Carcass Traits of Geese (Anser anser) as Affected by Age, Gender and Their Interactions

The goose one of the oldest birds that were domesticated in the world due to its economic importance, as it was raised to produce meat, feathers, also used to get rid of weeds as it was released in the fields, which the cost of raising it was low. Also, geese have some characteristics that make them a suitable bird for grazing, as they have a serrated beak in order to be able to cut grass and have a strong memory, as they can graze for a distance of 5 km and return to their home again (Buckland and Gérard, 2002; Makram, 2018). The production of geese carcass depends on the fattening period, which is from 10 to 12 weeks and in parents after the end of their productive season, the broiler goose in Egypt is depend on Native geese which descended from Grey lag goose (Anser anser), (Makram, 2018; Makram, 2016). Carcass traits and quality related to age and sex (Ziolecki, 1980; Szabone Willin and Bögre, 1992). Tilki et al., (2004) reported that slaughtered at around 10-12 weeks of age in order to have more meat and less fat than 16 weeks of age in the native Turkish goose. Pingel (1999) stated that the skin increased and the breast muscle decreased in Muscovy, Pekin and Mulard before marketing age.
       
The goose carcass characteristics are affected by a lot of various factors including rearing system (Liu et al., 2011), genotype (Kapkowska et al., 2011; Tůmová and Uhlířová, 2013; Uhlířová and Tùmová, 2014; Uhlířová et al., 2018; Uhlířová et al., 2019). In addition, depending on goose breed, values of some physicochemical parameters of leg and breast muscles change differently through postmortem aging (Tůmová and Uhlířová, 2013; Okruszek, 2012; Okruszek et al., 2008) and variety (Boz et al., 2019). The aim of this study was to investigate effect of age (parents and young geese), gender (males and females) and their interactions on the carcass traits of geese (Anser anser).

Housing and management
 
A sample of 32 birds (sixteen parents of geese at the end of the third season and sixteen of their gosling hatched were reared until 10 weeks of age) for assessing carcass traits. All geese were reared under equal managerial, environmental and hygienic conditions. A diet containing 16% protein and 2800 Kcal/ME/kg of diet were offered plus a daily feeding on grass like alfalfa for the parents during the season. However, the goslings were feed on 23% protein and 2900 Kcal/ME/kg until 4 weeks of age with a daily feeding on grass like alfalfa from the second week of age, from 4-8 weeks of age, the gosling was feed on 18% protein and 2900 Kcal/ME/kg with a daily feeding on grass. From 8-10 weeks, the gosling and the parents were feed together in the same dies, 21% protein and 3000 Kcal/ME/kg without feeding on grass. Composition, chemical analysis and distribution of experimental diets, in addition, types of the grasses in pasture are shown in (Table 1 and 2). A normal natural daylight was provided during the whole experimental.
 

 

 
Carcass traits
 
Sixteen birds from each age, were randomly taken weighed and slaughtered for carcass evaluation to calculate edible meat parts (dressed carcass, gizzard, liver, heart, giblets) and non-edible meat parts (blood+feathers, head, leg and inner viscera) in addition, abdominal fat and gizzard fat. The neck were removed and weighed.
 
Statistical analysis
 
Data subjected to statistical analysis using two-way analysis of variance with age effect and the gender with interaction using General Linear Model (GLM) procedure of (SAS, 2003) as following model; 
   
Where,
Y_ij      =         Trait measured.  
µ       =         Overall mean. 
A_i      =         Age effect.
G_j     =         Gender effect (j=1 and2).
[A×G]_ij= Interaction between age and gender.
e_ijk      =         Experimental error.
       
Means were separated using Duncan’s multiple range tests, when significant differences among means were found.

Edible meat parts
 
The results of edible meat parts of Native geese (Anser anser) as affected by age, gender and their interactions are presented in Table 3. The present results indicate that live body weight was significantly affected by age and gender. The parent’s geese (3 years) were significantly heavier body weight compared to the young geese (10 wks); whereas body weight of the young geese represented only 81.4% of their parent’s geese. Males recorded a heavier body weight compared to females.
 

       
Age and gender had an impact on dressing percentage, we showed significantly (p≤0.0001) higher dressing percentage for parent stock (68.51%) compared to the young geese (62.5%). Regarding gender effect, males had higher significant dressed carcass percentage compared with females; No significant difference (P≥0.05) of interaction between age and gender of geese for dressed carcass percentage were found. However, No significant difference (P≥0.05) between age, gender and their interactions for liver, gizzard, heart and giblets percentages were found.
       
Concerning percentage of edible meat parts, the parents were significantly higher (76.69%) than the young geese (71.23%), also, the males was significantly higher percentage of edible meat parts compared to the females. Males’ geese had approximately 5.2% significantly higher percentage of edible meat parts than females.
       
Tilki et al., (2004) found that geese have actually achieved only 70% to 80% of their adult weight at the age of 9 wk. In our study, males’ geese had approximately a 17% significantly higher live weight than females. These findings are similar with a previous study with geese (Saatci et al., 2009; Kýrmýzýbayrak and Önk, 2011; Kýrmýzýbayrak and Boða, 2018) they reported that slaughter and Carcass weight statistical differences between male and female. Our results confirm those of Muth and Valle Zárate, (2017) and Hussein et al., (2019) who found that age at slaughter significantly affected (P<0.0001) slaughter weight and dressing percentage and they found that dressing percentage was significantly higher in older birds than smaller/ younger ones.
       
