The effect of age and sex on slaughter traits of pheasants

Animal Science Papers and Reports vol. 24 (2006) Supplement 2, 11-18
Institute of Genetics and Animal Breeding, Jastrzębiec, Poland
Presented at the III Conference
“Genetic and Environmental Possibilities
of Adjusting the slaughter value and meat quality
of animals to consumers’ requirements”
7-8 September 2006, Lublin-Krasnobród, Poland
The effect of age and sex on slaughter traits
of pheasants (Phasianus colchicus L.)*
Marek Adamski, Joanna Kuźniacka
Department of Poultry Breeding, University of Technology and Life Sciences in Bydgoszcz,
Mazowiecka 28, 85-084 Bydgoszcz, Poland
Slaughter traits were evaluated in pheasants slaughtered at the age of 12, 16 and 20 weeks. No
significant differences between week 16 and 20 were found in the trunk length with the neck, trunk
length, breast bone length and circumference and width of the chest as measured on the carcass, as
well as in the weight of eviscerated carcass with the neck, dressing percentage and muscle content of
carcass. The results show a feasibility of completing the rearing of slaughter pheasants between week
16 and 20 of life. The traits affected neither by age nor by sex of birds were the dressing percentage,
breast and leg muscles content of carcass (%) and the content (%) of skin with subcutaneous fat.
KEY WORDS: carcass / pheasant / sex / slaughter age
Pheasants are reared in Poland principally as game birds, and less frequently for
slaughter. Pheasant meat demonstrates a high nutritive value, as it contains high-
*Carried out upon the approval of the Local Ethics Committee in Bydgoszcz - opinion No. 8/04.
11
Marek Adamski, Joanna Kuźniacka
quality protein and little fat, as well as more essential unsaturated fatty acids than
the meat of broiler chickens, ducks and geese [Torgowski et al. 1990, Hargis and Van
Elswyk 1993, Leskanich and Noble 1997, Rutkowski 2001]. It can then enjoy a high
demand on the market as a valuable foodstuff, especially with a growing interest of
consumers in safe food. The length of the rearing period of pheasants depends on their
body weight which should be about 1 kg and on full feathering of the bird. Meeting
of these requirements is affected by nutrition and keeping conditions as well as by
variety and age of pheasants [Mróz 1998].
According to Torgowski et al. [1990], the pheasant meat production can be
increased by rearing birds up to week 16-18 of life, which, however, causes an
increased feed intake per 1 kg body weight gain as well as leads to obtaining pheasant
carcasses in late autumn. The mentioned authors reported that rearing pheasants up to
week 12 of life did not guarantee an adequate carcass weight, no matter if the birds
were reared with a semi-intensive (the aviary system) or intensive system (indoors).
Upon still ambiguous opinions upon the optimum slaughter age of pheasants
[Znaniecka 1973, Znaniecka i Sobina 1973, Znaniecka I Wajda 1976, 1977, Jamroz
et al. 1982, Torgowski et al. 1990, Sarica et al. 1999] as well as limited information
available on the pheasant slaughter traits, taking up this study seemed justified. It
aimed at determining the effect of age and sex of pheasants on their slaughter traits.
Material and methods
Pheasants were reared up to week 20 of life. Up to week 8 the birds were kept
in the rearing house, under controlled environment, and from week 9 to the end of
rearing in partially roofed aviaries. Up to end of week 8 the pheasants were fed with
all-mash starter R-301 (27.32% protein and 2800 kcal ME/kg), from week 9 to 16
with a grower R-302 (24.21% protein and 2765 kcal ME/kg), and from week 17 to
the slaughter – with a finisher R-303 (18.06% of protein and 2750 kcal ME/kg). Birds’
feeding followed the standards recommended by the Institute of Animal Physiology
and Nutrition [1996].
On week 12, 16 and 20 of rearing five males and five females were selected;
with body weight similar to the mean weight of birds of a given sex in the flock and
slaughtered. After plucking and prior to evisceration, the carcasses were measured.
With accuracy of up to 0.1 cm the following dimensions were tape-determined:
- the length of the trunk with the neck (between the first cervical vertebra and the
posterior edge of the ischium);
- the length of the trunk (between shoulder joint and the posterior edge of the
ischium);
- the breast bone length (between anterior and posterior edge);
- the chest circumference (behind the wings across the front edge of the breast
bone and the middle thoracic vertebra).
