Genetic changes in ruminants: Historic trends and future prospects

2000 ◽  
Vol 27 ◽  
pp. 29-38
Author(s):  
Brian McGuirk
Keyword(s):  
Beef Cattle ◽  
Disease Incidence ◽  
Dairy Industry ◽  
Progeny Testing ◽  
Production Traits ◽  
Genetic Progress ◽  
Genetic Changes ◽  
Frozen Semen ◽  
Type Traits ◽  
Cattle And Sheep

AbstractThe major ruminant species, dairy and beef cattle and sheep, represent a rather heterogeneous group as regards genetic improvement, which to a large extent reflects their respective breeding structures. In the UK, the beef cattle and sheep industries still span many different breeds, have small herds/flocks, and have been relatively unaffected by agribusiness investment, and are assumed to have a traditional pyramid breeding structure, in which progress is determined by a small number of breeders. Recording of production information, which to date has focussed on terminal sire characteristics, is relatively recent, and until the use of across herd evaluations, genetic progress was probably limited. However in recent years there have been gains in both growth and muscling. There is little evidence or concern for undesired consequences in commercial flocks, partly because of the extensive use of crossbreeding in these industries, which exploits both breed complementarity and heterosis.By contrast, the dairy industry is now dominated by purebred Holsteins. Increasingly breeding activities are both global in scope and dominated by a small number of large breeding companies. Because most traits of interest are only expressed in the female, improvement programmes have continued to focus on progeny testing, with test daughters in many herds. Most recording schemes and promotional activities emphasise production and type traits. The dairy industry is also notable for the publication of bull progeny test results, so that top bulls can then be used as sires of the next generation of by all companies. These bull evaluations now extend to international rankings.Data from the US indicates continuing genetic progress for production traits in the Holstein, particularly since the 1960s, by when progeny testing had been established, frozen semen widely used, and adequate statistical procedures in place for evaluating bulls. Genetic progress is also evident for type traits. There is now growing concern and evidence of undesirable genetic changes in fertility, disease incidence and overall stress, despite improved nutrition and general management. Altering this situation will require both the recording of such traits and the use of that information by breeding companies, especially in sire selection.

Genetic and phenotypic trends and parameters in reproduction, greasy fleece weight and liveweight in Merino lines divergently selected for multiple rearing ability

2004 ◽  
Vol 44 (8) ◽  
pp. 745 ◽  
Author(s):  
S. W. P. Cloete ◽  
A. R. Gilmour ◽  
J. J. Olivier ◽  
J. B. van Wyk
Keyword(s):  
Genetic Correlations ◽  
Annual Production ◽  
Production Traits ◽  
Genetic Progress ◽  
Additive Variance ◽  
Genetic Changes ◽  
Environmental Correlations ◽  
Breeding Values ◽  
Reproduction Traits ◽  
Fleece Weight

Genetic and phenotypic trends and parameters were estimated for reproduction, fleece weight and liveweight in a South African Merino population, divergently selected from 1986, either for (H line) or against (L line) maternal multiple rearing ability. Annual reproduction, ewe greasy fleece weight and pre-joining liveweight data were recorded on 809 Merino ewes, from 1986 to 2002. Phenotypic trends indicated divergence in reproduction traits between the H and L lines. The direct additive variance ratio (h2 ± s.e.) for day of lambing was 0.08 ± 0.02. Estimates of h2 for reproduction traits were: 0.10 ± 0.02 for number of lambs born per ewe; 0.04 ± 0.02 for number of lambs weaned per ewe; and 0.04 ± 0.02 for weight of lamb weaned per ewe, corrected for the gender of the lamb. Corresponding h2 estimates for annual production were 0.57 ± 0.06 for greasy fleece weight and 0.48 ± 0.06 for ewe liveweight at joining. Service sire only exerted a significant (P<0.05) effect on day of lambing, but it accounted for merely 2% of the overall phenotypic variation. Ewe permanent environment variance ratios (c2ewe) for the reproduction traits were: 0.07 ± 0.03 for number of lambs born per ewe; 0.11 ± 0.03 for number of lambs weaned per ewe; and 0.11 ± 0.03 for total weight of lamb weaned per ewe. Corresponding c2ewe estimates for annual production traits were 0.14 ± 0.05 for greasy fleece weight and 0.27 ± 0.06 for ewe joining weight. Genetic and ewe permanent environmental correlations between measures of reproduction exceeded 0.7. Genetic correlations of reproduction traits with greasy fleece weight were low and variable in sign. Genetic correlations of reproduction traits with ewe joining weight were positive and particularly high for weight of lamb weaned. Permanent environmental correlations of reproduction traits with greasy fleece weight and joining weight were generally low to moderate. Genetic trends for the H and L lines (derived from averaged direct breeding values within birth years) were divergent (P<0.01) for all reproduction traits. Expressed as percentage of the overall least squares means of the respective traits, breeding values in the H line increased annually, with 1.3% for lambs born per ewe, 1.5% for lambs weaned per ewe and by 1.8% for weight of lamb weaned per ewe. Corresponding trends in the L line were, respectively, –0.6%, –1.0% and –1.2% per year. Substantial genetic progress in annual lamb output was attainable, despite relatively small h2 estimates. This response was achieved without unfavourable genetic changes in wool and liveweight.

