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Objective: The objective of this study was to associate the 1016G > A variant of the melanocortin-4 receptor gene with lamb's weight, growth, and meat quality in the Colombian hair sheep breed. Materials and Methods: A total of 168 lambs, weights were measured at birth weight (BW), at weaning adjusted weaning weight (AWW), at 6 months [adjusted weight (AW180)], at slaughter adjusted slaughter weight (ASW), daily weight gain preweaning daily gain (preWDG), and postweaning daily gain (postWDG) weaning, and after slaughter, pH, texture, and cook-loss (CL) in the longissimus thoracis et lumborum (LTL) muscle according to the American Meat Science Association methodology. The 1016G > A genotypes were obtained by sequencing. Genotypic and allele frequencies, heterozygosities, and Hardy-Weinberg equilibrium (HWE) were estimated. Using a generalized linear model, the genotype and the allelic substitution effect were associated with the evaluated traits. Results: The heterozygous genotype (0.48) and G allele (0.61) were the most frequent. Heterozygosities were similar (0.47), indicating HWE. The genotype affected the BW (p < 0.05), with a higher value for the GG genotype (2.69 kg). AWW (12.75 kg), AW180 (19.67 kg), and ASW (31.21 kg) weights and daily weight gain (preWDG = 115.41 gm; postWDG = 96.16 gm) were not associated. Average pH, Warner-Bratzler shear force, and CL were 5.75 units, 49.46 N, and 32.02%, with no genotype effect. The G > A substitution only affected BW at -388 gm (p < 0.05). Conclusion: The 1016G > A variant is polymorphic and affects the BW but not other growth traits or the meat quality of the LTL muscle.

RESUMEN

In Colombia, different dairy breeds were introduced from Europe and the United States, which underwent different crossing and selection processes that generated specific qualities or differences and which likely have their own genomic structure. To characterize genetic diversity, population structure, and admixture, we used genotypes from 23,182 autosomal single nucleotide polymorphisms (SNPs) of 130 animals representing four dairy cattle breed groups from Nariño. In addition, we merged genotypes from 43,043 autosomal SNPs, from 137 animals from the Decker database (Decker et al., 2014) (DRYAD doi:10.5061/dryad.th092). After the quality control process of pruning the merged dataset, we were left with 7,475 autosomal SNPs shared by both databases of Nariño (127 samples) and Decker (135 samples). Genetic diversity levels were moderate in all breeds (average observed heterozygosity = 0.40). Based on the fixation index values, we conclude that Brahman individuals were more differentiated than the taurine breeds (-0.374 to 0.076 for Brown Swiss). Pairs between taurine breeds showed low genetic differentiation (0.011-0.479). Principal component analysis revealed that in both the Nariño and Decker databases, the taurine formed the most compact cluster compared with other breeds known not to share the same ancestry, and Jersey, Brown Swiss, and Normand individuals exhibited high similarity with Holstein individuals. Hierarchical cluster analysis with Admixture revealed that Brahman, Jersey, Normand, and Holstein from the Decker databases most of which were clustered together with the dairy breeds of the Nariño highland tropics are not able to create different groups, thus having greater similarity with each other. This can be explained by the crosses made by farmers to increase milk production volume, always based on the Holstein breed with semen of bulls from America and Canada. Detrimental impacts due to intensive selection might cause some specific traits from the region to be fixed in the offspring, which can influence their adaptive capacity to the highland tropics.

