This study was conducted to determine the possibility to vary the proportion of bull spermatozoa with Y chromosome by using bovine serum albumin (BSA) in three methods: Double centrifugation in BSA (M1); centrifugation and migration in BSA (M2); Double migration in BSA (M3). The sperm samples were stored for 20-24 hours at 5 °C and then frozen in liquid nitrogen. The variation in the proportion of spermatozoa with Y chromosome (f-body) was determined by staining with quinacrine dihydrochloride. No significant difference was observed in the percentage of f-body (48.4±5.9% for the control and from 45.8±5.5 to 47.2±4.9% for the treatments. The spermatozoa retrieval rate was 50.7% for M1, 36.2% for M2, and 21.4% for M3 (p<0.01). The effect of ASB on sperm characteristics was significant (p<0.01): the sperm vitality was reduced from 64.2% in the control to 42.5, 37.2 and 27.2% in M1...

The basic hematological characteristics of a group of 184 Creole cattle (CRIZA) and 128 Brown Swiss cattle (BSZA) both male and females, reared in the Andes of Peru between 3213 and 4309 meters above sea level, were evaluated and compared with samples from a group of 11 cattle with brisket disease (BSMA) and with another group of 31 Brown Swiss cattle reared between 243 and 1306 meters above sea level (BSZB). The red blood cell count (RBC) was 14.95, 8.34, 8.25 and 7.10x106/μl in BSMA, BSZA, CRIZA and BSZB, respectively. Haematocrit (Ht) was 61.44, 45.83, 42.61 and 34.99% for BSMA, CRIZA, BSZA and BSZB, respectively. Haemoglobin (Hb) was 16.26, 12.86, 12.22 and 9.65 g/dl in BSMA, CRIZA, BSZA and BSZB, respectively. The averages showed wide variation. Taking the Ht criterion, BSZA and CRIZA cattle belonging to the upper decile were identified, forming two groups with extreme values (BSZA...

The genomes of 41 bovines of five breeds, existing in the SRA-NCBI database, were used to identify 17 single nucleotide polymorphisms (SNPs) which generate non-synonymous mutations in 10 hypoxia-inducible genes. Of this, only three SNPs located in positions c.1081G>C, c.2089G>A and c.2101G>A of exons 7 and 12 of the EPAS1 gene had different allelic frequencies between beef and dairy cattle (p<0.05). Based on the results of the bioinformatic analysis of the genomes, exonic regions of the EPAS1, NOS2, EPO and VEGFA genes were chosen, which were studied in 60 DNA samples from Creole and Brown Swiss cattle raised in the high Andean region (3213-4309 m above sea level). The cattle were grouped by their haemoglobin concentration (Hb) in Brown Swiss with high Hb (BSHbA) (n=13), Brown Swiss with low Hb (BSHbB) (n=11), Creoles with high Hb (CRHbA) (n=13) and Creoles with low Hb (CRHbB...

La investigación se hizo para determinar la posibilidad de variar la proporción de espermatozoides de toros con cromosoma Y mediante el uso de albúmina sérica bovina (ASB) en tres métodos propuestos: Doble centrifugación en ASB (M1); Centrifugación y migración en ASB (M2); Doble migración en ASB (M3). Las muestras de semen se conservaron durante 20-24 horas a 5 °C y luego se congelaron en nitrógeno líquido. La variación en la proporción de espermatozoides con cromosoma Y (cuerpo F) se determinó usando una tinción con diclorhidrato de quinacrina. No se encontraron diferencias significativas en el porcentaje de cuerpos F (48.4±5.9% para el control y de 45.8±5.5 a 47.2±4.9% para los tratamientos). La tasa de recuperación espermática fue de 50.7% para M1, 36.2% para M2 y 21.4% para M3 (p<0.01). Hubo una reducción significativa (p<0.01) de las características esp...

The basic hematological characteristics of a group of 184 Creole cattle (CRIZA) and 128 Brown Swiss cattle (BSZA) both male and females, reared in the Andes of Peru between 3213 and 4309 meters above sea level, were evaluated and compared with samples from a group of 11 cattle with brisket disease (BSMA) and with another group of 31 Brown Swiss cattle reared between 243 and 1306 meters above sea level (BSZB). The red blood cell count (RBC) was 14.95, 8.34, 8.25 and 7.10x106/μl in BSMA, BSZA, CRIZA and BSZB, respectively. Haematocrit (Ht) was 61.44, 45.83, 42.61 and 34.99% for BSMA, CRIZA, BSZA and BSZB, respectively. Haemoglobin (Hb) was 16.26, 12.86, 12.22 and 9.65 g/dl in BSMA, CRIZA, BSZA and BSZB, respectively. The averages showed wide variation. Taking the Ht criterion, BSZA and CRIZA cattle belonging to the upper decile were identified, forming two groups with extreme values (BSZA...

Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Producción Animal