Genetic trends for weaning weight during development of a multibreed population of beef cattle in two contrasting environments

2000 ◽  
Vol 80 (1) ◽  
pp. 191-193
Author(s):  
J. J. Tosh ◽  
R. A. Kemp
Keyword(s):  
Natural Selection ◽  
Beef Cattle ◽  
Key Words ◽  
Genetic Component ◽  
Weaning Weight ◽  
Common Base ◽  
The Difference ◽  
Selection Differentials ◽  
Genetic Trends

Genetic trends for weaning weight were determined in two herds of multibreed beef cattle that originated from a common base and were subject to mutual breeding policies in separate environments. The herds diverged for the direct though not the maternal genetic component of weaning weight within the 13-yr period examined; in the final year, the difference (P < 0.001) between the herds was almost 3 kg. This could have been partly due to unequal selection differentials and generation intervals. Results suggested the extent of natural selection also differed between the two environments. Key words: Beef cattle, crossbreeding, genetic trends, selection, weaning weight

EFFECTS OF YEARLING WEIGHT SELECTION IN SHORTHORN BEEF CATTLE ON AGE-OF-DAM ADJUSTMENT FACTORS

1990 ◽  
Vol 70 (3) ◽  
pp. 963-965
Author(s):  
J. C. OLTHOFF ◽  
G. H. CROW ◽  
G. W. RAHNEFELD
Keyword(s):  
Birth Weight ◽  
Beef Cattle ◽  
Key Words ◽  
Selection Line ◽  
Weaning Weight ◽  
Performance Change ◽  
Adjustment Factors ◽  
Over Time

Lines within a breed which differ in their level of performance may require different age-of-dam adjustment factors in the same way that different breeds do. Age-of-dam adjustments calculated from a control and a yearling weight selection line indicated lower values in the selected line for calf birth weight, weaning weight and yearling weight for 2- and 4-yr-old dams. Trends for adjustment factors in each line over time were generally not significant but tended to diverge. Age-of-dam adjustment factors within a breed may need to be reevaluated at intervals as levels of performance change. Key words: Beef cattle, age of dam adjustment, selection, yearling weight

A comparison of methods to evaluate beef cow productivity

1993 ◽  
Vol 73 (4) ◽  
pp. 971-975 ◽  
Author(s):  
G. W. Rahnefeld ◽  
Doug Ward ◽  
G. M. Weiss
Keyword(s):  
Beef Cattle ◽  
Key Words ◽  
Comparison Of Methods ◽  
Weaning Weight ◽  
Beef Cow

The following were compared as measures of cow productivity: (A) calf weaning weight per mating opportunity; (B) calf weaning weight per mating opportunity with cow weight at weaning as a covariate; (C) calf weaning weight per mating opportunity per unit of cow weight at weaning; and (D) calf weaning weight per mating opportunity per cow metabolic weight (kg0.75) at weaning. Results indicate that the method described under (C) is best at reducing error followed closely by the method described under (D). The least satisfactory measure of cow productivity was (B). Key words: Beef cattle, cow efficiency, productivity

Machine effects on accuracy of ultrasonic prediction of backfat and ribeye area in beef bulls, steers and heifers

2000 ◽  
Vol 80 (1) ◽  
pp. 19-24 ◽  
Author(s):  
P. K. Charagu ◽  
D. H. Crews Jr. ◽  
R. A. Kemp ◽  
P. B. Mwansa
Keyword(s):  
Beef Cattle ◽  
Key Words ◽  
Standard Error ◽  
Important Relationship ◽  
Ribeye Area ◽  
Beef Bulls ◽  
The Difference

