scholarly journals Genetic parameter estimation for beef bull semen attributes

2021 ◽  
Vol 99 (2) ◽  
Author(s):  
Madison L Butler ◽  
Ashley R Hartman ◽  
Jennifer M Bormann ◽  
Robert L Weaber ◽  
David M Grieger ◽  
...  
Keyword(s):  
Fixed Effects ◽  
Genetic Parameter ◽  
Reproductive Technologies ◽  
Climate Index ◽  
Bull Semen ◽  
Scrotal Circumference ◽  
Covariate Effects ◽  
Semen Collection ◽  
Beef Bull ◽  
Heritability Estimates

Abstract Improvements in bull reproductive performance are necessary to optimize the efficiency of cattle production. Female fertility has been enhanced through assisted reproductive technologies as well as genetic selection; however, improving beef bull fertility has been largely ignored. Phenotypes routinely collected at bull semen collection facilities are believed to affect fertility and provide the phenotypes necessary for a genetic evaluation. The first objective of this study was to determine the significant fixed effects for modeling beef bull fertility using data from bull semen collection facilities. The second objective was to estimate variance components, heritabilities, repeatabilities, and correlations between beef bull semen attributes. Beef bull fertility phenotypes including volume (VOL), concentration (CONC), number of spermatozoa (NSP), initial motility (IMot), post-thaw motility (PTMot), 3-h post-thaw motility (3HRPTMot), percentage of normal spermatozoa (%NORM), primary abnormalities (PRIM), and secondary abnormalities (SEC) were obtained from two bull semen collection facilities. A total of 1,819 Angus bulls with 50,624 collection records were analyzed. Of the fixed class and covariate effects tested, the significant class effects were collection location and collection day within year and the significant covariate effects included age at collection, days since previous collection, and cumulative comprehensive climate index (CCI). For this study, the CCI was calculated for a 75-d period including the 61-d spermatogenesis cycle and 14-d epididymal transit time. The 75 d prior to collection accounted for the environmental stress a bull may have experienced over the course of development of the spermatozoa, which was more significant than the CCI calculated for collection day or spermatogenesis start date. Pre-thaw beef bull semen traits had low heritability estimates of 0.11 ± 0.02 (VOL), 0.09 ± 0.02 (CONC), 0.08 ± 0.02 (NSP), and 0.12 ± 0.03 (IMot). Heritabilities of post-thaw beef bull semen attributes were more variable at 0.10 ± 0.02 (PTMot), 0.05 ± 0.04 (3HRPTMot), 0.10 ± 0.04 (%NORM), 0.03 ± 0.03 (PRIM), and 0.18 ± 0.04 (SEC). Correlations of breeding values for these traits with scrotal circumference (SC) expected progeny difference (EPD) are low. The low to moderate heritability estimates indicate that genetic improvement can be made in beef bull semen quality traits if new tools are developed to augment the scrotal circumference EPD that are currently available within the industry.

scholarly journals 96 Estimation of the genetic parameters of beef bull semen attributes

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 26-26
Author(s):  
Madison L Butler ◽  
Jennifer M Bormann ◽  
Robert L Weaber ◽  
David M Grieger ◽  
Megan M Rolf
Keyword(s):  
Fixed Effects ◽  
Semen Quality ◽  
Critical Factor ◽  
Production Costs ◽  
Quality Traits ◽  
Forward Selection ◽  
Bull Semen ◽  
Scrotal Circumference ◽  
Beef Bull ◽  
Heritability Estimates

Abstract Fertility is a critical factor in cattle production because it directly relates to producing offspring to offset production costs. A number of semen attributes are believed to affect fertility and are frequently measured as part of routine breeding soundness exams or semen collection procedures. The objective of this study was to estimate the variance components for different semen quantity and quality traits that may influence fertility using phenotypes collected on 369 Simmental bulls. A total of 7,436 bull collection records including volume and concentration were obtained from two bull studs and evaluated utilizing a linear univariate animal model with repeated records. The five-generation pedigree used in the analysis consisted of 3,336 sires and 7,225 dams. Volume is the total amount of ejaculate and measured as milliliters of total ejaculate. Volume measurements ranged from 0.100 to 41.30 milliliters, with an average of 7.599 milliliters. Concentration is a measurement of millions of spermatozoa per milliliter. Concentration measurements ranged from 10 to 3,651 with an average of 1,053 million spermatozoa per milliliter. Fixed effects were included in the model if the effect was significant (P ≤ 0.05) for either backward or forward selection. Fixed effects included bull owner, collection center, location within center, collection day within year as a Julian day, collection year fit as class variables. Fixed effects fit as covariates included age of bull at collection (linear and quadratic), days since previous collection (linear and quadratic), and scrotal circumference (quadratic). Heritability estimates of volume and concentration were 0.43 ± 0.14 and 0.40 ± 0.15. These moderate heritability estimates indicate genetic improvement can be made in beef bull semen quality traits through selection.

