scholarly journals Expected efficiency of selection for growth in a French beef cattle breeding scheme II. Prediction of asymptotic genetic gain in a heterogeneous population

1995 ◽  
Vol 27 (2) ◽  
pp. 171 ◽  
Author(s):  
F Phocas ◽  
JJ Colleau ◽  
F Ménissier
Keyword(s):  
Beef Cattle ◽  
Genetic Gain ◽  
Heterogeneous Population ◽  
Breeding Scheme ◽  
Cattle Breeding ◽  
Selection For ◽  
Efficiency Of Selection ◽  
French Beef

scholarly journals The relevance of milk protein polymorphisms for dairy cattle breeding.

1993 ◽  
Vol 1993 ◽  
pp. 46-46
Author(s):  
Henk Bovenhuis
Keyword(s):  
Genetic Variants ◽  
Milk Protein ◽  
Production Traits ◽  
Milk Production Traits ◽  
Breeding Scheme ◽  
Cattle Breeding ◽  
Dairy Cattle Breeding ◽  
Nucleus Breeding ◽  
Selection For ◽  
Β Lactoglobulin

Several studies have shown milk protein genetic variants to be associated with manufacturing properties of milk. The main findings were that κ-casein genetic variants affect renneting time of milk and βlactoglobulin genetic variants are associated with casein number (reviewed by Grosclaude, 1988). There are reports also of associations between milk protein genetic variants and milk production traits. Results from these studies indicate that κ-casein genotypes are associated with protein content and βlactoglobulin genotypes are related to fat content (reviewed by Bovenhuis et al., 1992). Therefore, κ-casein and βlactoglobulin genotypes might be of value as selection criteria. The aim of the present study was to quantify the potential effects of selection for κ-casein and β-lactoglobulin genotypes by using stochastic simulation of a closed adult MOET nucleus breeding scheme.

scholarly journals Beef cattle breeding in Australia with genomics: opportunities and needs

2012 ◽  
Vol 52 (3) ◽  
pp. 100 ◽  
Author(s):  
D. J. Johnston ◽  
B. Tier ◽  
H.-U. Graser
Keyword(s):  
Beef Cattle ◽  
Genomic Selection ◽  
Genetic Gain ◽  
Information Needs ◽  
Genomic Information ◽  
Female Reproduction ◽  
Genetic Progress ◽  
Cattle Breeding ◽  
Phenotypic Data ◽  
Genomic Predictions

Opportunities exist in beef cattle breeding to significantly increase the rates of genetic gain by increasing the accuracy of selection at earlier ages. Currently, selection of young beef bulls incorporates several economically important traits but estimated breeding values for these traits have a large range in accuracies. While there is potential to increase accuracy through increased levels of performance recording, several traits cannot be recorded on the young bull. Increasing the accuracy of these traits is where genomic selection can offer substantial improvements in current rates of genetic gain for beef. The immediate challenge for beef is to increase the genetic variation explained by the genomic predictions for those traits of high economic value that have low accuracies at the time of selection. Currently, the accuracies of genomic predictions are low in beef, compared with those in dairy cattle. This is likely to be due to the relatively low number of animals with genotypes and phenotypes that have been used in developing genomic prediction equations. Improving the accuracy of genomic predictions will require the collection of genotypes and phenotypes on many more animals, with even greater numbers needed for lowly heritable traits, such as female reproduction and other fitness traits. Further challenges exist in beef to have genomic predictions for the large number of important breeds and also for multi-breed populations. Results suggest that single-nucleotide polymorphism (SNP) chips that are denser than 50 000 SNPs in the current use will be required to achieve this goal. For genomic selection to contribute to genetic progress, the information needs to be correctly combined with traditional pedigree and performance data. Several methods have emerged for combining the two sources of data into current genetic evaluation systems; however, challenges exist for the beef industry to implement these effectively. Changes will also be needed to the structure of the breeding sector to allow optimal use of genomic information for the benefit of the industry. Genomic information will need to be cost effective and a major driver of this will be increasing the accuracy of the predictions, which requires the collection of much more phenotypic data than are currently available.

scholarly journals Opportunities and challenges from the use of genomic selection for beef cattle breeding in Latin America

2012 ◽  
Vol 2 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Hugo H. Montaldo ◽  
Eduardo Casas ◽  
José Bento Sterman Ferraz ◽  
Vicente E. Vega-Murillo ◽  
Sergio Iván Román-Ponce
Keyword(s):  
Latin America ◽  
Beef Cattle ◽  
Genomic Selection ◽  
Cattle Breeding ◽  
Selection For

scholarly journals REPRODUCTIVE TRAITS SELECTION IN NELORE BEEF CATTLE

2015 ◽  
Vol 39 (4) ◽  
pp. 355-362 ◽  
Author(s):  
Heverton Luis Moreira ◽  
Marcos Eli Buzanskas ◽  
Danisio Prado Munari ◽  
Érika Breda Canova ◽  
Raysildo Barbosa Lôbo ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Genetic Gain ◽  
Selection Criterion ◽  
Reproductive Traits ◽  
Productive Efficiency ◽  
Gestation Length ◽  
Breeding Programs ◽  
Scrotal Circumference ◽  
Selection For ◽  
Nelore Cattle