Na Colômbia foram introduzidas diferentes raças leiteiras trazidas da Europa e dos Estados Unidos, que passaram por diferentes processos de cruzamento e seleção, gerando o desenvolvimento de características ou diferenças específicas nas raças bovinas e provavelmente, exibem sua própria estrutura genômica. Para caracterizar a diversidade genética e estrutura populacional foram utilizados genótipos de 23.182 polimorfismos de nucleotídeo único (SNPs) autossômicos de 130 animais, representando quatro grupos de raças de gado leiteiro de Nariño. Além disso, juntamos genótipos de 43.043 SNPs autossômicos, de 137 animais do banco de dados Decker (Decker et al., 2014) (DRYAD doi:10.5061/dryad.th092). Após o processo de controle de qualidade, o conjunto de dados misto ficou com 7.475 SNPs autossômicos compartilhados em ambos os bancos de dados de Nariño (127 amostras) e Decker (135 amostras). Os níveis de diversidade genética foram moderados em todas as raças (heterozigose média observada = 0,40). Com base nos valores do índice de fixação, concluímos que os indivíduos Brahman (zebuínos) foram mais diferenciados em comparação às raças taurinas (-0,374 a 0,076 para Pardo Suíço). Pares entre as raças taurinas apresentaram baixa diferenciação genética (0,011 ­ 0,479). O resultado dos componentes principais mostra que nos dois bancos de dados, Nariño e Decker, os taurinos formaram o cluster mais compacto em comparação com outras raças conhecidas por não compartilharem a mesma ancestralidade; indivíduos Jersey, Pardo Suíço e Normando denotaram alta similaridade com indivíduos Holandeses. A análise de agrupamento hierárquico com Admixture mostrou que Brahman, Jersey, Normando e Holandês da base de dados Decker, a maioria deles também agrupados com as raças leiteiras do alto trópico de Nariño, não são capazes de criar grupos diferentes, portanto, mostram maior semelhança entre eles. Isso pode ser explicado devido aos cruzamentos feitos pelos pecuaristas para aumentar o volume de produção de leite, sempre tendo como base a raça Holandesa com sêmen de touros da América e Canadá. Impactos prejudiciais, devido à seleção intensiva, podem fazer com que algumas características específicas da região sejam fixadas na prole e isso pode influenciar a sua capacidade adaptativa aos trópicos altos.

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The Blanco Orejinegro (BON) is a Colombian creole cattle breed that is not genetically well characterized for growth traits. The aim of this work was to estimate genetic parameters for birth weight (BW), weaning weight (WW), yearling weight (YW), daily weight gain between birth and weaning (DWG), time to reach 120 kg of live weight (T120), and time to reach 60% of adult weight (T60%), and establish the selection criteria for growth traits in the BON population of Colombia. Genealogical and phenotypic information for BW, WW, YW, DWG, T120, and T60% traits of BON animals from 14 Colombian herds were used. These traits were analyzed with the AIREML method in a uni- and bi-trait animal model including the maternal effect for BW, WW, DWG, and T120. The direct heritability estimates values were 0.22 ± 0.059 (BW), 0.20 ± 0.057 (WW), 0.20 ± 0.153 (YW), 0.17 ± 0.07 (DWG), 0.26 (T120), and 0.44 ± 0.03 (T60%). The maternal heritability estimates values were 0.14 ± 0.040 (BW), 0.15 ± 0.039 (WW), 0.25 ± 0.06 (DWG), and 0.16 (T120). The direct genetic correlations were high ( >|0.60|) among all the traits, except between T60% with BW, WW, YW, and DWG (ranged from - 0.02 to - 0.51), all in a favorable direction. The results showed that there is genetic variation in the growth traits associated with the additive genetic effect, and they might respond to selection processes. Furthermore, genetic gains would improve through selection, especially for YW and T60% when WW is used as criterion.

