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'Bovine Leukocyte Adhesion Deficiency' (BLAD) is a recessive monofactorial, lethal inheritable defect occurring in Holstein-Friesian cattle and often passed on by well-known top bulls. The aim of this study was to find a relationship between the BLAD genotype of bulls, their genetic evaluation for milk and their daughters' milk production. BLAD-carrier and healthy bulls were compared on the basis of their breeding value published in November 1997. The first 100 bulls ranked according to the Total Production Index (TPI) were used, including nine BLAD carriers with 2,835 daughters and 77 healthy sires with 21,950 female progenies. For 14 bulls the BLAD genotype was not indicated. The healthy animals significantly outperformed the BLAD carriers, which result contradicts our earlier findings (Dohy et al., 1996; Jánosa and Dohy, 1997). In a BLAD elimination programme, the identification of BLAD carriers and properly planned mating are of great importance in order to avoid'inter se'mating of BLAD-carrier top animals which can be of significant influence in Holstein breeding.

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Cows of different breeds with high lifetime production were analysed in order to choose the best producers for embryo donors. The cows were ranked based on their milk protein yield, and a rank correlation was calculated between milk and protein yield and age. The probability of a correlation breaker was also investigated. In the Swiss Simmental breed it was found that the lower the protein production, the lower the correlation. This tendency was characteristic for the Brown Swiss population, too. In the first Osnabrück Holstein subpopulation a close correlation (0.74) was found, but not in the other two. The ratio of correlation breakers in the three subpopulations was 12.5%, 33.3% and 56.3%. In populations of German Black & White and Red & White the correlation was very close (0.9 and 0.84, respectively). The ratio of correlation breakers was 26.7% and 22.2%. In the Hungarian Holstein population the correlation was weak (0.29), so the ratio of correlation breakers was relatively high. The value of the rank correlation coefficient between the milk fat and milk quantity of the top cows of the Jersey breed was 0.26, indicating a weak correlation. The ratio of correlation breakers was 36.4%.

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Acta Veterinaria Hungarica
S. Bodó
B. Baranyai
Elen Gócza
J. Dohy
, and
Merja Markkula

Preimplantation Genetic Diagnosis (PGD) is reviewed and novel fields where it may be applied are investigated. Technical advances of PGD in cattle embryos have already enabled its integration as a part of the MOET (Multiple Ovulation Embryo Transfer) breeding system. PGD for well-defined selection targets can enhance cattle breeding and embryo trade. It allows embryo selection according to their sex, and it may be used to breed special cow lines, or top bulls, by selecting embryos for valuable production traits using Marker Assisted Selection (MAS). A good allelic profile and/or the insertion of a transgene can be detected by PGD. This review article presents the technical requirements for PGD, and shows that this biotechnological method has great economic potential.

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