Morphological divergence in the West African shorthorn Lagune cattle populations from Benin

Quantifying morphometric and adaptive characteristics of indigenous cattle genetic resources in northwest Ethiopia

Ethiopia is the gateway of livestock genetic resources to Africa and has a wide range of altitude. It is endowed with huge diverse cattle genetic resources. The aim of this research was to determine the morphometric and potentioally adaptive characteristics of cattle populations. Multi-stage purposive and random sampling methods were employed to select the study areas, households and animals. A total of 1200 adult cattle were sampled and characterized for 14 qualitative and eight morphometric variables. The comparison of marginal means, chi-square tests, canonical discriminant analysis, and clustering analysis were employed using SAS and SPSS statistical software. The sex of the animal, location and agro-ecology were fitted as fixed effects in the model and had highly significant (p<0.001) effects for most body measurements. The chi-square test values of all categorical variables were significantly different (p<0.001) and potentioally adaptive characteristics such as coat colour type, navel flap, and tail length had higher association (> 0.45) values. White with red, light red, black and dark red were the most predominant coat colour types of cattle. The maximum hit rates were recorded in Enebsie and Sinan cattle. From five extracted canonical variate, (can1 and can2) accounted 75.4% and 78.8% in the female and male cattle populations, respectively. The canonical class has separated cattle populations of Sinan from Banja at can1 and Mecha from Sinan populations at can2. The square Mahalanobis distances between sites were significant (p<0.001) and the largest distance was found between Banja and Sinan locations. Cluster analysis result classified the study populations into four major cattle groups. The cumulative analysis results showed that the cattle populations of the study area can be categorized into four breed types as Jawi Sanga, Gojjam Zenga, Banja cattle, and Sinan cattle. However, this morphology based grouping need to be confirmed by molecular data.

Productive and reproductive performances of smallholder West African shorthorn Lagune cattle herds under village conditions in Southern Benin

The West African shorthorn Lagune cattle has long been incriminated as of low productivity and subjected to gradual replacement or indiscriminate crossbreeding with zebu breeds. But there are still insufficient studies reporting the productive and reproductive performances of this breed under village conditions. This study aimed to evaluate the productive and reproductive performances of the Lagune cattle herds kept under village conditions in two agroecological zones in Southern Benin. Sixteen herds (seven in the Oueme Valley zone and nine in the Pobe zone), chosen from a previous retrospective survey, were regularly visited on a bi-monthly basis between January 2018 and February 2019. At the first visit to each selected herd, all animals present were identified, their ages determined through their dentition, and their breeding history recorded. At each subsequent visit, information on calving, birth weights, herd entries and exits, disease incidence, and changes in the physiological status of the animals were recorded. In addition, all suckling calves from birth to 6 months of age were weighted and measured. The average age at first calving was 37.2 ± 3.5 months and varied from 3 to 4 years. With no significant variations between agroecological zones, the parturition rate, fertility rate, fecundity rate, and abortion rate were, respectively, 74.3% ± 10.7, 77.0% ± 12.0, 68.9% ± 9.1, and 2.7% ± 1.4. The overall annual mortality rate and perinatal mortality rate were 8.4% ± 3.1 and 7.3% ± 2.7, respectively. The annual offtake rate was 12.9% ± 4.3 and varied significantly (P ≤ 0.05) between zones. The average birth weight varied significantly (P ≤ 0.05) between sex and was 10.2 ± 0.7 kg and 10.8 ± 0.9 kg for female and male, respectively. The average daily body weight gain of calves, calculated over the period from birth to 6 months of age, was 160.5 ± 8.5 g/day. In addition to environmental conditions, individual farmers' management practices varied significantly among herds and probably influenced the recorded reproductive and productive performances. The estimates of reproductive parameters obtained in this study suggest a good reproductive ability of the Lagune breed which could be improved with better management conditions.

Assessing Genomic Diversity and Selective Pressures in Bohai Black Cattle Using Whole-Genome Sequencing Data

Simple Summary

Bohai Black cattle are one of the indigenous black coat cattle breeds in China, which are famous for their excellent meat quality. Whole-genome sequencing technology has been extensively developed to study species genome genetic diversity, population structure, selection pressure, demographic events, etc. However, a limited number of studies have reported genomic diversity and selection pressures in Bohai Black cattle. The purpose of this study is to analyze population structure and genomic differences between Bohai Black cattle and five “core” cattle populations from all over the world, mainly oriented on the identification of selection signatures using whole-genome sequencing data. In addition, we identify a series of candidate genes that can potentially be related to black coat color, meat quality, immunity, and reproduction in this breed. This study provides valuable genomic resources and theoretical basis for the future breeding of Bohai Black cattle.

