A note on the estimation of economic values for selection indices

1980 ◽  
Vol 31 (1) ◽  
pp. 115-117 ◽  
Author(s):  
R. Thompson
Keyword(s):  
Profit Function ◽  
Economic Values ◽  
Mean Values ◽  
Selection Indices

ABSTRACTA procedure has recently been developed for estimating economic values which employs a profit function implying that animals with mean values for variates in the profit function give the most profit. However, the proposed index selects extreme animals, a paradox which is explained by showing that the index is appropriate for only part of the profit function. More appropriate selection indices are developed and illustrated graphically.

Estimation of economic values for selection indices

1979 ◽  
Vol 28 (3) ◽  
pp. 279-286 ◽  
Author(s):  
Bryan E. Melton ◽  
Earl O. Heady ◽  
Richard L. Willham
Keyword(s):  
Production Function ◽  
Selection Index ◽  
Profit Function ◽  
Economic Values ◽  
First Order ◽  
Numerical Example ◽  
Selection Indices ◽  
Index Value ◽  
Derivatives Of ◽  
Production Conditions

ABSTRACTA procedure to estimate economic values for use in selection indices is developed. A profit function is specified and a production function that links output to the several inputs developed. The profit function is maximized by equating the partial derivatives of the function with respect to each input to zero and simultaneously solving the resulting system of first-order equations for optimal levels of the variables. These variables include economic values for animal traits and levels of exogenous, producer-supplied inputs. The economic values are then used in a selection index. The resulting index value is therefore determined by the average values of the traits, the available inputs and their prices, output price and the specified production function. The procedure has the flexibility, through varying these parameters, to provide index solutions that are tailored to suit individual production conditions. A numerical example is provided.

Testing selection indices for sustainable hill sheep production – lamb growth and carcass traits

2006 ◽  
Vol 82 (4) ◽  
pp. 445-453 ◽  
Author(s):  
J. Conington ◽  
S. C. Bishop ◽  
N. R. Lambe ◽  
L. Bünger ◽  
G. Simm
Keyword(s):  
Flock Size ◽  
Economic Values ◽  
Maternal Characteristics ◽  
Selection Indices ◽  
Best Linear Unbiased ◽  
Selection Indexes ◽  
Sheep Production ◽  
On Farm ◽  
Lamb Growth

AbstractTwo selection indexes, one intended for lamb producers and finishers and one for store lamb producers, were derived using genetic parameters for carcass and maternal characteristics from Conington et al. (2001) and economic values from Conington et al. (2004). This paper summarizes responses to selection for lamb traits only, after 5 years of selection (1998 to 2003) on two farms using these selection indexes. The index for lamb producers and finishers, evaluated on farm 1, with a flock size of 680 ewes, includes economic weightings for maternal traits as well as carcass weight, fat and conformation grades, whereas the index for store lamb producers, evaluated on farm 2, with a flock size of 580 ewes, only includes economic values for maternal traits and lamb growth to weaning. Three selection lines of Scottish Blackface sheep per farm were created with the first lambs born to each line in 1999. These lines were selection (S), control (C) and industry (I); they were of equal size on each farm. Five top- and five average-performing ram lambs were selected each year for the S and C lines respectively using a multi-trait best linear unbiased prediction (BLUP) implementation of the indexes. The I-line used four mature rams bought from industry, selected on appearance only, i.e. adherence to breed ‘type’. Results showed that 5 years after the implementation of the index, the S line had significantly higher index scores than the C or I lines on both farms. The means (s.d.) for the average index scores in 2003 are 114 (328), 119 (371) and 451 (328) (farm 1), and −8 (146), −11 (130), and 250 (129) (farm 2) for the C, I and S lines, respectively, giving predicted net differences (S-C) of £3·38 (farm 1) and £2·58 (farm 2) per ewe. Phenotypic responses showed significant S v. C differences in weaning weight on both farms. As predicted from previous analyses, no changes in carcass quality traits were seen at farm 1 although S-line carcass weights tended to be heavier than those from the C or I lines. The results show that genetic improvement using multi-trait selection indices has been successful and it is a viable, long-term strategy to improve levels of production for hill sheep in extensive environments.

