Diferenciales de selección genética en Holando Argentino

La selección genética en ganado lechero a nivel global ha resultado en aumentos considerables en la productividad. En contraste, la producción de leche en Argentina se ha mantenido estable durante los últimos 20 años, aún cuando otros países con sistemas productivos similares han incrementado significativamente su producción en el mismo periodo. El objetivo de este estudio fue determinar los diferenciales de selección realizados en la población de Holando Argentino bajo el modelo de selección de 4 víasEEA BalcarceFil: Pardo, Alan M. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Corva, Pablo. Unidad Integrada Balcarce. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Dillon Anabella Unidad Integrada Balcarce. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Rubio, Natalia. Universidad Nacional del Centro de la Provincia de Buenos Aires, Facultad de Ciencias Veterinarias; Argentina.Fil: Andere, C. Universidad Nacional del Centro de la Provincia de Buenos Aires, Facultad de Ciencias Veterinarias; Argentina.Fil: Casanova, D. Universidad Nacional del Centro de la Provincia de Buenos Aires, Facultad de Ciencias Veterinarias; Argentina

Criterios de selección por fertilidad de la hembra en bovinos para carne

Tesis de maestría para obtener el grado de Magister Scientiae en Sanidad Animal presentada en la Facultad de Ciencias Agrarias, Universidad Nacional de Mar del Plata en Junio de 2017El objetivo de este estudio fue identificar criterios de selección para mejorar la aptitud reproductiva de la hembra bovina. Para ello se realizaron estudios de pubertad en vaquillonas, y productividad media anual en vacas. El espesor de grasa dorsal medido por ultrasonografía a los 450 días de edad (15 meses) resultó un buen predictor de la edad a la pubertad y un criterio de selección potencialmente utilizable para mejorar la fertilidad de la hembra. La selección por precocidad sexual brindaría la posibilidad de mejorar la productividad media anual de las vacas y de esta manera la fertilidad del rodeo.In order to identify selection criteria to improve the reproductive capacity of the female bovine, we studied 132 heifers born in 2011 and 2012, belonging to 5 genetic groups (GG): Angus (A), Hereford (H), AH, HA and Creole (C) in two years (Trials 1 and 2). After weaning, the presence of corpus luteum, live weight, body condition, rump height, rump fat thickness, rib fat thickness and rib eye area were recorded every 28 days. By DNA analysis we determined the genotype for a total of 70 SNPs of genes involved in the hypothalamic-gonadal metabolic pathways, growth and fat metabolism. On the other hand, in order to evaluate the relationships between the beginning of the reproductive life of the females and their productive efficiency, the annual records of 895 cows (217 A, 253 H, 125 C, 116 AH y 184 HA) born between 1986 and 2009 in Experimental Unit Nº 7 - EEA INTA Balcarce were analyzed to estimate the average annual productivity of the cow (PRODAM), its components of (Co) variance and breeding values (EBV). The environmental differences between the two trials evaluated conditioned the age at which the heifers reached puberty, which was higher in those who had lower postweaning gains. HA heifers reached puberty 54±15 days before C (p 0.05). The rib fat thickness measured by ultrasonography at 450 days of age (15 months) was a good predictor of age at puberty and consequently a selection criterion potentially useful to improve the fertility of the female. Estimation of (co)variance components for PRODAM showed a heritability of 0.14±0.05. Age at puberty of the evaluated heifers was associated with the average annual productivity of their mothers, which would be a good predictor of the productive performance of cows. SNPs in SPAG11 and PTGER2 showed a certain association with age, weight and height at puberty. From the analysis performed, the nutritional conditions immediately after weaning are of vital importance for an earlier presence of the first corpus luteum, an indicator of puberty. The rib fat thickness in the heifers could be used as a selection criterion for sexual precocity. However, it is important for future studies to analyze in more detail the relationship between fat deposition dynamics and the onset of puberty, in order to determine the existence of critical thresholds (minimum and maximum) for the onset of reproductive activity. Selection for sexual precocity provides an opportunity to improve the annual average productivity of cows and thus cattle fertility. At the molecular level, the associations found among the genotypes of the SNPs evaluated should be validated in populations with a larger number of animals before being identified as selection criteria to increase the female fertilityEEA BalcarceFil: Pardo, Alan Maxs. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación experimental Agropecuaria Balcarce; Argentin

