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

Evaluating alternate models to estimate genetic parameters of calving traits in United Kingdom Holstein-Friesian dairy cattle

<p>Abstract</p> <p>Background</p> <p>The focus in dairy cattle breeding is gradually shifting from production to functional traits and genetic parameters of calving traits are estimated more frequently. However, across countries, various statistical models are used to estimate these parameters. This study evaluates different models for calving ease and stillbirth in United Kingdom Holstein-Friesian cattle.</p> <p>Methods</p> <p>Data from first and later parity records were used. Genetic parameters for calving ease, stillbirth and gestation length were estimated using the restricted maximum likelihood method, considering different models i.e. sire (−maternal grandsire), animal, univariate and bivariate models. Gestation length was fitted as a correlated indicator trait and, for all three traits, genetic correlations between first and later parities were estimated. Potential bias in estimates was avoided by acknowledging a possible environmental direct-maternal covariance. The total heritable variance was estimated for each trait to discuss its theoretical importance and practical value. Prediction error variances and accuracies were calculated to compare the models.</p> <p>Results and discussion</p> <p>On average, direct and maternal heritabilities for calving traits were low, except for direct gestation length. Calving ease in first parity had a significant and negative direct-maternal genetic correlation. Gestation length was maternally correlated to stillbirth in first parity and directly correlated to calving ease in later parities. Multi-trait models had a slightly greater predictive ability than univariate models, especially for the lowly heritable traits. The computation time needed for sire (−maternal grandsire) models was much smaller than for animal models with only small differences in accuracy. The sire (−maternal grandsire) model was robust when additional genetic components were estimated, while the equivalent animal model had difficulties reaching convergence.</p> <p>Conclusions</p> <p>For the evaluation of calving traits, multi-trait models show a slight advantage over univariate models. Extended sire models (−maternal grandsire) are more practical and robust than animal models. Estimated genetic parameters for calving traits of UK Holstein cattle are consistent with literature. Calculating an aggregate estimated breeding value including direct and maternal values should encourage breeders to consider both direct and maternal effects in selection decisions.</p

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

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

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