Associations of PrP genotypes with live weight and slaughter traits in an experimental flock of Swaledale sheep in Great Britain

2006 ◽  
Vol 82 (5) ◽  
pp. 607-614 ◽  
Author(s):  
W. Y. N. Man ◽  
S. Brotherstone ◽  
B. G. Merrell ◽  
W. A. Murray ◽  
B. Villanueva
Keyword(s):  
Great Britain ◽  
Maternal Effects ◽  
Mixed Models ◽  
Fixed Effects ◽  
Genetic Selection ◽  
Live Weight ◽  
Eradication Programme ◽  
Gene Encoding ◽  
Significant Relationships ◽  
Selection For

AbstractPolymorphisms at codons 136, 154 and 171 of the gene encoding the prion protein (PrP) are associated with susceptibility to classical scrapie in sheep. Genetic selection for scrapie resistance based on PrP genotypes is central to the scrapie eradication programme in Great Britain but there are concerns about how this may affect other economically important traits. The objective of this study was to evaluate associations of PrP genotypes with live weight and slaughter traits in a hill sheep breed in Great Britain. Data used were from an experimental flock of Swaledale sheep in which the alleles ARR, ARQ, AHQ and VRQ were present. About 1450 genotyped lambs with birth, marking and weaning weights, and 620 with slaughter records were used for the study. Mixed models with various fixed effects and random direct genetic and maternal effects were tested to determine the appropriate model to use for each trait. None of the differences in lamb performance between PrP genotypes consistently reached significance. Therefore, this study does not support existence of significant relationships between PrP genotype and lamb performance traits in this breed.

The inheritance of faecal egg count following natural Ostertagia circumcinctainfection in Scottish Blackface lambs

1996 ◽  
Vol 1996 ◽  
pp. 117-117
Author(s):  
S.C. Bishop ◽  
K. Bairden ◽  
Q.A. McKellar ◽  
M. Park ◽  
M.J. Stear
Keyword(s):  
Genetic Selection ◽  
Live Weight ◽  
Gastrointestinal Parasites ◽  
Sheep Industry ◽  
Environment Effects ◽  
Faecal Egg Count ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
The Uk ◽  
Production Losses

The use of genetic selection as a means of reducing the welfare and production losses caused by gastrointestinal parasites has hitherto been ignored by the UK sheep industry. The aim of this study is to assess the potential for selection for reduced faecal egg count, as an indicator of parasitism, and to establish relationships with live weight.Faecal egg counts and live weights were measured on approximately 200 predominantly twin born Scottish Blackface lambs each year for three years following natural, predominantly Ostertagia circumcincta , infection on pasture. Measurements were made from one to six months of age, at four week intervals, following anthelmintic treatment. Heritabilities, maternal common environment effects, genetic and phenotypic correlations were calculated using Residual Maximum Likelihood techniques.

Genetics of food intake, live weight, condition score and energy balance

1999 ◽  
Vol 24 ◽  
pp. 63-73 ◽  
Author(s):  
R. F. Veerkamp ◽  
E. P. C. Koenen
Keyword(s):  
Energy Balance ◽  
Food Intake ◽  
Weight Change ◽  
Genetic Selection ◽  
Metabolic Stress ◽  
Live Weight ◽  
Food Utilization ◽  
Score Change ◽  
Condition Score ◽  
Selection For

AbstractThe objectives of this study were to investigate genetic variation for traits that are part of the food utilization complex and to investigate the scope for future genetic improvement of traits possibly linked to metabolic stress: live weight (change), condition score (change) and energy balance. Many aspects of the food utilization complex appear to be heritable and are affected by genetic selection for yield. In general, genetic selection for yield increases intake and body tissue mobilization and energy balance is expected to decrease. However, unfavourable effects of genetic selection can be compensated for by measuring additional traits to be included in breeding programmes. Food intake, live weight (change) and condition score (change) are all potential options. Which traits should be measured, at what lactation stages and in which (nutritional) environment will merely depend on the coheritability with health and fertility, the genetic correlation with milk yield and the cost of measuring the trait effectively in a breeding programme.

Options to reduce vulnerability to metabolic stress by genetic selection

1999 ◽  
Vol 24 ◽  
pp. 119-127 ◽  
Author(s):  
J. E. Pryce ◽  
P. Løvendahl
Keyword(s):  
Milk Production ◽  
Genetic Selection ◽  
Metabolic Stress ◽  
Live Weight ◽  
Genetic Merit ◽  
Condition Score ◽  
Breeding Programmes ◽  
Selection For ◽  
Breeding Goals ◽  
High Yields

AbstractGenetic selection for milk production has been very successful. However to achieve high yields, the metabolic load on dairy cows is believed to be substantial. If the size of this load is large enough then the animal may become ‘metabolically stressed’. Signs of this may include some sort of distortion of normal physiological function. There is evidence from both population studies and research herds to suggest that intense selection for milk yield has led to a deterioration in some aspects of health and fertility. Genetic correlation estimates between production and measures of fertility are unfavourable. As an example, calving intervals of high merit animals from Langhill are on average 12 days longer than those of average genetic merit, which is mostly due to a delay in days to first heat. It is suggested that some aspects of health and fertility problems in high genetic merit animals are a consequence, in part, of so-called metabolic stress. Future breeding goals should be broadened to include a broad spectrum of traits related to efficient milk production, in addition to either health and fertility traits themselves, or traits believed to be precursors of them, such as those related to metabolic stress. The complexity and subjectivity of metabolic stress and its components makes it very difficult to include in future breeding goals. However, traits related to energy balance, such as some measures of condition score, dry-matter intake and live weight may be useful in breeding programmes where one of the goals is to alleviate metabolic stress.