Pre-slaughter ultrasound and carcass measurements of ribeye area (REA) and backfat (FAT) were recorded on composite beef bulls (n = 60), heifers (n = 60) and steers (n = 60). Breed composition of the composite was: 0.44 British (Hereford, Angus and Shorthorn) 0.25 Charolais, 0.25 Simmental and 0.06 Limousin. The Aloka SSD-1100 (AL) and the Tokyo Keiki CS 3000 (TK) ultrasound machines were compared by evaluating the difference between ultrasound and carcass measurements (bias), and the standard error of prediction (SEP). AL under-predicted REA in all three sexes while TK overpredicted heifers and steers and underpredicted bulls. Both machines were similar in accuracy among bulls for REA. For FAT AL underpredicted all three sexes while TK underpredicted heifers and had very small bias for bulls and steers. SEP for FAT were similar for both machines. Both machines underpredicted REA in larger muscled cattle and overpredicted in smaller-muscled cattle. Both machines also underpredicted FAT in fatter animals and overpredicted FAT in leaner animals. Machines were similar in accuracy among cattle with larger REA but differed significantly (P < 0.05) among smaller-muscled cattle. Machines were comparable in accuracy among animals of all FAT sizes. This study demonstrates that there is an important relationship between machine and the size and depth of muscle and backfat, respectively, and consequently between machine and sex, in accuracy of ultrasound prediction. Key words: Beef cattle, ultrasound, accuracy, back fat, ribeye area

scholarly journals INFLUENCE OF CALF GENETIC TYPE ON PREWEANING TRAITS UNDER COMMERCIAL BEEF CATTLE CONDITIONS

1982 ◽  
Vol 62 (1) ◽  
pp. 287-290
Author(s):  
D. K. AARON ◽  
F. A. THRIFT
Keyword(s):  
Birth Weight ◽  
Beef Cattle ◽  
Key Words ◽  
Genetic Type ◽  
Weaning Weight ◽  
Genetic Types ◽  
Weight Data

Birth and weaning weight data were evaluated on 1/2 Simmental (SH, SA), 1/2 Maine-Anjou (MH, MA), 3/4 Simmental (S.SH, S.SA) and 3/4 Maine-Anjou (M.MH, M.MA) calves. For birth weight, 1/2 Simmental calves were lighter (P < 0.01) than 1/2 Maine-Anjou calves, and calves from Hereford cows were heavier (P < 0.01) than calves from Angus cows. Also, S.SH calves were heavier (P < 0.01) than S.SA calves. For weaning weight, 3/4 Simmental calves were heavier (P < 0.01) than 3/4 Maine-Anjou calves, and 1/2 Simmental and Maine-Anjou calves were lighter (P < 0.01) than 3/4 Simmental and Maine-Anjou calves. Key words: Calf genetic types, grading-up, beef cattle

Differences in production and type trait selection differentials between bulls used in official and owner/sampler dairy herds

1992 ◽  
Vol 72 (4) ◽  
pp. 783-789
Author(s):  
T. P. Brown ◽  
R. I. Cue
Keyword(s):  
Key Words ◽  
Dairy Herd ◽  
Dairy Herds ◽  
Production Traits ◽  
Selection Differential ◽  
The Difference ◽  
Student’S T ◽  
Selection Differentials ◽  
Student’S T Test ◽  
General Appearance

Differences in the emphasis placed on type and production traits between bulls used in official herds and those used in owner/sampler (O/S) herds registered at the Quebec Dairy Herd Analysis Service were calculated. For 543 881 Holsteins and 41 955 Ayrshires, service records (containing the cow and service sire identification and the service sire's production and type proofs) were used to calculate selection differentials (SD) for the bulls used in official and O/S herds for each 6-mo period between 1980 and 1983. An SD was calculated as the difference between a bull's proofs in a service record and the average proof of all bulls available in the same period. Selection differential means and variances were calculated within each herd, and the average and variance of these means were determined for each 6-mo period. Differences in SD between bulls used in official and O/S herds were determined using the Student's t-test for differences between means. Within Holsteins, SD for final class, general appearance, fore udder, rear udder, size and stature of bulls used in official herds were significantly higher in O/S herds. Within Ayrshires, no significant differences in type-trait SD were found because a very small number of prominent bulls were used extensively throughout both official and O/S Ayrshire herds. Although not significant, in all periods production trait SD tended to be higher for bulls used in O/S herds than for bulls used in official herds for both Holsteins and Ayrshires. Key words: Dairy cattle, bull selection, official, owner/sampler

The effect of castration age, method and implant regime on growth and carcass traits of male beef cattle

