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This study aimed to estimate the heterosis for productive traits in a two-way crossbreeding scheme. Four guinea pig lines were originally selected for the following traits: line P1 for the growth rate, P2 for the partial feed conversion rate, M1 for the growth rate of the litter at 10 days of age, and M2 for the litter size at birth. The comparison included 176 purebreds (P1: 46, P2: 43, M1: 54 and M2: 33) and 150 crosses (P1P2: 42, P2P1: 38, M1M2: 11 and M2M1: 59); body weights at birth, 10 days, weaning and 60 days of age were analyzed. A linear fixed-effect model was used, and heterosis was estimated as the difference between the average performance of the crossbred and pure-line animals. The pure line comparisons showed that P2 was lower than P1 for weight at 10 days and weaning weight, while all other comparisons between the paternal and maternal pure lines were not significant. The results indicated significant positive heterosis effects for both types of crosses, but only for birth weight: 3.7% for paternal crosses and 12.7% for maternal crosses. The heterosis estimates were mostly positive but not significant for all other traits. A reason for the low levels of heterosis could be that the lines are not very genetically differentiated. These results suggest that applying a two-way crossbreeding scheme within paternal and maternal guinea pig lines for meat production is not recommended due to the absence of heterosis for growth traits.
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Improving textile characteristics is the main objective of alpaca breeding. A recently developed SNP chip for alpacas could potentially be used to implement genomic selection and accelerate genetic progress. Therefore, this study aimed to compare the increase in prediction accuracy of three important fiber traits: fiber diameter (FD), standard deviation of fiber diameter (SD), and percentage of medullation (PM) in Huacaya alpacas. The data contains a total pedigree of 12,431 animals, 24,169 records for FD and SD, and 8386 records for PM and 60,624 SNP markers for each of the 431 genotyped animals of the Pacomarca Genetic Center. Prediction accuracy of breeding values was compared between a classical BLUP and a single-step Genomic BLUP (ssGBLUP). Deregressed phenotypes were predicted. The accuracies of the genetic and genomic values were calculated using the correlation between the predicted breeding values and the deregressed values of 100 randomly selected animals from the genotyped ones. Fifty replicates were carried out. Accuracies with ssGBLUP improved by 2.623%, 6.442%, and 1.471% on average for FD, SD, and PM, respectively, compared to the BLUP method. The increase in accuracy was relevant, suggesting that adding genomic data could benefit alpaca breeding programs.
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Over the past decade, community-based breeding programs (CBBPs) have been promoted as a viable approach to improving smallholder livelihoods through a systematic livestock breeding. CBBPs aim to initiate systematic breeding at the community level, including an organized animal identification and recording of performance and pedigree data. To ensure the breeding programs' continuity, building capacities, and ownership among participants are essential to the approach. This study's purpose was to understand how CBBPs have evolved in specific institutional settings and which dynamics occur in the course of implementation. We addressed these questions in reflective conversations with six coordinators of a diverse sample of CBBPs: goats (Malawi, Uganda, and Mexico), sheep (Ethiopia), alpaca (Peru), and cattle (Burkina Faso). The interviews and analysis were guided by categories of the multi-level perspective. The respondents considered lack of funding and weak institutionalization as the main constraints on the CBBPs. While the idea of participation and localized ownership was at the center of the programs, linear paradigms of knowledge transfer prevailed. In all cases, the impulse to start a CBBP came from individual researchers, who relied on intermediaries, such as extension agents, for implementation. Personal relations and trust were seen as both a factor in the success and a positive outcome of CBBPs. We conclude that these findings have different implications depending on how rural development is conceptualized: proponents of the innovation systems perspective would call for stakeholders to further align their interests and coordinate their actions. Proponents of process-relational concepts, in contrast, would not consider the CBBP a product but a starting-point for initiators and participants to continuously discover new ways of collaboration and engagement.
