Performance of Hereford and crossbred Hereford cattle in the subtropics of New South Wales: genetic analyses of pre-weaning performance of first-cross calves

1980 ◽  
Vol 31 (2) ◽  
pp. 417 ◽  
Author(s):  
R Barlow ◽  
GH O'Neill
Keyword(s):  
Birth Weight ◽  
Genetic Correlations ◽  
Environmental Variation ◽  
Direct Selection ◽  
Gestation Length ◽  
Strongly Correlated ◽  
Weaning Weight ◽  
Selection For ◽  
Sire Breed ◽  
Size At Birth

First-cross calves of Simmental (S), Friesian (F), and Brahman (B) sires were compared with straight-bred calves of Hereford (H) sires over 5 years at Grafton, N.S.W. There was a total of 775 calves sired by 205 bulls with complete records of performance from conception to weaning. Analyses were conducted to determine sire breed and sire breed x environment effects, and to provide paternal half-sib estimates of heritabilities and genetic and phenotypic correlations. Various models were used to ascertain the sensitivity of genetic parameters to the removal of different sources of variation. Among females, S x H were heaviest at birth, while among males, B x H were heaviest. The regression coefficient of birth weight on gestation length was significantly greater for B x H calves than for other crosses. All crosses grew significantly faster to weaning and were significantly heavier at weaning than H x H calves. However, there were a number of significant interactions between sire breed and environmental variables for measures of pre-weaning growth. S x H and F x H calves appeared most sensitive to environmental variation, while B x H appeared least sensitive. The significance of this is discussed. Estimates of heritability for most traits were high. Values derived by using simple models were: gestation length, 0.68; birth weight, 0.56; average daily gain (ADG) to weaning, 0.47; weaning weight, 0.54; eyelid pigmentation, 0.50. Heritabilities of birth weight and ADG during the early pre-weaning period appeared most sensitive to the amount of environmental variation removed in the model. Gestation length was positively correlated with size at birth but negatively correlated with growth to weaning. There were large positive genetic correlations among various measures of size at birth, and among various measures of growth to weaning. When compared with ADG to weaning, weaning weight was more strongly correlated with birth weight, but less strongly correlated with gestation length. The results also indicated that selection for gain over a fixed time period, immediately prior to weaning, would be as efficient as direct selection for total ADG to weaning.

Estimates of genetic parameters for pre-weaning and post-weaning growth traits of Chios lambs

1980 ◽  
Vol 30 (2) ◽  
pp. 271-276 ◽  
Author(s):  
A. P. Mavrogenis ◽  
A. Louca ◽  
O. W. Robison
Keyword(s):  
Body Weight ◽  
Birth Weight ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Heritability Estimate ◽  
Weaning Weight ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Daily Gain

ABSTRACTData on 792 Chios lambs born during the 1972/73 and 1973/74 lambing seasons were used to estimate genetic and phenotypic parameters for birth weight, weaning weight, age at weaning, pre-weaning daily gain, body weight at 5, 10, 15 and 20 weeks of age, and postweaning daily gain. Body weight at 15 weeks of age had the highest heritability estimate (0·73 ± 0·17) and that of post-weaning daily gain was also high (0·56 ± 0·15). Selection for either weight at 15 weeks or post-weaning daily gain would be expected to yield a greater response than selection for pre-weaning daily gain or weaning weight. Genetic correlations among weights and/or gains were positive (approximately 0·20). Phenotypic correlations among weights and gains were generally higher than genetic correlations. However, the correlation between pre— and post-weaning daily gain was small (0·08). Likewise, post-weaning daily gain had low correlations with all weights before 10 weeks. Age at weaning had moderate negative associations with all weights but a very low positive correlation with post-weaning daily gain.

MASS SELECTION FOR POST-WEANING GROWTH IN SWINE. V. CORRELATED RESPONSE OF REPRODUCTIVE TRAITS AND PRE-WEANING GROWTH

1976 ◽  
Vol 56 (4) ◽  
pp. 791-801
Author(s):  
I. GARNETT ◽  
G. W. RAHNEFELD
Keyword(s):  
Birth Weight ◽  
Average Daily Gain ◽  
Reproductive Traits ◽  
Correlated Response ◽  
Mass Selection ◽  
Gestation Length ◽  
Control Line ◽  
Weaning Weight ◽  
Selection For ◽  
Daily Gain