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The Chino Santandereano (CHS) creole cattle breed has undergone an adaptation process of more than 500 years to the Colombian mountainous tropics. Despite its advantages, the breed has been replaced by specialized cattle that put it at risk of extinction. The aim of this work was to estimate the genomic diversity and population structure of the nucleus of conservation of the CHS breed. Thirty-seven CHS and 20 Brahman animals were genotyped due to the possible introgression of genes with the GGP Bovine LD v3 chip. Quality control was performed, and linkage disequilibrium (LD), effective population size (Ne), ROH segments, homozygosity, and genomic inbreeding in the breed were estimated. Subsequently, 50 K genomic information of the Holstein (n = 30) and Romosinuano (n = 8) breeds were included to estimate the minor allele frequency (MAF) with common markers and constructing the graphs of the principal component analysis (PCA). Pairwise FSTs were estimated and a neighbor-joining tree was constructed using the IBS matrix. Admixture was used with k = 2 to 10 for the racial composition. LD (r2) was found up to a distance of 0.13 Mb, r2 > 0.3 at a distance of 340.3 kb, and Ne of 32 ± 1. ROH inbreeding was 5.36 ± 0.86%, with a higher contribution from recent inbreeding (4.55%). The PCA showed that the creole breeds were closer together, and the Brahman was more distant. The admixture analysis suggested k = 5 possible ancestral groups and shows that within the CHS breed, there seem to be two different groups with little Holstein and Brahman introgression. The genetic diversity parameters obtained in this work show minimal diversity in this breed and reinforce the need to protect this resource and the conservation banks.

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Traditional selection programs for dairy cattle, based on quantitative principles, have worked well and allowed strong selection processes in the world over many decades. The objectives of this work were to estimate linkage disequilibrium (LD) levels at varying SNPs densities, to evaluate the effective population size of Holstein cattle, to characterize runs of homozygosity (ROH) distribution through Holstein cattle from Nariño and, to estimate and compare inbreeding coefficient (F) based on genomic markers information, runs of homozygosity (FROH), genomic relationship matrix (FGRM), and excess of homozygous (FSNP). After quality control, the dataset used was composed of 606 Holstein animals and 22200 SNP markers. PLINK program was used to identify LD, Ne, ROH segment and FROH and FSNP, FGRM was calculated with BLUPF90 family of programs. The average of r2 in all chromosomes was 0.011, the highest r2 was found in BTA3 (0.0323), and the lowest in BTA12 (0.0039). 533 ROH segments were identified in 319 animals; findings obtained in this study suggest that on average 0,28% of Holstein genome is autozygous. Total length of ROH was composed mostly of small segments (ROH1-4Mb and ROH4-8Mb). These segments accounted for approximately 96%, while larger ROH (ROH>8Mb) were 3.37% of all ROH detected. Inbreeding averages FROH, FSNP and FGRM methodologies were 0.28%, 3.11% and 3.36% respectively. The Pearson's correlation among these different F values was: 0.49 (FROH-FSNP), 0.25 (FROH-FGRM), 0.22 (FSNP-FGRM). The distribution of ROH shared regions identified on 19 autosome chromosomes, cover a relevant number of genes inside these ROH. Our result evidenced lowest LD extension levels compared with other [...].

Los programas de selección tradicionales para ganado lechero, basados en principios cuantitativos, han funcionado bien y han permitido grandes procesos de selección en el mundo durante muchas décadas. Los objetivos de este trabajo fueron estimar los niveles de desequilibrio de ligamiento (LD) en diferentes densidades de SNPs, evaluar el tamaño efectivo de la población de ganado Holstein, caracterizar tramos de homocigosidad (ROH) distribuidas a través de ganado Holstein de Nariño y, estimar y comparar coeficiente de consanguinidad (F) basado en información de marcadores genómicos, tramos de homocigosidad (FROH), matriz de relación genómica (FGRM) y exceso de SNP homocigotos (FSNP). Después del control de calidad, el conjunto de datos utilizado estaba compuesto por 606 animales Holstein y 22200 marcadores SNP. Se utilizó el programa PLINK para identificar LD, Ne, segmentos de ROH, FROH y FSNP, FGRM se calculó con la familia de programas BLUPF90. El promedio de r2 en todos los cromosomas fue de 0.011, el r2 más alto se encontró en BTA3 (0.0323) y el más bajo en BTA12 (0.0039). Se identificaron 533 segmentos de ROH en 319 animales; los hallazgos obtenidos en este estudio sugieren que, en promedio, el 0,28% del genoma de Holstein es autocigoto. La longitud total de ROH se compuso principalmente de pequeños segmentos (ROH1-4Mb y ROH4-8Mb). Estos segmentos representaron aproximadamente el 96%, mientras que los ROH más grandes (ROH > 8Mb) representaron el 3.37% de todos los ROH detectados. Los promedios de consanguinidad de las metodologías FROH, FSNP y FGRM fueron 0.28%, 3.11% y 3.36% respectivamente. La correlación de Pearson entre estos diferentes valores de F fue: 0.49 (FROH-FSNP), 0.25 (FROH-FGRM), 0.22 (FSNP-FGRM). La distribución de las regiones compartidas de ROH identificadas en 19 cromosomas autosómicos cubre un número importante de genes dentro de estos ROH. Nuestro resultado evidenció niveles más bajos de extensión de LD [...].

