Estimating Body Weight and Body Composition of Chickens by Using Noninvasive Measurements

Abstract

The major objective of this research was to develop equations to estimate BW and body composition using measurements taken with inexpensive instruments. We used five groups of chickens that were created with different genetic stocks and feeding programs. Four of the five groups were from broiler genetic stock, and one was from sex-linked heavy layers. The goal was to sample six males from each group when the group weight was 1.20, 1.75, and 2.30 kg. Each male was weighed and measured for back length, pelvis width, circumference, breast width, keel length, and abdominal skinfold thickness. A cloth tape measure, calipers, and skinfold calipers were used for measurement. Chickens were scanned for total body electrical conductivity (TOBEC) before being euthanized and frozen. Six females were selected at weights similar to those for males and were measured in the same way. Each whole chicken was ground, and a portion of ground material of each was used to measure water, fat, ash, and energy content. Multiple linear regression was used to estimate BW from body measurements. The best single measurement was pelvis width, with an R2 = 0.67. Inclusion of three body measurements in an equation resulted in R2 = 0.78 and the following equation: BW (g) = -930.0 + 68.5 (breast, cm) + 48.5 (circumference, cm) + 62.8 (pelvis, cm). The best single measurement to estimate body fat was abdominal skinfold thickness, expressed as a natural logarithm. Inclusion of weight and skinfold thickness resulted in R2 = 0.63 for body fat according to the following equation: fat (%) = 24.83 + 6.75 (skinfold, ln cm) - 3.87 (wt, kg). Inclusion of the result of TOBEC and the effect of sex improved the R2 to 0.78 for body fat. Regression analysis was used to develop additional equations, based on fat, to estimate water and energy contents of the body. The body water content (%) = 72.1 - 0.60 (body fat, %), and body energy (kcal/g) = 1.097 + 0.080 (body fat, %). The results of the present study indicated that the composition of a chicken's body could be estimated from the models that were developed.

Phenotypic characterization of the indigenous chickens <i>(Gallus gallus)</i> in the northwest of Algeria

“…However, the precision of the regression could be increased up to 91.3 % when including BrW, WS, CH, and BL. The first research that related BW and tarsus length in one breed of chickens had an R 2 of 0.66 (Lerner, 1937, as cited in Latshaw andBishop, 2001). In females chickens (Table 8), WS alone accounted for 97.2 % of the variation in BW and was nearly not improved by the addition of BrW, TL, TC, CH, and BL in the regression equation.…”

Regression tree analysis for predicting slaughter weight in broilers

“…They reported that the best regression model to estimate body weight was BW=-93.0+68.5 (breast width)+48.5 (breast circumference)+62.8 (pelvis width). As one can see, breast circumference, which existed in Latshaw and Bishop's (2001) model also exists in our model. The difference between the results may be due to the use of different statistical techniques in data analysis, different lines of chickens as experimental material, and varied experimental conditions.…”

“…Many studies have investigated the relationship of different body measurements with body weight or slaughter weight (Wahid et al, 1975;Yamani et al, 1982;Abdellatif, 1999;Goswami et al, 2000;Latshaw and Bishop, 2001;Mendeş et al, 2005). In such studies, the relations between body weight and some of the body measurements have been discovered and the results have been used in estimating future steps.…”

“…Along with shank length, breast width, breast circumference, spine length and pelvis width are the other important body variables used in body weight estimations. Latshaw and Bishop (2001) investigated the relations between body weight and different body measurements in chickens from different breeds and diet programs. They reported that the best regression model to estimate body weight was BW=-93.0+68.5 (breast width)+48.5 (breast circumference)+62.8 (pelvis width).…”

Eco-innovations in the German fertilizer supply chain: Impact on the carbon footprint of fertilizers

“…It was presumed that the use of feathers as fertilizer is seen as a valuable alternative to waste disposal, but that only short transport distances are acceptable. A fattened chicken was expected to weight 1.75 kg with 8-10% feathers (0.16 kg) (Latshaw and Bishop 2001). To produce 1 kg chicken meat emissions of 2.4 kg CO 2 and 0.0245 kg N 2 O were assumed (Umweltbundesamt and Öko-Institut 2016).…”