Embryo manipulation in cattle breeding and production

1989 ◽  
Vol 48 (1) ◽  
pp. 3-30 ◽  
Author(s):  
J. A. Woolliams ◽  
I. Wilmut
Keyword(s):  
Gene Transfer ◽  
Beef Cattle ◽  
Embryo Transfer ◽  
Nuclear Transfer ◽  
Progeny Testing ◽  
Genetic Progress ◽  
Embryo Recovery ◽  
Multiple Ovulation ◽  
The Impact

ABSTRACTDevelopments, both recent and potential, in procedures for manipulating embryos are described. The procedures considered include: embryo transfer, multiple ovulation and embryo recovery, recovery of oocytes, in vitro maturation (IVM) and fertilization (IVF) of oocytes, in vitro culture of zygotes, embryo splitting and nuclear transfer, embryo storage, embryo sexing, gene transfer and embryo stem cells. The impact of these procedures on breeding strategies such as multiple ovulation and embryo transfer (MOET) nucleus breeding schemes and progeny testing are discussed for both dairy and beef cattle.For MOET nucleus schemes all these procedures have potential applications in producing maximal rates of genetic progress for a fixed rate of inbreeding. With the current effectiveness of the procedures, embryo sexing and nuclear transfer would have the most impact. The potential for increasing genetic progress through progeny testing is enhanced using multiple ovulation, embryo recovery and transfer in cows to breed bulls, but no other procedures appeared to offer major benefits. The efficiency of beef production from the dairy herd could be increased either by using IVM and IVF to produce more beef-type calves or, potentially, by cloning and embryo transfer, to produce pure beef calves. Procedures leading to the production of clone families would make an impact on the evaluation of genotypes and environments. Gene transfer may be used to modify the composition of milk including the production of pharmaceutical proteins, and to increase milk yield or the efficiency of lean meat production.It is concluded that, although much further research is required, the procedures discussed will have major implications for the structure and organization of dairy and beef cattle herds over the next decade.

scholarly journals PSIII-12 Peripheral blood parameters as proxies of performance in beef cattle: Heritability and genetic correlations between peripheral blood parameters and performance phenotypes

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 163-164
Author(s):  
Josue Chinchilla-Vargas ◽  
Luke M Kramer ◽  
John D Tucker ◽  
Donald S Hubbell ◽  
Jeremy G Powell ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Peripheral Blood ◽  
High Performance ◽  
Disease Incidence ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Blood Parameters ◽  
Production Traits ◽  
Blood Samples ◽  
Cell Parameters

Abstract Disease incidence and feed costs are two main drivers in cattle production operations. Frequently environmental stressors such as fescue toxicosis have negative effects on livestock performance and health. Low-cost methods to measure these types of health and stress response phenotypes are needed to capture their impact on production traits. Previous research has correlated white blood cell parameters to disease resistance in beef cattle. Based on this, blood parameters at weaning may be candidates that could be a proxy for selection and identification of high-performance animals in commercial settings. To identify candidate blood parameters, blood samples were collected at weaning on approximately 500 crossbred animals (Angus background crossed with Hereford, Charolais, Sim-Angus, Brangus) born between 2015 and 2016 and raised on toxic fescue. The animals were also genotyped at an approximate density of 50,000 SNPs. Complete blood counts (CBC) were obtained the blood samples and heritabilities for 15 peripheral blood parameters were estimated. For the CBC traits that were measured, heritabilities ranged from low to moderate (0.02 to 0.35). Based on current findings, a substantial genetic component for some CBC parameters exists and selection could be effective at improving these traits. Further research will estimate genetic correlations between peripheral blood parameters, weaning weight and average daily gain (ADG) with the intention of identifying correlated traits to be used in commercial selection programs.