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Traditional selection programs for dairy cattle, based on quantitative principles, have worked well and allowed strong selection processes in the world over many decades. The objectives of this work were to estimate linkage disequilibrium (LD) levels at varying SNPs densities, to evaluate the effective population size of Holstein cattle, to characterize runs of homozygosity (ROH) distribution through Holstein cattle from Nariño and, to estimate and compare inbreeding coefficient (F) based on genomic markers information, runs of homozygosity (FROH), genomic relationship matrix (FGRM), and excess of homozygous (FSNP). After quality control, the dataset used was composed of 606 Holstein animals and 22200 SNP markers. PLINK program was used to identify LD, Ne, ROH segment and FROH and FSNP, FGRM was calculated with BLUPF90 family of programs. The average of r2 in all chromosomes was 0.011, the highest r2 was found in BTA3 (0.0323), and the lowest in BTA12 (0.0039). 533 ROH segments were identified in 319 animals; findings obtained in this study suggest that on average 0,28% of Holstein genome is autozygous. Total length of ROH was composed mostly of small segments (ROH1-4Mb and ROH4-8Mb). These segments accounted for approximately 96%, while larger ROH (ROH>8Mb) were 3.37% of all ROH detected. Inbreeding averages FROH, FSNP and FGRM methodologies were 0.28%, 3.11% and 3.36% respectively. The Pearson's correlation among these different F values was: 0.49 (FROH-FSNP), 0.25 (FROH-FGRM), 0.22 (FSNP-FGRM). The distribution of ROH shared regions identified on 19 autosome chromosomes, cover a relevant number of genes inside these ROH. Our result evidenced lowest LD extension levels compared with other [...].(AU)

Los programas de selección tradicionales para ganado lechero, basados en principios cuantitativos, han funcionado bien y han permitido grandes procesos de selección en el mundo durante muchas décadas. Los objetivos de este trabajo fueron estimar los niveles de desequilibrio de ligamiento (LD) en diferentes densidades de SNPs, evaluar el tamaño efectivo de la población de ganado Holstein, caracterizar tramos de homocigosidad (ROH) distribuidas a través de ganado Holstein de Nariño y, estimar y comparar coeficiente de consanguinidad (F) basado en información de marcadores genómicos, tramos de homocigosidad (FROH), matriz de relación genómica (FGRM) y exceso de SNP homocigotos (FSNP). Después del control de calidad, el conjunto de datos utilizado estaba compuesto por 606 animales Holstein y 22200 marcadores SNP. Se utilizó el programa PLINK para identificar LD, Ne, segmentos de ROH, FROH y FSNP, FGRM se calculó con la familia de programas BLUPF90. El promedio de r2 en todos los cromosomas fue de 0.011, el r2 más alto se encontró en BTA3 (0.0323) y el más bajo en BTA12 (0.0039). Se identificaron 533 segmentos de ROH en 319 animales; los hallazgos obtenidos en este estudio sugieren que, en promedio, el 0,28% del genoma de Holstein es autocigoto. La longitud total de ROH se compuso principalmente de pequeños segmentos (ROH1-4Mb y ROH4-8Mb). Estos segmentos representaron aproximadamente el 96%, mientras que los ROH más grandes (ROH > 8Mb) representaron el 3.37% de todos los ROH detectados. Los promedios de consanguinidad de las metodologías FROH, FSNP y FGRM fueron 0.28%, 3.11% y 3.36% respectivamente. La correlación de Pearson entre estos diferentes valores de F fue: 0.49 (FROH-FSNP), 0.25 (FROH-FGRM), 0.22 (FSNP-FGRM). La distribución de las regiones compartidas de ROH identificadas en 19 cromosomas autosómicos cubre un número importante de genes dentro de estos ROH. Nuestro resultado evidenció niveles más bajos de extensión de LD [...].(AU)