PSIII-8 Genetic Parameter Estimates for Bull Prolificacy and Its Relationship with Scrotal Circumference in a Commercial Beef Cattle Population

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 158-159
Author(s):  
Chad A Russell ◽  
E J Pollak ◽  
Matthew L Spangler
Keyword(s):  
Beef Cattle ◽  
Breeding Season ◽  
Random Effects ◽  
Fixed Effects ◽  
Genetic Parameter ◽  
Additive Genetic Effect ◽  
Parameter Estimates ◽  
Contemporary Group ◽  
Scrotal Circumference ◽  
Heritability Estimates

Abstract The commercial beef cattle industry relies heavily on the use of natural service sires. Either due to the size of breeding herds or to safe-guard against injury during the breeding season, multiple-sire breeding pastures are utilized. Although each bull might be given an equal opportunity to produce offspring, evidence suggest that there is substantial variation in the number of calves sired by each bull in a breeding pasture. DNA-based paternity assignment enables correct assignment of calves to their respective sires in multi-sire pastures and presents an opportunity to investigate the degree to which this trait complex is under genetic control. Field data from a large commercial ranch were used to estimate genetic parameters for calf count (CC; n=623) and yearling scrotal circumference (SC; n=1962) using univariate and bivariate animal models. Average CC and SC were 12.1±11.1 calves and 35.4±2.30 cm, respectively. Average number breeding seasons per bull and bulls per contemporary group were 1.40 and 24.9, respectively. The model for CC included fixed effects of age during the breeding season (in years) and contemporary group (concatenation of breeding pasture and year). Random effects included additive genetic and permanent environmental effects, and a residual. The model for SC included fixed effects of age (in days) and contemporary group (concatenation of month and year of measurement). Random effects included an additive genetic effect and a residual. Univariate model heritability estimates for CC and SC were 0.237±0.156 and 0.456±0.072, respectively. Similarly, the bivariate model resulted in heritability estimates for CC and SC of 0.240±0.155 and 0.461±0.072, respectively. Repeatability estimates for CC from univariate and bivariate models were 0.517±0.054 and 0.518±0.053, respectively. The estimate of genetic correlation between CC and SC was 0.270±0.220. Parameter estimates suggest that both CC and SC would respond favorably to selection and that CC is moderately repeatable.

scholarly journals Genetic parameter estimates for bull prolificacy and its relationship with scrotal circumference in a commercial beef cattle population

2021 ◽  
Author(s):  
C A Russell ◽  
E J Pollak ◽  
M L Spangler
Keyword(s):  
Beef Cattle ◽  
Breeding Season ◽  
Random Effects ◽  
Fixed Effects ◽  
Genetic Parameter ◽  
Additive Genetic Effect ◽  
Parameter Estimates ◽  
Contemporary Group ◽  
Scrotal Circumference ◽  
Heritability Estimates