scholarly journals Genetic trends for production and non-production traits in Simmental breed in Slovenia

2007 ◽  
Vol 23 (5-6-1) ◽  
pp. 47-53
Author(s):  
K. Potocnik ◽  
M. Stepec ◽  
J. Krsnik
Keyword(s):  
Milk Production ◽  
Milk Production Trait ◽  
Production Traits ◽  
Genetic Trend ◽  
Genetic Progress ◽  
Genetic Changes ◽  
Economic Weight ◽  
Selection Of ◽  
Total Selection ◽  
Genetic Trends

The main part of Slovenian Simmental breed is selected for milk production. Genetic changes in a population should be checked in the case of selection on more traits at the same time. The estimation of genetic trend is the best tool to follow genetic changes in a population. In this paper we present the estimated genetic trends for traits with high economic weight in total selection of Slovenian Simmental breed. Results show that the greatest genetic progress was attained for milk production trait and conformation traits for udder. In other traits not so high genetic progress was attained. In the case of muscularity significant negative genetic progress was attained in the last 12 years.

scholarly journals Genomic Analysis, Progress and Future Perspectives in Dairy Cattle Selection: A Review

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 599
Author(s):  
Miguel A. Gutierrez-Reinoso ◽  
Pedro M. Aponte ◽  
Manuel Garcia-Herreros
Keyword(s):  
Dairy Cattle ◽  
Production Efficiency ◽  
Association Studies ◽  
Phenotypic Traits ◽  
Progeny Testing ◽  
Genome Wide Association Studies ◽  
Genetic Progress ◽  
Breeding Programs ◽  
Increased Risk ◽  
Selection Of

Genomics comprises a set of current and valuable technologies implemented as selection tools in dairy cattle commercial breeding programs. The intensive progeny testing for production and reproductive traits based on genomic breeding values (GEBVs) has been crucial to increasing dairy cattle productivity. The knowledge of key genes and haplotypes, including their regulation mechanisms, as markers for productivity traits, may improve the strategies on the present and future for dairy cattle selection. Genome-wide association studies (GWAS) such as quantitative trait loci (QTL), single nucleotide polymorphisms (SNPs), or single-step genomic best linear unbiased prediction (ssGBLUP) methods have already been included in global dairy programs for the estimation of marker-assisted selection-derived effects. The increase in genetic progress based on genomic predicting accuracy has also contributed to the understanding of genetic effects in dairy cattle offspring. However, the crossing within inbred-lines critically increased homozygosis with accumulated negative effects of inbreeding like a decline in reproductive performance. Thus, inaccurate-biased estimations based on empirical-conventional models of dairy production systems face an increased risk of providing suboptimal results derived from errors in the selection of candidates of high genetic merit-based just on low-heritability phenotypic traits. This extends the generation intervals and increases costs due to the significant reduction of genetic gains. The remarkable progress of genomic prediction increases the accurate selection of superior candidates. The scope of the present review is to summarize and discuss the advances and challenges of genomic tools for dairy cattle selection for optimizing breeding programs and controlling negative inbreeding depression effects on productivity and consequently, achieving economic-effective advances in food production efficiency. Particular attention is given to the potential genomic selection-derived results to facilitate precision management on modern dairy farms, including an overview of novel genome editing methodologies as perspectives toward the future.

scholarly journals Candidate genes for production traits in Nelore beef cattle

2012 ◽  
Vol 11 (4) ◽  
pp. 4138-4144 ◽  
Author(s):  
P.C. Tizioto ◽  
S.L. Meirelles ◽  
R.R. Tulio ◽  
A.N. Rosa ◽  
M.M. Alencar ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Candidate Genes ◽  
Production Traits

