Quantitative trait loci detection and benefits from marker-assisted selection in dairy cattle

Knowing the chromosomal areas or actual genes affecting the traits under selection would add more information to be used in the selection decisions which would potentially lead to higher genetic response. The first objective of this study was to map quantitative trait loci (QTL) affecting economically important traits in the Finnish Ayrshire population. The second objective was to investigate the effects of using QTL information in marker-assisted selection (MAS) on the genetic response and the linkage disequilibrium between the different parts of the genome. Whole genome scans were carried out on a grand-daughter design with 12 half-sib families and a total of 493 sons. Twelve different traits were studied: milk yield, protein yield, protein content, fat yield, fat content, somatic cell score (SCS), mastitis treatments, other veterinary treatments, days open, fertility treatments, non-return rate, and calf mortality. The average spacing of the typed markers was 20 cM with 2 to 14 markers per chromosome. Associations between markers and traits were analyzed with multiple marker regression. Significance was determined by permutation and genome-wise P-values obtained by Bonferroni correction. The benefits from MAS were investigated by simulation: a conventional progeny testing scheme was compared to a scheme where QTL information was used within families to select among full-sibs in the male path. Two QTL on different chromosomes were modelled. The effects of different starting frequencies of the favourable alleles and different size of the QTL effects were evaluated. A large number of QTL, 48 in total, were detected at 5% or higher chromosome-wise significance. QTL for milk production were found on 8 chromosomes, for SCS on 6, for mastitis treatments on 1, for other veterinary treatments on 5, for days open on 7, for fertility treatments on 7, for calf mortality on 6, and for non-return rate on 2 chromosomes. In the simulation study the total genetic response was faster with MAS than with conventional selection and the advantage of MAS persisted over the studied generations. The rate of response and the difference between the selection schemes reflected clearly the changes in allele frequencies of the favourable QTL. The disequilibrium between the polygenes and QTL was always negative and it was larger with larger QTL size. The disequilibrium between the two QTL was larger with QTL of large effect and it was somewhat larger with MAS for scenarios with starting frequencies below 0.5 for QTL of moderate size and below 0.3 for large QTL. In conclusion, several QTL affecting economically important traits of dairy cattle were detected. Further studies are needed to verify these QTL, check their presence in the present breeding population, look for pleiotropy and fine map the most interesting QTL regions. The results of the simulation studies show that using MAS together with embryo transfer to pre-select young bulls within families is a useful approach to increase the genetic merit of the AI-bulls compared to conventional selection.

Winter feeding strategies for suckler cows in cold climatic conditions

In Finland, suckler cow production is carried out in circumstances characterized by a long winter period and a short grazing period. The traditional winter housing system for suckler cows has been insulated or uninsulated buildings, but there is a demand for developing less expensive housing systems. In addition, more information is needed on new winter feeding strategies, carried out in inexpensive winter facilities with conventional (hay, grass silage, straw) or alternative (treated straw, industrial by-product, whole-crop silage) feeds. The new feeding techniques should not have any detrimental effects on animal welfare in order to be acceptable to both farmers and consumers. Furthermore, no official feeding recommendations for suckler cows are available in Finland and, thus, recommendations for dairy cows have been used. However, this may lead to over- or underfeeding of suckler cows and, finally, to decreased economic output. In Experiment I, second-calf beef-dairy suckler cows were used to compare the effects of diets based on hay (H) or urea-treated straw (US) at two feeding levels (Moderate; M vs. Low; L) on the performance of cows and calves. Live weight (LW) gain during the indoor feeding was lower for cows on level L than on level M. Cows on diet US lost more LW indoors than those on diet H. The cows replenished the LW losses on good pasture. Calf LW gain and cow milk production were unaffected by the treatments. Conception rate was unaffected by the treatments but was only 69%. Urea-treated straw proved to be a suitable winter feed for spring-calving suckler cows. Experiment II studied the effects of feeding accuracy on the performance of first- and second-calf beef-dairy cows and calves. In II-1, the day-to-day variation in the roughage offered ranged up to ± 40%. In II-2, the same variation was used in two-week periods. Variation of the roughages offered had minor effects on cow performance. Reproduction was unaffected by the feeding accuracy. Accurate feeding is not necessary for young beef-dairy crosses, if the total amount of energy offered over a period of a few weeks fulfills the energy requirements. Effects of feeding strategies with alternative feeds on the performance of mature beef-dairy and beef cows and calves were evaluated in Experiment III. Two studies consisted of two feeding strategies (Step-up vs. Flat-rate) and two diets (Control vs. Alternative). There were no differences between treatments in the cow LW, body condition score (BCS), calf pre-weaning LW gain and cow reproduction. A flat-rate strategy can be practised in the nutrition of mature suckler cows. Oat hull based flour-mill by product can partly replace grass silage and straw in the winter diet. Whole-crop barley silage can be offered as a sole feed to suckler cows. Experiment IV evaluated during the winter feeding period the effects of replacing grass silage with whole-crop barley or oat silage on mature beef cow and calf performance. Both whole-crop silages were suitable winter feeds for suckler cows in cold outdoor winter conditions. Experiment V aimed at assessing the effects of daily feeding vs. feeding every third day on the performance of mature beef cows and calves. No differences between the treatments were observed in cow LW, BCS, milk production and calf LW. The serum concentrations of urea and long-chain fatty acids were increased on the third day after feeding in the cows fed every third day. Despite of that the feeding every third day is an acceptable feeding strategy for mature suckler cows. Experiment VI studied the effects of feeding levels and long-term cold climatic conditions on mature beef cows and calves. The cows were overwintered in outdoor facilities or in an uninsulated indoor facility. Whole-crop barley silage was offered either ad libitum or restricted. All the facilities offered adequate shelter for the cows. The restricted offering of whole-crop barley silage provided enough energy for the cows. The Finnish energy recommendations for dairy cows were too high for mature beef breed suckler cows in good body condition at housing, even in cold conditions. Therefore, there is need to determine feeding recommendations for suckler cows in Finland. The results showed that the required amount of energy can be offered to the cows using conventional or alternative feeds provided at a lower feeding level, with an inaccurate feeding, flat-rate feeding or feeding every third day strategy. The cows must have an opportunity to replenish the LW and BCS losses at pasture before the next winter. Production in cold conditions can be practised in inexpensive facilities when shelter against rain and wind, a dry resting place, adequate amounts of feed suitable for cold conditions and water are provided for the animals as was done in the present study.