Determining the appropriate selection index for Rayeni Cashmere goat under pasture-based production system

2018 ◽  
Vol 58 (9) ◽  
pp. 1595
Author(s):  
Najmeh Kargar Borzi ◽  
Ahmad Ayatollahi Mehrgardi ◽  
Masood Asadi Fozi ◽  
Mahmood Vatankhah
Keyword(s):  
Production System ◽  
Selection Criteria ◽  
Selection Index ◽  
Economic Value ◽  
Herd Size ◽  
Cashmere Goat ◽  
Economic Values ◽  
Economic Weights ◽  
Selection Indices ◽  
Beneficial Traits

The aim of the present study was to identify the significance of Rayeni Cashmere goat’s socioeconomic traits so as to derive economic weights for the selection criteria that can be used easily by goat breeders. A deterministic bio-economic model was used to estimate economic value for adult bodyweight of doe (BWD), annual milk yield (MW), annual cashmere weight (CW), bodyweight of kids sold at 6.5 months (WK), and number of kids sold at 6.5 months per doe (NK). The relative importance of traits was determined on the basis of the estimated economic values, and, consequently, the most beneficial traits were applied to construct selection indices. Five selection indices with different herd sizes and buck ratios were proposed (I1–I5). The traits included in each index were as follows: BWD, MW, CW, WK and NK (I1); MW, CW, WK and NK (I2); BWD, MW, WK and NK (I3); BWD, MW and CW (I4); and BWD, CW, WK and NK (I5). Absolute economic values (US$) of BWD, MW, CW, WK and NK traits were $–0.870, $0.111, $5.660, $21.655 and $1.712 respectively. The results indicated that in all indices, the genetic and economic gains were elevated by an increased herd size and a decreased buck ratio. The maximum values of genetic and economic gains were obtained in herd size of 400 and buck ratio of 0.04. The highest genetic gain was obtained under Index 1, while the highest amount of economic gain was acquired under Index 2; however, the maximum accuracy of selection index was achieved under Index 1. The obtained results revealed that the most appropriate selection index for this breed is Index 1, which includes BWD, MW, CW, WK and NK. By applying Index 1, we could concurrently promote improvement of all traits, which highlights the potential of this index as a good promising strategy for developing selection criteria of Rayeni Cashmere goat under a pasture-based production system.

The derivation of economic values in breeding programs for Australian Merino sheep with changing wool prices and flock production averages

1990 ◽  
Vol 41 (4) ◽  
pp. 769 ◽  
Author(s):  
DJ Cottle
Keyword(s):  
Genetic Change ◽  
Future Price ◽  
Index Selection ◽  
Optimal Method ◽  
Breeding Programs ◽  
Economic Values ◽  
Merino Sheep ◽  
Selection Indices ◽  
The Impact ◽  
Australian Merino

The impact of fluctuating wool prices on setting economic values (EVs) in selection indices, e.g. WOOLPLAN, are studied by modelling genetic change in a flock following index selection, Operating under different wool price regimes. Because future price changes are difficult to predict, there is no guaranteed, optimal method of determining EVs. One possibility is the use of a moving regression of the last five years' wool prices (in real terms), rather than setting the index once, or every five years, or every year, based on current prices. The ratio (R) of clean wool price to micron premium is more important than actual prices. It is suggested that the default EVs used currently in WOOLPLAN are appropriate for strong wool Merino flocks. The choice and implications of EVs in other situations are discussed.

Economic values and selection indices for production and reproduction traits of Iranian buffaloes (Bubalus bubalis)

2019 ◽  
Vol 51 (5) ◽  
pp. 1209-1214
Author(s):  
Abbas Safari ◽  
Abdol Ahad Shadparvar ◽  
Navid Ghavi Hossein-Zadeh ◽  
Rostam Abdollahi-Arpanahi
Keyword(s):  
Bubalus Bubalis ◽  
Economic Values ◽  
Selection Indices ◽  
Reproduction Traits

scholarly journals Deriving Economic Values for Female Reproductive Traits in Lifetime Carcass Production of Japanese Black Cows Using Deterministic Profit Function

Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1055
Author(s):  
Shinichiro Ogawa ◽  
Suguru Kitajima ◽  
Hayato Saito ◽  
Masahiro Satoh
Keyword(s):  
Carcass Traits ◽  
Market Price ◽  
Regression Equation ◽  
Quadratic Term ◽  
Profit Function ◽  
High Quality ◽  
Economic Values ◽  
Response Variable ◽  
Feeder Cattle ◽  
First Order