12
Adjusting the slaughter value and meat quality of animals to consumers’ requirements
With the accuracy of up to 0.1 cm the following dimensions were determined
using the slide-caliper:
- chest width (between the side regions of shoulder joints from the ventral side);
- chest depth (between the breast bone and the dorsal line in the middle of the
breast bone length).
Carcasses were eviscerated and, after about 24-hour cooling, weighed and divided
to obtain the following elements: neck with no skin, breast and leg muscles, skin with
subcutaneous fat from the entire carcass, wings, remainders of the carcass and giblets.
Individual carcass elements were weighed and their contents (%) of eviscerated
carcass with the neck were determined.
The numerical data collected were verified statistically. With the use of software
STATISTICA PL [2002], means were calculated and their variation coefficients (V)
for the traits in question. The significance of differences between means for the traits
evaluated in the three terms of slaughter was verified with variance analysis and
Sheffē test.
Results and discussion
Pheasant carcasses evaluated in the 12th, 16th and 20th week of rearing (Tab. 1)
did not differ in the length of the trunk with the neck and the trunk itself. At all the
evaluation terms male carcasses showed a longer trunk with the neck (from 29.6 to
29.7 cm) as compared to females (from 25.2 to 27.4 cm). Similarly in males the trunk
was also longer in week 16 and 20 of life. In weeks 12, 16 and 20 male carcasses
showed a significantly greater breast bone length (from 9.8 to 11.1 cm), as compared
to females (from 8.5 to 9.7 cm). Differences in the breast bone length between week
16 and 20 of both sexes were not found significant.
The chest circumference was found increasing up to the 16th week of life. The
breast width increased with the pheasant age and was similar in male and female
carcasses, while the chest depth did not differ significantly betweent successive
evaluation terms. The chest depth of male carcasses ranged from 94.6 to 103.9 mm
and at all the evaluation terms was significantly greater than in carcasses of females – from 86.2 to 91.3 mm. Variation coefficients of carcass dimensions (Tab. 1) appeared
low and in most cases did not exceed 10%.
The analysis of figures characterizing dressing percentage and dissection data of
carcasses in 12-, 16- and 20-week old pheasants (Tab. 2) showed that the pre-slaughter
body weight and the weight of eviscerated carcass with the neck both increased with
the birds’ age. However there were found no significant differences in the values
of both traits between week 16 and 20 of rearing pheasants of both sexes in total.
Males, as compared to females, demonstrated a greater body weight at slaughter and
greater weight of the eviscerated carcass with the neck at all the evaluation terms.
The dressing percentage in 12-week-old pheasants of both sexes was 72.1%, and in
the 20-week-old – 73.4%. The means were not significantly different.
13
Marek Adamski, Joanna Kuźniacka
Table 1. Means and their variation coefficients (V) for carcass dimmensions in 12-, 16and 20-week-old pheasants
Age at
slaughter
(weeks)
Trait
12
Length of trunk
with neck (cm)
16
20
12
Length of trunk
(cm)
16
20
12
Breast bone length
(cm)
16
20
12
Chest circumference
(cm)
16
20
12
Chest width
(mm)
16
20
12
Chest depth
(mm)
ab
16
20
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
mean
V
Sex
males
29.7
3.0
29.6
3.4
29.6
4.4
17.8
3.4
17.8
5.0
18.2
3.3
9.8
5.1
11.1
2.7
10.8
2.8
23.9
1.2
26.6
3.4
27.6
1.4
45.5
5.9
54.0
4.1
61.1
9.3
94.6
4.6
103.9
2.0
100.3
3.4
females
27.4
1.4
27.4
2.9
25.2
1.6
16.4
4.3
16.3
3.1
16.1
3.1
8.5
5.9
9.7
4.1
9.3
4.3
21.7
2.8
23.4
4.3
24.3
2.0
41.8
5.7
47.3
8.2
53.9
2.2
86.2
4.4
90.3
3.9
91.3
3.2
sexes pooled
28.5*
4.9
28.5*
4.9
27.6*
8.3
17.1
5.8
17.1*
5.8
17.2*
7.0
9.1b*
8.8
10.4a*
7.8
10.1ab*
7.9
22.8b*
5.7
25.0a*
7.6
26.0a*
6.9
43.6c
7.1
50.7b
9.3
57.5a
9.4
90.4*
6.5
90.1*
7.9
95.8*
5.8
Within individual traits means for age groups for pooled sexes differ significantly at
P≤0.05.