The inheritance of faecal egg count following natural Ostertagia circumcinctainfection in Scottish Blackface lambs

1996 ◽  
Vol 1996 ◽  
pp. 117-117
Author(s):  
S.C. Bishop ◽  
K. Bairden ◽  
Q.A. McKellar ◽  
M. Park ◽  
M.J. Stear
Keyword(s):  
Genetic Selection ◽  
Live Weight ◽  
Gastrointestinal Parasites ◽  
Sheep Industry ◽  
Environment Effects ◽  
Faecal Egg Count ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
The Uk ◽  
Production Losses

The use of genetic selection as a means of reducing the welfare and production losses caused by gastrointestinal parasites has hitherto been ignored by the UK sheep industry. The aim of this study is to assess the potential for selection for reduced faecal egg count, as an indicator of parasitism, and to establish relationships with live weight.Faecal egg counts and live weights were measured on approximately 200 predominantly twin born Scottish Blackface lambs each year for three years following natural, predominantly Ostertagia circumcincta , infection on pasture. Measurements were made from one to six months of age, at four week intervals, following anthelmintic treatment. Heritabilities, maternal common environment effects, genetic and phenotypic correlations were calculated using Residual Maximum Likelihood techniques.

scholarly journals Wooden breast and white striping: comparative occurrence in three poultry companies

2021 ◽  
Vol 41 ◽  
Author(s):  
Sabrina T. Fraga ◽  
Fátima R.F. Jaenisch ◽  
Jane O. Peixoto ◽  
Arlei Coldebella ◽  
Karen A. Borges ◽  
...  
Keyword(s):  
Growth Rate ◽  
Pectoralis Major Muscle ◽  
Genetic Selection ◽  
Live Weight ◽  
Economic Losses ◽  
White Striping ◽  
Processing Plants ◽  
Poultry Processing ◽  
Selection For ◽  
Wooden Breast

ABSTRACT: To increase the amount of meat produced, researchers have promoted intensive genetic selection for growth rate and muscling and have improved nutrition and management conditions. However, there has been an increase in the number of reports of breast muscle myopathies observed in poultry processing plants, including white striping (WS) and wooden breast (WB). This study aimed to evaluate and to compare the occurrence of WS and WB myopathies in three poultry processing plants and to perform an anatomopathological characterization, including macroscopic and microscopic analyses. A total of 408,334 carcasses were condemned or downgraded due to the presence of WB or WS, which represents 0.73% of the total number of slaughtered animals during the evaluated period. WB was more frequent than WS, but the occurrence of each myopathy varied significantly according to each establishment. WB was more frequent in the establishment which includes only male flocks, an average age of 45 days, and an average live weight of 2775g (B). WS was more frequent in establishment with male, female and mixed flocks, average ages ranging from 41 to 44 days, and average live weight 1731g-2830g (A). It is probably related with specific condition of each poultry company, including genetics, age, nutrition and management conditions. Macroscopically, WB and WS lesions are characterized by hypertrophy and stiffness of the pectoralis major muscle. Under microscopy, the myopathies showed similarities regarding the detected histological abnormalities, characterized by a process of myodegeneration, although the connective tissue infiltrate was more severe in the breasts with WB than in those with WS myopathy. The results found in this study demonstrate that the rates of condemnation for these myopathies are high, vary significantly among the analyzed companies and may cause major economic losses for the productive sector in the region.

Field evidence of metabolic stress in dairy cows?

1999 ◽  
Vol 24 ◽  
pp. 21-26
Author(s):  
W. R. Ward ◽  
C. S. Parker
Keyword(s):  
Great Britain ◽  
Dairy Cows ◽  
Genetic Selection ◽  
Metabolic Stress ◽  
Energy Deficit ◽  
Dairy Herds ◽  
Elevated Blood ◽  
Field Evidence ◽  
Selection For ◽  
Beta Hydroxybutyrate

AbstractThe authors review their experiences of metabolic profiles in dairy herds, with a view to assessing whether metabolic stress is a problem in Great Britain at present. Many cows show elevated blood beta-hydroxybutyrate concentration, indicating energy deficit, or elevated urea levels, indicating an imbalance between energy and protein in the rumen but at present there is no evidence that high-yielding cows in commercial herds show more metabolic stress than low-yielding cows. The authors suggest that more cows could suffer metabolic stress in the future, unless farmers’ ability to feed and manage dairy cows develops as rapidly as genetic selection for high milk yield.

