Analysis of growth curves of fowl. II. Ducks

Abstract

1. Growth curves of nine selected lines and one random-bred control population (in total, n = 1070) were evaluated by the Richards function. The ducks were weighed at 7-d intervals and, after the tenth week, every second week (up to 18 weeks). Food and water were supplied ad libitum. 2. The predicted curves closely fitted the weight data points (R2 = 0.9991-0.9997). 3. The ducks are characterized by early maturity rate. The peak of the absolute growth rate (the inflection point of the curve) occurred at 24.1-27.6 d of age (t+). A higher ratio of the inflection to the asymptotic weights (y+/A = 0.380-0.424) was found in comparison to those from the Gompertz-type function of growth (y+/A = 0.368). 4. In the selected lines the degree of maturity at a slaughter age of 7 weeks (u7 = y7/A) ranged from 0.784 to 0.835 for males and from 0.819 to 0.889 for females. 5. Ducks within the non-selected control line had a significantly lower maturing rate than the selected lines. 6. Sexual dimorphism was recorded for all growth parameters analysed. Females have faster maturation rate than males (higher values of y+/A, u7, k and a shorter auto-acceleration phase of growth). 7. High interline differences were found for body weight (A, y+, y7) and for absolute growth rate (v, v+) and smaller ones for parameters of the maturation rate (y+/A, u7, k and t+). 8. The intragroup phenotype correlation between growth parameters and the use of weight data only up to 7 weeks of age for the estimation of parameters of the Richards function are discussed.

Modeling the growth pattern of in-season and off-season Ross 308 broiler breeder flocks

“…The present study supports the work of Knízetová et al (1991a), who compared the same 3 nonlinear functions and concluded that the Richards function is best for growth analyses of ducks and other poultry, such as geese and chickens. Yang et al (2006) compared the fit of logistic, Gompertz, and Bertalanffy curves to experimental growth data of Jinghai mixed-sex yellow chickens, and they found the Bertalanfly model to give the best approximation to experimental data.…”

The effect of age on the growth rate of tissues and organs and the percentage content of edible and nonedible carcass components in Pekin ducks

“…The growth rate of ducks and geese is fast at the early stages of life, and then it slows down (Knízetová et al, 1991). Broiler chickens grow more slowly than ducks and geese in the first few week of their life and faster in the subsequent week.…”

Functional Analysis of Growth in Large White Male Turkeys

“…In both models, weight of bending point (POI = point of inflection) is determined as (y +=5560 g) and age (t+=11.9 day), and bending/asymptotic weight ratio is determined as (y+/A=0.368), during 16th and 18th weeks maturity degree (ut = yt/A, degree of maturity), is determined respectively similar as: 0549 and 0627. Knizetova, et al [13][14][15], in their study using the Richards model, bending/asymptotic weight ratio (y+/A) estimated between 0.370 to 0.388 for broilers, 0.380 to 0.424 for ducks and 0.233 to 0.294 for geese.…”

“…In their application of Logistic and Gompertz model on broilers fed ad libitum Stephan, et al [18] calculated, the values of R2, respectively, at the level of 0.979 and 0.980 and similar to the actual values. In their application of Richards model on broiler chicks, ducks and geese, Knizetova, et al [13][14][15], calculated the values of R2 respectively between 0.9986-0.9995, 0.9994-0.9901. In their application of Richards model on White, Brown and wild male Japanese quail [19], estimate the values of R2 as 0.9996-0.997 in males and as 0.9986-0.9991 in females.…”

“…The description of growth in Japanese quails by Ricklefs [11] and description of growth in quail, chicken and female turkeys from hatching to maturity by Anthony, et al [12] are made by Gompertz model which is a non-linear growth model. Knizetova et al [13][14][15] use Richards model on the growth analysis of ducks, chickens and geese. Similarly, Sengül and Kiraz [16] use Gompertz, Richards, Logistics and Morgan-Mercer-Flodin (MMF) models on growth analyzes of White Large turkeys.…”