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VikingNews Global 1-2019
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proximately 40
bulls
are selected to be part of the yearly breeding
pro- gramme; and no more than three sons will come from the same sire (family). ?at vikinggenetics we use new bulls from 20 different sires of sons or family lines every year,? larson says. what is more, sires only stay on the active marketing list until such time the managers of the breeding pro- gramme decides the sire has contrib- uted enough to the gene pool in the population (normally for only 6-9 months). keeping a close eye on the number of sires of sons is not the only strict control vikinggenetics uses to design the breeding programme. saija tenhu- nen, breeding specialist at vikingge- netics explains that there is a high-quality support programme that focuses on population management to avoid inbreeding
. ?we also offer our own breeding tool vikmate, which enables us to control inbreeding and genetic gain at herd level. if mating plans are created in vikmate, we can limit the increase of inbreeding in a herd and find the most suitable sires based on the traits of interest. as such, we focus on con- trolling the problems caused by in- breeding at both population level and herd level,? she says. what does inbreeding cost you? inbreeding can cause many undesira- ble effects that reduce profitability. in- bred animals have lower fertility, re- duced milk production and a higher risk of contracting diseases resulting in a shorter productive life as well as more stillborn calves or born with ab- normalities. the council on dairy cattle breeding (cdcb) based in the united states, calculated the financial cost of one percent of inbreeding de- pression to better understand why it is important to prevent inbreeding. table 1 shows the size of the in- breeding depression for different traits per 1% increase in inbreeding. a con- servative estimate of how much 1% increased inbreeding would influence the lifetime net income is minus us$ 24.60 per cow by the year 2017. in us jerseys, the average inbreed- ing percentage in heifers born in 2018 is 8.09%, which will cause a consid- erable drop in production as well as in lifetime profitability. a better measurement of calculat- ing the effects of inbreeding is actually to look at future inbreeding instead of observed inbreeding per se. according to cdbc, in december 2018, the ex- pected future inbreeding among heif- ers born in us in 2019 is 8.1%, while the future inbreeding percentage for heifers from vikingjersey bulls would instead be 4.7% on average. that ef- fect is possible because of the different lineages in the danish jersey popula- tion compared to the us jersey popu- lation. importance of genetic diversity with closer relationships between an- imals in a population, the risk of ge- netic defects increases. ?when undesirable recessive genes appear in the homozygous state, the condition is often fatal. such fatality may occur very early in embryonic development and look like a failed conception to a dairy producer. if the genes are semilethal, and the individual does survive, it may be totally unprofitable,? bennet g. cassell, extension dairy scientist, of the virginia tech states in studies about inbreeding. accordingly, genetic diversity is an important consideration when dairy- men select genetics to improve their cattle, especially when the level of in- breeding is rather high. complete ped- igree information dating four or five generations back is needed to manage inbreeding well, cassell argues. choose outcross bulls where to find outcross bulls with a good ranking has become an open question for more and more dairy- men, especially among jersey breed- ers in the us. in each breeding population, the most successful pedigrees will be- come influential. offering outcross bulls of high merit to the global mar- kets comes with the added bonus that they are easier for any dairyman to se- lect and use. this is an advantage that vikingjersey?s breeding manager em- phasises when talking about the nor- dic offer. ?we have a better chance of finding an outcross bull among all the family lines we have in our vikingjer- sey breeding programme,? larson says. ?all females are registered and 95% are pure jersey while all bulls are minimum 99.5% pure. vikingjer- sey bulls are measured for any in- crease in inbreeding per generation and we are under 1% per generation - the limit recommended by the food and agriculture organization of the united nations (fao). ?inbreeding levels would most likely drop quite a lot when using danish bulls in the us,? tenhunen adds. ?we can lower inbreeding at herd levels when combining dk and us lines together. when we minimise in- breeding in a herd, there is less loss of production and greater survivabili- ty,? she says. % milk kg -63.9 fat kg -2.37 protein kg -1.89 productive life -0.26 somatic cell score 0.00 daughter pregnancy rate -0.13 heifer conception rate -0.08 cow conception rate -0.16 liveability -0.08 table 1: effect of inbreeding depression per 1% increase in inbreeding source: the council on dairy cattle breeding (cdcb). august 2017. 5 may 2019 | vikingnews
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