The objective of this study was to estimate genetic and phenotypic correlations of body weight at 6 weeks of age (BW6), as well as final carcass yield, and moisture, protein, fat and ash contents, using data from 3,422 F2 chickens originated from reciprocal cross between a broiler and a layer line. Variance components were estimated by the REML method, using animal models for evaluating random ...

Severe, chronic growth retardation of cattle early in life reduces growth potential, resulting in smaller animals at any given age. Capacity for long-term compensatory growth diminishes as the age of onset of nutritional restriction resulting in prolonged growth retardation declines. Hence, more extreme intrauterine growth retardation can result in slower growth throughout postnatal life. Howev...

Residual feed intake (RFI), defined as the difference in the observed and expected feed intake while accounting for growth and backfat, has gained much attention, but little is known about why pigs selected for reduced RFI are more efficient. To this end, a line of Yorkshire pigs selected for reduced RFI was developed. The objective of this study was to evaluate the 5th generation of this selec...

Fifty merino wethers (liveweight range from 44 to 81kg, average of 58.6kg) were lot fed for 42d and scanned through a dual X-ray absorptiometry (DXA) as both a live animal and whole carcass (carcass weight range from 15 to 32kg, average of 22.9kg) producing measures of total tissue, lean, fat and bone content. The carcasses were subsequently boned out into saleable cuts and the weights and yiel...

The current study was conducted to investigate the effects of genetic and non-genetic factors on body weight and carcass traits of Japanese quails. Two strains of Japanese quail (150 wild quails and 150 white quails) were used as base population. Four mating groups were used to produce progenies: wild male × wild female, white male × wild female, wild male × white female and white male × white ...

Dual-energy x-ray absorptiometry (DXA) was used as a noninvasive method to measure the composition of pig carcasses. A total of 181 half-carcasses (10 to 51 kg, from pigs slaughtered at approximately 30, 60, 90, and 120 kg) were scanned using a Lunar (Madison, WI) DPX-L densitometer. The DXA measurements of fat, lean, bone mineral, and total tissue mass were compared with chemical analysis for ...

The study was conducted to evaluate carcass yield and chemical composition of thigh and breast muscles of broilers fed three different lysine requirement levels: high lysine (+10% NRC), standard (NRC) and low lysine (-10% NRC) and two ways of expressing amino acids in feedstuffs (total or digestible amino acids). The results of this study showed that diet formulation based on digestible amino a...

The body composition of any animal is the consequence of the effect of nutrition over a period of time on the genetic and physiological factors that, together with nutrition, determine its phenotype. This paper will consider only those aspects of body composition that are of major importance, first in the conversion of animal feed to saleable product in meat animals and, secondly, in the qualit...

Correlated responses on carcass and meat quality characteristics after 3 generations of divergent selection for intramuscular fat (IMF) content were assessed by comparing the high and low lines. Selection was based on the phenotypic value of IMF content of LM, measured in 2 full sibs of the first parity. Traits measured were: BW, HCW, commercial carcass weight (CCW), reference carcass weight (R...

Current research was conducted to estimate heritability and genetic correlations for carcass composition and fat deposition in Japanese quail at 42 and 91 d of age. Studied traits were BW at 42 and 91 d of age (BW42, BW91), carcass weight and percentage, breast meat weight and percentage, thigh weight and percentage, abdominal fat weight and abdominal fat percentage (AFP), skin weight and skin ...