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K-casein is one of the most important milk proteins by their relationship to traits associated with the cheese production. Therefore, the aim of this study was to determine the relationship between some production traits and kappa casein content in the milk of cows in eight herds from Pereira, Risaralda. 48 milk samples from cows were analysed for k-casein content by polyacrylamide gel electrophoresis in one dimension (SDS-PAGE Triazine) and were taken the effect of the breed, the supplementation, calving number, days in milk and milk yield. The information was evaluated using a generalized linear model using R software with agricolae and car libraries (R Core Team). The mean of k-casein was 3.55 g/L and the coefficient of variation was 19.3%, the coefficient of variation for milk production was 40.3%. The traits evaluated was only significant (p<0.05) the type of supplementation and. Was found, an inverse relation of k-casein with the number of calving, although it was not significant, this may be due to number of calving it is indicative of the age of the cow and the racial component of the generation.

La k-caseína es una de las proteínas más importantes de la leche por su relación con diferentes características asociadas a la producción de quesos. Por lo anterior, el objetivo de este trabajo fue determinar la relación entre algunas características productivas y el contenido de kappa caseína de la leche de vacas en ocho hatos del Municipio de Pereira, Risaralda. Para esto, se tomaron muestras de leche de 48 vacas de diferente tipo racial, las que se les determinó el contenido de k-caseína mediante electroforesis en gel de poliacrilamida en una dimensión (Triacina SDS-PAGE) y se determinó el efecto que ejerce el grupo racial, el tipo de suplementación, el número de parto, los días en lactancia, y el volumen de leche producido. La información fue evaluada mediante un modelo lineal generalizado, usando el software R mediante las librerías agricolae y car (R Core Team). Se encontró un valor medio de k-caseína de 3,55 g/L y un coeficiente de variación del 19,3%, el coeficiente de variación para la producción de leche fue de 40,3%. De los caracteres evaluadas sólo fue significativo (p<0,05) el tipo de suplementación. Además, se encontró una relación inversa entre el contenido de k-caseína con el número de parto, aunque no fue significativa, esto se puede deber a que el número de partos es un indicativo de la edad de la vaca y el componente racial de la generación.

A k-caseína é uma das proteínas mais importantes do leite por sua relação com diferentes características associadas a produção de queijos. Pelo anterior, o objetivo deste trabalho foi determinar a relação entre algumas características produtivas e o conteúdo de kappa caseína do leite de vacas em oito rebanhos do município de Pereira, Risaralda. Para isto, tomaram-se amostras de leite de 48 vacas de diferente tipo racial, nas quais determinou-se o conteúdo de k-caseína mediante eletroforese em gel de poliacrilamida em uma dimens ão (Triacina SDS-PAGE) e determinou-se o efeito que exerce o grupo racial, o tipo de suplementação, o número de parto, os dias em lactação e o volume do leite produzido. A informação foi avaliada mediante um modelo linear generalizado usando o software R mediante as livrarias agricolae e car (R Core Team). Encontrou-se um valor médio de k-caseína de 3,55 g/L e um coeficiente de variação de 19,3%, o coeficiente de variação para a produção do leite foi de 40,3%. Dos caracteres avaliados só foi significativo (p<0,05) o tipo de suplementação. Além, encontrou-se uma relação inversa entre o conteúdo de k-caseína com o número de parto, ainda que não foi significativa, isto pode-se dever a que o número de partos é um indicativo da idade da vaca e o componente racial da geração.