Abstract The commercial beef cattle industry relies heavily on the use of natural service sires. When artificial insemination is deemed difficult to implement, multi-sire breeding pastures are used to increase reproductive rates in large breeding herds or to safe-guard against bull injury during the breeding season. Although each bull might be given an equal opportunity to produce offspring, evidence suggest that there is substantial variation in the number of calves sired by each bull in a breeding pasture. With the use of DNA-based paternity testing, correctly assigning calves to their respective sires in multi-sire pastures is possible and presents an opportunity to investigate the degree to which this trait complex is under genetic control. Field data from a large commercial ranch was used to estimate genetic parameters for calf count (CC; 574 records from 443 sires) and yearling scrotal circumference (SC; n=1961) using univariate and bivariate animal models. Calf counts averaged 12.2±10.7 and SC averaged 35.4±2.30 cm. Bulls had an average of 1.30 records and there were 23.9±11.1 bulls per contemporary group. The model for CC included fixed effects of age during the breeding season (in years) and contemporary group (concatenation of breeding pasture and year). Random effects included additive genetic and permanent environmental effects, and a residual. The model for SC included fixed effects of age (in days) and contemporary group (concatenation of month and year of measurement). Random effects included an additive genetic effect and a residual. Univariate model heritability estimates for CC and SC were 0.178±0.142 and 0.455±0.072, respectively. Similarly, the bivariate model resulted in heritability estimates for CC and SC of 0.184±0.142 and 0.457±0.072, respectively. Repeatability estimates for CC from univariate and bivariate models were 0.315±0.080 and 0.317±0.080, respectively. The estimate of genetic correlation between CC and SC was 0.268±0.274. Heritability estimates suggest that both CC and SC would respond favorably to selection. Moreover, CC is lowly repeatable and although favorably correlated, SC appears to be weakly associated with CC.

scholarly journals 37 Genetic parameter estimates for days on feed, age at slaughter, and carcass traits in a multi-breed beef cattle population

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 21-22
Author(s):  
Lindsay R Upperman ◽  
Larry A Kuehn ◽  
Matthew L Spangler
Keyword(s):  
Fixed Effects ◽  
Phenotypic Variability ◽  
Genetic Parameter ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Live Weight ◽  
Experimental Treatment ◽  
Parameter Estimates ◽  
Marbling Score ◽  
Heritability Estimates

Abstract The objective of this study was to estimate genetic parameters for days on feed (DOF), age at slaughter (AAS), and their relationships with carcass traits, including: marbling score (MARB), adjusted fat thickness (AFT), hot carcass weight (HCW), ribeye area (REA), and final live weight (FW). Data were from steers and heifers (n = 7,747) from the Germplasm Evaluation Program at the U.S. Meat Animal Research Center. All traits were analyzed with univariate and bivariate animal models using ASReml. Fixed effects fitted for all models included contemporary group (concatenation of birth year and season, sex, and experimental treatment group), breed fractions, and direct heterosis. Different endpoints were also investigated by fitting fixed linear covariates of AFT, HCW, REA, MARB, FW, and age (except AAS and DOF). For a given bivariate analyses, both traits were adjusted to the same endpoint. Univariate heritability estimates for AFT, AAS, DOF, FW, HCW, MARB, and REA ranged from 0.45–0.52, 0.52–0.59, 0.33–0.39, 0.34–0.55, 0.34–0.55, 0.54–0.55, and 0.50–0.56, respectively. Covariates of MARB and AFT led to the highest and lowest, respectively, heritability estimates for AAS and DOF. Depending on the endpoint, genetic correlations between AAS and AFT, FW, HCW, MARB, and REA ranged from 0.16 to 0.32, -0.08 to 0.33, 0.19 to 0.36, 0.14 to 0.20, and -0.06 to 0.13 (Table 1). Genetic correlations between DOF and AFT, MARB, and REA were negligible. Genetic correlations between DOF, FW, and HCW ranged from -0.10 to 0.29 and -0.37 to -0.17. Standard errors were less than 0.07 for all estimates. Phenotypic variability in DOF was low, and increased variability in AAS was due to differences in date of birth and thus weaning age. Results indicate DOF and AAS are moderately to highly heritable and generally lowly correlated with routine carcass traits. The USDA is an equal opportunity employer.

HERITABILITY OF SCROTAL CIRCUMFERENCE IN ONE- AND TWO-YEAR-OLD BULLS OF DIFFERENT BEEF BREEDS

1987 ◽  
Vol 67 (3) ◽  
pp. 645-651 ◽  
Author(s):  
G. H. COULTER ◽  
G. C. KOZUB ◽  
D. R. C. BAILEY ◽  
R. J. MAPLETOFT ◽  
W. F. CATES
Keyword(s):  
Statistical Model ◽  
Key Words ◽  
Fixed Effects ◽  
Performance Test ◽  
Age Groups ◽  
Scrotal Circumference ◽  
Sources Of Variation ◽  
Testicular Size ◽  
Heritability Estimates ◽  
Beef Bulls