1991 ◽  
Vol 71 (2) ◽  
pp. 301-309 ◽  
Author(s):  
R. D. H. Cohen ◽  
B. D. King ◽  
H. H. Nicholson ◽  
E. D. Janzen
Keyword(s):  
Beef Cattle ◽  
Key Words ◽  
Carcass Traits ◽  
Carcass Characteristics ◽  
Carcass Weight ◽  
Feedlot Performance ◽  
Weaning Weight ◽  
Growing Period

In 1984–1985 and 1985–1986 groups of 136 and 127 male calves were used to assess the effects of multiple implants (Ralgro and Steeroid), castration time (early and late) and castration method (surgical and chemical) on growth to weaning and feedlot performance and carcass characteristics. Ralgro increased calf rate of gain to weaning (P < 0.05) and adjusted weaning weight (P < 0.01) but did not affect rate of gain during the feedlot period. Although Ralgro increased (P < 0.001) weight at slaughter, it took longer (P < 0.05) for implanted cattle to reach Canada A1 than unimplanted cattle. Steeroid did not affect rate of gain to weaning but did increase (P < 0.05) adjusted weaning weight. Steeroid increased (P < 0.05) rate of gain relative to unimplanted cattle during the growing period in the feedlot and cattle implanted four times from birth to slaughter gained more (P < 0.05) than cattle implanted twice (birth and weaning). For the entire feedlot period, bulls receiving Steeroid gained faster (P < 0.05) than unimplanted bulls with no difference (P > 0.05) between implant groups (two or four implants). Ralgro implants increased (P < 0.05) carcass weight, rib-eye area and cutability while Steeroid increased (P < 0.05) only carcass weight. However, when rib-eye area was adjusted for carcass weight, the effect of Ralgro was not significant (P > 0.05). Bulls had greater (P < 0.05) shipping weight, carcass weight, rib-eye area, dressing percent and cutability than steers. Age at castration (early or late) had no effect on feedlot performance or carcass traits while method of castration (surgical or chemical) had some effects (P < 0.05) on ADG, liveweight, carcass weight and rib-eye area. Key words: Castration, Ralgro, Steeroid, beef, growth, carcass

35 Detecting Effective Starting Point of Genomic Selection by Divergent Trends from BLUP and ssGBLUP

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 19-19
Author(s):  
Rostam Abdollahi-Arpanahi ◽  
Daniela Lourenco ◽  
Ignacy Misztal
Keyword(s):  
Birth Weight ◽  
Beef Cattle ◽  
Genomic Selection ◽  
Single Step ◽  
Weaning Weight ◽  
Start Date ◽  
Angus Cattle ◽  
Starting Point ◽  
Essential Question ◽  
Genetic Trends

Abstract Genomic selection has been adopted nationally and internationally in different livestock and plant species. However, understanding whether genomic selection has been effective or not is an essential question for both industry and academia. Once genomic evaluation started being used, estimation of breeding values with pedigree BLUP became biased because this method does not consider selection using genomic information. Hence, the point of divergence of genetic trends obtained with BLUP and Single-step genomic BLUP (ssGBLUP) may indicate the start date of genomic selection. This study aimed to find the start date of genomic selection for a set of economically important traits in pigs and Angus cattle by comparing genetic and Realized Mendelian sampling (RMS) trends obtained using BLUP and ssGBLUP. In pigs, the genetic trends from ssGBLUP and BLUP diverged for all traits with different intensity. In beef cattle, the trends started diverging in 2009 for weaning weight and in 2016 for postweaning gain, with little divergence for birth weight. In pigs, the RMS trends from ssGBLUP and BLUP diverged strongly for one trait and weakly for another trait. In beef cattle, the RMS trends started diverging in 2009 for weaning weight and in 2016 for postweaning gain, with little trend for birth weight. Divergence of the genetic trends from ssGBLUP and BLUP indicate onset of the genomic selection. Presence of trends for RMS indicates selective genotyping, with or without the genomic selection. The onset of genomic selection and genotyping strategies agree with industry practices across the two species. In summary, the effective start of genomic selection can be detected by the divergence between genetic and RMS trends from BLUP and ssGBLUP.

