Additive Versus Multiplicative Correction Factors for Weaning Weight in Beef Cattle

The effects of age at weaning, type of birth and rearing, age of dam and sex on weaning weight of lambs were investigated among 4876 Merino and 1221 Poll Dorset lambs over two years on 11 properties in Victoria. The regression coefficients of weaning weight on age at weaning varied considerably between properties. Lambs born and reared as twins were about 15 per cent lighter at weaning than single lambs, and lambs born as twins and reared as singles had about half the handicap. The average weaning weight of lambs increased with age of ewe up till five years and declined thereafter. Corrections to weaning weight for these effects are required for efficient selection. These corrections vary between years and properties. In most flocks there are inadequate numbers of sheep to determine accurate correction factors for each property each year and so standard corrections must be used.

Download Full-text

Genotype by environment interaction for post-weaning weight gain, scrotal circumference, and muscling score of composite beef cattle in different regions of Brazil

Genetics and Molecular Research ◽

10.4238/2014.april.17.1 ◽

2014 ◽

Vol 13 (2) ◽

pp. 3048-3059

Author(s):

M.L. Santana Jr. ◽

J.P. Eler ◽

F.F. Cardoso ◽

L.G. Albuquerque ◽

J.C.C. Balieiro ◽

...

Keyword(s):

Weight Gain ◽

Beef Cattle ◽

Genotype By Environment Interaction ◽

Environment Interaction ◽

Weaning Weight ◽

Genotype By Environment ◽

Scrotal Circumference

Download Full-text

Factors affecting growth traits of beef cattle breeds raised inSlovakia

Czech Journal of Animal Science ◽

10.17221/3990-cjas ◽

2011 ◽

Vol 50 (No. 1) ◽

pp. 14-21 ◽

Cited By ~ 6

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.  

Download Full-text

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

Genetics Selection Evolution ◽

10.1186/s12711-020-00584-0 ◽

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.

Download Full-text