scholarly journals Consequences of selection for improving production traits on the frequency of deleterious alleles for fitness1

2009 ◽  
Vol 87 (3) ◽  
pp. 850-859 ◽  
Author(s):  
J. F. Kearney ◽  
P. Navarro ◽  
C. S. Haley ◽  
B. Villanueva
Keyword(s):  
Production Traits ◽  
Deleterious Alleles ◽  
Selection For

scholarly journals The relevance of milk protein polymorphisms for dairy cattle breeding.

1993 ◽  
Vol 1993 ◽  
pp. 46-46
Author(s):  
Henk Bovenhuis
Keyword(s):  
Genetic Variants ◽  
Milk Protein ◽  
Production Traits ◽  
Milk Production Traits ◽  
Breeding Scheme ◽  
Cattle Breeding ◽  
Dairy Cattle Breeding ◽  
Nucleus Breeding ◽  
Selection For ◽  
Β Lactoglobulin

Several studies have shown milk protein genetic variants to be associated with manufacturing properties of milk. The main findings were that κ-casein genetic variants affect renneting time of milk and βlactoglobulin genetic variants are associated with casein number (reviewed by Grosclaude, 1988). There are reports also of associations between milk protein genetic variants and milk production traits. Results from these studies indicate that κ-casein genotypes are associated with protein content and βlactoglobulin genotypes are related to fat content (reviewed by Bovenhuis et al., 1992). Therefore, κ-casein and βlactoglobulin genotypes might be of value as selection criteria. The aim of the present study was to quantify the potential effects of selection for κ-casein and β-lactoglobulin genotypes by using stochastic simulation of a closed adult MOET nucleus breeding scheme.

A genetic analysis of wool and lamb production traits in Scottish Blackface Sheep

2002 ◽  
Vol 2002 ◽  
pp. 21-21
Author(s):  
A. Murphy ◽  
J. Conington
Keyword(s):  
Genetic Relationships ◽  
Carcass Traits ◽  
Direct Selection ◽  
Meat Production ◽  
Production Traits ◽  
Selection For ◽  
Wool Quality ◽  
Sheep Production ◽  
The Uk ◽  
The Impact

Scottish Blackface sheep have a multi-purpose role in the UK to produce breeding females and lambs for meat consumption. Over the last fifty years, wool has accounted for a very low proportion of economical return from hill sheep production in the UK. In recent years, the ratio of the value of lamb meat to wool clip has altered, with wool becoming relatively more important in particular for hill breeds. The consequence of direct selection for improved carcass traits in these breeds on wool quality is unknown. With other sheep breeds such as Merino, selection for improved wool traits has largely been undertaken with little regard to the impact on meat production. The objectives of this study are to quantify wool quality traits and examine genetic relationships between wool quality and carcass traits in Scottish Blackface sheep.

scholarly journals Impact of selection for residual feed intake on production traits and behavior of mule ducks

2016 ◽  
Vol 95 (9) ◽  
pp. 1999-2010 ◽  
Author(s):  
L. Drouilhet ◽  
R. Monteville ◽  
C. Molette ◽  
M. Lague ◽  
A. Cornuez ◽  
...  
Keyword(s):  
Feed Intake ◽  
Residual Feed Intake ◽  
Production Traits ◽  
Selection For ◽  
And Behavior

Continued selection of Romney sheep for resistance or susceptibility to nematode infection: estimates of direct and correlated responses

2000 ◽  
Vol 70 (1) ◽  
pp. 17-27 ◽  
Author(s):  
C. A. Morris ◽  
A. Vlassoff ◽  
S. A. Bisset ◽  
R. L. Baker ◽  
T. G. Watson ◽  
...  
Keyword(s):  
Maximum Likelihood Estimates ◽  
Research Centre ◽  
Control Line ◽  
Production Traits ◽  
Correlated Responses ◽  
Breeding Lines ◽  
Nematode Parasites ◽  
Phenotypic Standard Deviation ◽  
Selection For ◽  
Fleece Weight

AbstractDivergent breeding lines of Romney sheep, selected as lambs for consistently high or low faecal worm egg count (FEC) following natural multi-species challenge by nematode parasites, were established in New Zealand at Wallaceville Animal Research Centre in 1979 and at Rotomahana Station in 1985. In 1988 the Rotomahana lines, including an unselected control line maintained under the same management conditions, were transferred to Tokanui Station where they remained for 4 years. In 1993 elite high and low FEC animals from Tokanui, along with the controls, were transferred to Wallaceville, where merged lines have since been managed together. Selection responses from the lines at Rotomahana and Tokanui, and from a further 5 years of divergent selection in the merged lines, are reported here. For the two most recent lamb crops (1996 and 1997 birth years), log-transformed FECs of the high and low lines were 1·27 and -1·46 phenotypic standard deviation units from the control. After back-transformation to the original scale, where the FEC for control line lambs averaged 1255 eggs per g, the means for the high and low lines were 3Ό5 and 0·27 times the control mean. Animal-model restricted maximum likelihood estimates of her it ability and repeatability for single-record FEC (following separate infections) were 0·28 (s.e. 0·02) and 0·42 (s.e. 0Ό1), respectively. Correlated responses in production traits include significantly decreased post-weaning weight gain and increased dags (breech soiling) in lambs, and decreased fleece weight in yearlings and ewes in the low FEC line, compared with those in the high line. However the low FEC line had proportionally 0·11 more lambs weaned per ewe mated than the high FEC line (F < 0·01). It is concluded firstly that selection for high or low FEC in Romney s has achieved an 11-fold difference between the divergent lines. Secondly, it will generally be necessary in a commercial environment to apply index selection for a combination of increased productivity, decreased FEC and possibly decreased dags, when potential candidates are recorded under conditions of nematode challenge.

