The effect of duration of performance test on genetic gain in pigs

1978 ◽  
Vol 29 (2) ◽  
pp. 423
Author(s):  
CP McPhee
Keyword(s):  
Growth Rate ◽  
Performance Test ◽  
Performance Testing ◽  
Breeding Value ◽  
Test Facility ◽  
Equal Weight ◽  
Feed Conversion ◽  
Two Stage ◽  
Selection Scheme ◽  
Value Determination

The problem of making the best use of a limited number of performance-testing places in the genetic improvement of pigs is examined. A model is given which balances the duration of testing and its effect on the accuracy of breeding value determination, against throughput and its effect on selection intensity. The model is a phenotypic one with easily estimated parameters in lieu of the more exact genetic one whose parameters are difficult to estimate. It is illustrated with data taken from the Queensland performance-testing station which evaluates boars on an index combining feed conversion ratio, growth rate and back fat. Full performance records from 26 to 90 kg liveweight are subdivided into four consecutive parts of equal weight interval. A range of feasible one and two stage selection schemes based on performance in one or more of these parts are compared. Relative to the present full testing scheme, the best single stage selection, that based on performance in the last two parts (3 + 4), is 14% more efficient. The best two stage selection scheme, also a 3 + 4 part test with a 50% culling at the end of part 3, is 19 0%, more efficient. Highest efficiencies are achieved by imposing a preliminary culling on growth rate before entry to the testing facility; e.g. selection of the best 25% on part 3 growth rate followed by part 4 index selection within the test facility is 36% more efficient than the present full test. The limitations of the model and some practical problems of part testing schemes are discussed.

Corrigendum - The effect of duration of performance test on genetic gain in pigs

1978 ◽  
Vol 29 (3) ◽  
pp. 423
Author(s):  
CP McPhee
Keyword(s):  
Growth Rate ◽  
Performance Test ◽  
Performance Testing ◽  
Breeding Value ◽  
Test Facility ◽  
Equal Weight ◽  
Feed Conversion ◽  
Two Stage ◽  
Selection Scheme ◽  
Value Determination

The problem of making the best use of a limited number of performance-testing places in the genetic improvement of pigs is examined. A model is given which balances the duration of testing and its effect on the accuracy of breeding value determination, against throughput and its effect on selection intensity. The model is a phenotypic one with easily estimated parameters in lieu of the more exact genetic one whose parameters are difficult to estimate. It is illustrated with data taken from the Queensland performance-testing station which evaluates boars on an index combining feed conversion ratio, growth rate and back fat. Full performance records from 26 to 90 kg liveweight are subdivided into four consecutive parts of equal weight interval. A range of feasible one and two stage selection schemes based on performance in one or more of these parts are compared.Relative to the present full testing scheme, the best single stage selection, that based on performance in the last two parts (3 + 4), is 14% more efficient. The best two stage selection scheme, also a 3 + 4 part test with a 50% culling at the end of part 3, is 19%, more efficient. Highest efficiencies are achieved by imposing a preliminary culling on growth rate before entry to the testing facility; e.g. selection of the best 25% on part 3 growth rate followed by part 4 index selection within the test facility is 36% more efficient than the present full test. The limitations of the model and some practical problems of part testing schemes are discussed.

ASSESSMENT OF COMPLETELY PELLETED DIETS FOR PERFORMANCE TESTING OF RAMS

1986 ◽  
Vol 66 (3) ◽  
pp. 817-820
Author(s):  
J. S. WALTON ◽  
B. W. McBRIDE ◽  
N. A. MARTINEAU ◽  
T. D. BURGESS
Keyword(s):  
Growth Rate ◽  
Key Words ◽  
Performance Test ◽  
Performance Testing ◽  
Ingestive Behavior ◽  
Test Procedures

Completely pelleted diets were fed to rams under a facsimile of Ontario Ram Performance Test procedures. Twenty rams were fed for 50 d on completely pelleted rations without impairment of growth rate and without any effects on rumen health or ingestive behavior. Key words: R.O.P. testing, rams, pelleted feeds, growth rate, rumen lining

Selection for efficient lean growth in a pig herd

1981 ◽  
Vol 32 (4) ◽  
pp. 681 ◽  
Author(s):  
CP McPhee
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Performance Test ◽  
Subcutaneous Fat ◽  
Performance Testing ◽  
Restricted Feeding ◽  
Food Conversion ◽  
Muscle Area ◽  
Eye Muscle ◽  
Lean Growth

