COMPARISON OF PHENOTYPIC VARIATION WITHIN PATERNAL HALF SIB FAMILIES FOR WEANING WEIGHT IN A PUREBRED AND A SYNTHETIC BEEF CATTLE POPULATION

1990 ◽  
Vol 70 (2) ◽  
pp. 703-706
Author(s):  
M. F. LIU ◽  
M. MAKARECHIAN
Keyword(s):  
Beef Cattle ◽  
Phenotypic Variation ◽  
Error Variance ◽  
Weaning Weight ◽  
Common Error ◽  
Sire Model ◽  
Synthetic Populations ◽  
Sib Families ◽  
Different Origins ◽  
Two Populations

Records of 1487 adjusted weaning weights expressed as deviations from year means in a multibreed Beef Synthetic and a purebred Hereford population raised and managed together under the same selection program from 1968 to 1978 were used to examine the behavior of the phenotypic variation within sire families in the two populations and to further test the conventional common error variance assumption imposed on a sire model. The results indicated that on the average there was no difference in the phenotypic variation within sire families between the purebred and the synthetic populations. Within-sire standard deviations in the two populations were also normally and similarly distributed. Within-sire variances were not heterogeneous. The results suggested that the conventional common error variance assumption imposed on a sire model would be a reasonable approximation applicable to the two populations of different origins. Key words: Beef cattle, variation among half-sibs, weaning weight

Comparison of genetic and phenotypic parameters in a purebred and a synthetic beef cattle population

1991 ◽  
Vol 71 (2) ◽  
pp. 279-285 ◽  
Author(s):  
M. F. Liu ◽  
M. Makarechian ◽  
R. T. Berg
Keyword(s):  
Growth Rate ◽  
Birth Weight ◽  
Beef Cattle ◽  
Variance Components ◽  
Growth Traits ◽  
Cattle Population ◽  
Coefficients Of Variation ◽  
Sib Families ◽  
Phenotypic Variations ◽  
Two Populations

Genetic and phenotypic parameters of growth traits from birth to 1 year of age were compared in a multibreed Beef Synthetic (SY) and a purebred Hereford (HE) population managed together under the same environmental conditions and selected for growth rate from 1961 to 1979. Growth traits studied were birth weight, preweaning and postweaning gains. Records of 2077 calves of 70 HE and 100 SY paternal half-sib families were used for analysis. Except for birth weight, phenotypic variances of growth traits were similar for the synthetic (SY) and purebred (HE) populations, but genetic variances were larger in SY than in HE for all growth traits except postweaning gain in males. The coefficients of variation were comparable for all the traits studied in the two populations, indicating that phenotypic variations in the multibreed population and the purebred population were similar. Key words: Variance components, heritability, beef cattle

SEX OF CALF AND AGE OF DAM ADJUSTMENTS FOR SOME PERFORMANCE TRAITS IN TWO POPULATIONS OF BEEF CATTLE

1982 ◽  
Vol 62 (3) ◽  
pp. 699-708 ◽  
Author(s):  
A. K. SHARMA ◽  
L. WILLMS ◽  
R. T. HARDIN ◽  
R. T. BERG
Keyword(s):  
Birth Weight ◽  
Beef Cattle ◽  
Least Squares ◽  
Key Words ◽  
Weaning Weight ◽  
Adjustment Factors ◽  
Main Effects ◽  
Two Populations ◽  
Age And Sex ◽  
Methods Of Application

Sex of calf and age of dam effects on birth weight, preweaning ADG, 180-day weaning weight; and age of dam effects on yearling weight, postweaning ADG in males, and 18-mo weight in females were studied in a Hereford and a beef Synthetic population. The effects of breed, sex of calf, age of dam and year were significant on preweaning traits. The superior milking ability of Synthetic cows over Herefords was more pronounced for male than female calves. Additive and multiplicative adjustment factors were calculated from the least squares analyses. Additive adjustments for age of dam and multiplicative adjustments for sex of calf were found most suitable for preweaning traits. Three methods of application of adjustment factors were studied. Multiplicative sex of calf adjustment followed by additive age of dam adjustment was found to be most effective as indicated by the reductions in mean squares for main effects and interactions. Additive and multiplicative age of dam factors are presented for yearling weight in males and 18-mo weight in females. Use of additive factors is recommended. Extending weaning weight age of dam adjustments for postweaning traits was not found suitable in this study. Key words: Beef cattle, age and sex, adjustment factors

scholarly journals Genetic differences between populations of Drosophila melanogaster for a quantitative trait: I. Laboratory populations

1973 ◽  
Vol 22 (1) ◽  
pp. 51-68 ◽  
Author(s):  
C. López-Fanjul ◽  
W. G. Hill
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Frequency ◽  
Total Response ◽  
Selected Lines ◽  
Synthetic Populations ◽  
Bristle Number ◽  
Laboratory Populations ◽  
Selection For ◽  
Different Origins ◽  
Two Populations

SUMMARYAn experiment was carried out to test whether two laboratory cage populations of Drosophila melanogaster from different origins (Kaduna and Pacific) differed in the genes for sternopleural bristle number. The means, variances and heritabilities of the two populations and the synthetic formed from crosses between them were very similar.Selection for low bristle number was practised in small replicate lines, six of each pure population and nine of the synthetic. On average, Pacific responded to selection rather more rapidly than either Kaduna or the synthetic, but there was little difference in the limit achieved.Crosses between replicates within populations were made and selection continued, and these lines subsequently crossed between populations and reselected. Additional response was obtained by this procedure but the crosses between the replicates of the pure and synthetic populations attained similar selection limits.An analysis of effects of individual chromosomes from the selected lines on bristle number indicated that the contribution of each chromosome to total response was about the same in Pacific, Kaduna and the synthetic.It is concluded that differences in gene frequency, rather than the presence or absence of particular alleles, are mainly responsible for the differences observed between the populations.

