Population structure and genetic diversity in ColombianSimmental cattle
Fecha de publicación: 19/11/2019

A vital requirement to design and implement a breeding program is to know the structure and genetic diversity of a population.The aim of this study was to characterize population structure and genetic diversity of the Colombian Simmental cattle. Thepedigree file included 27,985 animals born from 1975 to 2017. The level of genetic diversity and breed structure was evaluatedthrough probabilities of gene origin expressed via effective number of founders, ancestors and founders genomes. The inbreedingrates and the degree of genetic connectivity were estimated using a regression analysis and a genetic drift variance analysis,respectively. The lowest effective number of founders and ancestors were 50 and 38 by year, respectively. The average inbreedingby year of birth decreased from 5.06% in 1980 to 2.25% in 2017. The dairy line genetic contributions in the overall populationincreased significantly in the last 37 years, and the beef line contribution decreased. Regarding the genetic connectivity,Colombian regions (administrative divisions) with the largest cattle population had higher values. The results indicate that theavailability of European and North American bulls contributes to genetic diversity by increasing the effective number of foundersover time in the Colombian Simmental cattle population. However, the intensive use of relatively few founders causes anunbalanced genetic contribution and the loss of genetic diversity by gene pool erosion.

Parámetros genéticos para producción de leche en ganado Simmental (Bos taurus) mediante modelos genómicos y poligénicos
Fecha de publicación: 05/05/2019

El objetivo de este estudio fue estimar parámetros genéticos con y sin la inclusión de parentesco genómico para la producción de leche acumulada a 60 (PL60), 150 (PL150), 210 (PL210) y 305 días (PL305) en ganado Simmental en Colombia. Un total de 2883 controles lecheros en 620 vacas de primer parto fueron utilizados. La información genómica se obtuvo a partir de 718 animales genotipados con un chip de una densidad de 30106 marcadores genéticos tipo polimorfismo de nucleótido simple (SNP). Se construyeron modelos de tipo univariado y bivariado bajo la metodología del mejor predictor lineal insesgado (BLUP) y genómico en una etapa (ssGBLUP). Los valores de heredabilidades para PL60, PL150, PL210 y PL305 variaron entre 0,20 a 0,27; 0,25 a 052; 0,30 a 0,35 y 0,20 a 0,23; respectivamente. La inclusión de parentesco genómico no aumentó las heredabilidades y tampoco la precisión de las estimaciones para las características asociadas a producción de leche. La escasez de información fenotípica y la baja conectividad genética entre la población genotipada y no genotipada podrían limitar procesos de selección genética para producción de leche a través del ssGBLUP en la población de ganado Simmental de Colombia.

Molecular characterization of Cryptosporidium parvum and Cryptosporidium hominis GP60 subtypes worldwide
Fecha de publicación: 01/09/2017

Cryptosporidium is a zoonotic parasite very important in animal health as well as in public health. It is because this is one of the main causes of diarrhea in children, calves, lambs and other variety of youth mammalians in a lot of countries. The globalization has enabled the exchange of biological material in different regions worldwide, encouraging the spread of diseases and exposure to these biological agents to different environmental conditions, inducing adaptation through genetic changes. Based in the polymorphism of the gene for GP60, this review intended to present the distribution of Cryptosporidium parvum and Cryptosporidium hominis in humans and calves worldwide. The subtype that affects cattle more frequently corresponds to IIaA15G2R; while the subtype most frequently isolated from human samples is IaA19G2.