Undesirable side effects of selection for high production efficiency in farm animals: a review

1. Body composition was determined in 9‐week‐old chickens sampled from four lines selected either for increased body‐weight gain (line W), for increased food consumption (line F), for decreased food conversion ratio (line E), or at random (line C), after three, four and five generations of selection. 2. After five generations of selection the proportions of carcass water (678 g/kg) and protein (187 g/kg) were highest in line E and lowest (636, 180 g/kg respectively) in line F. The proportion of fat was lowest (83 g/kg) in line E and highest (134 g/kg) in line F. 3. Lines W and C were similar and intermediate to lines E and F for all the carcass constituents. 4. There was more fat in females (115 vs 98 g/kg) and less protein (177 vs 190 g/kg) and water (652 vs 665 g/kg) than in males. 5. Line differences in carcass composition were not appreciably altered if birds were killed at equal weight rather than equal age.

Selection for food conversion in broilers: Body composition of birds selected for increased body‐weight gain, food consumption and food conversion ratio

Genetic selection for growth parameters in broiler stocks has created parent stocks that are unable to self-regulate feed intake to a level that permits reproductive function. Modern broiler breede...

Defining normal: comparison of feed restriction and full feeding of female broiler breeders

Individual phenotypic selection for high 4 week body weight was conducted for 40 generations in two lines of Japanese quail under two protein environments. Line P was selected on an adequate 28% protein diet, and line T was selected on a 20% protein diet containing 0.2% thiouracil (TU). In generation 20, a subline R was established by subjecting progeny from the T line to a 20% protein diet; in generation 27, a subline S was developed by subjecting progeny from the T line to a 28% protein diet containing 0.2% TU. Progeny from a nonselected control line (C) were reared with selected lines and sublines in all generations.

Long term selection for four-week body weight in Japanese quail under different nutritional environments.

Inheritance of antibody response to sheep erythrocytes in lines of chickens divergently selected for fifty-six-day body weight and their crosses.

Divergent Selection for Twelve-Week Body Weight in the Domestic Fowl

https://academic.oup.com/ps/article-pdf/42/2/326/4299341/poultrysci42-0326.pdf

M. A. Maloney

Papers

Divergent Selection for Twelve-Week Body Weight in the Domestic Fowl

Two-Way Selection for Body Weight in Chickens 1. The Effectiveness of Selection for Twelve-Week Body Weight

Size, Shape and Color Pattern as Criteria for Identifying Coturnix Eggs

Two-Way Selection for Body Weight in Chickens 2. The Effect of Selection for Body Weight on other Traits

Differential Effects of Reserpine by Sexes in Breeding Turkeys