*Within individual traits means and age groups differences between sexes are
significant at P≤0.05.
14
mean
V
♀
mean
V
♂♀ mean
V
♂
mean
V
♀
mean
V
♂♀ mean
V
♂
mean
V
♀
mean
V
♂♀ mean
V
♂
Sex
937
4.0
710
2.5
823b*
14.9
1198
2.9
874
4.8
1036a*
16.9
1247
2.3
888
1.8
1067a*
17.8
Body
weight at
slaughter
(g)
681
5.0
509
4.4
595b *
15.9
876
3.4
638
3.8
757a*
16.9
920
5.3
649
2.4
785a*
18.7
Eviscerated
carcass
weight with
neck (g)
72.6
1.9
71.6
3.5
72.1
2.8
73.2
1.9
73.0
3.1
73.1
2.5
73.7
3.2
73.1
1.5
73.4
2.4
Dressing
percentage
201.7
7.7
149.3
5.9
175.5b*
17.1
276.6
7.3
194.3
6.4
235.4a*
19.6
306.7
11.2
215.2
4.2
261.0a*
20.6
g
29.6
4.4
29.3
2.3
29.5b
3.4
31.6
7.0
30.5
6.2
31.0b
6.4
33.3
7.5
33.1
3.6
33.2a
5.4
%
breast muscles
154.8
5.4
119.4
8.2
137.1b*
14.9
216.1
6.3
147.6
5.5
181.8a*
20.7
221.0
6.1
143.0
3.3
182.0a*
23.2
g
22.8
7.4
23.4
4.7
23.1
6.1
24.6
5.6
23.1
3.5
23.9
5.4
24.0
4.2
22.0
4.5
23.0
6.1
%
leg muscles
Weight and content of
356.4
3.6
268.7
6.3
312.6b*
15.5
492.6
6.5
341.9
5.2
417.2a*
19.9
527.8
8.2
358.2
3.1
443.0a*
21.3
g
52.4
2.1
52.8
1.9
52.6b
1.9
56.2
6.0
53.6
4.3
54.9ab
5.6
57.3
4.5
55.2
3.4
56.2a
4.2
%
total muscles
Within columns means for pooled sexes bearing different superscripts differ significantly at P≤0.05.
*Within columns differences between sexes are significant at P≤0.05.
ab
20
16
12
Age at
slaughter
(weeks)
43.2
10.6
36.6
14.2
39.9b
14.5
60.3
20.9
49.4
23.3
54.8a
23.7
58.5
7.3
57.6
23.9
58.0a
16.7
6.3
6.3
7.2
11.1
6.7
10.4
6.9
20.2
7.7
20.8
7.3
20.5
6.4
10.2
8.9
23.6
7.6
26.3
Weight and
content of skin
with
subcutaneous fat
g
%
53.0
2.1
44.1
12.0
48.5
12.2
66.0
14.2
47.3
13.9
56.6*
21.9
70.6
10.2
49.7
7.8
60.1*
20.4
Giblets
weight
(g)
83.8
6.3
59.0
2.3
71.4*
19.0
85.9
6.7
64.4
2.3
75.1*
16.0
90.0
3.2
63.6
3.4
76.7*
18.4
Wings
weight
(g)
Table 2. Means and their variation coefficients (V) for dressing percentage and selected elements of carcass in 12-, 16- and 20-week-old pheasants
Adjusting the slaughter value and meat quality of animals to consumers’ requirements
15
Marek Adamski, Joanna Kuźniacka
The weight and content of breast muscles of the carcass were greatest in birds
slaughtered in their 20th week of life, whereas the weight of breast muscles in 16- and
20-week-old birds did not differ significantly. Significantly heavier breast muscles at
each evaluation term were found in males than in females, while the muscles content
(%) of carcass was similar in both sexes. The leg muscle weight in birds of both
sexes in total increased with pheasant age and significant differences were found only
between week 12 and 16 or 20 of rearing. Values of that trait ranged from 137.1 g in
week 12 to 182.0 g in week 20. At all the slaughter terms the leg muscle weight was
greater in males than in females. The leg muscles content of carcass in pheasants of
both sexes was similar at the three evaluation terms and in male carcasses was from
1.5 to 2 per cent points (pp) greater than in the 16th and 20th week of life in females.
