feed conversion, and mortality. REFERENCE

SUMMARY

Birds from commercial meat-type strains

Selye, H., 1952. The Story of the Adaptation Syndrome. Acta, Inc., Montreal.

FEBRUARY 9-11. 33RD ANNUAL FACT FINDING CONFERENCE, INSTITUTE OF AMERICAN POULTRY INDUSTRIES, MUNICIPAL AUDITORIUM, KANSAS CITY, MO. MARCH 15-17. ANNUAL EXPOSITION AND CONVENTION OF PACIFIC DAIRY AND POULTRY ASSOCIATION, BILTMORE HOTEL, LOS ANGELES.