Improving reproductive efficiency is required to strengthen the production base of high-quality Wagyu beef in Japan. We developed a deterministic profit function (P) for lifetime carcass production of Japanese Black cows to calculate economic values (EVs) for representative female reproductive and carcass traits. The total calving number per cow was expressed using the age at first calving (AFC) and calving interval (CI). Revenues and costs were calculated from calf market price (CaP) and carcass unit price (CUP). A cubic regression equation was developed with CaP as the response variable and calf market weight as the explanatory variable. A multiple linear regression equation was developed with CUP as the response variable and five carcass traits as explanatory variables. EVs were calculated using the first-order partial derivatives of P. The first-order partial derivative of CI was a function of CI with the quadratic term of CI in the denominator. Values of EVs for AFC and CI were negative, suggesting that earlier AFC and shorter CI increase the lifetime profit of Japanese Black cows through producing higher numbers of feeder cattle per cow. However, this might bring benefit to only calf-producing farmers. The results would contribute to achieving sustainable high-quality Wagyu beef production.

scholarly journals Estimation of the economic values for the important traits of Zel Sheep in the intensive production system using a bio-economic model

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Kian Pahlevan Afshari ◽  
Mehran Aboozari
Keyword(s):  
Economic Model ◽  
Production System ◽  
Live Weight ◽  
Mazandaran Province ◽  
Economic Values ◽  
Mean Values ◽  
Income Sources ◽  
Intensive Production ◽  
Important Trait ◽  
Feed Costs

To estimate economic values (EVs) of seven important traits including pregnancy rate (PR), litter size (LS), lamb weight at birth (BW0), three (weaning; BW3), six (BW6) and nine (BW9) months weight and survival rate until the age of 6 months (SR) in Zel sheep under an intensive production system in Mazandaran province of Iran, data from two farms were analysed using a bio-economic model. Variable costs accounted for about 99% of the total costs and the feed costs had the highest proportion with 72.54%. Among the income sources, the sale of surplus animals formed 81.4% of the total revenues. The EVs were estimated as the amount of change in the profit of the system after each trait mean increased by both 1% and one unit, while all other traits were constant at their mean values. The most important trait in this system was LS, followed by SR, PR, BW9, BW3, BW6 and BW0 respectively. The sensitivity of EVs was investigated by changing prices of feed and live weight of 9-month-old lambs by ±20%. Results showed that the EV of BW9 was the most constant and EV of BW0 was the most variable. As the prices of feed and live weight of 9-month-old lambs were simultaneously changed by ±20%, the variation in the EVs decreased and they showed more consistency. This study showed that the profitability in an intensive production system of Zel sheep could be increased by improving LS, SR, PR and BW9.

A note on the estimation of economic values for selection indices: a response

1994 ◽  
Vol 59 (3) ◽  
pp. 455-459 ◽  
Author(s):  
B. E. Melton ◽  
R. L. Willham ◽  
E. O. Heady
Keyword(s):  
Theoretical Basis ◽  
Profit Maximization ◽  
Economic Values ◽  
Economic Theories ◽  
Economic Behaviour ◽  
Selection Indices ◽  
Multitrait Selection ◽  
Firm Profit

Various procedures for estimating the economic values required to weight characteristics in multitrait selection have been proposed. Some, despite their theoretically sound foundations, are frequently misinterpreted. One such method involves the derivation of economic values based upon accepted economic theories of the firm, profit maximization, and the concepts of marginal economic behaviour. An amplified and more rigorous presentation of this method and its theoretical basis is presented that confirms the basic propriety of the method, clarifies the misinterpretations surrounding its application, and offers additional insights into the potential fallacy of less economically rigorous alternatives.

Articulatory Behavior Pre and Post Full-Mouth Tooth Extraction and Alveoloplasty

1980 ◽  
Vol 23 (3) ◽  
pp. 630-645 ◽  
Author(s):  
Gerald Zimmermann ◽  
J.A. Scott Kelso ◽  
Larry Lander
Keyword(s):  
Control Subject ◽  
High Speed ◽  
Tooth Extraction ◽  
Kinematic Parameters ◽  
Experimental Conditions ◽  
Mean Values ◽  
Articulatory Movements ◽  
The Mean ◽  
Experimental Subjects ◽  
Normal Speech

High speed cinefluorography was used to track articulatory movements preceding and following full-mouth tooth extraction and alveoloplasty in two subjects. Films also were made of a control subject on two separate days. The purpose of the study was to determine the effects of dramatically altering the structural dimensions of the oral cavity on the kinematic parameters of speech. The results showed that the experimental subjects performed differently pre and postoperatively though the changes were in different directions for the two subjects. Differences in both means and variabilities of kinematic parameters were larger between days for the experimental (operated) subjects than for the control subject. The results for the Control subject also showed significant differences in the mean values of kinematic variables between days though these day-to-day differences could not account for the effects found pre- and postoperatively. The results of the kinematic analysis, particularly the finding that transition time was most stable over the experimental conditions for the operated subjects, are used to speculate about the coordination of normal speech.

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