The incorporation of fertility indices in genetic improvement programmes

2001 ◽  
Vol 26 (1) ◽  
pp. 237-249 ◽  
Author(s):  
J.E. Pryce ◽  
R.F. Veerkamp
Keyword(s):  
Genetic Variance ◽  
Selection Index ◽  
Genetic Correlations ◽  
Live Weight ◽  
Parameter Estimates ◽  
Phenotypic Variance ◽  
Production Traits ◽  
Genetic Progress ◽  
Detection Rates ◽  
Days Open

AbstractIn recent years there has been considerable genetic progress in milk production. Yet, increases in yield have been accompanied by an apparent lengthening of calving intervals, days open, days to first heat and a decline in conception rates, which appears to be both at the genetic and phenotypic level. Fertility has a high relative economic value compared to production traits such as protein, making it attractive to include in a breeding programme. To do this there needs to be genetic variance in fertility. Measures of fertility calculated from service dates have a small genetic compared to phenotypic variance, hence heritability estimates are small, typically less than 5%, although coefficients of genetic variance are comparable to those of production traits. Heritabilities of commencement of luteal activity determined using progesterone profiles are generally higher, and have been reported as being from 0.16 to 0.28, which could be because of a more precise quantification of genetic variance, as management influences such as delaying insemination and heat detection rates are excluded. However, it might not be the use of progesterone profiles alone, as days to first heat observed by farm staff has a heritability of 0.15. The most efficient way to breed for improved fertility is to construct a selection index using the genetic and phenotypic parameter estimates of all traits of interest in addition to their respective economic values. Index traits for fertility could include measures such as calving interval, days open, days to first service, or days to first heat but there may also be alternative measures. Examples include traits related to energy balance, such as live weight and condition score (change), both of which have higher heritabilities than fertility measures and have genetic correlations of sufficient magnitude to make genetic progress by using them feasible. To redress the balance between fertility and production, some countries already publish genetic evaluations of fertility including: Denmark, Finland, France, Germany, Israel, The Netherlands, Norway and Sweden.

scholarly journals Combining multi-OMICs information to identify key-regulator genes for pleiotropic effect on fertility and production traits in beef cattle

PLoS ONE ◽  
2018 ◽  
Vol 13 (10) ◽  
pp. e0205295 ◽  
Author(s):  
Pablo Augusto de Souza Fonseca ◽  
Samir Id-Lahoucine ◽  
Antonio Reverter ◽  
Juan F. Medrano ◽  
Marina S. Fortes ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Pleiotropic Effect ◽  
Production Traits ◽  
Regulator Genes

scholarly journals Phenotypic characteristics of linear traits of udder and angularity in Holstein-Friesian cows and their correlation with milk yield traits

2020 ◽  
Vol 36 (4) ◽  
pp. 407-416
Author(s):  
Radica Djedovic ◽  
Vladan Bogdanovic ◽  
Dragan Stanojevic ◽  
Hasan Ismael ◽  
Dobrila Jankovic ◽  
...  
Keyword(s):  
Milk Yield ◽  
Phenotypic Variability ◽  
Phenotypic Correlation ◽  
Progeny Testing ◽  
Multiple Traits ◽  
Linear Type ◽  
Data Set ◽  
Holstein Friesian ◽  
Type Traits ◽  
Important Trait

Data set including 10860 primiparous Holstein-Friesian breed cows first calved in the period from 2011 to 2015, was used in determining phenotypic variability and correlation between the traits of milk yield and linearly estimated traits of udder and angularity. The average values obtained for type traits (angularity, fore udder attachment, front teats placement, teats length, udder depth and rear udder height) were 6.47; 5.74; 4.96; 5.20; 5.99 and 6.25, respectively. The values obtained for phenotypic correlations between linear type traits and traits of milk yield ranged from -0.042 (udder depth and milk yield) to 0.335 (fore udder attachment and protein yield). Positive phenotypic correlation (0.293) was recorded also between fore udder attachment and milk yield which is deemed the most important trait of milk yield while the lowest correlation between milk yields was determined in relation to udder depth (-0.033). The results obtained indicate a possibility of applying direct and indirect multiple traits selection which should be conducted within a national progeny-testing programme on Holstein-Friesian bulls by using the method of selection indexes.

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