Livestock breeding Systems Flashcards | Quizlet Specific crossbreeding systems use a specific pattern of consistently mating a particular breed of bull to a particular breed or breed-cross of cow. Therefore, it makes sense to cross a straightbred bull on crossbred females to take advantage of maternal heterosis instead of the reverse. In a two-breed rotation, females sired by breed A are always mated to males of breed B. This system provides maximum individual heterosis because the sire and dam have no common breed composition. To remain competitive with alternative meat products, particularly pork and poultry, the beef industry must reduce cost of production and fat while maintaining tenderness and palatability of its products. The system does not provide for replacement females internally. A terminal, static cross (Figure 1) in which all offspring are market animals takes greatest advantage of differences in the strengths of lines or breeds. Which of the following is essential to cell functions and contains nuclear sap from which chromosomes arise? However, commercial cattle producers should study crossbreeding systems and evaluate them before deciding which one is suitable for their environment and resources. system in which replacement females must be purchased from or produced in. This system crosses Breed A females with Breed T sires to produce a crossbred animal that is half Breed A and half Breed T and known as an F1. The two-breed rotation can be used with fewer cows; however, bull expenses per cow will be greater. Both tools offer the benefits of heterosis, breed differences and complementarity to help producers match genetic potential with market preferences, the climatic environment and available feed resources. Diverse breeds may lead to calving difficulty and problems associated with feeding and marketing heterogeneous calves. For the best experience on our site, be sure to turn on Javascript in your browser. Basically, there are two methods of breeding which are as follows: Inbreeding : Breeding of the related animals as sire (male) and dam (female) are known as inbreeding. This compares with 409 pounds expected from the optimum two-breed rotation and 350 pounds average of the genetic means of the two pure breeds. Only one breeding pasture is needed, labor and management are minimized, and progeny produced are highly uniform and marketable. Additional crossbreeding opportunities are available to the producer with a slightly larger beef herd. It involves two (different) breeds of animal that have been crossbred.The female offspring of that cross is then mated with a male (the terminal male) of a third breed, producing the terminal crossbred animal.. Productivity, which might be less than expected, is due to low heterosis in the substantial proportion of the herd involved in the two-breed rotation used to produce replacement females. The downsides are that more labor, management, and breeding pastures are needed than in a two-breed rotation. What is crossbreeding - definition, mechanism, meaning 2. A well designed and implemented crossbreeding system in commercial cattle operations is one proven way to increase productivity and, ultimately, profitability. What two types of breeding systems are generally used by individuals in the purebred industry? Farm animals, crops and soil bacteria are genetically modified to produce GMOs. Lastly, the ability to locate three breeds that fit a given breeding scheme can be challenging and limit the ability to readily use three breeds. Replacement females should be environmentally adapted with the necessary maternal capacities. The advantage was especially large in Florida (Figure 4). What method of breeding can increase conception rates by five to ten percent? Animal breeding - Breeding systems | Britannica Which of the following is a complex solution outside the cell nucleus contained by a cell membrane? How does the structure of a cell suggest its function? Breeding scheme for a two-breed rotational crossbreeding system. Again, no breed complementation is available. Maternal heterosis is maximized because the breeds crossed to produce the maternal line (the black-baldies) have no common composition. An example of a crossbred dog is shown in Figure 1. Crossbred cows from the maternal rotation are mated to a terminal sire breed. Which crossbreeding system produces replacement females through the rotation and produces crossbred offspring? Breed complementary results when crossbred animals exhibit desirable characteristics from each parents breed, resulting in a more valuable animal. University of Missouri Extension is an equal opportunity/access/affirmative action/pro-disabled and veteran employer. All of the offspring from this initial cross are marketed, and replacement heifers are purchased. What is the proper term for the measure of how inbred an animal is? A GMO, or genetically modified organism, is a plant, animal, microorganism or other organism whose genetic makeup has been modified in a laboratory using genetic engineering or transgenic technology. Heterosis is usually, but not invariably, favorable. Cross-pollination is quite easy with dioecious species. The rototerminal system is essentially a hybrid crossbreeding program using aspects of a terminal program and a rotational program. A three-breed rotaterminal crossbreeding system is illustrated in Figure 4. If a civilization lived on an exoplanet in an E0 galaxy, do you think it would have a "Milky Way" band of starlight in its sky? Effective use of a crossbreeding system allows producers to take advantage Livestock Breeding System Flashcards | Chegg.com An example of a two-breed specific cross would be mating Angus bulls to Hereford cows. Shorthorn and ? These herds are not large enough to take advantage of conventional crossbreeding systems. This will result in lower production per breeding female than will be seen in crossbred females because 0 percent maternal