Genetics of adaptation in domestic farm animals: a review

Selection for Profit in Cattle: I. Economic Weights for Purebred Dairy Cattle in the Czech Republic

Incidence and economics of clinical mastitis in five Holstein herds in the Czech Republic.

The inclusion of functional traits in a total merit index is expected to have some consequences on the design of progeny testing schemes in dairy cattle. Due to the usually low heritabilities of functional traits more daughter records per sire seem to be necessary to improve the accuracy of the breeding values of these traits. A complex deterministic approach was used to optimize the design of progeny testing schemes for Austrian Simmental and Brown Swiss cattle. The total merit index for Simmental included dairy traits (fat and protein yield), beef traits (daily gain, dressing percentage, EUROP grading score) and functional traits (functional longevity, persistency, fertility, calving ease, stillbirth and somatic cell count); the Brown Swiss total merit index consisted of dairy and functional traits only. The proportion of recorded cows mated with test bulls (test capacity) and the number of test bulls were varied. Annual monetary genetic gain and discounted profit were used to evaluate the different progeny testing schemes. The inclusion of functional traits in a total merit index has a positive effect on the annual monetary genetic gain. The annual genetic gains of functional traits are either positive or at least the negative trend can be reduced. Extending the number of daughter records per test bull from 60 (current situation) up to around 100 leads to a small increase of annual monetary genetic gain for Simmental, whereas no positive effect can be found for Brown Swiss. Discounted profit can be considerably improved, especially for Brown Swiss.  2002 Elsevier Science B.V. All rights reserved.

https://journal.interbull.org/index.php/ib/article/view/397/396

Optimisation of progeny testing schemes when functional traits play an important role in the total merit index

proportional hazards method was used to estimate breeding values for functional length of productive life within the endangered Slovak Pinzgau population. The analyzed data set contained 21,985 cows, daughters of 254 sires. The risk of culling was higher for cows with lower milk production relative to herd average, higher age at first calving and in herds decreasing in size. In the first lactation the culling risk was highest at the beginning, and decreased during lactation. From second lactation onwards an increasing risk was observed. The effect of breed composition was found insignificant, and was not included into final model. A heritability of 0.05 was estimated for functional length of productive life. The average reliability of estimates was 0.25. No clear tendency in average breeding values by year of birth of bulls was observed.

/pdf/genetic-evaluation-for-length-of-productive-life-in-slovak-51hh47rtkz.pdf

Genetic evaluation for length of productive life in Slovak Pinzgau cattle

. The economic efficiency of dual purpose cattle is influenced by a large number of traits which may be classified in groups of dairy, beef and functional traits. The combination of estimated breeding values for single traits in a total merit index, as long practised in some Scandinavian countries, is currently being implemented in a number of Central European states. Economic values for populations of dual purpose cattle in Austria derived from a deterministic herd model are presented. Traits in the dairy group are fat and protein yield; beef traits are daily gain, dressing percentage and carcass conformation; functional traits are longevity, persistency, fertility, calving ease, stillbirth and somatic cell count. A rough average over populations of the relative economic importance of dairy vs. beef vs. functional traits is 37:18:45 (economic weights of the traits are scaled with their genetic Standard deviations, differences in expression of traits are taken into account). Due to the covariance structure of the traits most of the gain is expected for fat and protein yield (moderate heritabilities and high positive correlation of the two traits). The proportions in expected monetary gains from the three sets of traits are 81:9:10. Omission of beef and functional traits from the index would lead to a 13 percent loss in total merit and negative responses for beef and functional traits. Inclusion of conformation as an early predictor of longevity has very little effect on total merit. The indices presented are compared with total merit indices used in other European countries.

/pdf/total-merit-indices-in-dual-purpose-cattle-vzchkel4wo.pdf

Josef Miesenberger

Papers

Total merit indices in dual purpose cattle