However, these differences were not found significant.
The weight and content of muscles in total, as well as the weight of skin with
subcutaneous fat increased significantly at all the evaluation terms, while the content
of skin with subcutaneous fat from the 12th to the 20th week of birds’ life assumed
similar values (Tab. 2). In week 16 and 20 the weight of skin with subcutaneous fat
was significantly greater in males than in females, however, its content was similar
in pheasants of both sexes at all the evaluation terms. Despite an increasing weight
of wings and giblets in successive evaluation terms, differences in those traits from
week 12 to 20 were non-significant. The weight of wings was, however, significantly
greater in males than in females at all three terms analysed, while the weight of giblets
was significantly greater in males in week 16 and 20 of evaluation.
Values of variation coefficients (Tab. 2) of most slaughter traits were low and
assumed similar values in males and in females. The weight of skin with subcutaneous
fat was the only one for which the variation at the rearing evaluation dates was high
and greater in females as compared with males.
Znaniecka and Wajda [1976] in 12-week-old pheasant hens recorded a lower
mean value of the weight of eviscerated carcass and leg muscles and a greater weight
of breast muscles than it was observed in the present study. Values of slaughter traits
lower than those presented here in 12-week-old pheasants, kept and fed differently,
are given by Torgowski et al. [1990].
Sarica et al. [1999] studying the effect of slaughter age and sex on slaughter traits
in 13-, 14- and 15-week-old pheasants, did not observe significant differences in the
weight of eviscerated carcass, slaughter yield and the breast muscles content of carcass
depending on the slaughter age. It was also demonstrated that the male carcasses were
heavier, contained less abdominal fat and more thigh muscles. Similarly as in the
present study, the cited authors showed that the trait which was affected by neither the
slaughter age nor the bird sex was the dressing percentage.
Figures reported by Winnicka [cited by Mróz 1998, 2003] concerning the body
weight of pheasants slaughtered in their week 12 and 16 of life were similar or lower,
and in the week 20 of life – greater, while the dressing percentage evaluated at the
same terms of slaughter lower (from 64.66 to 70.02%) as compared with the results of
16
Adjusting the slaughter value and meat quality of animals to consumers’ requirements
the present report. The weight of breast and leg muscles and giblets weight reported
by the same author are mostly similar. In those experiments 12- and 16-week-old
pheasants showed a lower weight of skin with fat, while 20-week-old birds – a higher
weight of skin, as compared with the results reported here.
To sum up, one can say that rearing pheasants for slaughter can be completed
between the 16th and the 20th week of birds’ life, as shown by the lack of significant
differences in the dimensions of carcass, the eviscerated carcass weight with the
neck, dressing percentage as well as the weight of content of meat and skin with
subcutaneous fat in pheasant carcasses of both sexes at three terms of evaluation.
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In Polish. 3rd edition, pp. 93–96.
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17
Marek Adamski, Joanna Kuźniacka
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Marek Adamski, Joanna Kuźniacka
Wpływ wieku i płci na cechy rzeźne bażantów
łownych (Phasianus colchicus L.)
Streszczenie
Oceniono rzeźne cechy bażantów ubijanych w wieku 12, 16 i 20 tygodni. Stwierdzono brak istotnych
różnic między danymi poubojowymi uzyskanymi w 16 a w 20 tygodniu życia pod względem długości
tułowia z szyją, długości tułowia, długości grzebienia mostka oraz obwodu i szerokości klatki piersiowej
tuszek bażancich. Istotnych różnic nie udowodniono również w masie tuszki patroszonej z szyją,
wydajności rzeźnej i udziale mięśni w tuszy, co świadczy o możliwości kończenia wychowu bażantów
rzeźnych między 16 a 20 tygodniem życia. Cechą, na którą nie miały wpływu wiek ani płeć ptaków była
wydajność rzeźna, udział w tuszy (%) mięśni piersiowych i mięśni nóg, a także udział skóry z tłuszczem
podskórnym.
18