Lidauer M.H.,Natural Resources Institute Finland |
Poso J.,Faba |
Lassen J.,University of Aarhus |
Madsen P.,University of Aarhus |
And 6 more authors.
Journal of Dairy Science | Year: 2015
Three random regression models were developed for routine genetic evaluation of Danish, Finnish, and Swedish dairy cattle. Data included over 169 million test-day records with milk, protein, and fat yield observations from over 8.7 million dairy cows of all breeds. Variance component analyses showed significant differences in estimates between Holstein, Nordic Red Cattle, and Jersey, but only small to moderate differences within a breed across countries. The obtained variance component estimates were used to build, for each breed, their own set of covariance functions. The covariance functions describe the animal effects on milk, protein, and fat yields of the first 3 lactations as 9 different traits, assuming the same heritabilities and a genetic correlation of unity across countries. Only 15, 27, and 7 eigenfunctions with the largest eigenvalues were used to describe additive genetic animal effects and nonhereditary animal effects across lactations and within later lactations, respectively. These reduced-rank covariance functions explained 99.0 to 99.9% of the original variances but reduced the number of animal equations to be solved by 44%. Moderate rank reduction for nonhereditary animal effects and use of one-third-smaller measurement error correlations than obtained from variance component estimation made the models more robust against extreme observations. Estimation of the genetic levels of the countries' subpopulations within a breed was found sensitive to the way the breed effects were modeled, especially for the genetically heterogeneous Nordic Red Cattle. Means to ensure that only additive genetic effects entered the estimated breeding values were to describe the crossbreeding effects by fixed and random cofactors and the calving age effect by an age × breed proportion interaction, and to model phantom parent groups as random effects. To ensure that genetic variances were the same across the 3 countries in breeding value estimation, as suggested by the variance component estimates, the applied multiplicative heterogeneous variance adjustment method had to be tailored using country-specific reference measurement error variances. Results showed the feasibility of across-country genetic evaluation of cows and sires based on original test-day phenotypes. Nevertheless, applying a thorough model validation procedure is essential throughout the model building process to obtain reliable breeding values. © 2015 American Dairy Science Association. Source
Kargo M.,University of Aarhus |
Kargo M.,Knowledge Center for Agriculture |
Hjorto L.,Knowledge Center for Agriculture |
Toivonen M.,Faba |
And 3 more authors.
Journal of Dairy Science | Year: 2014
Within a group of cooperating countries, all breeding animals are judged according to the same criteria if a joint breeding goal is applied in these countries. This makes it easier for dairy farmers to compare national and foreign elite bulls and may lead to more selection across borders. However, a joint breeding goal is only an advantage if the countries share the same production environment. In this study, we investigated whether the development of a joint breeding goal for each of the major dairy cattle breeds across Denmark, Finland, and Sweden would be an advantage compared with national breeding goals. For that purpose, economic values for all breeding goal traits in the 3 countries were derived, and estimated rank correlations between bulls selected for a national breeding goal and a joint breeding goal were compared. The economic values within country were derived by means of an objective bio-economic model, and the basic situation in each of the 3 production environments was based on an average dairy cattle herd with regard to production system, production level, and management strategy. The common Nordic economic values for each trait were calculated as the average of that specific trait in each of the 3 production environments. Balanced breeding goals were obtained in all situations because the derived economic values for traits related to health, fertility, milk production, and longevity were sizeable. For both Nordic Red Dairy Cattle and Nordic Holstein, the estimated rank correlations between bulls selected for a national breeding goal and a joint breeding goal were very high. Thus, a joint breeding goal within breed is feasible for Denmark, Finland, and Sweden. © 2014 American Dairy Science Association. Source
Korhonen K.,Mtt Agrifood Research Finland |
Julkunen H.,University of Eastern Finland |
Kananen K.,University of Eastern Finland |
Kananen K.,Ovumia Ltd. |
And 10 more authors.
Theriogenology | Year: 2012
Multiple ovulation embryo transfer (MOET) is used to make more rapid progress in animal breeding schemes. On dairy farms, where female calves are more desired, embryo sex diagnosis is often performed before embryo transfer. Fresh transfers have been favored after biopsy due to cumulative drop in pregnancy rates following cryopreservation. The aim of this study was to explore whether exposure to ascorbic acid (AC) during biopsy and freezing increases the viability of biopsied embryos after cryopreservation. Data on presumptive pregnancy and calving rates of biopsied and cryopreserved/overnight-cultured embryos were gathered. Results showed differences in presumptive pregnancy rates between the groups: 45% for both biopsied-cryopreserved groups (control and AC), 51% for biopsied-overnight-cultured embryos and 80% for intact-fresh embryos. Differences between the groups were also apparent in calving rates: 22% for biopsied-cryopreserved control embryos, 31% for biopsied-cryopreserved AC-embryos, 23% for biopsied-overnight-cultured embryos and 63% for intact-fresh embryos. It is concluded that manipulated embryos are associated with lower presumptive pregnancy and calving rates compared with intact-fresh embryos. The highest calving rates for groups of manipulated embryos were achieved in the AC-group. Therefore, addition of AC can be recommended if biopsy is combined with freezing before transfer. © 2012 Elsevier Inc. Source