Year: 2000
Type: dissertation
Abstract: Over 90% of beef produced in Finland is generated as a by-product of milk production with dairy breed animals, the majority of which are pure-bred Finnish Ayrshires.Some beef production traits have long been included in the breeding programs of dairy cattle breeds, but the selection pressure on these beef traits has remained weak.Consequently, the carcass quality of Finnish dairy cattle breeds is relatively poor, and the current income from beef for farmers is low.Upon joining the European Union in 1995, Finland formally adopted a new national cattle identification system.When this new system is fully operating throughout the cattle production chain, it will be possible to routinely acquire large amounts of carcass data directly from slaughterhouses.This new source of data will offer many opportunities for animal breeders to improve beef production traits.The objective of this study was to collect basic information on routinely collected field carcass data to see how it could best be used in genetic evaluation of dairy breeds for beef production traits.To this end, a data set of 122 000 carcasses was obtained from six slaughterhouses.From this data, the genetic parameters for carcass traits of bulls, heifers and cows were estimated, and non-genetic factors affecting the carcass traits of dairy breed animals were studied.Carcass data was further combined with milk recording data, and genetic correlations of carcass traits with milk production traits were estimated.Alternative strategies for combining carcass traits into breeding programs of dairy cattle were also studied.Effects of including carcass traits in breeding goals of dairy cattle were analysed, and different information sources for carcass traits in sire evaluations were compared.In addition, efficiency of simplified and multi-trait evaluations, and one-stage and multi-stage selection for carcass and milk traits in sire selection were compared.Based on the analyses of selection strategies, it is feasible to expand the total merit index of Finnish dairy cattle breeds to include carcass traits.The inclusion of carcass traits in the breeding goal does not hinder progress of milk traits.It would also reflect the income sources of the farms better.Data for progeny testing young AI-sires for carcass traits is already available due to the evaluation system of AI-sires in Finland, which ensures close to 200 sons for each tested bull.Results show that it is possible to breed for improved carcass weight and quality of young Finnish Ayrshire and Holstein-Friesian slaughter animals.The carcass traits are heritable, although the heritability estimates of bull and heifer carcass traits were relatively low.The genetic correlations of bull and heifer carcass traits are also generally favourable, both among themselves and between the carcass traits and milk production traits.The relatively high heritability of carcass traits of cows suggest that it would be easy to breed for improved carcass quality and optimal body weight of dairy cows.Although dairy cows are not intended for beef production, improved carcass fatness and fleshiness, and thus, improved body condition, might help to reduce stress caused by lactation in high-yielding cows.Due to the negative genetic correlations estimated between the carcass quality and milk traits of dairy cows, their carcass fatness and fleshiness will continue to deteriorate as a result of selection on milk production traits unless some counteractive selection is practised.Reliable breeding values for carcass traits can be estimated for young dairy AI-sires based solely on their male progeny, but inclusion of some carcass information on female progeny might also be of value, especially in predicting carcass fatness more accurately.If body weight and condition of dairy cows are of interest, including some cow carcass data in selection decisions is necessary.Young dairy AI-bulls have been tested in official testing stations for their own growth rates in Finland since the mid-1960s.The importance of sires' own growth in selection of dairy breed sires has, however, been on the decline for years.In future, if all test sires get breeding values for carcass weight and carcass quality traits based on their progeny information, the need for an individual growth testing period for sires themselves will have to be reconsidered.Large differences exist between proven sires with respect to carcass breeding values.Among Finnish Ayrshire, in particular, individual sires can be found that combine excellent milk production, health and fertility traits with good carcass weight and carcass quality traits.If animal breeding associations do not want to further expand the breeding goals of dairy cattle breeds, they could promote the use of sires with good carcass breeding values by, for example, annually naming some "dual-purpose" sires with both promising milk and beef traits.
Source: Työväentutkimus Vuosikirja
Author: Anna-Elisa Liinamo
Language: English
Subfield: Genetics
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W1510941177