Feed efficiency has a major influence on the unit cost of beef cattle production. Gibb and McAllister (1999) have reported that a 5% improvement in feed efficiency has an economic impact four times greater than a 5% improvement in average daily gain. In addition, the cost of feed is second only to fixed costs in importance to the profitability of commercial beef operations (Basarab, 1999). The ...

In this study phenotypic and genetic factors affecting the reproductive efficiency of Lori-Bakhtiari ewes were determined using 8202 reproductive records of 2478 ewes collected at Shooli research station in the southwestern part of Iran (Shahrekord) during 1989 to 2012. Reproductive efficiency over all consecutive lambing opportunities were calculated by adding the total reproductive efficiency...

Genetic parameters for the efficiency of gain traits on 380 boars and the genetic relationships with component traits were estimated in 1,642 pigs (380 boars, 868 gilts, and 394 barrows) in 7 generations of a Duroc population. The efficiency of gain traits included the feed conversion ratio (FCR) and residual feed intake (RFI) and their component traits, ADG, metabolic BW (MWT), and daily feed ...

This study was carried out to determine the effect of different levels of clove essential oil, as a natural growth promoter and probiotic on performance,carcass traits and serum components of broiler chickens. A total of 240 straight run day-old commercial broiler chicks (Cobb 500) were distributed randomly into five groups. Each group was subdivided into four replicates with 12 chicks each. Th...

this experiment was conducted to investigate the effects of using protexin, propionic acid growth promoters, and a blend of them on broilers performance. in a completely randomized design, three hundreds and twenty unsexed 1-d-old chicks were divided into four groups. dietary treatments were consisted of 1) control diet without any supplement, 2) the control diet + 0.01 % protexin, 3) the contr...

Breeding standards of most dog breeds specify tolerable ranges of certain conformation traits. In the German shepherd dog (GSD), current means for withers height (WH) and BW are close to the upper breed limits. Therefore, strategies to avoid a further increase in size and to maximize the proportion of dogs fitting the breeding standard with respect to WH and BW should be compared. Body measurem...

In order to study the effects of long-term selection on genetic parameters, the effect of selection on selected and correlated traits and to develop lines for various physiological, biochemical and molecular genetic studies a comprehensive selection study for body weight in chickens has been conducted at the Biotechnical Faculty of University in Ljubljana. Long-term divergent selection in chick...

The effect on thermotolerance of the incompletely dominant frizzle (F) gene, which causes feather curling and feather mass reduction, was investigated in 281 laying hens that were homozygous for the frizzle mutation (FF), heterozygous (FN), or normally feathered (NN). One-half of the birds were kept under standard conditions (22°C) and half were exposed to high ambient temperatures (32°C) betwe...

The present study and field measurements were carried out at broiler farms in Menoufia Governorate (Tala) during the period 2017 2018. great object of this was to determine effect some environmental factors (such as type strains, densities additions seasons effects) on production economical efficiency Government.The places these (Meet ElKeram, Kafer El Alawy, Bemam, Rabea.) - studied traits...