Males’ geese had approximately a 4.6% significantly higher dressed carcass percentage than females. Uhlířová et al., (2018) observed the same trend. However, Saatci et al., (2009) and Buzała et al., (2014) found a higher dressing percentage in females.
       
In our study, No significant difference (P≥0.05) of interaction between age and gender of geese for dressed carcass percentage were found. However, Uhlířová et al., (2018) revealed a significant interaction effect of age and sex in the dressing percentage.
       
The gender effect on some carcass characteristics (liver, heart and gizzard) determined in the present study are contrary to results those reported by Tilki et al., (2004) on heart and liver, by Kirmýzýbayrak and Önk, (2011) on gizzard, and by Sarica et al., (2015) on heart when comparing male and female geese. In addition, Kirmizibayrak and Boða, (2018) find a significant effect of goose gender on liver, heart and gizzard; whereas male’s geese were statistically higher compared to those of females. These differences among studies may be attributed to age at slaughter, genotype, and feeding practices.
 
Non-edible meat parts
 
Data presented in Table 4 show non-edible parts of native geese (Anser anser) as affected by age, gender and their interactions. In the present study observed that the intestine and neck percentages were significantly affected only by age, whereas blood and feather percentages were significantly affected only by gender. Moreover, for leg percentage the interaction only between the age and gender (p=0.001) was significant. While, abdominal fat and gizzard fat percentages were affected by all observed factors.
 

       
Females were significantly higher blood and feather percentages in comparison with males. On the contrary, males were significantly higher head percentage compared to the females. Significant interaction effect were noted between the age and gender (p<0.05) in head percentage. The intestine and neck percentages significantly increased with age. No significant difference (P≥0.05) between genders for intestine percentage.
       
The non-edible meat percentage was influenced significantly by the age and gender. The young geese had approximately a 24.7% higher non-edible meat percentage than the parent’s geese. Females’ geese had approximately 8.7% higher non-edible meat percentage than males.
       
The young geese were significantly higher neck, abdominal fat and gizzard fat percentages than parent’s geese. The females were significantly higher than males for the abdominal fat and gizzard fat. Concerning interaction effect, abdominal fat and gizzard fat percentages were significantly (p<0.05) affected by interaction between age and gender of geese.
       
No significant difference (P≥0.05) between genders for intestine percentage. These findings are consistent with the results of Kýrmýzýbayrak and Boða, (2018). 
       
In this study, the young geese were significantly higher neck, abdominal fat and gizzard fat percentages than parent’s geese. Similar trend was noticed by Uhlířová et al., (2018) who stated that percentage of abdominal fat was significantly affected by the age and genotype, with higher values in the 8­wk­old ES birds. Compared to the results of Saatci et al., (2009) and Hamadani et al., (2013) who detected a higher abdominal fat percentage in females; the same result was obtained in the present experiment. Contrary to our results, Uhlířová et al., (2018) not find a significant effect of interaction between age and gender (p=0.07) for abdominal fat percentage trait.
 
Correlation coefficients
 
Pearson correlation coefficients and probabilities between edible parts of carcass characteristics weights for goose males (Upper part) and females (Lower part) at 3 years of age are presented in Table 5. It could be observed that a significant positive correlation coefficient was detected between live body weight and all edible parts of carcass characteristics weights for goose males; we can observe that all studied traits in males had a significant positive correlation coefficient, except the correlation between giblets and heart were not statistically significant. On the other hand, this trend was not observed for goose females. Almost, live body weight was positively correlated with both gizzard and heart, dressed was positively correlated with both heart and giblets, gizzard was positively correlated with both liver and giblets, liver correlated with heart, and edible parts was positively correlated with heart and giblets, but these coefficients were not statistically significant. A significant negative correlation coefficient was detected between dressed and gizzard, also, edible parts and gizzard.
 

       
Table 6 clarifies pearson correlation coefficients and probabilities between edible parts of carcass characteristics weights for goose males (Upper part) and females (Lower part) at 10 weeks of age. In goose males, a significant positive correlation coefficient was detected between all studied traits. While, in goose females, a significant positive correlation coefficient was observed between edible parts with both live body weight and dressed. The same trend was observed between giblets with both gizzard and liver. Negative correlation coefficient detected between dressed and whoever gizzard, liver, heart and giblets, but these coefficients were not statistically significant. The same trend was observed between edible parts gizzard, liver and giblets.
 

It could be concluded that the increase of age had a positive effect on the carcass traits of geese (Anser anser). Males’ geese had a better carcass characteristics compared to females; in addition, the females were significantly higher than males for the abdominal fat and gizzard fat percentages.

This work was supported by the Deanship of Scientific Research, Vice Presidency for Graduate Studies and Scientific Research, King Faisal University, Saudi Arabia [Project No. GRANT713].

There is no conflict of interests among authors and organizations.