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.

A genetic analysis of wool characteristics and lamb performance traits in Scottish Blackface sheep

2003 ◽  
Vol 77 (3) ◽  
pp. 355-362 ◽  
Author(s):  
J. Conington ◽  
A. Murphy
Keyword(s):  
Genetic Correlations ◽  
Live Weight ◽  
Scoring Systems ◽  
Production Traits ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
Heritability Estimates ◽  
Wool Quality ◽  
Fleece Weight ◽  
The Uk

AbstractGenetic parameters were estimated for wool quality, fleece characteristics and lamb production traits for Scottish Blackface sheep reared under extensive hill conditions in the UK. In two separate studies, heritabilities and genetic correlations were estimated for wool quality traits measured on lambs at 5 months of age and again on the shorn fleece a year later. The wool traits included birth coat length (BCT), 10-point scores for proportion of grey and kemp fibres present in the fleece (grey, kemp), British Wool Marketing Board (BWMB) recommendation (REC), greasy fleece weight (FLWT), BWMB fleece grade (FLGR), and average staple length (ASL). Genetic and phenotypic correlations were estimated between lamb wool traits and lamb live weights at birth (BWT), marking (at mid lactation with an average age of 7 weeks) (MWT), weaning (at an average age of 17 weeks) (WWT) and slaughter (SLWT), average fat depth (AVFD) and average muscle depth (MD). Individual lamb carcass measurements included Meat and Livestock Commission (MLC) conformation score (CONF) and fat class (FATC). Heritability estimates measured on 2524 or more live lambs were 0·69, 0·52, 0·26, 0·42 and 0·31 for BCT, ASL, grey, kemp and REC respectively. Heritability estimates for traits measured on the shorn fleece a year later for 1415 ewes were 0·37, 0·02, 0·57, 0·43, 0·46 and 0·14 for ASL, grey, kemp, REC, FLWT and FLGR respectively. Genetic correlations between FLWT in hoggets and other wool were positive and moderate to high in magnitude, ranging from 0·22 for kemp in lambs to 0·48 for grey in hoggets. Genetic correlations between REC and live-weight traits were 0·39 for MWT, 0·37 for WWT and 0·44 for SLWT. Genetic correlation between ASL and ultrasonic fat depth was 0·15 and for ASL and ultrasonic muscle depth was -0·30. The results indicate that the simple scoring systems derived to assess these traits are useful indicators of fleece quality, are highly repeatable over time and are a good gauge of likely future wool production. The results indicate that selection for heavier, leaner lambs should not compromise fleece quality, as assessed in this study.

scholarly journals Results of selection for breast muscle percentage and feed conversion ratio in Pekin ducks

2011 ◽  
Vol 27 (3) ◽  
pp. 769-776 ◽  
Author(s):  
H. Pingel
Keyword(s):  
Feed Efficiency ◽  
Conversion Ratio ◽  
Feed Conversion Ratio ◽  
Breast Muscle ◽  
Feed Consumption ◽  
Direct Selection ◽  
Meat Production ◽  
Feed Conversion ◽  
Nitrogen And Phosphorus ◽  
Selection For

Increasing breast muscle percentage by selection for breast layer thickness (muscle and skin) of living ducks by needle probe improves carcass quality as could be demonstrated by experiments and by applied breeding programs. In addition direct selection for individual feed conversion ratio can increase the efficiency of duck meat production. Divergent selection for feed conversion ratio from the age of 4 - 7 weeks over 11 generations has differentiated the feed efficiency by about 25 %. Causes for the reduction in feed conversion ratio are lower fat content of carcass, lower locomotor activity, higher enzymatic activity (alkaline phosphatase and creatinkinase in blood plasma) and better feed protein utilization. Because of lower feed consumption in the line selected for lower feed conversion ratio the emission of nitrogen and phosphorus via manure was reduced by about 39 and 26 %, respectively. That means, selection for better feed efficiency is not only an important economical but also an important ecological factor.