Työ- ja pääomapanokset maidontuotannon kannattavuustekijöinä - asema- ja automaattilypsytilojen vertailu

Maatalousyrittäjä toimii muuttuvassa toimintaympäristössä, jonka muutokset asettavat yrittäjälle ja yritykselle haasteita ja vaatimuksia. Tuotantoteorian mukaisesti maatalousyrittäjän oletetaan maksimoivan voittoa ja/tai minimoimaan kustannuksia. Tavoitteen saavuttamiseksi yrittäjä sopeuttaa tuotosmääriään ja panoskäyttöään vallitsevien olosuhteiden mukaan. Tuotantoteknologialla voidaan puolestaan vaikuttaa siihen, millaisia panoksia tuotoksen aikaansaamiseksi tarvitaan. Maidontuotannossa lypsyjärjestelmä on yksi keskeinen teknologiavalinta. Kannattavuus on Suomessa kriittinen tekijä maataloustuotannon kilpailukykyä ja pitkän ajan toimintaedellytyksiä ajatellen. Yhtenä merkittävänä tuotantokustannuksiin vaikuttavana tekijänä maidontuotannossa voidaan pitää keskimäärin korkeaa työkustannusta tuoteyksikköä kohden. Rakennekehityksellä tavoitellaan suurtuotannon etuja ja yksikkökustannusten alentamista. Yrityskoon kasvattamisen yhteyteen liittyy usein uuden tuotantoteknologian käyttöönotto. Uudella teknologialla ja siihen sijoitetulla pääomalla korvataan yhä kallistuvaa työpanosta. Uutta teknologiaa edustavat mm. automaattinen lypsyjärjestelmä. Keskeisintä kehityksessä on, että viljelijöiden on ollut mahdollista vähentää työn määrää tuotettua yksikköä kohti. Tämä on helpottanut tilakoon kasvua ja samalla on ollut mahdollista kasvattaa työmenekin silti olennaisesti kasvamatta. Ensimmäiset automaattilypsyjärjestelmät otettiin Suomessa käyttöön vuonna 2000 ja vuoden 2009 lopussa niitä oli jo 563 laitetta yhteensä 465 maidontuotantotilalla. Tutkimuksen tarkoituksena oli tutkia asema- ja automaattilypsyä käyttävien tilojen tuottavuus- ja kannattavuuseroja ja miten investoinneilla pystytään korvaamaan työtä. Aineistona käytettiin maatalouden kannattavuuskirjanpitoaineistoa vuosilta 2005- 2008. Tutkimusaineistossa olivat mukana kaikki tilat, joilla tutkimusjakson alussa oli automaattinen lypsyjärjestelmä tai jotka siirtyivät siihen ajanjakson aikana. Automaattilypsytilojen vertailuryhmänä olivat maidontuotantoon keskittyneet samaan kokoluokkaan kuuluvat asemalypsytilat. Lypsyjärjestelmän valinnan maidontuottaja tekee omista lähtökohdistaan. Tässä tutkimuksessa tehty lypsyjärjestelmän taloudellinen valintaperusteiden tarkastelu osoittaa, että uuden teknologian käyttöönotto on haasteellista. Valinnan taustalla olevat odotukset eivät välttämättä toteudu ainakaan heti investoinnin jälkeisinä vuosina. Työn tuottavuus, määriteltynä työtuntia kohden tuotettuina maitokiloina, oli automaattilypsytiloilla parempi kuin asematiloilla. Pääoman tuottavuus, määriteltynä lypsykarjatalouden pääomaa (1000 €) kohti tuotettuina maitokiloina oli puolestaan asemalypsytiloilla parempi kuin automaattilypsytiloilla. Asemalypsytiloilla nettotuottavuus, työn sekä pääoman nettotuottavuudet olivat parempia kuin automaattitiloilla. Automaattitilojen kokonaistuottavuuden muutos oli 7,49 %, kun asematiloilla se oli vain 2,30 % tutkimusajanjakson aikana. Lehmää kohti työkustannukset pienenivät ja maksettujen korkojen määrät kasvoivat kummallakin lypsytavalla. Verrattaessa työkustannusten ja maksettujen korkomenojen muutosta voitiin havaita, että työkustannukset eivät automaattilypsytiloilla kuitenkaan pienentyneet niin paljon, että ne olisivat kattaneet maksettujen korkomenojen lisäyksen. Kannattavuuskertoimen perusteella kumpikaan tilaryhmä ei saavuttanut asettamiaan tavoitteita oman työn palkkavaatimuksen eikä oman pääoman korkovaatimuksen suhteen. Asemalypsytiloilla kannattavuus oli parempi ja yrittäjäntappio oli alhaisempi kuin automaattitiloilla.