A pig herd was selected for 6 years by using an economic index combining growth rate, food conversion efficiency and carcass leanness. These three traits were all measured in a performance test which permitted appetite variation between pigs to be expressed. Boars selected with an intensity of 118 were used for 6 months, and sows with an intensity of 114 were kept for two farrowings. An unselected control herd was maintained concurrently. To measure selection response, selected (S) and control (C) pigs were compared as they grew from 25 to 90 kg liveweight on ad lib. and restricted feeding during the last 2 years of selection. The following significant (P < 0.05) responses occurred in the selection herd: (i) A slight increase in growth rate on restricted feed, balanced by a similar decrease on ad lib, feeding. (ii) A decline in food conversion ratio of 5 % (C, 2.79; S, 2.65) due mainly to a reduction in appetite. (On ad lib. feeding, food intake per day declined by 6 % (C, 2.30 kg/d; S, 2.16 kg/d.)). (iii) A decline in average subcutaneous fat depth by 11 % (C, 27.8 mm; S, 24.7 mm) and in fat dissected from the ham by 7 % (C, 2.80 kg; S, 2.61 kg). (iv) An increase in estimated lean in the carcass by 2% (C, 30.3 kg; S, 31.0 kg). (v) A decline in dressing percentage of the carcass by 1 % (C, 77.1 %; S, 76.2 %). There was no change in eye muscle area or carcass length. The results are discussed in terms of changes in the ratio of food intake to lean growth. In the group fed ad lib., this ratio declined by 7 %, mainly because of a decline in food intake. On restricted feeding it fell by 6 %, mainly owing to an increase in lean growth. That portion of the selection effort absorbed in reducing food intake may have been more profitably directed to increasing lean growth by suppressing appetite variation during performance testing, rather than allowing it to be expressed.

Selecting terminal beef sires on their estimated breeding values for economic efficiency

1995 ◽  
Vol 1995 ◽  
pp. 127-127
Author(s):  
Margaret E King ◽  
P J Broadbent
Keyword(s):  
Economic Efficiency ◽  
Feed Intake ◽  
Performance Test ◽  
Production Systems ◽  
Selection Index ◽  
Performance Testing ◽  
Breeding Value ◽  
Gestation Length ◽  
Beef Production ◽  
Calving Difficulty

The selection objective of the SAC Simmental MOET Project, is to improve the economic efficiency of lean, or saleable, meat production in crossbred beef production systems.The factors which contribute to the selection objective are the yield of saleable meat, feed intake and calving difficulty. These goal characteristics are combined into an index by taking into account their respective financial values and costs. Calves generated by multiple ovulation and embryo transfer (MOET) are weaned from their recipient dams at 10 weeks old and placed in performance test from 5 to 11 months of age. At the end of the performance test, saleable meat yield is estimated from liveweight at end of test, ultrasonic fat depth measurements and muscling score. Calving difficulty is predicted from the birthweight and gestation length of the animal on test whilst feed intake is measured directly by recording individual food intakes during performance testing. The estimated breeding value for the selection index of an animal is expressed in £'s (pounds sterling) as deviations from a mean of zero for the SAC population of Simmentals. It is calculated using the information for each animal plus that of all its relatives in its own and other performance tests by means of BLUP procedures.The objective of the work described here was to evaluate the effectiveness of the selection index in identifying sires of superior genetic merit for use in crossbred beef production systems.

Design of Small Centrifugal Compressors Performance Test Facility

2004 ◽  
Author(s):  
Fahad A. Al-Sulaiman ◽  
Amro M. Al-Qutub
Keyword(s):  
Performance Test ◽  
Performance Testing ◽  
Selection Procedure ◽  
Power Input ◽  
Test Facility ◽  
Design Stage ◽  
Centrifugal Compressors ◽  
Drive Unit ◽  
Actual Performance ◽  
Wide Range