Female reproductive performance and pre-weaning survival and growth were examined in a population of swine over 11 generations of selection for post-weaning average daily gain (ADG). Three separate breeding groups were used: (1) a Lacombe (L) line selected each generation for ADG, (2) a Yorkshire control (Y) line, and (3) a crossbred Lacombe × Yorkshire group (LY) generated each generation from the L and Y lines. Breeding group differences were evident for litter size, perinatal mortality, pre-weaning mortality, gestation length, birth weight, pre-weaning average daily gain (PreADG) and weaning weight. Selection did not affect number born, number born alive, number weaned or birth weight. When the values for the L line were expressed as a deviation from the control, pre-weaning mortality showed an increase. The increase appeared to be due to a decrease in the control rather than an increase in the L line. Gestation length showed a negative response to selection. As in the case of pre-weaning mortality, the response appeared to be a reflection of the instability of the control line. Genetic gains in PreADG of 0.004 kg/day/generation were realized in both the L line and LY group. Correspondingly, responses of 0.18 and 0.19 kg/generation were realized for weaning weight in the L line and LY group.

Selection for cow lifetime pregnancy rate using bull and heifer growth and reproductive traits in composite cattle

2000 ◽  
Vol 80 (3) ◽  
pp. 507-510 ◽  
Author(s):  
P. B. Mwansa ◽  
R. A. Kemp ◽  
D. H. Crews Jr ◽  
J. P. Kastelic ◽  
D. R. C. Bailey ◽  
...  
Keyword(s):  
Birth Weight ◽  
Key Words ◽  
Pregnancy Rate ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Genetic Change ◽  
Direct Selection ◽  
Scrotal Circumference ◽  
Selection For

Genetic correlations of lifetime pregnancy rate with bull and heifer growth and reproductive traits in a beef composite population were estimated. Yearling scrotal circumference had an unfavorable genetic correlation (rg = −0.25) while yearling tonometer score was favorably related (rg = 0.22) to lifetime pregnancy rate. Heifer pregnancy rate, birth weight, weaning weight, yearling weight and age at puberty in heifers had significant genetic correlations (rg = 0.97, 0.58, 0.57, 0.33 and −0.21, respectively) with lifetime pregnancy rate. Lifetime pregnancy rate may be successfully predicted by easy-to-measure heifer growth traits. Using indices including scrotal and heifer growth traits, annual genetic change in lifetime pregnancy rate may be increased 3.1 times compared with direct selection. Key words: Scrotal circumference, tonometer, pregnancy, reproduction, puberty

Lamb production from diverse genotypes. 1. Lamb growth and survival and ewe performance

2000 ◽  
Vol 70 (1) ◽  
pp. 135-145 ◽  
Author(s):  
N. M. Fogarty ◽  
D. L. Hopkins ◽  
R. van de Ven
Keyword(s):  
Birth Weight ◽  
Gestation Length ◽  
Weaning Weight ◽  
Growth And Survival ◽  
Frozen Semen ◽  
Lamb Survival ◽  
Lamb Growth ◽  
Sire Breed ◽  
Selection Of ◽  
Birth Type

AbstractGrowth and survival of 3673 female and cryptorchid lambs representing the range of types (second cross, first cross and Merino) produced in the Australian lamb industry are reported. The lambs were sired by a selection of Poll Dorset (D; no. = 7), Texel (T; no. = 10), Border Leicester (BL; no. = 12) and Merino (M; no. = 12) rams and born to Border Leicester × Merino (BLM) and Merino (M) dams, which resulted in six lamb genotypes (D×BLM, T×BLM, D×M, T×M, BL×M and M×M). The second cross lambs (D×BLM, T×BLM) were heavier at birth, weaning and post-weaning and had higher growth rates, than first cross lambs (D×M, T×M, BL×M), which were higher than M×M lambs (P< 0·01). For post-weaning weight (cryptorchids at 156 days) second cross lambs were 4·2 (s.e. 0·3) kg heavier than comparable sired first cross lambs, with the BL×M 2·6 (s.e. 0·5) kg lighter than other first cross types and the MxM a further 4·2 (s.e. 0·6) kg lighter. The average advantage of D over T crosses was 1·0 kg for post-weaning weight, with greater variation amongst individual sires.Lamb survival to weaning was 76% and it was affected by birth weight and birth type (P< 0·01). Sire breed had no significant effect on lamb survival, whereas lambs from BLM ewes had higher survival than those from M ewes (P< 0·01).Overall the proportion of ewes lambing was 84% with a mean litter size of 1·77. There was no difference infertility between AI (thawed frozen semen and laparoscopic insemination) and natural (single sire) mating, although the M were higher than the BLM ewes (P< 0·01). Gestation length was 2·3 days shorter (P< 0·01) for BLM than M ewes and there was no difference between D and T sire breeds. There was little effect of birth type on gestation length but it increased with birth weight within birth type categories. Between year repeatability of gestation length for ewes was 0·33 (s.e. 0·05).

