Resumen El objetivo de este estudio consistió en un relevamiento de las principales enfermedades hereditarias BLAD, DUMPs y Citrulinemia, en una población representativa de terneras Holando de la región este del Uruguay utilizando el panel GGP-BovineLDv3, así como en el análisis de la frecuencia del alelo mutante de BLAD desde que fue reportado por primera vez en Uruguay. El ADN fue extraído a partir de sangre fresca de 190 terneras Holando de la cuenca lechera de Cerro Largo (Uruguay) y genotipado con el mencionado panel, validando así técnicas previamente utilizadas tales como PCR-RFLP y PCR-secuenciación. Se detectó la presencia del alelo mutante para BLAD en una ternera y se estimó una frecuencia alélica de 0.28 %. Las frecuencias reportadas del alelo BLAD durante los últimos 15 años fueron comparadas, encontrándose una disminución de la misma en los trabajos reportados hasta llegar a cero en 2018, lo cual podría deberse al uso de semen genotipado libre de estas enfermedades durante los últimos años. No se encontraron alelos mutantes para DUMPs ni para Citrulinemia. El uso de paneles de baja densidad sería una herramienta muy útil para establecer estrategias de cría en tambos y monitorear las enfermedades hereditarias en la raza Holando.

Abstract The objective of this study consisted in a screening of the main hereditary diseases BLAD, DUMPs and Citrullinaemia using the GGP-BovineLDv3 panel in a representative population of Holstein heifers of the eastern area of Uruguay, as well as the analysis of BLAD mutant allele frequency since it was first reported in Uruguay in 2003. DNA was extracted from fresh blood of 190 Holstein heifers in the dairy area of Cerro Largo (Uruguay) and genotyped using the above mentioned panel, thus validating previously used techniques, suhc as PCR- RFLP and PCR- sequencing. We detected the presence of the BLAD mutant allele in one heifer, and allele frequency was estimated as 0.28%. Reported frequencies of BLAD allele during the last 15 years were compared and the reported studies revealed that the frequency progressively decreased and fell to zero in 2018, which can be due to the use of genotyped semen free of these diseases during the last years. No mutant alleles were found for DUMPs or Citrulinaemia. The use of low-density panels would be a useful tool to develop breeding strategies in dairly farms and to monitor hereditary diseases in Holstein breed.

Six species of Trifolium (T. polymorphum Poir., T. riograndense Burkart, T. argentinense Speg., T. medium L., T. pratense L. and T. repens L.) were analyzed using inter-simple sequence repeats (ISSR) markers. Six selected primers generated 186 polymerase chain reaction (PCR) products exploring 112 loci in 34 genotypes analyzed with molecular sizes ranging from 200 to 1300 bp. These primers were able to discriminate among and within species, with the PCR products being on average 41.6% species-specific and 59.9% polymorphic at the within species level. Nuclear DNA content was determined by flow cytometry and revealed variation among species. The 1Cx genome size values were calculated and were found to range from 0.46 pg (T. pratense) to 0.96 pg (T. polymorphum). Genome size values of South American species were higher than those of Eurasiatic origin. The analyses of the molecular data grouped the six species in agreement with their geographical origin and clearly differentiate T. polymorphum from T. argentinense. The Eurasiatic group showed the highest average of species-specific bands (45.3%) and the South American group exhibited the highest amount of total bands (59.7). The highest level of intra-species polymorphisms was detected in T. argentinense (92.9%), followed by T. medium (89.5%).