scholarly journals Group Selection for Adaptation to Multiple-Hen Cages: Production Traits During Heat and Cold Exposures ,

1996 ◽  
Vol 75 (11) ◽  
pp. 1308-1314 ◽  
Author(s):  
PATRICIA Y. HESTER ◽  
W.M. MUIR ◽  
J.V. CRAIG ◽  
J.L. ALBRIGHT
Keyword(s):  
Group Selection ◽  
Production Traits ◽  
Selection For

scholarly journals Comparative transcriptomics reveals domestication-associated features of Atlantic salmon lipid metabolism

2019 ◽  
Author(s):  
Yang Jin ◽  
Rolf Erik Olsen ◽  
Thomas Nelson Harvey ◽  
Mari-Ann Østensen ◽  
Keshuai Li ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Dietary Lipids ◽  
Production Traits ◽  
Feeding Trial ◽  
Wild Salmon ◽  
Glucose And Lipid Metabolism ◽  
Selection For ◽  
Fat Uptake ◽  
Radical Shift ◽  
Lower Expression

AbstractDomestication of Salmo salar has imposed strong selection for production traits since the 1970s. The domestication has also imposed a radical shift in diet. Whereas wild salmon eats invertebrates, crustaceans and fish, the dietary lipids in domestic feed has since 1990 gradually shifted from fish oil (FO) to vegetable oil (VO), causing a decrease intake of long-chain polyunsaturated fatty acids (LC-PUFA). We tested the hypothesis that this shift has induced domestication-specific features of lipid metabolism in a 96-day feeding trial of domesticated and wild salmon fed diets based on FO, VO or phospholipids (PL). We addressed this by sampling tissues central in fat uptake (pyloric caeca) and processing (liver) and quantifying RNA expression and fatty acid composition. Domesticated salmon grew faster than wild salmon, with higher gene expression in glucose and lipid metabolism pathways. The promoters of differentially expressed genes were enriched for transcription factors involved in circadian clock regulation. Domesticated salmon had lower expression of cry2 and nr1d1, genes involved in negative regulation of circadian rhythm, with possible implications for the diurnal cycle of feed ingestion and basal metabolic rate. Only wild salmon showed a significant impact on growth of VO versus PL or FO feed, whereas domesticated but not wild salmon upregulated key LC-PUFA synthesis genes fads2d5 and fads2d6a in response to VO diet. Domesticated salmon had higher LC-PUFA but lower 18:3n-3 and 18:2n-6 in liver when fed VO, suggesting that domesticated salmon can better compensate for dietary shortage of LC-PUFA compared to wild salmon.

scholarly journals Effect of Selection for Weight of Early Eggs on Egg Production Traits in Japanese Quail

2015 ◽  
Vol 9 (4) ◽  
pp. 179-190 ◽  
Author(s):  
Mohamed Bahie El- Deen ◽  
Ayman A. Nour ◽  
Waleed S. El- Tahawy ◽  
Hala A. Fouad
Keyword(s):  
Japanese Quail ◽  
Egg Production ◽  
Production Traits ◽  
Selection For

scholarly journals Selection for prolificacy in Finnsheep and in Norwegian sheep

1988 ◽  
Vol 60 (6) ◽  
pp. 518-522
Author(s):  
T. Ådnøy
Keyword(s):  
Litter Size ◽  
No Reduction ◽  
Selection Response ◽  
The Other ◽  
Group Differences ◽  
Carcass Quality ◽  
Production Traits ◽  
Breeding Scheme ◽  
Breed Group ◽  
Selection For

Litter size (LS) at birth and other production traits were recorded for Finnsheep (F), Norwegian(N) breeds Dala (D), Steigar (St) and Spael (Sp), for N sheep crossed with 1/4 F and ½ F and for a group of sheep established by collecting offspring of highly prolific N(N+) ewes. The N breeds and the ¼ F group were part of the national breeding scheme. In the 1/2F and N+, selection was solely for LSB. The other groups were selected normally. There were 4263 lambings. In adults, there were no breed group differences in lambing-% (mean 94 %), but in 1-yr. olds there were differences: Sp 90 %, F and F-crosses 80—85 %, D 70 %, N+ 60 % and St 50 %. F-crosses had clearly the best LS’s (Fca. 3.0, 1/2F2.4, 1/4F2.0). Those of N+ decreased through the 5 years recorded from near 2.0 to 1.8 lambs. The other breed groups gave LS’s of 1.7—1.8. In the two groups selected for LS, no selection response was found. The reasons are not known. Although the pure F and ½ F gave lower weaning weights (34 and 38 kg at 150d.) than the other groups (41—45 kg), their weaned lamb yield per ewe was ca. 20 kg higher. Considering the poorer carcass quality observed in earlier experiments for these groups, the use of 1/4 F is recommended for Norwegian conditions. This breed group gave no reduction in weaning weight, but increased the LS by some 0.2 lambs.

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