Electronic Journal of Polish Agricultural Universities (EJPAU) founded by all Polish Agriculture Universities presents original papers and review articles relevant to all aspects of agricultural sciences. It is target for persons working both in science and industry,regulatory agencies or teaching in agricultural sector. Covered by IFIS Publishing (Food Science and Technology Abstracts), ELSEVIER Science - Food Science and Technology Program, CAS USA (Chemical Abstracts), CABI Publishing UK and ALPSP (Association of Learned and Professional Society Publisher - full membership). Presented in the Master List of Thomson ISI.
2008
Volume 11
Issue 1
Topic:
Animal Husbandry
ELECTRONIC
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Pieniak-Lendzion K. , Niedziółka R. , Horoszewicz E. , Borkowska T. 2008. EVALUATION OF SLAUGHTER VALUE AND PHYSICOCHEMICAL ATTRIBUTES OF GOAT MEAT, EJPAU 11(1), #11.
Available Online: http://www.ejpau.media.pl/volume11/issue1/art-11.html

EVALUATION OF SLAUGHTER VALUE AND PHYSICOCHEMICAL ATTRIBUTES OF GOAT MEAT

Krystyna Pieniak-Lendzion, Roman Niedziółka, ELżbieta Horoszewicz, Teresa Borkowska
Departament Sheep and Goat Breeding, University of Podlasie in Siedlce, Poland

 

ABSTRACT

The research aimed at analysing the slaughter value and physicochemical attributes of goat kids slaughtered at 90 and 180 days of age. After weaning at 60 days of age, a balanced mixture, containing 18.2% protein and 5.63 MJ net energy, was applied as a feed. Live and slaughtered animal weight attributes were analysed. Moreover, tissue composition of the half carcass and meat physicochemical properties were determined. The carcass of older male kid goats was by 5.08 kg heavier and the weight of primal cuts, including high-priced cuts, was by 0.87 kg higher. Half carcass tissue composition was similar and was as follows: 60.13–60.50% of meat, 25.48–25.37% of bones, and 14.39–14.13% of fat. Significant differences in fat and bone contents were found in the leg only. Furthermore, physiochemical properties indicated that the meat of older animals was darker and had higher values of chemical parameters.

Key words: kids goat, physical and chemical composition, valuable cuts.

INTRODUCTION

Meat obtained from young goats is a material of full value which can be utilised in the production of cured meats. It is characterised by a low intramuscular fat content and a high level of protein and mineral elements [3,4,9,11].

Research on the slaughter value of goat kids butchered at various body weight yielded varying results. They show that the share of high-priced cuts and meat tissue in animals slaughtered at higher body weights was higher and the meat was characterised by more favourable physicochemical parameters [2,7,14]. Intensive feeding increases the slaughter performance of goat kids therefore it is profitable to fatten intensively and obtain heavier animals, providing cheap feeds are available and the demand for goat meat is high. An exception to it is the goat kids destined to obtain the so-called “white meat”. They are slaughtered at lower body weight and fed mainly on goat milk [1,5,6,10].

The research aimed at analysing the slaughter value and physiochemical attributes of goat kids slaughtered at 90 and 180 days of age.

MATERIAL AND METHODS

An experiment was carried out on white improved breed goat kids which were raised in tie-stall barns and fattened up to the age of 90 and 180 days. After weaning at 60 days of age, a balanced mixture, containing 18.2% protein, 88.6% dry matter, 5.46% fibre and 5.63 MJ net energy NE, was applied as a feed. The feeding was supplemented by an addition of meadow hay. The animals were fed ad libitum, castrated and raised in tie-stall barns on deep litter. Slaughter and an analysis were performed in compliance with the methodology for small ruminants developed by the Institute of Animal Husbandry [8]. After 24-hour cooling at 4°C the division into cuts was carried out. Next the cuts were dissected into meat, fat and bone tissues.

Meat samples of the broadest back (m. longissimus dorsi) were subjected to chemical analysis in respect to the content of dry matter (drier method, 105°C) protein (Kjeldahl’s method) and fat (Soxhelt method). The muscle was also used to determine water-holding capacity by the Grau-Hamm method, at pH measured after 4 min. and 24 h from the slaughter (CP-315 integrated electrode pH-meter) and muscle fibre darkening (m. semimembranosus) with the Minolta Chroma Meter CR-300.

Statistical analysis included the ANOVA procedure and was carried out by means of the Stat. 6.0 PL package [13].

RESULTS AND DISCUSSION

The average body weight (Table 1) of the goat kids slaughtered at 180 days of age was significantly higher by 9.86 kg compared with the weight of younger goat kids, and was similar to the results obtained in earlier studies by the authors [10] and the research results, concerning different time of goat kid slaughter, by other investigators [11,12]. Moreover, the weight of cooled carcass obtained from older animals was significantly higher by 5.08 kg and equaled 14.64 kg in the present study. Carcass weight losses were similar and ranged from 1.64 to 2.17%.

Table 1. Body weight, slaughter value and weight cuts in half-carcass

Traits

90 days

180 days

S

S

Body weight at the slaughter (kg)

20.57A

2.99

30.43B

3.41

Carcass weight chilled (kg)

9.56a

1.53

14.64b

1.89

Loss during cooling (%)

1.64

0.08

2.17

0.15

Body right half-carcass (kg)

4.92a

0.82

7.31b

0.95

Weight cuts half-carcass (kg)

       

- neck

0.34a

0.07

0.47b

0.04

- middle neck

0.48a

0.10

0.76b

0.09

- shoulder

0.76a

0.14

1.15b

0.17

- tlank with ribs

0.65a

0.13

0.97b

0.12

- cuttlet

0.31a

0.08

0.45b

0.09

- leg

1.20a

0.16

1.78b

0.28

- loin

0.29a

0.08

0.44b

0.09

- sternum

0.22

0.04

0.29

0.07

- fore shank

0.23a

0.02

0.36b

0.04

- hind shank

0.25a

0.05

0.39b

0.05

Valuable cuts in half-carcass (%)

36.58

5.34

36.53

4.67

a,b – followed by the same small and capital letters did not differ significantly at (P≤0.05) respectively.
A,B – followed by the same small and capital letters did not differ significantly at (P≤0.01) respectively.

