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This study aimed to estimate the growth parameters of Muscovy ducks. The superiority of the study offers insightful information on the Muscovy duck growth curve, makes quantitative comparisons easier, allows for predictive capacities, and quickly finds problems. A total of 40 Muscovy ducks called “Rambon” were used in the study, consisting of 12 males and 28 females. Body weight was weighed periodically every two days from the day-old ducks (DOD) until 60 days of age. The data was analyzed by using Gompertz and Logistic models. The growth curves were analyzed, and parameters such as adult body weight (A), integral constant (B), and growth rate (K) were determined. Inflection points were also identified. Body weight (Wi) and age at the inflection (Ai) point using Gompertz were 1060.95 g and 46.34 d; 613.41 g and 30.52 d; 712.56 g and 36.81 d, respectively for males, females, and the unsexed. By using Logistic model, the Wi and Ai for males were 934.60 g and 41.46 d, females were 670.52 g and 32.96 d, and unsexed were 739.11 g and 36.56 d. Results showed that the Gompertz model generally outperformed the Logistic model, with lower AIC, BIC, MSE values and slightly higher R2 for all sex groups, indicating superior fit and predictive accuracy. These findings offer valuable insights into Rambon Muscovy duck growth dynamics, aiding in breeding and production strategies to enhance economic efficiency and sustainability. Farmers can utilize these models to optimize feeding schedules and make informed decisions about slaughtering, ultimately improving Muscovy duck production. [ABSTRACT FROM AUTHOR]

The study aims to investigate the heterosis effect of crossing two imported rabbits with local rabbits on growth characteristics and performance using a nonlinear regression model. The study utilized three rabbit breeds: Flemish Giant rabbits (F), Rex rabbits (R), and Indonesian local rabbits (L). Selective breeding consisted of three breeds: F (FF), R (RR), and L (LL). Two crosses were formed between the male ancestors of L and the respective female ancestors of F (LF) and R (LR). Each offspring's body weight (BW) was measured every 3 d starting from birth. FF exhibited the highest BW among purebred animals. The LF crossbreed had a greater estimated mature weight compared with purebred animals. The predicted mature live weight of the asymptotic value for LR animals was higher than for LL rabbits but lower than for RR rabbits. The heterosis effect was lower when crossing L and F animals compared with crossing L and R animals. The average heterosis impact values were 4.68 for LF and 15.32 for LR. LF rabbits showed superior heterosis effects when the growth parameter and inflection point were determined using a logistic model. This study emphasizes the use of strategic breeding to optimize rabbit growth and performance by offering detailed insights into growth dynamics and heterosis effects in different crossbreeding situations. [ABSTRACT FROM AUTHOR]

The study was carried out to characterize different body types of rabbits based on the phenotypic relationship between body weight and body measurements. The materials used were 135 of New Zealand Grade, 115 heads of Rex, and 60 heads of Flamish Giant. Rabbits were categorized into three groups: semi-commercial, commercial, and semi-arc body types. Pearson correlation was used to estimate the correlation coefficients between body weight and body measurements with 1% and 5% significant level. Principal component analysis (PCA) representing a linear combination of the body measurement into a factor or component was determined separately for each body type of rabbit. BW showed a significant correlation with all of the variables measured on semi-commercial and semi-arc body types. The result of PCA showed a lower factors of PC1 (-0.04 - 0.41). The highest component loaded were CD in PC3 for all body types and TB in PC2 for semi-arc body type. Chest circumference, chest depth, and chest width (chest shape) are more appropriate in predicting body weight in rabbits than body length. Body length is highly correlated with body weight, but shows low factors in the principal component analysis. [ABSTRACT FROM AUTHOR]

This study was carried out to estimate general combining ability (GCA) and specific combining ability (SCA) of pre-and post-weaning traits from a partial diallel cross in three rabbit breeds: Local rabbit (L), Flemish Giant (F), and Rex (R). Body weight at 0 (BW0), 30 (BW30), 42 (BW42), and 63 (BW63) days of age, average daily gains from 0 to 30 d of age (ADG0-30), from 30 to 42 d of age (ADG30-42), from 42 to 63 d of age (ADG42-63), and from 30 to 63 d of age (ADG30-63), litter size at birth (LS0) and at weaning (LS42), and mortality at weaning (MR42) were studied in crossing LL, FF, RR, LF, LR, and FR. Local breed had the highest GCA for BW0, BW30, BW42, and average daily gain before weaning (ADG0-30, and ADG30-42) compared to Flemish Giant and Rex, while GCA of Local breed for average daily gain after weaning (ADG42-63), litter size (LS0, and LS42), and mortality (MR42) was higher than for Rex and similar to that of Flemish Giant. Crossing LF and LR showed higher SCA for BW30, BW42, BW63, ADG0-30, ADG42-63 and ADG30-63 than FR. In conclusion, based on GCA and SCA, the Indonesian Local breed has a high genetic potential in the crossing with Flemish Giant and Rex breeds. [ABSTRACT FROM AUTHOR]