Genetic breeding programs of beef cattle in Brazil are including new features, mainly related to reproductive efficiency.Thus, it is necessary to study the effectiveness of selection and quantify genetic gain for these traits in herds. This study estimated genetic and phenotypic parameters and genetic trends for reproductive traits used in breeding programs for Nelore beef cattle. The traits studied were the scrotal circumference (SC) at 365 and 450 days of age (SC365 and SC450), age at first calving (AFC) and gestation length, as a cow trait (GLcow) and a calf trait (GLcalf). The (co)variance components were obtained with the Restricted Maximum Likelihood Methodology in a single and double-trait analysis of the animal model. For scrotal circumference (SC365 and SC450), positive and favorable genetic gains were observed. For AFC, GLcow and GLcalf, the trends were favorable for selection, but without significant genetic gain. Selection for large SC may reduce AFC and improve female reproductive efficiency. The selection for reproductive traits (SC365, SC450, AFC and GL) may improve reproductive and productive efficiency of Nelore cattle, if used as a selection criterion.

Economic evaluation of beef cattle breeding schemes incorporating performance testing of young bulls for feed intake

2004 ◽  
Vol 44 (5) ◽  
pp. 393 ◽  
Author(s):  
J. A. Archer ◽  
S. A. Barwick ◽  
H.-U. Graser
Keyword(s):  
Beef Cattle ◽  
Feed Intake ◽  
Genetic Gain ◽  
Selection Criterion ◽  
Performance Testing ◽  
Cattle Breeding ◽  
Commercial Unit ◽  
Base Scenario ◽  
Breeding Schemes ◽  
The Impact

A model beef cattle breeding scheme consisting of a breeding unit and a commercial unit was used to evaluate the impact on genetic gain and profitability of incorporating feed intake measurements as an additional selection criterion in breeding programmes. Costs incurred by the breeding unit were compared with returns generated in the commercial unit, with bulls from the breeding unit being used as sires in the commercial unit. Two different market objectives were considered — a grass-fed product for the Australian domestic market, and a grain-fed product for the Japanese market. Breeding units utilising either artificial insemination or natural service were also considered. A base scenario was modelled incorporating a range of criteria available to Australian cattle breeders. A second scenario incorporated selection of sires for the breeding unit using a 2-stage selection process, with a proportion of bulls selected after weaning for measurement of (residual) feed intake. Measurement of feed intake of bulls improved accuracy of breeding unit sire selection by 14–50% over the equivalent base scenario, and genetic gain in the breeding objective was improved for all scenarios, with gains ranging from 8 to 38% over the base scenario. After accounting for the cost of measuring feed intake ($150–450), additional profit was generated from inclusion of feed intake measurement on a proportion of bulls for all breeding schemes considered. Profit was generally maximised where 10–20% of bulls were selected at weaning for measurement of intake, with improvement in profit ranging from 9 to 33% when optimal numbers of bulls were selected for intake measurement.

Multistage selection for maximum economic return with an application to beef cattle breeding

1995 ◽  
Vol 73 (3) ◽  
pp. 699-710 ◽  
Author(s):  
Shizhong Xu ◽  
Truman G. Martin ◽  
William M. Muir
Keyword(s):  
Beef Cattle ◽  
Cattle Breeding ◽  
Economic Return ◽  
Selection For ◽  
Multistage Selection

Utilization of the sex-determining region Y gene in beef cattle breeding schemes

1991 ◽  
Vol 53 (2) ◽  
pp. 157-164 ◽  
Author(s):  
S. C. Bishop ◽  
J. A. Woolliams
Keyword(s):  
Beef Cattle ◽  
Male Offspring ◽  
Biological Efficiency ◽  
Normal Male ◽  
Sry Gene ◽  
Breeding Scheme ◽  
Genetic Progress ◽  
Cattle Breeding ◽  
Breeding Schemes ◽  
Normal Males

AbstractIn mammals ‘maleness’, i.e. the presence of testes, is thought to be controlled by a single gene on the Y chromosome. Recently, a candidate gene termed the SRY (sex-determining region Y) gene has been located. If the SRY gene is the gene causing maleness then a transgenic male with the SRY gene on an autosome would produce a greater proportion of male offspring than a normal male. This would be advantageous in situations where male offspring are more valuable than females. Such transgenic males have a reduced probability of propagating their genotype and an effort has to be made to avoid their extinction. This is at the cost of genetic progress which must be made to enable the transgenics to remain competitive with normal males.In a simulated beef cattle breeding scheme if half of the annual matings were made to transgenics then after 15 years of selection the transgenic males fell the equivalent of 2·6 years of selection behind males in a traditional herd. If all matings were made to transgenics they fell over 9 years behind. Selection for lean food conversion ratio was considered as an example. After 15 years of selection the gain in biological efficiency from more male offspring outweighed the loss from reduced genetic progress only when more than 0·5 of the bulls used in the breeding scheme were normal males. In practice, the difficulty of maintaining a small population of transgenic males along with other costs not included in the calculations suggest that breeding schemes in beef cattle with an SRY transgene would not be practicable without further technology.

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