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BON cattle is an important genetic resource. It is necessary to describe the productive behavior of BON to improve the use of this breed. The objective of this study was to determine the model that best fit BON growth. Nonlinear models (Gompertz, logistic, Brody and von Bertalanffy) were compared to determine the one with the best fit and estimate the parameters for each model. Brody showed the best fit, with the lowest sum of squared errors (SQE) for both Akaike information criterion (AIC) and Bayesian information criterion (BIC). Brody parameters were β0 (mature weight: 590 kg) and β2 (maturity index: 0.00153 ± 0.0000042 kg/day). The maturity index was similar and in some cases higher to that found in some crosses of commercial beef cattle, highlighting the precocity of BON, which reaches about 52.9% maturity at 12 months. Additionally, the age BON reaches 75% maturity was approximately 708 days, which shows its precocity and growth potential. This results highlight the importance of this breed as a valuable genetic resource for cattle farming in the tropics.

El ganado BON constituye un recurso genético y ganadero de gran importancia, por lo que describir su comportamiento productivo es necesario para garantizar su utilización. El objetivo del presente trabajo fue determinar el modelo que mejor se ajustara al crecimiento del ganado BON, por lo que se compararon diferentes modelos no lineales (Gompertz, Logístico, de Brody y de Von Bertalanffy), con el fin de determinar el que mejor se ajusta y estimar los parámetros para cada uno. El modelo que mejor se ajustó al crecimiento del BON fue el de Brody, mostrando menores valores de sumatoria de cuadrados del error (SQE), de AIC y de BIC. Por otra parte, los parámetros hallados para el modelo de Brody fueron: β0 , interpretado como el peso maduro, de 590 kg y el parámetro β2 , correspondiente con el índice de madurez, de 0,00153 ± 0,0000042 kg/día. El índice de madurez fue similar y en algunos casos superior al encontrado en algunos cruces y ganados de carne comerciales, lo que resalta la precocidad que presenta el ganado BON, que alcanza aproximadamente 52,9% de madurez a los 12 meses. Adicionalmente, se encontró que la edad a la cual el BON alcanza el 75% de madurez fue de 708 días aproximadamente, lo que muestra su precocidad y capacidad de crecimiento. Lo expuesto anteriormente resalta la importancia del ganado BON como un recurso genético y productivo para los programas de producción bovina en el trópico.

O gado BON, constitui um recurso genético e de produção de grande importância, pelo qual, descrever seu comportamento e desempenho produtivo e mostrar suas fortalezas é necessário para garantir sua utilização. O objetivo do presente trabalho foi determinar o modelo que melhor tivesse ajuste não linear (Gompertz, Logístico, de Brody e de Von Bertalanffy), com o fim de determinar o modelo que melhor se ajustasse e estimar os parâmetros para cada um deles. O modelo que melhor se ajustou ao crescimento do gado BON foi o de Brody, apresentando menores valores na somatória de quadrados do erro (SQE), de AIC e de BIC. Por outro lado, os parâmetros encontrados para o modelo de Brody foram: β0, interpretado como o peso maduro, de 590 kg e o parâmetro β2, que corresponde com o índice de maturidade, de 0,00153 ± 0,0000042 kg/dia. O índice de maturidade foi similar e em alguns casos até superior ao encontrado em alguns cruzamentos e gados de corte não registrados, o que ressalta a precocidade que apresenta o gado BON, que consegue aproximadamente 52,9% de maturidade aos 365 dias (12 meses). Adicionalmente, encontrou-se que a idade na qual o gado BON consegue o 75% de maturidade foi de 708 dias (23,6 meses) aproximadamente, o que demostra sua precocidade e capacidade de crescimento. O exposto anteriormente ressalta a importância do gado BON como um recurso genético com boas qualidades produtivas e reprodutivas para os programas de produção bovina no tropico.