Effects of cow families on production traits in dairy cattle

2000 ◽  
Vol 71 (1) ◽  
pp. 49-57 ◽  
Author(s):  
T. Roughsedge ◽  
P. M. Visscher ◽  
S. Brotherstone
Keyword(s):  
Milk Yield ◽  
Genetic Relationships ◽  
Phenotypic Variance ◽  
Production Traits ◽  
Maternal Lineage ◽  
Environment Effects ◽  
Holstein Friesian ◽  
Lactation Curve ◽  
Two Measures ◽  
The Uk

AbstractThe components of phenotypic variance attributable to maternal lineage for production traits of the UK Holstein Friesian dairy population were estimated. First lactation production records of 55 230 cows calving between 1996-1998 in the UK Holstein Friesian population were used in the analysis. Maternal pedigree records were traced back to 1960 to establish maternal lineages. The tracing resulted in 36 320 cows being assigned to 11 786 cow families with more than one cow per maternal lineage. Using test day records it was possible to explore aspects of the lactation curve in terms of persistency and different periods of production. The traits analysed were 305-day milk yield and composition traits, the first three milk yield tests of lactation and two measures of persistency. A contemporary record design was used to minimize pair-wise additive direct genetic relationships between cows within a maternal lineage and to remove both the effect of heterogeneous variance over time and the complications of permanent environment effects. No significant component of variance attributable to maternal lineage was found for yield traits. When data were restricted to maternal lineages with five or more records, persistency, as a ratio of cumulative yield in the last third to that in the first third of a 300-day lactation, was estimated to have a 4·4% component due to maternal lineage variance significant at the 5% level. The study also investigated the preferential treatment of cow families. Some evidence of maternal lineage×herd interaction was found.

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.

Breeding for reduced methane emissions in extensive UK sheep systems

2012 ◽  
Vol 150 (5) ◽  
pp. 570-583 ◽  
Author(s):  
D. J. COTTLE ◽  
J. CONINGTON
Keyword(s):  
Production Systems ◽  
Selection Index ◽  
Farming Systems ◽  
Cost Effective ◽  
Carbon Price ◽  
Methane Emissions ◽  
Direct Selection ◽  
Production Traits ◽  
The Uk ◽  
Carbon Prices

SUMMARYSelection index theory was used to model the effects of methane (CH4) production in the breeding objective on genetic responses in Scottish Blackface sheep in hill production systems in the UK. A range of economic values (EVs) were assumed for CH4 production calculated from possible carbon prices (£/t CO2 equivalent (CO2-e)). The implicit price of carbon required for maintenance of CH4 levels or to reduce CH4 production by 0·1 kg/head/yr in a hill flock was calculated. The predicted genetic changes in CH4 production from current selection programmes that have an implicit methane EV of zero were calculated. Correlations between production traits and CH4 production were sampled from assumed normal distributions, as these correlations are currently unknown. Methane emissions are likely to increase at a rate of c. 3 kg CO2-e/ewe/yr as a result of using current industry selection indices in hill sheep farming systems in the UK. Breeding objectives for more productive hill sheep include reducing lamb losses and rearing more, heavier lambs. By placing a cost on carbon emissions to halt the genetic increase in methane, heavy penalties will be incurred by farmers in terms of reduced productivity. This amounts to £6/ewe/yr or a 5% discounted loss of £2851 per 100 ewe flock over a 10-year selection horizon. If the correlations between production traits and CH4 are positive (as expected) then an implicit carbon price of c. £272/t CO2-e is required for no genetic increase in CH4 production if methane is not measured and c. £50/t CO2-e if methane could be measured. Achievement of government targets for the whole economy of a 20% reduction in greenhouse gases (GHGs) over a 30-year period would require carbon prices (/t CO2-e) of £1396 (indirect selection) or £296 (direct selection) for the sheep industry to achieve a 20% reduction entirely via a genetic change of c. –0·1 kg methane/head/yr. These carbon prices are placed in the context of possible government policies. A combination of genetic and non-genetic measures will probably be required for cost-effective reduction in methane production to meet government targets.

Estimation of genetic parameters using health, fertility and production data from a management recording system for dairy cattle

1998 ◽  
Vol 66 (3) ◽  
pp. 577-584 ◽  
Author(s):  
J. E. Pryce ◽  
R. J. Esslemont ◽  
R. Thompson ◽  
R. F. Veerkamp ◽  
M. A. Kossaibati ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Genetic Parameters ◽  
Genetic Relationships ◽  
Genetic Correlations ◽  
Selection Criterion ◽  
Production Traits ◽  
Linear Type ◽  
Cell Counts ◽  
Estimation Problems ◽  
Selection For