Abstract

Bohai Black cattle are one of the well-known cattle breeds with black coat color in China, which are cultivated for beef. However, no study has conducted a comprehensive analysis of genomic diversity and selective pressures in Bohai Black cattle. Here, we performed a comprehensive analysis of genomic variation in 10 Bohai Black cattle (five newly sequenced and five published) and the published whole-genome sequencing (WGS) data of 50 cattle representing five “core” cattle populations. The population structure analysis revealed that Bohai Black cattle harbored the ancestry with European taurine, Northeast Asian taurine, and Chinese indicine. The Bohai Black cattle demonstrated relatively high genomic diversity from the other cattle breeds, as indicated by the nucleotide diversity (pi), the expected heterozygosity (H_E) and the observed heterozygosity (H_O), the linkage disequilibrium (LD) decay, and runs of homozygosity (ROH). We identified 65 genes containing more than five non-synonymous SNPs (nsSNPs), and an enrichment analysis revealed the “ECM-receptor interaction” pathways associated with meat quality in Bohai Black cattle. Five methods (CLR, θπ, F_ST, θπ ratio, and XP-EHH) were used to find several pathways and genes carried selection signatures in Bohai Black cattle, including black coat color (MC1R), muscle development (ITGA9, ENAH, CAPG, ABI2, and ISLR), fat deposition (TBC1D1, CYB5R4, TUSC3, and EPS8), reproduction traits (SPIRE2, KHDRBS2, and FANCA), and immune system response (CD84, SLAMF1, SLAMF6, and CDK10). Taken together, our results provide a valuable resource for characterizing the uniqueness of Bohai Black cattle.

Unraveling Admixture, Inbreeding, and Recent Selection Signatures in West African Indigenous Cattle Populations in Benin

The Dwarf Lagune and the Savannah Somba cattle in Benin are typical representatives of the endangered West African indigenous Shorthorn taurine. The Lagune was previously exported to African and European countries and bred as Dahomey cattle, whereas the Somba contributed to the formation of two indigenous hybrids known as Borgou and Pabli cattle. These breeds are affected by demographic, economic, and environmental pressures in local production systems. Considering current and historical genomic data, we applied a formal test of admixture, estimated admixture proportions, and computed genomic inbreeding coefficients to characterize the five breeds. Subsequently, we unraveled the most recent selection signatures using the cross-population extended haplotype homozygosity approach, based on the current and historical genotypes. Results from principal component analyses and high proportion of Lagune ancestry confirm the Lagune origin of the European Dahomey cattle. Moreover, the Dahomey cattle displayed neither indicine nor European taurine (EUT) background, but they shared on average 40% of autozygosity from common ancestors, dated approximately eight generations ago. The Lagune cattle presented inbreeding coefficients larger than 0.13; however, the Somba and the hybrids (Borgou and Pabli) were less inbred (≤0.08). We detected evidence of admixture in the Somba and Lagune cattle, but they exhibited a similar African taurine (AFT) ancestral proportion (≥96%) to historical populations, respectively. A moderate and stable AFT ancestral proportion (62%) was also inferred for less admixed hybrid cattle including the Pabli. In contrast, the current Borgou samples displayed a lower AFT ancestral proportion (47%) than historical samples (63%). Irrespective of the admixture proportions, the hybrid populations displayed more selection signatures related to economic traits (reproduction, growth, and milk) than the taurine. In contrast, the taurine, especially the Somba, presented several regions known to be associated with adaptive traits (immunity and feed efficiency). The identified subregion of bovine leukocyte antigen (BoLA) class IIb (including DSB and BOLA-DYA) in Somba cattle is interestingly uncommon in other African breeds, suggesting further investigations to understand its association with specific adaptation to endemic diseases in Benin. Overall, our study provides deeper insights into recent evolutionary processes in the Beninese indigenous cattle and their aptitude for conservation and genetic improvement.

Morphological variability within the indigenous sheep population of Benin

Knowledge of both the genetic diversity and geographical distribution of animal genetic resources is a prerequisite for their sustainable utilization, improvement and conservation. The present study was undertaken to explore the current morphological variability within the sheep population in Benin as a prelude for their molecular characterization. From November 2018 to February 2020, 25 quantitative linear body measurements and 5 qualitative physical traits were recorded on 1240 adult ewes from the 10 phytogeographic zones that comprise the three vegetation zones of Benin. Fourteen morphological indices were calculated based on the linear body measurements. The collected data were first analyzed using multiple comparisons of least-square means (LSmeans), followed by generalized linear model (GLM) procedures, to explore the relationships among the measured morphometric traits and the 10 phytogeographic zones. Next, the presence of any genetic sub-populations was examined using multivariate analytical methods, including canonical discriminant analysis (CDA) and ascending hierarchical clustering (AHC). Univariate analyses indicated that all quantitative linear body measurements varied significantly (P<0.05) across the phytogeographic zones. The highest values (LSmean± standard error) of withers height (68.3±0.47 cm), sternum height (46.0±0.35 cm), and rump height (68.8±0.47 cm) were recorded in the Mekrou-Pendjari zone, the drier phytogeographic zone in the North, whereas the lowest values, 49.2±0.34, 25.9±0.26, and 52.0±0.35 cm, respectively, were recorded in the Pobe zone in the South. Multivariate analyses revealed the prevalence of four distinct sheep sub-populations in Benin. The sub-population from the South could be assimilated to the short-legged and that from the North to the West African long-legged sheep. The two other sub-populations were intermediate and closer to the crossbreeds or another short-legged sub-breed. The proportion of individuals correctly classified in their group of origin was approximately 74%. These results uncovered a spatial morphological variation in the Beninese sheep population along a South-North phytogeographic gradient.