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High-throughput genomic markers provide an opportunity to assess important indicators of genetic diversity for populations managed in livestock breeding programs. While well-structured breeding programs are common in developed countries, in developing country situations, especially in West Africa, on-farm performance and pedigree recordings are rare, and thus, genomic markers provide insights to the levels of genetic diversity, inbreeding and introgression by other breeds. In this study, we analysed key population parameters such as population structure, admixture and levels of inbreeding in three neighbouring populations of African taurine and taurine × Zebu crosses managed by community-based breeding programs in the South-West of Burkina Faso. The three populations were pure Baoulé (called Lobi locally) in sedentary production systems, Baoulé x Zebu crossbreds in sedentary systems and Zebu × Baoulé crossbreds in transhumant production systems, respectively. The total sample analysed included 631 animals and 38,207 single nucleotide polymorphisms after quality control. Results of principal component and admixture analyses confirmed the genetic background of two distinct ancestral populations (taurine and zebuine) and levels of admixture in all three breeding populations, including the presumably pure Baoulé group of animals. Inbreeding levels were moderate, compared to European dairy and beef cattle populations and higher than those of Brazilian Nellore cattle. Very few animals with inbreeding levels indicating parent-offspring or full sib mating were observed, and inbreeding levels indicating half sib mating were also rare. For the management of breeding populations, farmers were advised to exchange best young bulls. The crossbreeding levels of presumably pure Baoulé animals are of concern to the breeding program due to the high level of endangerment of pure African taurine cattle populations across West Africa. Future rounds of bull selection in the community-based breeding program will make use of genomic information about admixture levels.
Assuntos
Endogamia , Animais , Brasil , Burkina Faso , Bovinos , Genoma , Gado , MasculinoRESUMO
Resumen En alpacas los fenotipos del color de vellón tienen diferentes terminologías que induce a una confusión dentro del color marrón y sus tonalidades, el que requiere de una mejor descripción y cuantificación. En consecuencia los objetivos del estudio fueron cuantificar el color de fibra e identificar los PNSs informativos del gen MC1R (receptor 1 de melanocortina) en alpacas marrones y negras. Un fenotipo vicuña (n=14) y cuatro fenotipos de alpacas (n=79), marrón claro, marrón oscuro, marrón-negro y negro fueron evaluados por colorimetría. El vellón de vicuña mostró mayor luminosidad (47.74) e intensidad de color (24.33) respecto a las alpacas marrones. Los valores obtenidos de CIE L*a*b* (luminosidad e intensidad) sugieren valores bajos en alpacas eumelánicas y altos en alpacas feomelánicas. En vicuña y alpaca la secuencia codificante del gen MC1R tiene un solo exón de 954 pb, las vicuñas no mostraron la deleción (c.224_227del). Sin embargo, esta deleción se ha observado en los tres fenotipos de alpaca (marrón claro, marrón oscuro y negro), al igual que los cinco PNSs no sinónimos que ya fueron descritos en otras poblaciones, c.82A>G, c.259G>A, c.376G>A, c.587T>C, c.901C>T (p.T28A, p.M87V, p.G126S, p.F196S y p.R301C). Para las dos especies, se identificaron un total de ocho haplotipos definidos por los cinco PNSs. No se observaron asociaciones entre los fenotipos de color y los PNSs: c.259G>A, c.376G>A y c.901C>T (p>0.05), probablemente debido a la influencia de otros genes como el ASIP en la expresión del color. Nuestros resultados, así como los estudios previos evidenciaron regiones altamente conservadas en la secuencia codificante del gen MC1R.
Abstract In alpacas color fleece phenotypes have different terminologies that induces confusion within the brown color and its shades, it requires a better description and quantification. Consequently, the aims of the study were to quantify the color of fiber and identify the informational SNPs in the MC1R gene (melanocortin 1 receptor) in brown and black alpacas. A vicuña phenotype (n=14) and four alpaca phenotypes (n=79), light brown, dark brown, brown-black and black were evaluated by colorimetry. The vicuña fleece showed greater lightness (47.74) and color intensity (24.33) compared to brown alpacas. The CIE L*a*b* values (lightness and intensity) suggest low values in eumelanic alpacas and high in pheomelanic alpacas. In vicuña and alpaca, the coding sequence of the MC1R gene has a single exon of 954 bp, in vicuñas the deletion (c.224_227del) was not observed. However, this deletion was observed in three alpaca phenotypes (light brown, dark brown and black), as well as the five non-synonymous SNPs described in other populations, c.82A>G, c.259G>A, c.376G>A, c.587T>C, c.901C>T (p.T28A, p.M87V, p.G126S, p.F196S, and p.R301C). Eight haplotypes defined by the five SNPs were identified in both species. The associations between color phenotypes and SNPs were not observed (p>0.05), probably due to the influence of other genes such as ASIP on color expression. Our results as well as previous studies showed highly conserved regions in the coding sequence of the MC1R gene.