Over an 8-yr interval, (1975–1982) scrotal circumference (SC) was measured on 4557 1-yr-old beef bulls from 1796 sires and eight breeds. Measurements were taken upon completion of a 140-d growth performance test. During the period 1977–1983, SC was measured on 7835 2-yr-old beef bulls from 2570 sires and six breeds. Two-year-old bulls were measured during reproductive examinations at spring bull sales. All SC measurements were adjusted for fixed effects of location-year and age, and heritability estimates were calculated within-breed using a paternal half-sib analysis. Heritability estimates for the SC trait in Angus, Charolais, horned Hereford, polled Hereford, Shorthorn, Simmental, Limousin and Maine-Anjou breeds in 1-yr-old bulls were 0.22 ± 0.20, 0.46 ± 0.14, 0.89 ± 0.17, 0.83 ± 0.26, 1.01 ± 0.31, 0.63 ± 0.19, 0.94 ± 0.29 and 0.59 ± 0.22. Heritability estimates for SC in 2-yr-old bulls of the first six breeds were 0.00 ± 0.21, 0.60 ± 0.25, 0.57 ± 0.07, 0.65 ± 0.10, 0.69 ± 0.34 and 0.20 ± 0.24. Owing to the small number of sires or sons within sires for some breed-age groups and the exclusion of some sources of variation in the statistical model, the estimates of heritability may not be precise and should be used to indicate approximate levels of heritability for a particular breed. Key words: Heritability, testicular size, scrotal circumference, beef bulls

scholarly journals Genetic parameter of birth and weaning weights for Friesian calves by using an animal model

2005 ◽  
Vol 48 (3) ◽  
pp. 261-269 ◽  
Author(s):  
H. Atil ◽  
A. S. Khattab ◽  
L. Badawy
Keyword(s):  
Animal Model ◽  
Birth Weight ◽  
Fixed Effects ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Likelihood Method ◽  
Multiple Trait ◽  
Breeding Values ◽  
Heritability Estimates ◽  
Maternal Heritability

Abstract. Birth and weaning weights of 556 Friesian calves by 41 sires out of 318 different dams over a 11 years period were obtained from a herd of Friesian in Sakha Experimental Farm, Ministry of Agriculture, Egypt were used. The records were analyzed by Multiple Trait Likelihood Method (MTDFREML) by using a repeatability animal model (BOLDMAN et al., 1995). Convergence was attained after 699 iterations. The fixed effects included in the model were season and year of calving, parity and sex and the random effects were direct and maternal genetic, permanent maternal environmental and error. Direct heritability estimates for birth weight (BW) and weaning weight (WW) are 0.28 and 0.13, respectively, while, maternal heritability estimates for the same traits are 0.14 and 0.06, respectively. Repeatability estimates are 0.75 and 0.15 for BW and WW, respectively. Phenotypic and genetic correlations are 0.89 and 0.80, respectively. Estimates of calve breeding values ranged from −3.12 to 4.11 kg for BW and ranged from −4.10 to 5.11 kg for WW. Sire breeding values ranged from −3.40 to 2.99 kg for BW and ranged from −2.50 to 4.47 kg for WW. Dam breeding values ranged from −6.80 to 5.54 kg for BW and ranged from -6.10 to 6.39 kg for WW.

scholarly journals Realized Sampling Variances of Estimates of Genetic Parameters and the Difference Between Genetic and Phenotypic Correlations

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1409-1416 ◽  
Author(s):  
Kenneth R Koots ◽  
John P Gibson
Keyword(s):  
Genetic Correlation ◽  
Genetic Parameters ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Phenotypic Correlation ◽  
Parameter Estimates ◽  
Sampling Variance ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Heritability Estimates

Abstract A data set of 1572 heritability estimates and 1015 pairs of genetic and phenotypic correlation estimates, constructed from a survey of published beef cattle genetic parameter estimates, provided a rare opportunity to study realized sampling variances of genetic parameter estimates. The distribution of both heritability estimates and genetic correlation estimates, when plotted against estimated accuracy, was consistent with random error variance being some three times the sampling variance predicted from standard formulae. This result was consistent with the observation that the variance of estimates of heritabilities and genetic correlations between populations were about four times the predicted sampling variance, suggesting few real differences in genetic parameters between populations. Except where there was a strong biological or statistical expectation of a difference, there was little evidence for differences between genetic and phenotypic correlations for most trait combinations or for differences in genetic correlations between populations. These results suggest that, even for controlled populations, estimating genetic parameters specific to a given population is less useful than commonly believed. A serendipitous discovery was that, in the standard formula for theoretical standard error of a genetic correlation estimate, the heritabilities refer to the estimated values and not, as seems generally assumed, the true population values.

