Zootecnista egresada de la Universidad Nacional de Colombia, con Maestría en Ciencias Agropecuarias, línea producción Animal Tropical y Doctora en Genética y Mejoramiento Animal de la Universidad Estatal Paulista «Júlio de Mesquita Filho» (UNESP) de Brasil. Con más de 3 años de experiencia docencia en cursos de Genética, Mejoramiento Animal, Investigación y Bioestadística. Investigador en áreas de Genética Molecular Animal, Mejoramiento Animal y Conservación de recursos Zoogenéticos. Investigador Junior de Colciencias
Random regression models for milk, fat and protein in Colombian Buffaloes
Fecha de publicación: 30/04/2015
Objective. Covariance functions for additive genetic and permanent environmental effects and, subsequently, genetic parameters for test-day milk (MY), fat (FY) protein (PY) yields and mozzarella cheese (MP) in buffaloes from Colombia were estimate by using Random regression models (RRM) with Legendre polynomials (LP). Materials and Methods. Test-day records of MY, FY, PY and MP from 1884 first lactations of buffalo cows from 228 sires were analyzed. The animals belonged to 14 herds in Colombia between 1995 and 2011. Ten monthly classes of days in milk were considered for test-day yields. The contemporary groups were defined as herd-year-month of milk test-day. Random additive genetic, permanent environmental and residual effects were included in the model. Fixed effects included the contemporary group, linear and quadratic effects of age at calving, and the average lactation curve of the population, which was modeled by third-order LP. Random additive genetic and permanent environmental effects were estimated by RRM using third- to- sixth-order LP. Residual variances were modeled using homogeneous and heterogeneous structures. Results. The heritabilities for MY, FY, PY and MP ranged from 0.38 to 0.05, 0.67 to 0.11, 0.50 to 0.07 and 0.50 to 0.11, respectively. Conclusions. In general, the RRM are adequate to describe the genetic variation in test-day of MY, FY, PY and MP in Colombian buffaloes
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Intramammary infusion of Weissella confusa affects somatic cell counts and milk differential leukocyte count
Fecha de publicación: 10/03/2015
The use of lactic acid bacteria (LAB) as an alternative to antimicrobial usage has been proposed for the control of bovine mastitis. However, before its application, the in vivo effects of the LAB on mammary gland must be carefully evaluated. The objective of this study was to determine whether the intramammary infusion of Weissella confusa and its metabolites in cows affects the somatic cell counts (SCCs) and milk differential leukocyte count. Twenty-four mammary quarters of six Hartón del Valle cows were selected for the investigation. A 5mL aliquot of an aqueous solution of W. confusa cells (W) (concentration of 109cfu mL-1), 5mL of W. confusa cells with its metabolites (W+W10b) or 5mL of metabolites (W10b) was randomly applied to three mammary quarters of each cow. The remaining teat on each udder represented the experimental control units (C). At 1, 2, 3, 5, 7, 9, 13 and 15 days post-infusion (PI), the SCCs, pH, titrable acidity and milk differential leukocyte count were evaluated. The application of the three biological substances produced significant increases in SCCs, pH and polymorphonuclear neutrophil counts. No significant differences between W and W+W10b infusion were found. W10b resulted in a lesser alteration on the variables evaluated. The results suggest that the intramammary infusion of W. confusa and its metabolites affect the SCCs and milk differential leukocyte count in cows.
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Effect of the g.98535683A > G SNP in the CAST gene on meat traits of Nellore beef cattle (Bos indicus) and their crosses with Bos taurus
Fecha de publicación: 31/01/2017
The objective of this study was to estimate allele frequencies of the g.98535683A > G:BTAU7 SNP in the CAST gene in different genetic groups of beef cattle produced in Brazil (Nellore and their crosses with Bos taurus), and to evaluate associations between this polymorphism and meat traits. Five hundred animals from six different genetic groups were genotyped and phenotyped for shear force (SF), myofibrillar fragmentation index (MFI), rib eye area, backfat thickness, and total lipids. Alleles A and G of the SNP were detected in all genetic groups and the frequency of A was higher than G. Significant association (P < 0.05) was observed between the polymorphism and meat tenderness (SF and MFI), in which genotype AA exhibited the best values. These results demonstrate for the first time the occurrence of the studied SNP in a Zebu breed and its potential application to the genetic improvement of meat tenderness in the Nellore breed (Bos indicus) and its crosses with Bos taurus.
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Cellular response of the bovine mammary gland after Weissella confusa infusion to control Streptococcus agalactiae
Fecha de publicación: 16/05/2013
The use of lactic acid bacteria (LAB) as a potential therapeutic agent to control bovine mastitis was previously proposed. However, little is known about the cellular response of the bovine mammary gland in cattle infected with Streptococcus agalactiae and treated with LAB. To assess the cellular response by the mammary gland in lactating cows after infection with Streptococcus agalactiae followed by infusion with Weissella confusa as antibacterial treatment. Healthy udder quarters of lactating cows were infected with S. agalactiae (107 cfu/mL). After 24 h of pathogen infusion, 50% of the quarters were infused with 109 cfu/mL of W. confusa (SW) and the remaining 50% were kept as control units (S). At days 1, 2, 3, 4, 5, 11, and 14 post-infusion of the pathogen, the clinical signs of mastitis and the degree of cellular response by the mammary gland were evaluated using the California mastitis test, somatic cell count, electrical conductivity, and differential leukocyte count in milk. The SW quarters showed clinical inflammation of the mammary gland associated with a significant increase in somatic cell count, California mastitis test, electrical conductivity and high proportion of polymorphonuclear neutrophils. The results suggest that the infusion with W. confusa cells induced a higher cellular immune response in the bovine mammary gland than S. agalactiae alone. Results indicate that W. confusa infusions for controlling S. agalactiae should not be adopted. However, the activation mechanism of somatic cells in the mammary gland needs to be elucidated.
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Association of CAST2, HSP90AA1, DNAJA1 and HSPB1 genes with meat tenderness in Nellore cattle
Fecha de publicación: 30/04/2018
The objective of this study was to evaluate the association of expression of CAPN1, CAPN2, CAST, HSP90AA1, DNAJA1 and HSPB1 genes with meat tenderness in Nellore cattle. Three experimental groups were selected by shear force (SF): moderately tender (SF = 34.3 ± 5.8 N), moderately tough (SF = 56.8 ± 7.8 N), and very tough meat (SF = 80.4 ± 15 N). Gene expression was evaluated by real-time PCR. Expression of the CAPN1, CAPN2, CAST and CAST1 genes did not differ between groups. Expression of the CAST2 was up-regulated (P < 0.05) in the moderately tough and very tough meat groups. Down-regulation of the HSP90AA1, DNAJA1 and HSPB1 genes (P < 0.05) was observed in the moderately tender meat group. The present results suggest that meat tenderness in Nellore cattle does not directly depend on the expression of the CAPN1 and CAPN2 genes, but is associated with the expression of other genes such as CAST2, HSP90AA1, DNAJA1 and HSPB1.
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