scholarly journals Responses to selection for lean growth in sheep

2002 ◽  
Vol 74 (1) ◽  
pp. 39-50 ◽  
Author(s):  
G. Simm ◽  
R.M. Lewis ◽  
B. Grundy ◽  
W.S. Dingwall
Keyword(s):  
Fixed Effects ◽  
Mixed Model ◽  
Live Weight ◽  
Control Line ◽  
Breeding Values ◽  
Breeding Goal ◽  
Lean Growth ◽  
Selection For ◽  
Estimated Breeding Values ◽  
And Control

AbstractThis paper reports the selection responses achieved, and related results, following 9 years of index selection for lean growth in Suffolk sheep. The breeding goal of the index used comprised carcass lean weight and carcass fat weight at a constant age, with relative economic values of + 3 and –1 per kg. The selection criteria were live weight (LWT), ultrasonic fat depth (UFD) and ultrasonic muscle depth (UMD) adjusted to a constant age of 150 days. By year 9, responses in LWT, UFD and UMD in both sexes, as judged by the divergence between selection and control line performance, amounted to 4·88 kg, -1·1 mm and 2·8 mm respectively; these responses are between 7 and 15% of the overall means of the traits concerned. Although selection was originally on index scores based on phenotypic records, the retrospective analyses reported here used the mixed model applications of residual maximum likelihood to estimate parameters and best linear unbiased prediction to predict breeding values. The statistical model comprised fixed effects plus random effects accounting for direct additive, maternal additive and temporary environmental variation. Estimated genetic trends obtained by regressing estimated breeding values on year of birth were similar to annual responses estimated by comparing selection and control line means. Estimates of direct heritabilities were 0·054, 0·177, 0·286, 0·561 and 0·410 for birth weight (BWT), weaning weight (WWT), LWT, UFD and UMD respectively. Corresponding estimates of maternal heritabilities were 0·287, 0·205, 0·160, 0·083 and 0·164. Phenotypic correlations between all pairs of traits were positive and usually moderately high. There were low negative direct additive correlations between BWT and WWT, and between BWT and LWT, but higher positive maternal additive correlations between all other pairs of weight traits.

scholarly journals Genetic parameters of growth traits in Nellore cattle

2017 ◽  
Vol 38 (3) ◽  
pp. 1513
Author(s):  
Leandro Molina Kamei ◽  
Edson Luis De Azambuja Ribeiro ◽  
Nilva Aparecida Nicolao Fonseca ◽  
Carolina Amália De Souza Dantas Muniz ◽  
Tatiane Vito Camiloti ◽  
...  
Keyword(s):  
Genetic Correlation ◽  
Maternal Effects ◽  
Fixed Effects ◽  
Growth Traits ◽  
Correlation Coefficients ◽  
Correlated Response ◽  
Environmental Correlations ◽  
Nellore Cattle ◽  
Selection For ◽  
Heritability Estimates

This study evaluated non-genetic factors and calculated heritability estimates of direct and maternal effects for growth traits in Nellore cattle raised in southern Brazil. Performance records of 4170, 1538, 3139, 1830, and 1151 calves born from 2005 to 2011 were analyzed for birth weight (BW), adjusted120-day weight (W120), adjusted 205-day weight (W205), adjusted365-day weight (W365), and adjusted 550-day weight (W550), respectively. The components of (co)variance used to calculate heritability estimates were determined by Derivative-Free Restricted Maximum Likelihood using the MTDFREML software. Contemporary groups were included in the model as fixed effects, and direct and maternal effects, permanent environmental effects, and residual errors were included as random effects. Phenotypic correlations were estimated using the PROC CORR procedure from SAS. Overall means for BW, W120, W205, W365, and W550 were 38, 138, 201, 270, and 376 kg, respectively. Heritability estimates for direct and maternal effects were 0.17 ± 0.04 and 0.11 ± 0.03 (BW), 0.14 ± 0.03 and 0.03 ± 0.04 (W120), and 0.17 ± 0.04 and 0.09 ± 0.03 (W205). Genetic, phenotypic, and environmental correlations were 0.79, 0.44, and 0.32 for BW and W120, 0.79, 0.39, and 0.26 for BW and W205, and 0.96, 0.74, and 0.75 for W120 and W205. The results indicate that selection for pre-weaning weight would be more efficient using W205, and genetic correlation coefficients indicate that selection at any age should produce a positively correlated response at older ages. Genetic, phenotypic, and environmental correlation coefficients between W365 and W550 were 0.99, 0.75, and 0.76, respectively. Selection for adjusted 550-day weight should produce the greatest genetic gains. Genetic correlation coefficients between weight traits indicate that selection for weight at older ages, which could help reduce the number of weighings and increase accuracy of selection at younger ages, produces gains at older ages.

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