heterosis results. Approximately 60 to 65 percent of the youngest cows in this system are in the rotational phase and the remaining cows are in the terminal phase. Crossbreeding for the Commercial Beef Producer - Beef Cattle - Extension Most important, these breeds will be used consistently in their role as a maternal or paternal breed in this particular crossing system. In addition to source, cost of replacement heifers needs to be evaluated. Crossbreeding: Crossbreeding can be used to mate two genetically related organisms that will never cross naturally. Help improve lives, communities and economies throughout the state. To predict weaning weight per cow exposed, heterosis for conception rate and calf survival also needs to be considered. Individual heterosis is maximized because the maternal line (Angus and Hereford) has no common breed composition with the terminal sire (Charolais). 1. Efficient crossbreeding systems for herds of this size would increase the productivity and profitability of the states beef industry. This program is appropriate for herds of all sizes because only one sire breed is used, just one breeding pasture is needed, and replacement females are purchased. No one system is optimum for all beef cattle producers. For the first four years the largest proportion of cows are breed A. GMO: GMO results from the genetic modification of the genetic make-up of an organism. Since generations overlap in cattle, females from both breeds of sire will simultaneously be present in the herd requiring at least two breeding pastures to ensure correct use of the system if natural mating is used. Average expected levels of individual and maternal heterosis for the first 20 years of operation of the crossbreeding systems described above are summarized in Table 7. This type of heterosis is generally seen in growth traits of the crossbred offspring. The first crossbreeding may produce a superior animal due to hybrid vigor. The offspring exceed the average performance of their parents for traits for which hybrid vigor is expressed. This single-sire rotation is expected on average to yield 59 percent of maximum individual heterosis and 47 percent of maximum maternal heterosis for the first twenty years of operation. As more breeds contribute to the composite, retained individual and maternal heterosis increases. Type 2 or more characters into the input search below for suggested results, use up and down arrow keys to navigate through suggest box. No single breed excels in all important beef production traits. Static-terminal sire crossing systems. Expected performance is very similar for the two systems. Why or why not? What is the difference between the F1 and F2 generation? All calves from the terminal mating are sold. A three-breed rotaterminal system provides breed complementation in the terminal mating, which involves about the oldest 40 percent of the cow herd. Breeds should not only be adapted to the production environment, but must be compatible with each other in a rotational system. A. Hybrid vigor, or heterosis, is the increased production of certain traits from the crossing of genetically different individuals. Crossbreeding Systems. Applying Principles of Crossbreeding - Utah State University You should not use this every solve since many scrambles are just as fast doing cross and the first pair separately.. After watching the tutorial, the best way to practice is to predict when corners/edges will be solved after making the cross. Figure 3. Registered in England and Wales. Individual heterosis is the increase in production seen in the crossbred offspring. The main difference between crossbreeding and GMOs is that crossbreeding is the mating of two organisms from two races, while GMOs are the organisms whose genetic material is modified by . Management of matings for this system can also be somewhat complex. Choosing a bull of a terminal sire breed also results in breed complementation. Crossbred cattle at the University of Missouri South Farm Beef Research and Teaching Unit. Breeding scheme for a three-breed rotaterminal crossbreeding system. This system suffers the drawback of complexity and unequal usage of bulls. X-Cross is short for Extended Cross. By mating two different races, a new organism with hybrid power can be created. Golden Rice by the International Rice Research Institute (IRRI) - (CC BY 2.0) via Commons Wikimedia, Lakna, a graduate in molecular biology and biochemistry, is a molecular biologist and has a broad and strong interest in discovering things related to nature, What are the similarities between crossbreeding and GMO, What is the difference between crossbreeding and GMO. Choice of breeds is of great importance. Sci. Each parent contributes one gamete or sex cell to each of its offspring. It is also known as a two- breed rotation with terminal sire system. The parent organisms must be genetically compatible and may be from different varieties or closely related species. This is only a slight gain from the three-breed rotation with the added cost of labor, management, and another breed of sire. Prediction of weaning weight per cow exposed is similar to calculation above, except individual heterosis is 8 percent and maternal heterosis is 19 percent: = [(0.5 (396) + (0.25 (349) + (0.25 351)] (1 + 0.08) (1 + 0.19). weaned over 9.4 years) or Herefords (2,405 lbs. The rotaterminal system is more sensitive to management than are the other systems. All rights reserved. Because replacement heifers are purchased, a source of quality crossbred females is essential. All rights reserved. GMOs: GMOs are sometimes linked to susceptibility to disease. Such a system should be used to take advantage of breed complementarity and heterosis while also fitting the herd size and resources of the operation. Seedstock producers have only recently begun to produce F1 bulls in significant numbers for use in commercial production. Adapting data for weaning weight