A 6-wk growth study was conducted comparing fingerling (mean weight = 24.7 g) USDA103 strain channel catfish Zctulunrspunctatus to Norris strain channel catfish in an effort to determine strain dmerences in growth and nutrient efficiency. Variability within strains also was assessed by randomly selecting four families from each strain for comparison. On average, USDA103 fish gained significantl...

Improved feed efficiency is a primary goal in dairy production to reduce feed costs and negative impacts of production on the environment. Estimates for efficiency of feed conversion to milk production based on residual feed intake (RFI) in dairy cattle are limited, primarily due to a lack of individual feed intake measurements for lactating cows. Feed intake was measured in Holstein cows durin...

Records on 514 bulls from the sire population born from 1978 to 2004, and on 22,099 of their field progeny born from 1997 to 2003 with available pedigree information (total number = 124,458) were used to estimate genetic parameters for feed intake and energy efficiency traits of bulls and their relationships with carcass traits of field progeny. Feed intake and energetic efficiency traits were ...

A better understanding of the factors regulating feed efficiency and their potential as predictors of feed efficiency in cattle is needed. Therefore, the potential of three classes of traits, namely, feeding behavior characteristics: daily time at feeder (TF; min/day), time per meal (TM; min), meal size (MS; g DM), eating rate (ER; g DM/min), number of daily meals (NM) and daily visits to the f...

Providing feed is a major input cost in beef production, hence improvements in the efficiency of feed utilisation will reduce the cost of production. Residual feed intake (RFI) is a measure of feed efficiency, and is defined as the difference between an animal's actual feed intake and its expected feed intake based on its size and growth. It is independent of the level of production, and the lo...

to evaluate antioxidant effects of tomato pomace in broiler diets contained full-fat linseed on the production index, energy and protein efficiency, 396 one-day old ross 308 broilers were randomly allocated to 36 cages for nine dietary treatments with four replicate. this experiment were carried out in a completely randomized design with 3*3 factorial arrangement with three levels of full-fat l...

In France, about 95% of the fatty liver production comes from mule ducks, an infertile hybrid cross between female common ducks (Anas platyrhynchos) and Muscovy drakes (Cairina moschata). As a hybrid, genetic improvement of the performance of mule ducks is achieved by selection of the parental populations. Feed represents two-thirds of the total costs of duck production; thus, the breeders’ mai...

A review is presented of the genetic and physiological aspects of growth, body composition and feed efficiency in mice. The genetic parameters considered are: nature and extent of within and between-line genetic variation for body weight and growth rate; direct and correlated responses to selection for body weight, weight gain, feed intake and feed efficiency; direct genetic effects of the offs...