scholarly journals Genetic Analysis Of Rabbit Litter Traits At Birth And Weaning

2021 ◽  
Vol 19 ◽  
pp. 64-69
Author(s):  
I. K Odubote ◽  
B. Somade
Keyword(s):  
Birth Weight ◽  
Genetic Analysis ◽  
Litter Size ◽  
Weaning Weight ◽  
Litter Weight ◽  
Phenotypic Correlations ◽  
Litter Traits ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
Size At Birth

Data on 260 litters were used to provide therefore to estimate the heritability and estimates of heritability, repeatability, genetic and phenotypic correlations for litter traits at birth and at weaning. Breed, sire within breed and doe within sire effects were found to be significant, (P<0.05) for litter size at birth and at weaning and for litter weight at birth and at weaning. Heritability estimates of 0.33±0.08, 0.38±0.02, 0.03±0.02 and 0.16±0.05 were obtained for litter birth weight, litter size at birth, litter size at weaning and litter weaning weight, respectively. Repeatability estimates were found to be generally moderate to high. Genetic and phenotypic correlations were positive and significant (P<0.01). Selection for litter size at birth and litter birth weight are likely to result in improved litter size at weaning and litter weaning weight respectively.

scholarly journals Differential response from selection for high calving ease vs. low birth weight in American Simmental beef cattle

2020 ◽  
Vol 98 (7) ◽  
Author(s):  
Hamad M Saad ◽  
Milton G Thomas ◽  
Scott E Speidel ◽  
Richard K Peel ◽  
W Marshall Frasier ◽  
...  
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Selection Index ◽  
Differential Response ◽  
Direct Selection ◽  
Weaning Weight ◽  
Calving Ease ◽  
Selection For ◽  
Maternal Grandsire ◽  
Genetic Trends

Abstract Data on calving ease (CE) and birth, weaning weight (WW), and yearling weight (YW) were obtained from the American Simmental Association (ASA) and included pedigree and performance information on 11,640,735 animals. Our objective was to quantify differential response from selection for high CE vs. low birth weight (LBW) in first-calf Simmental heifers. We hypothesized that direct selection for CE should be used as the primary approach to reduce dystocia and mitigate losses in growth-related traits. WW and YW were adjusted to 205 and 365 d of age, respectively. Sire and maternal grandsire (co)variance components for CE, birth weight (BW), and 205-d weaning weight (205-d WW), and sire covariance components for 160-d postweaning gain (160-d gain) were estimated using a sire-maternal grandsire model. Direct and maternal expected progeny differences (EPD) for CE, BW, and 205-d WW and direct EPD for 160-d gain and 365-d yearling weight (365-d YW) for first-calf Simmental heifers population (465,710 animals) were estimated using a threshold-linear multivariate maternal animal model. This population was used to estimate genetic trends and as a selection pool (control) for various selection scenarios. Selection scenarios were high CE (HCE), LBW, the all-purpose selection index (API = −1.8 BW + 1.3 CE + 0.10 WW + 0.20 YW) of the ASA and its two derived subindices: (API1 = 1.3 CE + 0.20 YW) and (API2 = −1.8 BW + 0.20 YW), and lastly Dickerson’s selection index (DSI = −3.2 BW + YW). Data for each selection scenario were created by selecting sires with EPD greater than or equal to the average along with the top 75% of dams. Comparison between selection scenarios involved evaluating the direct and maternal genetic trends from these scenarios. Direct heritabilities for CE, BW, 205-d WW, 160-d gain, and 365-d YW of Simmental cattle were 0.23, 0.52, 0.28, 0.21, and 0.33, respectively. The single trait, HCE, selection scenario, as opposed to LBW, increased the intercept for CE by 57.7% and the slopes (P &lt; 0.001) for BW, 205-d WW, 160-d gain, and 365-d YW by 27.9%, 37.5%, 16%, and 28%, respectively. Comparisons of various selection scenarios revealed that the CE-based selection scenarios (HCE, API, and API1) had a greater response for CE and growth traits.

