What the Breeder Sells and the Producer Buys: Breeding Value

A breeding value is the value of an individual as a parent. This is precisely what breeding stock herds sell. It is the value of the progeny from their breeding stock in the herd of the buyer that is the issue. As specification of product becomes more important in the beef industry, breeders can be merchandizing breeding value. Beef breeders are selling a product that must transmit a sample half of its germ plasm to progeny before the result is realized. Commercial producers sell pounds, not breeding value, but they need to buy breeding value as well as combine breeds in logical combinations to obtain the crossbred advantages especially for the reproductive complex. Thus, both the commercial and breeding stock producer can benefit from understanding the concept of breeding value. The purpose of this paper is to define and describe the breeding value concept and to examine ways to use the concept in practice

Inheritance of coat coloration and spotting patterns of cattle: A review

An understanding of the inheritance of coat coloration and white markings in cattle is useful for several reasons. The first is its potential usefulness in the teaching of Mendelian principles to agricultural students. A second would be its usefulness in the development of composite breeds of cattle in which a uniform coat coloration may be desirable. A third is that there may be interest in determining which breeds could be used in crossbreeding programs to produce uniformly colored terminal cross calves. Also, Lauvergne (1966) discussed a review article by J. D. Findlay where it is concluded that pigmentation can affect the productive performance of animals under certain conditions such as in the tropics where animals with darkly pigmented skins and light-colored coats seem best adapted. Finally, animals without pigmented eyelids seem more susceptible to cancer eye” (Anderson et al., 1957). The inheritance of coat coloration and white spotting in cattle has been studied by many scientists since the beginning o f this century. Ibsen (1933) provided a summary of the segregating loci that had been reported and postulated others. Lauvergne (1966) produced an excellent summary of the existing information, but his summary is not readily useful in the United States, primarily because it is published in the French language. This publication will draw upon the conclusions of Lauvergne and modify and expand them

Evaluation of Selection Practices in Three Lines of Beef Cattle

Selection practices in three synthetic lines of beef cattle were evaluated based on data collected over 12 to 13 years. Sires from the Jersey, Angus and Simmental breeds were mated to three lines of foundation crossbred dams to produce first generation progeny. Subsequent calves were produced mating crossbred parents of the same generation. Crossbred sires were selected based on an index that included hip height and weight at weaning. At Rhodes, a total of 2.84 to 3.07 generations of selection have been carried out. This provided a mean generation interval of 4.33, 4.23 and 4.58 years in small, medium and large lines, respectively. At McNay, the corresponding generation interval values were 4.15 years for small and medium lines and 5.29 years for the large. The mean weighted sire selection differential for the index in the small line was 1.28 s/generation. In the medium cattle these values were -.57 s/generation (Rhodes) and -.36 s/generation (McNay). For the large synthetic cattle the index differential ranged from .71 s/generation at McNay to .92 s/generation at Rhodes. Of the total mean parental selection differential, sire contribution ranged from 86% to 95%. Selection differential values for components of the index indicated that the index equations often favored weaning weight, and this was very pronounced in the medium line. Regardless of the line, selection criteria have been strictly followed. However, all the maximum potential sires have not been utilized

A Project to Develop Genetic Specification for the Beef Industry

A new beef breeding project will be conducted at the Rhodes and McNay farms of ISU. The project will use the field data of the American Angus Association along with the research resources (cattle) of the farms to study questions that will enhance the genetic investigations using the field data. It will build on the expertise developed at ISU with ultrasound to measure body composition in the live animal and in the carcass. Two selection lines, using registered Angus obtained as heifers and through ET, of 200 females each will be selected for increased intramuscular fat (Q line) and for increased retail product (R line). The estimation of the genetic correlation between quality and amount of product can best be accomplished through the study of one generation of selection using measures of body composition derived from ultrasound. A progeny test herd will be maintained to evaluate all sires used through progeny carcass testing and to further research with ultrasound. The project will study efficiency of body maintenance. Results will be shared through the Beef Improvement Federation to benefit all producers in the development of sound programs to profitably produce specified beef products

IMPUTING CHARACTERISTIC VALUES OF AGRICULTURAL SEED-STOCK

Statistical methods of regression and mathematical (linear) programming are employed to combine principles of economics and genetics in a conceptual, multi-step, model of valuation for biotechnical change. The resulting model has the capacity to estimate the value of changes in specific characteristics for specific production environments, whether those changes are accomplished by traditional plant and animal breeding methods or by genetic engineering. The application of the model is illustrated with an example of commercial cow-calf production under conditions typical of the Texas Panhandle using a total of 32 breed groups

Individual descriptive record system

An electronic individual descriptive record system for storing the individual\u27s identification and descriptive data on a programmable electronic identification and data storage module carried with the individual so that the individual\u27s identification, the individual\u27s descriptive data and the individual itself become one. The system includes an implantable programmable electronic identification and data storage module carried by the individual, and a reading and recording device which communicates with the electronic identification and data storage module

An Evaluation of Four Procedures to Rank Centrally Tested Boars

Four procedures, one using genetic relationships, were evaluated to rank centrally tested boars from records on 9,093 boars tested in central stations. Breeds with larger numbers of tested boars were found to have more total relationship ties than were breeds with smaller numbers of boars tested. Of the breeds with greater tested numbers, Durocs and Yorkshires Were genetically more tied than were the Hampshire or Spotted breeds. Among breeds with fewer observations, Berkshires had the most relationship ties, while Poland Chinas had the fewest. When the number of ties between boars in each season-year with boars in the most recent season-year were evaluated, only the last six or seven-season-year groups were needed to provide sufficient relationship ties with pigs currently tested. The four evaluation procedures were performance value (PV), deviation of the performances value from the station-season-year subclass mean (SSYD), mixed model without relationships (MM) and mixed model including relationships (MMR). The MM procedure produced much lower prediction error variances than did the PV or SSYD procedures; whereas the MMR procedure produced the lowest prediction error variances. Although the MM and MMR procedures gave far more precise estimates than did PV and SSYD, they do involve more complex computing procedures. When the cost of these morecomplex computations is reasonable, the MMR procedure should be considered to evaluate centrally tested boars because it allows a fair comparison of boars across stations in the same season. The value of across station evaluation is discussed

Prediction of Percent Retail Product, Retail Product Weight and Hot Carcass Weight From Serially Measured Live Animal Traits

A total of 1,072 observations collected over a six-year period were used to develop prediction models for retail product (percentage and weight) and hot carcass weight from live cattle measures. Independent variables used were: ultrasound fat thickness (UFAT), ultrasound longissimus muscle Area (ULMA), age, hip height (HT), live weight (WT), ultrasound-predicted percent Intramuscular fat (UIMF) and breed composition. Pearson product moment correlations between the dependent and independent variables were often significant (P \u3c .01, P \u3c .05). In the prediction of percent retail product, UFAT accounted for 29 to 42% of the variation. A complete model including all the independent variables explained 20% more of the variation. In the prediction of retail product weight, WT remained a highly significant independent variable accounting for 32 to 78% of the variation. Similarly, WT accounted for 38 to 81% of the variation in hot carcass weight. When independent variables were adjusted to a constant age, models from data adjusted to earlier ages (M-414, M-382) explained more variation than models from data adjusted to a mean age at slaughter (M-448)