Economic values for production and functional traits in Holstein cattle of Costa Rica

Vargas, B.; Groen, A.F.; Herrero, Mario; Arendonk, J.A.M. van

doi:10.1016/s0301-6226(01)00305-0

Cited by 37 publications

(48 citation statements)

References 25 publications

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“…This is a questionable assumption, because both sexes are generally kept under the same feeding conditions till weaning (or till the end of rearing of dairy calves), and both sexes are used for fattening (especially in sheep). Vargas et al (2002) changed the mature body weight parameter a in the Brody growth curve, causing a shift in the entire growth curve; moreover, they expressed the EV for the growth potential per change in body weight of heifers at 28 month of age (the only growth trait evaluated).Linear approximations of parts of the growth curve The third approach for the calculation of EVs for growth traits uses the growth curve to estimate animal weight at specified ages. On the basis of these weights, linear daily gains for the sequential age intervals are calculated.…”

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confidence: 99%

“…Roughsedge et al (2005) related the effect of changes in the calving interval in all lactations to the appropriate change in the first calving interval. Vargas et al (2002) chose the average performance of a heifer with an age at first calving of 28 months and with a calving interval of 12 months as reference value for milk production traits, and then applied multiplicative factors to adjust for different ages, parities and calving intervals. For conception rate, the reference trait was the value obtained for a single insemination at the 2nd month of the first lactation.…”

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Strategies for defining traits when calculating economic values for livestock breeding: a review

Wolfová

Wolf

2013

Animal

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The objective of the present review was (i) to survey different approaches for choosing the complex of traits for which economic values (EVs) are calculated, (ii) to call attention to the proper definition of traits and (iii) to discuss the manner and extent to which relationships among traits have been considered in the calculation of EVs. For this purpose, papers dealing with the estimation of EVs of traits in livestock were reviewed. The most important reasons for incompatibility of EVs for similar traits estimated in different countries and by different authors were found to be inconsistencies in trait definitions and in assumptions being made about relationships among traits. An important problem identified was how to choose the most appropriate criterion to characterise production or functional ability for a particular class of animals. Accordingly, the review covered the following three topics: (i) which trait(s) would best characterise the growth ability of an animal; (ii) how to define traits expressed repeatedly in subsequent reproductive cycles of breeding females and (iii) how to deal with traits that differ in average value between sexes or among animal groups. Various approaches that have been used to solve these problems were discussed. Furthermore, the manner in which diverse authors chose one or more traits from a group of alternatives for describing a specific biological potential were reviewed and commented on. The consequences of including or excluding relationships among economically important traits when estimating the EV for a specific trait were also examined. An important conclusion of the review is that, for a better comparability and interpretability of estimated EVs in the literature, it is desirable that clear and unique definitions of the traits, complete information on assumptions used in analytical models and details on interrelationships between traits are documented. Furthermore, the method and the model used for the genetic evaluation of specific traits in a certain breeding organisation are important for the exact definition of traits, for which the economic values will be calculated, and for the inclusion or exclusion of relationships among traits in the calculation of the EVs in livestock breeding. Keywords: livestock, economic values, definition of traits, relationships among traits ImplicationsA literature review was conducted on different ways of defining traits and considering relationships among them in the calculation of economic values (EVs) in livestock breeding. Diversity among trait definitions makes it difficult to compare EVs from different investigations and individual authors. It was shown that, for the EV of a trait to be correctly interpreted, it is necessary to know exactly how the trait was defined, how its relationships with other traits were accounted for and what assumptions were made in the model for the calculation of EVs. IntroductionHazel (1943) proposed the breeding objective or aggregate genotype of an animal to be defined as 'the sum of its sever...

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Strategies for defining traits when calculating economic values for livestock breeding: a review

Wolfová

Wolf

2013

Animal

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“…These analyses focus mainly on the impact of changes in economic input parameters (product prices and costs) and on the impact of output or input restrictions (milk or meat quotas, restricted feed resources). See, for example, Kosgey et al (2003), Haghdoost et al (2008) and Byrne et al (2010) in meat sheep and Wolfová et al (2001) and Vargas et al (2002) in dairy cattle. Fewer sensitivity analyses have investigated the influence of performance levels of traits or of management practices on MEVs or on REVs.…”

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Impact of production strategies and animal performance on economic values of dairy sheep traits

Krupová

Wolfová

Krupa

et al. 2012

Animal

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The objective of this study was to carry out a sensitivity analysis on the impact of various production strategies and performance levels on the relative economic values (REVs) of traits in dairy sheep. A bio-economic model implemented in the program package ECOWEIGHT was used to simulate the profit function for a semi-extensive production system with the Slovak multi-purpose breed Improved Valachian and to calculate the REV of 14 production and functional traits. The following production strategies were analysed: differing proportions of milk processed to cheese, customary weaning and early weaning of lambs with immediate sale or sale after artificial rearing, seasonal lambing in winter and aseasonal lambing in autumn. Results of the sensitivity analysis are presented in detail for the four economically most important traits: 150 days milk yield, conception rate of ewes, litter size and ewe productive lifetime. Impacts of the differences in the mean value of each of these four traits on REVs of all other traits were also examined. Simulated changes in the production circumstances had a higher impact on the REV for milk yield than on REVs of the other traits investigated. The proportion of milk processed to cheese, weaning management strategy for lambs and level of milk yield were the main factors influencing the REV of milk yield. The REVs for conception rate of ewes were highly sensitive to the current mean level of the trait. The REV of ewe productive lifetime was most sensitive to variation in ewe conception rate, and the REV of litter size was most affected by weaning strategy for lambs. On the basis of the results of sensitivity analyses, it is recommended that economic values of traits for the overall breeding objective for dairy sheep be calculated as the weighted average of the economic values obtained for the most common production strategies of Slovak dairy sheep farms and that economic values be adjusted after substantial changes in performance levels of the traits.

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“…, nutrition (Kadokawa and Martin, 2006;Robinson et al, 2006;Chagas et al, 2007;Friggens and Newbold, 2007;Wathes et al, 2007) Economics (Vargas et al, 2002;Esslemont, 2003;Santarossa et al, 2004;McGuirk et al, 2007), veterinary interventions and management (Refsdal, 2000;Roche et al, 2000;Sheldon et al, 2004;Bertoni et al, 2006;Diskin et al, 2006;Drillich et al, 2006;Mansell et al, 2006;Mee, 2007;Valergakis et al, 2007). It has also prompted the development of new technology and applications in the field.…”

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Fertility in dairy cows: bridging the gaps

Royal

Smith

Friggens

2008

Animal

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Economic values for production and functional traits in Holstein cattle of Costa Rica

Cited by 37 publications

References 25 publications

Strategies for defining traits when calculating economic values for livestock breeding: a review

Strategies for defining traits when calculating economic values for livestock breeding: a review

Impact of production strategies and animal performance on economic values of dairy sheep traits

Fertility in dairy cows: bridging the gaps

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