The Use of Beef Bull Semen Reduced the Risk of Abortion in Neospora-seropositive Dairy Cows

2005 ◽  
Vol 52 (2) ◽  
pp. 88-92 ◽  
Author(s):  
F. Lopez-Gatius ◽  
P. Santolaria ◽  
J. L. Yaniz ◽  
J. M. Garbayo ◽  
S. Almeria
Keyword(s):  
Dairy Cows ◽  
Bull Semen ◽  
Beef Bull

Genetic parameter estimates (full sib and half sib analysis) of fertility and hatchability in two strains of Rhode Island chickens

2021 ◽  
Vol 38 (1) ◽  
pp. 14-22
Author(s):  
M. Orunmuyi ◽  
I. A. Adeyinka ◽  
O.O Oni
Keyword(s):  
Rhode Island ◽  
Additive Genetic Variance ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Parameter Estimates ◽  
Phenotypic Correlations ◽  
Poultry Breeding ◽  
Genetic And Phenotypic Correlations ◽  
Heritability Estimates

A study was conducted to estimate the genetic parameters of fertility and hatchability in two strains of Rhode Island Red (RIR) Chickens denoted as Strain A and Strain B respectively using the full-sib (sire +dam variance) and maternal half-sib (dam variance) components. The birds were obtained from the selected populations of RIR Chickens kept at the poultry breeding programme of National Animal Production Research Institute, Shika, Zaria, Nigeria. Settable eggs were collected from mating 28 cocks to 252 hens in a ratio of 1cock:9 hens from each strain. Eggs were pedigreed according to sire and dam. Results showed that values obtained for number of egg set (EGGSET), number of fertile eggs (NFERT), number of hatched chicks (NHATCH), percentage of chicks hatched from total eggs set (PHATCH) and percentage of chicks hatched from fertile eggs (PHATCHBL) were all higher in strain A than strain B. Heritability estimates obtained from the full-sib and maternal half-sib analysis ranged from medium to high for the two strains (0.24-0.96). The maternal half sib estimates were higher (0.40-0.96) than the estimates obtained from full sibs (0.24- 0.48). Genetic and phenotypic correlations obtained for both strains were positive and similar regardless of method of estimation. Genetic correlations between EGGSET and PFERT were low in strain A using both full-sib and maternal half-sib analyses (0.09-0.14). Phenotypic correlations between EGGSET and PFERT, PHATCH and PHATCHBL were also low in both strains and regardless of method of analyses. Moderate to high heritability estimates suggest that genetic improvement can be obtained by selection of these reproductive traits. The full-sib analysis for estimating heritability will be preferred since it is assumed that only additive genetic variance contributes to the covariance between family members.

Twins Studies in Economics

2015 ◽  
pp. 384-404 ◽  
Author(s):  
Jere Behrman
Keyword(s):  
Fixed Effects ◽  
Family Background ◽  
Variance Decomposition ◽  
Common Environment ◽  
Genetic Sequencing ◽  
Investment In Children ◽  
Heritability Estimates ◽  
Mz Twins

This chapter describes strengths and limitations of three twins methods developed in economics: control for unobserved genetic and family background endowments using monozygotic (MZ) twins fixed effects (FE) to estimate e.g. impacts of schooling on wages, health, and other outcomes; estimation of key parameters in intrafamilial models of investment in children using MZ and dizygotic (DZ) twins; and investigation of familial responses to fertility shocks within the quantity-quality fertility model using MZs and DZs. It also describes strengths and limitations of a fourth twins method used most widely outside of economics: variance decomposition of phenotypes into genetic and environmental components to obtain heritability estimates with additive genetics, common environment and unique environment (ACE) models using MZs and DZs. The chapter concludes that the first three twins methods remain valuable for learning about important empirical parameters in economics despite development of genetic sequencing. The fourth method is less useful in economics.

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