AbstractThe Dairy Information System (DAISY) was developed to record fertility and health information for use in research and to help farmers manage their farms. Data from 33 herds recording health and fertility over a 6-year period were used to study genetic relationships of several health, fertility and production traits. There were 10 569 records from 4642 cows of all parities. These were used to estimate genetic parameters for health: mastitis, lameness and somatic cell score (SCS), for fertility: calving interval, days to first service, conception to first service and for production: 305-day milk, butterfat and protein yields. Heritabilities for these traits were also estimated for the first three lactations. (Co)variances were estimated using linear, multitrait restricted maximum likelihood (REML) with an animal model. Mastitis and lameness were treated as all-or-none traits. The incidence of these diseases increased with lactation number, which may lead to variance component estimation problems, as the mean is linked to the variance in binomial distributions. Therefore, a method was used to fix the within-lactation variance to one in all lactations while maintaining the same mean. The heritability for SCS across lactations was 0·15. Heritabilities for other health and fertility traits were low and ranged between 0·013 and 0·047. All genetic correlations with the production traits were antagonistic implying that selection for yield may have led to a deterioration in health and fertility. The genetic correlation between SCS and mastitis was 0·65 indicating that indirect selection for improvements in mastitis may be achieved using somatic cell counts as a selection criterion. The potential use of linear type scores as predictors of the health traits was investigated by regressing health traits on sire predicted transmitting abilities for type. The results indicate that some type traits may be useful as future selection criteria.

scholarly journals PSV-30 Influence of crossbreeding on meat production, growth, meat quality, and carcass traits within sheep fed the same diet

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 360-361
Author(s):  
Valentina Sabrekova ◽  
Daria A Nikanova ◽  
Yulia Timoshenko ◽  
Ilyas Shaydullin ◽  
Feyzullah Feyzullaev
Keyword(s):  
Amino Acid ◽  
Meat Quality ◽  
Total Protein ◽  
Carcass Traits ◽  
Lower Amount ◽  
Meat Production ◽  
Production Traits ◽  
Food Energy ◽  
Production Growth ◽  
Stock Feed

Abstract The aim of this study was to determine the effect of crossbreeding on meat production traits of sheep. Purebred (Volgograd breed, n = 30) and crossbred (F3, Volgograd x ¼ North Caucasian breed, n=30) sheep were fed for 60 days from the age of 8 months. The diet was the same for both groups and included: a dry fodder of mixed herbs, green-cut fodder, stock feed of barley, and salt. The initial liveweight for purebred sheep was 42.39±0.38 kg and for crossbred sheep was 44.41±0.47 kg (P < 0.01). The final liveweight for purebred sheep was 50.10±0.43 kg. Crossbred sheep were heavier at 52.40±0.36 kg (P < 0.001). The weight of carcasses was greater for crossbred sheep at 22.87±0.53 kg (P < 0.05) and 20.67±0.76 kg for purebred sheep. Compared with purebred sheep, crossbred sheep had a lower amount of internal fat (0.92±0.27 kg vs. 1.18±0.35 kg). The weight of meat from purebred sheep was less than crossbred sheep (16.12±0.63 kg vs. 18.28±0.43 kg, P < 0.05) while the weight of bone was almost the same (4.55 vs. 4.59 kg). Consequently, the ratio of meat/bone was 5.54 vs. 3.98. The food energy value for the meat of purebred sheep was greater at 259.36±16.78 kcal than the meat of crossbred sheep at 233.85±11.10 kcal. Total moisture in the meat of purebred sheep was lower (60.11±0.67 vs. 63.05±0.65, P < 0.05), total protein was a little higher (17.71±0.77 vs. 17.63±0.24), and lipids were higher (20.73±0.73 vs. 17.89±0.82, P < 0.05) than in the meat of crossbred sheep. The meat of purebred sheep had a lower concentration of non-replaceable amino acid (12.47 g) compared with meat of crossbred sheep (17.20 g), and a lower concentration of replaceable amino acid (23.08 g vs. 26.84 g). The results of this study can be used to improve meat production and meat quality.

scholarly journals Effects of polymorphisms at <i>LEP</i>, <i>CAST</i>, <i>CAPN1</i>, <i>GHR</i>, <i>FABP4</i> and <i>DGAT1</i> genes on fattening performance and carcass traits in Simmental bulls

2017 ◽  
Vol 60 (2) ◽  
pp. 61-70 ◽  
Author(s):  
Sena Ardicli ◽  
Deniz Dincel ◽  
Hale Samli ◽  
Faruk Balci
Keyword(s):  
Average Daily Gain ◽  
Carcass Traits ◽  
Meat Production ◽  
The Novel ◽  
Nucleotide Polymorphisms ◽  
Production Traits ◽  
Single Nucleotide ◽  
Fattening Performance ◽  
Pcr Rflp ◽  
Fattening Period