Bayesian analysis of selection for greater weaning weight while maintaining birth weight in beef cattle

2009 ◽  
Vol 87 (10) ◽  
pp. 3089-3096 ◽  
Author(s):  
L. M. Melucci ◽  
A. N. Birchmeier ◽  
E. P. Cappa ◽  
R. J. C. Cantet
Keyword(s):  
Birth Weight ◽  
Beef Cattle ◽  
Bayesian Analysis ◽  
Weaning Weight ◽  
Selection For

Opportunities for genetic improvement of lamb survival

2010 ◽  
Vol 50 (12) ◽  
pp. 1017 ◽  
Author(s):  
F. D. Brien ◽  
M. L. Hebart ◽  
D. H. Smith ◽  
J. E. Hocking Edwards ◽  
J. C. Greeff ◽  
...  
Keyword(s):  
Rectal Temperature ◽  
Selection Index ◽  
Genetic Correlations ◽  
Direct Selection ◽  
Reproduction Rate ◽  
Crown Rump Length ◽  
Selection For ◽  
Lamb Survival ◽  
Net Reproduction ◽  
Birth Time

Data on lamb survival and associated traits involving records from 15 192 lambs, 6308 dams and 284 sires from the Sheep CRC’s Information Nucleus were studied. Lamb survival to 3 days of age and to weaning was 85 and 80%, respectively, and heritability (±s.e.) was 0.014 ± 0.010 and 0.010 ± 0.010, respectively. Of the 14 traits recorded at birth, time taken for the lamb to bleat, rectal temperature and crown–rump length had the highest genetic correlations with lamb survival to weaning (–0.43 ± 0.32, 0.56 ± 0.33 and –0.38 ± 0.36, respectively). Under selection for a multi-trait objective including net reproduction rate (but not lamb survival), survival was predicted to decline genetically by 0.25 lambs weaned per 100 lambs born.year, although this was reversed to a gain of 0.20 lambs weaned per 100 lambs born.year by including the trait in the breeding objective and using 50 half-sib and 50 progeny records per selection candidate. Accuracy of selection for lamb survival was improved to 0.735 with a selection index of lamb survival to weaning, lamb ease, birth coat score, time taken to bleat, rectal temperature and crown–rump length, with the addition of 50 half-sibs and 50 progeny records per candidate. Our results suggest that unless actively incorporated into breeding objectives, lamb survival may genetically decline; however, gains are possible with direct selection using half-sib and progeny records. The addition of indirect selection criteria for lamb survival can further improve accuracy, up to 93.4%, but requires further investigation.

The role of selection in the improvement of Welsh Mountain sheep

1958 ◽  
Vol 9 (6) ◽  
pp. 819 ◽  
Author(s):  
JM Doney
Keyword(s):  
Birth Weight ◽  
Maternal Environment ◽  
Weaning Weight ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Heritability Estimates ◽  
Fleece Weight ◽  
Staple Length

Means and variances of several economic characters in Welsh Mountain sheep are given. The repeatabilities of, and phenotypic correlations between, these characters are generally within the range of similar estimates given for other breeds. Heritabilities, calculated from parent-offspring correlations, were : birth weight 0.39, weaning weight 0.68, 18-month weight 0.59, greasy fleece weight 0.61, and staple length 0.73. These values are in general higher than similarly derived estimates from other breeds. A method of correcting heritability estimates to remove the error due to correlation between maternal environment, and the character as measured in the dam, is described. This reduces the estimate for weaning weight to 0.48, and that for 18-month weight to 0.16, but does not change that for fleece weight. The use of such estimates in predicting the effect of selection is discussed, and it is concluded that accurate selection for the chosen economic characters will result in improvement at the present genetic stage of the breed.

ESTIMATES OF GENETIC CORRELATIONS AMONG CERTAIN CARCASS AND PERFORMANCE TRAITS IN SWINE

1968 ◽  
Vol 48 (1) ◽  
pp. 1-6 ◽  
Author(s):  
G. L. Roy ◽  
W. J. Boylan ◽  
M. E. Seale
Keyword(s):  
Birth Weight ◽  
Genetic Correlation ◽  
Genetic Relationships ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Development Project ◽  
Carcass Trait ◽  
Selection For ◽  
And Performance ◽  
Daily Gain

Data from a swine breed development project provided estimates of the genetic correlation among six performance and carcass traits. The data from the new breed, called Managra, were obtained over a 7-year period. Most genetic relationships examined were such that selection for improvement of one trait would yield a favorable improvement in another. Both carcass backfat and live backfat probe were found to be negatively correlated with area of loin eye and length of carcass. A positive genetic correlation was found between post-weaning daily gain and loin eye area. A high positive genetic correlation was found between birth weight and loin eye area. An unfavorable association involved a positive genetic correlation between birth weight and backfat.Correction factors for effect of carcass weight on the magnitude of carcass trait measurements and differences in means between sexes were obtained.Heritability of the traits was estimated by paternal half-sib correlation. The estimates for carcass traits were moderately high and agree well with most other estimates reported in the literature.

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