from Notter, 1989 (Beef Improvement Federation Proceedings), Angus were 432, Hereford 435, and Charolais 490 pounds. Optimal sequence for bulls in a two-sire, three-breed rotation is shown in Table 5. Angus and ? This often means replacing the herd sire or adding breeding pastures and separating females from their sires. The information given here is for educational purposes only. Unfortunately, it also requires multiple breeding pastures or artificial insemination (AI) to ensure correct matings resulting in maximum heterosis. Throughout this publication, % heterosis will be in reference to an F1 (first-generation cross) with 100 percent heterosis. Terminal crossbreeding is a breeding system used in animal production. Since a single bull is used, not all matings can be optimal as in the two-breed rotation. "Dollyscotland (Crop)" By TimVickers in the English Wikipedia (Original text: User: Llull in the English Wikipedia) - Image: Dollyscotland.JPG (Public Domain.)) Before implementing a crossbreeding program, a producer needs to have well-defined goals for the operation. GMO: The desired trait can be genetically engineered at once. What is the difference between relax and rebound? Systems using one and two bulls are described. Crossing: The crossing of animals takes place through artificial insemination. Table 7. In general, EPDs available for bulls from purebreds used in rotational systems tend to be more accurate than EPDs for bulls used in a composite population because they're based on a larger number of records. Perfor-mance expectations using example breeds have been calculated for each breeding system for comparison purposes. Considerations when using the two-breed rotation are breed type, resources available to raise replacement heifers, and size of cowherd. Crossbreeding in commercial beef cattle production improves efficiency through heterosis and breed complementation (Figure 1). Implementing a well-designed crossbreeding system is an important management practice for improving profitability on commercial cattle operations. National Beef Cattle Evaluation Consortium. In fact, if discounts for yield grade differences are similar to those for USDA quality grade, in temperate environments, cattle that are half-Continental and half-British have a much better chance of hitting profitable targets for retail product percentage, marbling and carcass weight. Disadvantages of the three-breed rotation are that an additional breeding pasture and breed of bull(s) must be maintained. Commercial cattle producers face input cost management decisions every year. Additional heterosis is lost if improper matings are made. For example, crossbreeding can increase the milk production of cattle. Heterosis Heterosis can have substantial effect on profitability. "Genetically Modified Organisms (GMO): Transgenic Plants and Recombinant DNA Technology." No single system is suited for all herds. What is the difference between crossbreeding and GMO - comparison of the main differences, Key Terms: Animals, Crossbreeds, Genetically Modified Organisms (GMOs), Hybrid Vigor, Plants, Traits. Hereford. Crossbreeding systems fall into four categories: specific or terminal systems, rotational systems, rotaterminal systems and composite or synthetic systems. Cost and availability of these resources need to be considered. After three generations, breed composition stabilizes at approximately ? Because preferred feed resources vary by area, breeds chosen for the cowherd should be well adapted to feed resources within a given area. Several questions need to be asked. In terminal crossing systems, crossbred females excelling in maternal performance are mated to sires of a different breed that excels in growth traits, ensuring excellence in carcass and meat characteristics in the resulting progeny. When composites are used sires and dams do not differ, thus no breed complementation is offered. Therefore, it is important to weigh all of these considerations before selecting the most appropriate crossbreeding system for a commercial herd. Modern reproductive technologies can greatly facilitate implementation of a crossbreeding program for herds of any size. Normally, breeds are chosen that have complementary traits that will enhance the offsprings' economic value. GMO: Salmon that has been genetically engineered to get bigger is an example of GMO. Will calves be marketed as feeder calves, or will ownership be retained through stockering and/or finishing? This system results in 100 percent of both individual and maternal heterosis over the average of the parent breeds, which results in an increase of 24 percent in pounds of calf weaned per cow exposed. For example, lifetime production and longevity of Hereford x Angus cows (3,258 lbs. Because of this variation, rotational systems using comparable breeds work best. Defined as the difference between the average of reciprocal F1 crosses (A x B and B x A) and the average of the two parental breeds (A and B) mated to produce the reciprocal crosses, heterosis was found in one study to increase weaning weight per cow exposed 23%. Livestock Breeding Systems - Crossbreeding Methods Directions: Answer the following questions. These values compare with 72 percent for individual heterosis and 56 percent maternal heterosis in a system in which all matings are correct. Crossbreeding Systems for Beef Cattle | Mississippi State University Remember, reproduction potential of cows with large size and high milk declines if environment and feed can't meet the higher requirements for maintenance and lactation. GMO: GMO (genetically modified organism) refers to an organism whose genetic material is modified by genetic engineering. All crossbred BA females are mated to breed C, a terminal sire breed. Table 1 provides a summary of beef cattle crossbreeding system details and considerations. Genetically modified plants can also mature more quickly and can tolerate drought, salt and frost.