Abstract. The aim of this study was to investigate the effects of single nucleotide polymorphisms (SNPs) at six candidate genes (LEP, CAST, CAPN1, GHR, FABP4 and DGAT1) on fattening performance and carcass traits of Simmental bulls in Turkey. The analysis covered a total of 81 Simmental bulls grown on a private farm that were randomly selected for their fattening period for use in this study. Genotyping was performed using the PCR-RFLP method. The S20T polymorphism at the CAST gene and the G316A polymorphism at the CAPN1 gene were associated with variation in final weight, fattening period, weight gain and average daily gain (P < 0.05). In addition, LEP A80V had a significant effect on hot and chilled carcass weight and dressing percentage (P < 0.05). There was no association between GHR S555G, FABP4 V110M and DGAT1 K232A markers with the traits analysed. These results suggested that focusing on the novel effects of LEP, CAST and CAPN1 gene polymorphisms on meat production traits might be useful for marker-assisted selection in Simmental cattle.

Genotyping of New Zealand White Rabbits by PCR-RFLP Markers

2015 ◽  
Vol 2 (2) ◽  
pp. 21-25
Author(s):  
Ye. Shevchenko ◽  
K. Kopylov
Keyword(s):  
New Zealand ◽  
Dna Markers ◽  
Rflp Analysis ◽  
Rflp Markers ◽  
Meat Production ◽  
Production Traits ◽  
Daily Growth ◽  
Myostatin Gene ◽  
New Zealand White Rabbits ◽  
The Impact

Aim. To investigate the genetic structure of New Zealand white rabbits population by different types of DNA- markers. Methods. The individual genotypes of animals were identifi ed using the polymerase chain reaction with further determination of the restriction fragment length polymorphism (RFLP-analysis). Results. The data on the distribution of allele variants of molecular markers in the population of rabbits were obtained; the impact of the genotype factor on meat production, prolifi cacy and milk production traits was determined. The relationship between genotypes by polymorphic DNA-markers of myostatin and progesterone receptor of animals and the values of meat productivity traits and reproduction capability was established. It was demonstrated that TT homozygotes excel other animals in the indices of average daily growth, while GG homozygotes excel others in prolifi cacy. Conclusions. The “desired” genotypes by myostatin gene (CC) and myostatin of rabbits were revealed. They may be used for targeted selection with the purpose of increasing the indices of meat production.

Weaner survival is heritable in Australian Merinos and current breeding objectives are potentially leading to a decline in survival

2019 ◽  
Vol 59 (1) ◽  
pp. 35
Author(s):  
S. F. Walkom ◽  
A. N. Thompson ◽  
E. Bowen ◽  
D. J. Brown
Keyword(s):  
Production Systems ◽  
Genetic Relationships ◽  
Survival Rates ◽  
Production Traits ◽  
Weaning Weight ◽  
Australian Sheep ◽  
Potential Impact ◽  
Selection For ◽  
Fleece Weight ◽  
The Relationship

There is little evidence to show that mortality rates during the period after weaning are improving over time in Australian sheep. The average mortality rate of Merino lambs during the post-weaning period has been estimated to be 5.2%. The present study explored the potential for producers to breed for improved survival rates during the post-weaning period and the potential impact this would have on key production traits. A total of 122526 weaner survival (mortality) records were obtained from 18 Merino flocks, between 1989 and 2014, encompassing a wide variety of Australian Merino sheep types and production systems. The heritability of weaner survival from a sire model was estimated to be 0.07 ± 0.01 and was significantly greater than zero. The survival of lambs post-weaning was significantly influenced by weaning weight, with higher survival rates observed in the heavier lambs. The phenotypic relationship with weight indicates that selection for heavier weaning and post-weaning weights, and in turn larger growth rates, will improve survival rates. There is genetic variation in weaner survival not explained by the relationship with weaning weight. Weight-corrected weaner survival was antagonistically genetically correlated with fleece weight. Due to these antagonistic genetic relationships selection based on popular MERINOSELECT indexes is leading to a very small reduction in the survival rate of lambs after weaning through to the post-weaning stage. To prevent a decline in weaner survival, producers are advised to record weaner survival and include it in their breeding objective.

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