An insight into population structure and genetic progress of Argentinean Holstein cattle

The objective of the present study was to investigate the most critical issues associated with the limited genetic progress evidenced in the Argentinean Holstein (“Holando Argentino”) breed in the last 20 years (only 26% of the phenotypic trend in milk yield was due to genetics). The study comprised the analysis of population structure, realized genetic selection differentials, genetic progress and partition of genetic trends by sex and country of origin from 1936 to 2019 (1,045,582 records; 24,680 sires and 619,322 dams in the pedigree). Average inbreeding steadily increased in the last 15 generations (ΔF = 0.6%, which translates to Ne = 75). Partition of genetic trends revealed that local genetics made a negligible contribution to genetic progress, which for most traits was highly dependent on imported genetics (>80%). Mean generation intervals were fairly constant until 2009 (8–9 years for males and 5–6 years for females, respectively) and then decreased, especially in the paths of sires of bulls and dams of bulls (to 5 and 4 years, respectively) mostly due to the influence of imported sires. The reduction in generation intervals was counterbalanced by a marked deterioration of realized selection differentials, particularly in the path of sires of bulls that nevertheless made the largest contribution to genetic progress. In the last 20 years, realized selection differentials in this path went from 533.6 to 170.8 kg for milk yield and from 16.7 to 13.3 kg for protein yield (1.7–0.5 and 1.6–1.3 standard deviation units, respectively). Among all considered traits (milk yield, fat yield, protein yield, stature, final score and daughter pregnancy rate) in the analysed period, annual genetic gain was negative for milk yield, fairly constant for composition and conformation traits, and positive only in the case of daughter pregnancy rate. Considered together, these results suggest that limited genetic progress is due to the absence of a sound breeding programme that includes genomic selection and a carefully defined selection objective, together with the absence of stronger regulations in germplasm importation; however, other factors such as potential genetics by environment interactions cannot be ruled out.EEA BalcarceFil: Pardo, Alan Maxs. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Pardo, Alan Maxs. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Casanova, Daniel. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; Argentina.Fil: Rubio, Natalia. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; Argentina.Fil: Andere, Cecilia. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; Argentina.Fil: Rodríguez, Edgardo. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; Argentina.Fil: Corva, Pablo M. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina

Characterization of experimental cattle populations from Argentina with a low-density SNP genotyping panel

The objectives of the present experiment were to evaluate a low-density SNP array designed for the molecular characterisation of gene banks and to assess the genetic diversity and population structure of beef cattle herds from an Argentinean research station. Forty-nine animals from three breeds (Angus, Hereford, and Argentinean Creole) were genotyped using the multi-species IMAGE001 60-K SNP array (10 K for cattle). Genotypes of other 19 cattle populations from Argentina, other American countries, and Europe were included in the study. Of special interest was the characterization of the Argentinean Creole, the only autochthonous cattle breed in the country. Due to the merging of different datasets, approximately 5 K SNPs were effectively used. Genetic differentiation (FST), principal component analysis, neighbour-joining tree of Reynolds distances and ancestry analysis showed that autochthonous American breeds are clearly differentiated, but all have genetic influences of Iberian cattle. The analysed herds of Argentinean Creole showed no evidence of recent admixture and represent a unique genetic pool within local American breeds. An experimental herd and the local commercial Hereford population have also diverged, probably due to the influence of current selection objectives in the breed. Our results illustrate the utility of using low-cost, low density SNP arrays in the evaluation of animal genetic resources. This type of panels could become a very useful resource in developing countries, where most endangered cattle breeds are located. The results also reinforce the importance of experimental herds as reservoir of genetic diversity, particularly in the case of local breeds under-represented in traditional production systems.EEA BalcarceFil: Michiels, Brian. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Pardo, Alan Maxs. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Pardo, Alan Maxs. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Ortega Masagué, Maria F. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto De Investigación Animal del Chaco Semiárido; ArgentinaFil: Giovambattista, Guillermo. Universidad Nacionald La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Genética Veterinaria; Argentina.Fil: Corva, Pablo M. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina

Impact of the duration of rearing and finishing periods on steer performance and carcass and meat quality characteristics

The present study evaluates the effects of extending the rearing period on pasture for 0, 49, and 98 d (beyond 300 kg of live weight) and of finishing on a concentrate diet for 49 and 98 d on beef carcass quality, meat and subcutaneous fat color, shear-force, fatty acid profile and on consumer sensory quality of meat. No major interactions were observed throughout the study. Increasing the rearing period increased slaughter and carcass weight and fat thickness with no other effects on meat quality. Extending the finishing period increased slaughter and carcass weight, fat thickness, and longissimus muscle area with no effects on meat color, shear-force and cooking loses. Longissimus fatty acid profile was altered by extending the finishing period with greater amounts of total FA and proportion of C18:1 cis-9 while decreasing the proportion of n-3 polyunsaturated FA. There were no effects of extending the rearing and finishing periods on consumer evaluation of sensory traits. However, evaluation of consumer clusters found greater overall and flavor liking scores for meat from steers with the shortest rearing period for Cluster-1 while Cluster-2 gave greater flavor liking scores to beef from steers where the finishing period was extended. The results suggest slaughter weight can be increased by extending the finishing period without negatively affecting consumer quality, while extending the rearing period may have a negative impact on.EEA BalcarceFil: Pavan, Enrique. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Pavan, Enrique. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Pouzo, Laura Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Pouzo, Laura Beatriz. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Testa, María Laura. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Testa, María Laura. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Maglietti, Carlos Sebastián. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Maglietti, Carlos Sebastián. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Papaleo Mazzucco, Juliana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Pardo, Alan Max. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Pardo, Alan Max. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina

Growth, carcass and meat quality traits in beef from Angus, Hereford and cross-breed grazing steers, and their association with SNPs in genes related to fat deposition metabolism

Grazing steers from Angus and Hereford breeds, their cross-breeds and a three-way cross-breed (Limousin × Angus–Hereford) were measured for growth, carcass andmeat quality traits. Breed effectswere studied, and the association of SNPswith fat deposition and fatty acid (FA) composition (leptin,melanocortin-4 receptor, stearoyl-CoA desaturase, FA synthase and thyroglobulin) was tested. Limousin cross-breed showed the greatest final bodyweight, ultrasound rib eye area, dressing percentage, carcass and leg length, and the lowest backfat thickness and intramuscular fat content. Genetic groups had similar pH, shear force, cooking loss, L* and b* and n-6:n-3 ratio. Meat from1/2-Angus presented greater a* than Limousin cross-breed. Whereas Angus had the highest total SFA content, Hereford had the lowest total SFA and the highest total MUFA. Limousin cross-breed had greater content of several individual PUFAs, total PUFA, n-6 and n-3 FA than Angus and 1/2-Angus. Leptin and FA synthase were associated with some FAs, supporting their influence over fat metabolism for grazing animals.EEA BalcarceFil: Papaleo Mazzucco, Juliana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Área de Investigación en Producción Animal; ArgentinaFil: Goszczynski, Daniel Estanislao. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Ripoli, María Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Melucci, Lilia Magdalena. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias. Departamento de Producción Animal; ArgentinaFil: Pardo, Alan Maxs. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Área de Investigación en Producción Animal; ArgentinaFil: Colatto, E. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias. Departamento de Producción Animal; ArgentinaFil: Rogberg Muñoz, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Genética Veterinaria; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Producción Animal; ArgentinaFil: Mezzadra, Carlos Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Área de Investigación en Producción Animal; ArgentinaFil: Depetris, Gustavo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Área de Investigación en Producción Animal; ArgentinaFil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Villarreal, Edgardo Leopoldo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Área de Investigación en Producción Animal; Argentin