نتایج جستجو برای: crossbreeding
تعداد نتایج: 8975 فیلتر نتایج به سال:
Breed diversity is a valuable resource of the sheep industry. Crossbreeding systems use breed diversity to increase productivity relative to purebred flocks. Crossbreeding systems vary in managerial complexity and in use of beneficial effects due to crossbred ewes and lambs. Efficiency of meat production is maximized in terminal crossbreeding systems by use of specialized sire breeds to complem...
The Genetic Basis For Increased Productivity Considerable research by various State Agricultural Experiment Stations and the USDA has clearly demonstrated the potential for increasing beef cattle productivity through crossbreeding. Consequently, the use of crossbreeding for the commercial production of beef is rapidly increasing. Crossbreeding (the mating of animals from different breeds) is si...
SUMMARY Results from various straight-and crossbreeding trials South Africa were reviewed. The conclusion is drawn that in instances, initial crossbreeding followed by inter ~ matin, crossbred cattle give the same if not better results than crossbreeding. This facilitates rangeland improvement as it number of pastures needed during the breeding season.
High calf and feeder cattle prices during the past couple of years have helped many of Missouri’s cowcalf producers achieve profitability. Even though many cattle producer’s operations are profitable, work should continue to improve the economic position of the farm or ranch. Profitability may be enhanced by increasing the volume of production (i.e. the pounds of calves you market) and/or the v...
Crossbreeding can improve the profit for most dairy producers if economically similar breeds are used. However, it is important to stress that crossbreeding cannot replace pure breeding. Pure breeding is a prerequisite for crossbreeding. The heterosis obtained from crossbreeding is an added bonus on top of the genetic gain created by pure breeding. The size of the bonus depends on the number an...
Crossbreeding has been the breeding method of choice for several species in plants and livestock. In plants, the main reason for crossbreeding is to exploit heterosis effects which can be maximized via the use of highly inbred parental strains. In livestock, notably in poultry and swine, positional effects of pure-bred parents of crosses are well known and hence crossbreeding systems are set up...
Introduction While there are many types of crossbreeding systems possible, the ones most likely to be useful and practical for use in Florida are some form of a rotational crossbreeding system or, in small herds and a few specialized systems, a terminal crossbreeding program. A third option, the rota-terminal, combines both systems and could also be considered for more intensively managed opera...
Eleven thousand forty-nine pigs produced from 934 litters using 262 rotational and F1 crossbred sows were used to study differences in pig weights, survival rates and pen average daily gain, daily feed intake, and feed conversion between pigs from equivalent three-breed rotational and three-breed terminal crossbreeding systems using Duroc, Yorkshire, and Landrace breeds. Pig weights at birth an...
Crossbreeding is a popular tool for genetic improvement of pigs, beef cattle, and other livestock species, but its use in US dairy cattle has been limited for several reasons. The primary reason is the advantage of Holstein cows in milk volume, coupled with a milk pricing system that still tends to reward quantity, rather than quality, in many regions of the country (i.e., through volume premiu...
The basic objectives and procedures for successful crossbreeding of beef cattle were considered, with special reference to the levels of realized hybrid vigor that might be anticipated for different crossbreeding programs involving the American Brahman (Z1) and European (Ej) breeds. Intralocus heterozygosis levels with respect to breed origin of genes (breed heterozygosis) were computed for var...
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