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

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

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

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

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

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

GENETIC PARAMETERS OF THE MATERNAL GRANDSIRE CONTRIBUTION TO BEEF CATTLE WEANING WEIGHTS

1982 ◽  
Vol 62 (4) ◽  
pp. 1057-1062
Author(s):  
G. H. CROW ◽  
W. E. HOWELL
Keyword(s):  
Beef Cattle ◽  
Key Words ◽  
Variance Components ◽  
Genetic Parameters ◽  
Mixed Model ◽  
Genetic Effects ◽  
Performance Data ◽  
Maternal Influence ◽  
Weaning Weight ◽  
Maternal Grandsire

Genetic aspects of maternal influence on weaning weights in beef cattle were examined using analyses within breed and parity of dam (first, second, third and fourth and greater parities) of Angus, Charolais and Hereford Record of Performance data. A mixed model which included herd-year and maternal grandsire (MGS) was used. The data were adjusted for calf sex within breed and parity of dam prior to analysis. The heritability of dam influence on her offspring weaning weight averaged 0.23 for first parity data of the three breeds. Heritability for second and third parities of the three breeds were lower than this but averaged 0.16 in parity four and greater. MGSs contributed significantly to variation in weaning weights. Their contribution, however, is a composite of both direct and maternal genetic effects. Key words: Beef cattle, weaning weight, maternal, variance components, heritability

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
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