There were found statistically significant differences in the weights of the following primal cuts: chuck, neck, rib, loin, leg, fore shank and shin, to the advantage of older goat kids, which is an obvious phenomenon due to higher carcass weight. High-priced cut weights in older goat kids were higher by 0.87 kg. The weight of leg, rib and loin was by 0.58, 0.14 and 0.15 kg higher, respectively. However, the percentage of high-priced cuts in the half carcass was similar in both examined groups and was at the level of 36.5%. It indicates that age did not influence significantly their share in the half carcass. The leg share in the half carcass was similar in both groups (it did not exceed 24.5%) and roughly equaled the result (24.71%) obtained by Kalinowska et al. [1]. In the studies on 5-month goat kids with the Boar breed genes, Stanisz and Gut [12] obtained the share of high-priced cuts and leg amounting to 35.63 and 23.14%, respectively. A higher percentage of leg and lion in the half carcass was found by Sen et al. [11], the respective values being 28.19 and 13.43%.

Dissection results (Fig.1) revealed that the fat tissue content in older goat kids was by 1.04% higher and the bone tissue content was by 1.5% lower. It is an indicator of fat accumulation in the leg of older goat kids aged 180 days, which may indicate the slaughter time. No significant differences in the content of individual tissues were found in respect to the whole half carcass. Its meat share slightly exceeded 60% and was similar in both examined groups. Tshabalala et al. [14] obtained congruent results in respect to the share of meat tissue in the goat kid half carcass. By contrast, Luo et al. [6] recorded a lower meat tissue share (57.1%) and a higher fat and bone fibre percentage (20.2 and 20.6%, respectively) in goat kids slaughtered at 50 weeks of age. The analysis of tissue composition showed that the culinary meat share in the leg was over 69% and was similar to the values obtained by Kędzior et al. [4] as well as earlier studies by Pieniak-Lendzion et al. [9]. On the contrary, Sen et al. [11] recorded the value of 76.77% meat tissue and barely 6.93% fat tissue in the leg.

Fig. 1. Tissue composition in leg and half-carcass

Dry matter, protein, fat and mineral compounds content in the meat of goat kids slaughtered at 180 days of age was significantly higher by 1.55, 0.93, 0.69 and 0.04%, respectively (Fig. 2). The results obtained in respect to dry matter and protein, were similar to the earlier studies on the Polish white improved bread (23.53 and 20.21%, respectively) [10] and the research on the Alpine and Saan breeds (23.74 and 19.64%; 21.96 and 20.65%, respectively) [7]. The W/B index (water-protein) indicates meat maturity and it was significantly higher in the group of goat kids slaughtered at 90 days of age and amounted to 3.98 (Fig. 3). The value of the index calculated by Kesava Rao et al. [3] was within the limits of 3.10-3.87 according to the protein content in the ration.

Fig. 2. Chemical composition of muscle

Fig. 3. Physical properties of muscles

Among the analysed physical meat attributes, significant differences were found only in the case of colour darkness. The values of L* reading for tissue indicate a lighter colour of meat obtained from younger goat kids and the differences between them were highly significant. As far as pH1 measurement is concerned, after 45 minutes pH1 was higher in the meat of older animals and equaled 6.03 whereas after 24 hours pH2 dropped to 5.66. This phenomenon is a symptom of glycolysis – the process, which contributes to meat acidification. Kesava Rao et al. [3] observed pH2 decrease to 5.71 after 24 hours whereas Sen et al. [11] obtained even lower pH2 value of 5.48 in 5-to-6-year old goat kids.

CONCLUSIONS

  1. Prolonged fattening of goat kids up to 180 days of age with the same balance mixture enabled obtaining higher values of parameters for most analysed attributes of slaughter value.

  2. It spite of the fact that the weight of high-priced cuts was higher, their share in the half carcass was similar in both analysed groups (36.53– 36.58%).

  3. The adequate physicochemical composition of goat kid meat determines its dietary as well as culinary value. It should be stressed that the meat of goat kids slaughtered at 180 days of age contained more dry matter, protein, fat and mineral compounds and it was of a darker colour.


REFERENCES

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Accepted for print: 30.01.2008


Krystyna Pieniak-Lendzion
Departament Sheep and Goat Breeding,
University of Podlasie in Siedlce, Poland
B. Prusa 14, 08-110 Siedlce, Poland
email: owce@ap.siedlce.pl

Roman Niedziółka
Departament Sheep and Goat Breeding,
University of Podlasie in Siedlce, Poland
B. Prusa 14, 08-110 Siedlce, Poland
email: romann@ap.siedlce.pl

ELżbieta Horoszewicz
Departament Sheep and Goat Breeding,
University of Podlasie in Siedlce, Poland
B. Prusa 14, 08-110 Siedlce, Poland
email: owce@ap.siedlce.pl

Teresa Borkowska
Departament Sheep and Goat Breeding,
University of Podlasie in Siedlce, Poland
B. Prusa 14, 08-110 Siedlce, Poland

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