Sire × herd interactions for weaning weight in beef cattle

1992 ◽  
Vol 70 (8) ◽  
pp. 2359-2365 ◽  
Author(s):  
D. R. Notter ◽  
B. Tier ◽  
K. Meyer
Keyword(s):  
Beef Cattle ◽  
Weaning Weight

Genetic variation of the weaning weight of beef cattle as a function of accumulated heat stress

2015 ◽  
Vol 133 (2) ◽  
pp. 92-104 ◽  
Author(s):  
M.L. Santana ◽  
A.B. Bignardi ◽  
J.P. Eler ◽  
J.B.S. Ferraz
Keyword(s):  
Genetic Variation ◽  
Heat Stress ◽  
Beef Cattle ◽  
Weaning Weight

scholarly journals Factors affecting growth traits of beef cattle breeds raised inSlovakia

2011 ◽  
Vol 50 (No. 1) ◽  
pp. 14-21 ◽  
Author(s):  
E. Krupa ◽  
M. Oravcová ◽  
P. Polák ◽  
J. Huba ◽  
Z. Krupová
Keyword(s):  
Birth Weight ◽  
Beef Cattle ◽  
Least Squares ◽  
Linear Model ◽  
Growth Traits ◽  
General Linear Model ◽  
Weaning Weight ◽  
Factors Affecting ◽  
Sex Effect ◽  
Beef Cattle Breeds

Growth traits of purebred calves of six beef breeds (Aberdeen Angus – AA, Blonde d’Aquitaine – BA, Charolais – CH,Hereford – HE, Limousine – LI and Beef Simmental – BS) born from 1998 to 2002 were analysed. Traits under study were birth weight (BW), weight at 120 days (W120), weight at 210 days – weaning weight (WW), weight at 365 days – yearling weight (YW) and average daily gains from birth to 120 days (ADG1), from birth to 210 days (ADG2), from birth to 365 days (ADG3), from 120 to 210 days (ADG4). General linear model with class effects of breed, dam’s age at calving, sex, herd-year-season (HYS) and covariation of age at weighing was used for analyses. All effects significantly affected both weight and gain traits except for dam’s age that was significant for BW, W120, YW and ADG3, and age at weighing that was significant for W120, WW, YW, ADG2, ADG3, ADG4. Estimated least squares means of growth traits were compared using Scheffe’s multiple-range tests. Highest BW (40.57 kg) and W120 (172.43 kg) were found for BA calves. BS calves had highest WW (260.30 kg), YW (424.07 kg), ADG1 (1 154 g), ADG2 (1 053 g), ADG3 (1 054 g) and ADG4 (1 098 g). Highest BW, YW, ADG3 and ADG4 were found for males-singles. Males-twins had highest W120, WW, ADG1 and ADG2. Calves descending from 5–7 years old dams had highest BW, W120, WW, ADG1, ADG2 and ADG4. The proportion of variability of growth traits explained by HYS effect (42.96–71.69%) was high, whereas proportions of variability explained by SEX effect (2.03–5.77%), age of dam (1.02–2.24%) and breed (1.05–2.21%) were low. Residuals accounted for 23.71 up to 53.79% of total variance.  

scholarly journals Development of a genetic evaluation for hair shedding in American Angus cattle to improve thermotolerance

2020 ◽  
Vol 52 (1) ◽  
Author(s):  
Harly J. Durbin ◽  
Duc Lu ◽  
Helen Yampara-Iquise ◽  
Stephen P. Miller ◽  
Jared E. Decker
Keyword(s):  
Heat Stress ◽  
Beef Cattle ◽  
Tall Fescue ◽  
The United States ◽  
Genetic Evaluation ◽  
Functional Enrichment ◽  
Fescue Toxicosis ◽  
Weaning Weight ◽  
Angus Cattle ◽  
Genetic Evaluations

Abstract Background Heat stress and fescue toxicosis caused by ingesting tall fescue infected with the endophytic fungus Epichloë coenophiala represent two of the most prevalent stressors to beef cattle in the United States and cost the beef industry millions of dollars each year. The rate at which a beef cow sheds her winter coat early in the summer is an indicator of adaptation to heat and an economically relevant trait in temperate or subtropical parts of the world. Furthermore, research suggests that early-summer hair shedding may reflect tolerance to fescue toxicosis, since vasoconstriction induced by fescue toxicosis limits the ability of an animal to shed its winter coat. Both heat stress and fescue toxicosis reduce profitability partly via indirect maternal effects on calf weaning weight. Here, we developed parameters for routine genetic evaluation of hair shedding score in American Angus cattle, and identified genomic loci associated with variation in hair shedding score via genome-wide association analysis (GWAA). Results Hair shedding score was moderately heritable (h2 = 0.34 to 0.40), with different repeatability estimates between cattle grazing versus not grazing endophyte-infected tall fescue. Our results suggest modestly negative genetic and phenotypic correlations between a dam’s hair shedding score (lower score is earlier shedding) and the weaning weight of her calf, which is one metric of performance. Together, these results indicate that economic gains can be made by using hair shedding score breeding values to select for heat-tolerant cattle. GWAA identified 176 variants significant at FDR < 0.05. Functional enrichment analyses using genes that were located within 50 kb of these variants identified pathways involved in keratin formation, prolactin signalling, host-virus interaction, and other biological processes. Conclusions This work contributes to a continuing trend in the development of genetic evaluations for environmental adaptation. Our results will aid beef cattle producers in selecting more sustainable and climate-adapted cattle, as well as enable the development of similar routine genetic evaluations in other breeds.

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