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 AN APPRAISAL OF SELECTION IN THE ROMNELET SHEEP

1961 ◽  
Vol 41 (2) ◽  
pp. 205-211
Author(s):  
H. F. Peters ◽  
S. B. Slen ◽  
H. J. Hargrave
Keyword(s):  
Birth Weight ◽  
Selection Pressure ◽  
Upward Trend ◽  
Weaning Weight ◽  
Selection For ◽  
Fleece Weight ◽  
One Year ◽  
Selection Differentials ◽  
Made In ◽  
Genetic Trends

The amounts of selection for birth weight, weaning weight, post-weaning gain up to about 1 year of age and yearling clean fleece weight in the development of the Romnelet breed of sheep are reported.The selection differentials for weaning weight only were statistically significant (P < 0.05) for both sexes. Analyses of regression of mean differential on time showed an upward trend in the differentials for birth weight and weaning weight, but there was no evidence of significant yearly trend in the differentials for post-weaning traits. Trends in selection pressure were consistent with the reported genetic trends in performance after the initial decline in performance from F1 to F2.Weaning weight received more attention in selection than any other trait studied, and the most genetic improvement was made in this trait. The large reduction in numbers of animals available for selection from birth to one year of age, due mainly to heavy culling of lambs at weaning, brought about a reduction in selection intensity from 22 per cent to 10 per cent for post-weaning gain and from 42.5 to 22 per cent for clean fleece weight.

scholarly journals Detecting effective starting point of genomic selection by divergent trends from BLUP and ssGBLUP in pigs, beef cattle, and broilers

2021 ◽  
Author(s):  
Rostam Abdollahi Arpanahi ◽  
Daniela Lourenco ◽  
Ignacy Misztal
Keyword(s):  
Birth Weight ◽  
Beef Cattle ◽  
Genomic Selection ◽  
Broiler Chickens ◽  
Average Daily Gain ◽  
Breeding Cycle ◽  
Production Traits ◽  
Weaning Weight ◽  
Daily Gain ◽  
Genetic Trends

Genomic selection has been adopted nationally and internationally in different livestock and plant species. However, understanding whether genomic selection has been effective or not is an essential question for both industry and academia. Once genomic evaluation started being used, estimation of breeding values with pedigree BLUP became biased because this method does not consider selection using genomic information. Hence, the effective start point of genomic selection can be detected in two possible ways including the divergence of genetic trends and Realized Mendelian sampling (RMS) trends obtained with BLUP and Single-step genomic BLUP (ssGBLUP). This study aimed to find the start date of genomic selection for a set of economically important traits in three livestock species by comparing trends obtained using BLUP and ssGBLUP. For this purpose, three datasets comprised a pig dataset with 117k genotypes and 1.3M animals in pedigree, Angus cattle dataset consisted of ~842k genotypes and 11.5M animals in pedigree, and a purebred broiler chicken dataset included ~154k genotypes and 1.3M birds in pedigree were used. The genetic trends for pigs diverged for the genotyped animals born in 2014 for average daily gain and backfat. In beef cattle, the trends started diverging in 2009 for weaning weight and in 2016 for postweaning gain, with little diverging for birth weight. In broiler chickens, the genetic trends estimated by ssGBLUP and BLUP diverged at breeding cycle 6 for two out of three production traits. The RMS trends for the genotyped pigs diverged for animals born in 2014, more for average daily gain than for backfat. In beef cattle, the RMS trends started diverging in 2009 for weaning weight and in 2016 for postweaning gain, with a trivial trend for birth weight. In broiler chickens, the RMS trends from ssGBLUP and BLUP diverged strongly for two production traits at breeding cycle 6, with a slight divergence for another trait. Divergence of the genetic trends from ssGBLUP and BLUP indicates onset of the genomic selection. Presence of trends for RMS indicates selective genotyping, with or without the genomic selection. The onset of genomic selection and genotyping strategies agree with industry practices across the 3 species. In summary, the effective start of genomic selection can be detected by the divergence between genetic and RMS trends from BLUP and ssGBLUP.

Sign in / Sign up

Export Citation Format

Share Document