Actual performance testing is a key element in the design stage, development and troubleshooting of centrifugal compressors. The present work discusses the procedure for designing the experimental setup and the selection of drive unit for variable centrifugal compressors sizes. It starts with setting criteria of selection. A survey over different types of drive units and facility setup was conducted. It was found that the electric drive unit with the aid of transmission for stepping-up the speeds is the most suitable type. This is due mainly to the excellent control property of electric motors allowing for wide range of operational speed and power. A new methodology was developed for selecting operational power and speeds of the drive unit for different sizes of impellers. The code, used for the analysis, was developed by the authors. It calculates the range of input power, input torque, and rotational speeds, as well as, the mass flow rate, total pressure and temperature ratios for different sizes of impellers. This will aid in selecting the proper instrumentation for the experiments. The code used for design methodology is based on one dimensional through flow formulation and validated with experimental results in the literature. It is expected that the present methodology will enhance selection procedure for designing compressor test facility.

Influence of the correlation between growth rate and backfat on selection response in pigs

1990 ◽  
Vol 1990 ◽  
pp. 84-84
Author(s):  
P. R. Bampton ◽  
A. J. Webb
Keyword(s):  
Growth Rate ◽  
Performance Test ◽  
Performance Testing ◽  
Selection Response ◽  
Economic Traits ◽  
Lean Growth ◽  
Genetic And Phenotypic Correlations ◽  
Ad Libitum ◽  
Selection For ◽  
Ad Libitum Feeding

Backfat levels in pigs have declined rapidly in the last decade and are approaching an economic optimum. As optimal levels of backfat are achieved this has two important implications for selection objectives. First, the relative emphasis of selection will shift to other traits, particularly lean growth rate. Second, there will also be a move towards ad libitum feeding on performance test to allow expression of appetite and to increase response to selection for lean growth rate. The effect of very lean pigs coupled with ad libitum feeding may result in changes in the genetic and phenotypic relationship between growth rate and fat depths. Reported genetic and phenotypic correlations between growth rate and backfat range from +0.3 on ad libitum feeding to -0.3 on restricted feeding. In most performance testing regimes the key relationship is between growth rate and ultrasonic fat depths which in contrast to other economic traits are often unfavourably correlated.

Heritability of teat number and its relationship to production characters in male pigs

1986 ◽  
Vol 26 (5) ◽  
pp. 539 ◽  
Author(s):  
PR Smith ◽  
CP McPhee ◽  
WJ Natoli
Keyword(s):  
Growth Rate ◽  
Performance Testing ◽  
Heritability Estimate ◽  
Conversion Ratio ◽  
Feed Conversion Ratio ◽  
Feed Conversion ◽  
Large White ◽  
Phenotypic Correlations ◽  
Teat Number

Heritability of teat number and its correlation with the production characters, growth rate, feed conversion ratio and backfat depth, were examined. Data were obtained from 456 Large White, 1370 and race and 78 Synthetic boars submitted to the Queensland boar performance testing station.Teat number (mean � s.e.) of Large White boars was 14.44 � 0.05, significantly ( P < 0.05) more than either Landrace (14.27 � 0.03) or Synthetic boars (14.10 �0.12). The heritability estimate (� s.e.) for teat number of boars was 0.20 �0.08 obtained from L paternal half-sib analysis of 1519 boars from 198 sires. Phenotypic correlations between teat number and the production characters were all almost zero.

Genetic changes in Canadian performance-tested pigs for fat depth and growth rate

1996 ◽  
Vol 76 (1) ◽  
pp. 41-48 ◽  
Author(s):  
B. W. Kennedy ◽  
V. M. Quinton ◽  
C. Smith
Keyword(s):  
Growth Rate ◽  
Performance Testing ◽  
Economic Benefits ◽  
Breeding Value ◽  
Improvement Program ◽  
Linear Unbiased Prediction ◽  
Genetic Changes ◽  
Best Linear Unbiased ◽  
The Mean ◽  
Genetic Trends

