The goal of this study was to estimate genetic parameters for the growth, conformation, and survival of goat kids raised in smallholder farming systems in Burundi. To do this, measurements were taken on live weight, thoracic perimeter, length, and height at birth (n = 1538 animals), at 3 months (n = 1270 animals), at 6 months (n = 992 animals), at 9 months (n = 787 animals), and at 12 months (n = 705 animals). Kids were born between 2016 and 2019, from 645 dams and 106 bucks. Three bivariate animal models were used to estimate genetic parameters of body weight and conformation measurements as potential indicators of this weight. According to the measure, heritability was estimated between 15 and 17% and genetic correlations between 65 and 79%. An accelerated failure time animal model was used to estimate the heritability of survival for kids under one year, adjusted for birth weight. Goat survival was significantly prolonged by 0.64 days per kilogram of birth weight. The estimated heritability for this trait was 2%. Overall, these results suggest that a selection program could be implemented to improve animal growth, either directly on weight or indirectly on conformational traits. At the same time, efforts need to be made to improve rearing conditions to increase the survival of kids.

As part of a national action plan to manage animal genetic resources in Burundi, we characterized smallholders' goat production systems and assessed the effect of Boer crossbreeding on animal body measures. To that end, 319 farmers were surveyed in the five agro-ecological zones of Burundi and the zootechnical measures of 939 adult goats were taken. Cluster analysis of the goat production systems resulted into two opposed groups and one intermediate. On the one hand, there are the dry lowlands systems characterized by large herds composed mainly of indigenous animals grazing freely, and having high market characteristics. On the other hand, there are the humid highlands systems characterized by small herds composed of indigenous and crossbred animals in stall feeding or herding/tethering systems, and by low market characteristics. Fixed effect linear models were used to evaluate the effect of Boer crossbreeding on body weights and linear body measures, after adjustment for age, sex, grazing systems and agro-ecological zones. Results showed that least square means for body weights of adult Boer crossbreds were 4.74 kg higher than those of indigenous goats, which was lower than expected. Least square means for linear body measures of Boer crossbreds were significantly higher than those of indigenous breeds: differences in chest girth, body length and height at withers were 4.88 cm, 5.59 cm and 4.82 cm, respectively. Goats were heavier and greater in linear measures in lowlands than in highlands. The advantages and issues of a selection programme within indigenous breeds are discussed as an alternative to the crossbreeding programme.

Different breeding systems associated with specific bovine genetic resources have coexisted in Burundi. To prepare for the development of a national action plan for the improvement of bovine genetic resources in Burundi, we aimed at performing genetic characterization of Ankole and Ankole × European crossbred individuals and assessing the effect of European ancestry on milk productivity of cows kept under the mixed crops livestock system. To that end, we genotyped 37 Ankole and 138 crossbred individuals on 42 636 SNPs and combined these genotypes with those from 21 cattle breeds, representative of the bovine genetic diversity. We also measured milk yield not suckled and estimated suckled milk. Given the results, we confirmed the indicine × African taurine admixed origin of the Ankole in Burundi and showed that crossbred individuals present a high proportion of European ancestry (i.e. 57% on average). As the proportion of European ancestry increased, milk yield increased by 0.03 ± 0.01 l/day, at a lower extent than expected. We also observed that breeders were unable to correctly evaluate the European proportion in their livestock. Our results may provide useful information for objective dairy breeding in Burundi. As an example, an ex-situ conservation program of Ankole within the framework of value chains is proposed as an accompanying strategy to improve the sustainability of the crossbreeding program.

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