Data on more than 1.3 million pigs of four breeds in four regions of Canada were used to estimate genetic changes in fat depth and growth rate from 1976 to 1993. Analysis was by a multi (two)-trait best linear unbiased prediction (BLUP) animal model within breed and across regions. The genetic changes were measured as the changes in average estimated breeding value (EBV) over years.The across-breed average total phenotypic changes from 1976 to 1993 were− 3.9 mm in fat depth (26% of the mean) and− 17 d in age at 100 kg (9% of the mean). The multi-trait BLUP estimates of the genetic trends were similar to single-trait BLUP estimates. The mean EBV and the changes were similar for the four regions. The changes were larger in the Landrace and Yorkshire breeds than in the Duroc and Hampshire. The overall genetic trends were − 1.44% of the mean yr−1 in fat depth and − 0.36% of the mean yr−1 in age at 100 kg. The trend for age at 100 kg increased over time as better methods of deriving the EBV were implemented. The current rates of pig improvement in Canada are good and yield large economic benefits. However, they could be improved to recoup the full gains possible through the Canadian Swine Improvement Program. Key words: Canadian pigs, performance testing, genetic trends

scholarly journals TWO-STAGE COOKING AS A METHOD OF IMPROVING THE NUTRITIVE VALUE OF JACKBEAN (Canavalia ensiformis) FOR BROILERS

2021 ◽  
Vol 23 (2) ◽  
pp. 107-110
Author(s):  
A. B. I. UDEDIBIE ◽  
B. O. ESONU ◽  
C. UNACHUKWU ◽  
N. C. IWUOMA
Keyword(s):  
Growth Rate ◽  
Broiler Chickens ◽  
Nutritive Value ◽  
Human Consumption ◽  
Feed Conversion ◽  
Feeding Trial ◽  
Two Stage ◽  
Canavalia Ensiformis ◽  
Cooking Water ◽  
The Village

  A 4 - week feeding trial was conducted to determine the effect of 2-stage cooking on the 1988; Wyss and Bickel, 1988). The best known nutritive value of jackbean (Canavalia ensiformis) for broilers. Two-stage cooking is one of the practices employed in the village for preparing toxic foodstuffs for human consumption. Jack Beans were cooked for 40 minutes at the end of which the cooking water was thrown out. Fresh water was added and it was valuable as a protein and energy supplement cooking continued thereafter for another 40 minutes. The two-stage cooked jackbeans were dried, ground and included in a broiler finisher diet at 0,10,15 and 20% levels, respectively, and each diet fed to 30 broiler chickens for 4 weeks. There were no significant (P <0.05) differences in feed intake, growth rate and feed conversion ration among the four experimental groups.

scholarly journals Analysis of the Possibility of Improving the Indicators of Pork Quality Through Selection with Particular Consideration of Intramuscular Fat (MF) Content / Analiza możliwości poprawy wskaźników jakości wieprzowiny na drodze selekcji ze szczególnym uwzględnieniem zawartości tłuszczu śródmięśniowego (IMF)

2013 ◽  
Vol 13 (1) ◽  
pp. 33-44 ◽  
Author(s):  
Mirosław Tyra ◽  
Grzegorz Żak
Keyword(s):  
Meat Quality ◽  
Genetic Correlations ◽  
Performance Testing ◽  
Intramuscular Fat ◽  
Breeding Value ◽  
Entire Group ◽  
Quality Traits ◽  
Feed Conversion ◽  
Meat Quality Traits ◽  
Imf Content

Abstract The aim of the study was to estimate coefficients of heritability for intramuscular fat (IMF) content and other fattening, slaughter and meat quality traits of the pig breeds raised in Poland. In addition, genetic correlations were estimated between IMF content and a group of fattening, slaughter and meat quality traits, which enables this parameter to be included in the BLUP estimation of breeding value. The experiment used Polish Landrace (PL), Polish Large White (PLW), Puławska, Hampshire, Duroc, Pietrain and line 990 animals. A total of 4430 gilts of these breeds, tested at Pig Performance Testing Stations (SKURTCh), were investigated. Heritability of IMF was at intermediate level for the two most common breeds raised in Poland (h2 = .318 for PLW, h2 = .291 for PL). In the group of meat quality traits, high heritability was noted for meat colour lightness (L*) measured by Minolta (from h2 = .453 to h2 = .572). No relationships were found between IMF level and indicators of fattening performance. The highest value observed in this group of traits concerned the genetic relationship with daily feed intake (rG = .227) for the entire group of animals. For the PLW and PL breeds, these relationships were with feed conversion (kg/kg gain) (rG = .151 and rG = .167, respectively). One of the higher relationships observed were genetic correlations with water holding capacity (above rG = -.3) and, for the PLW and PL breeds, with meat redness (a*), which amounted to rG = .155 and rG = .143, respectively.

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