Tannins are secondary metabolites naturally present in various plants as a defense mechanism. In animal nutrition, they play a dual role, acting as both antinutritional factors and bioactive agents, with potential benefits in nutrient metabolism and product quality. This meta-analysis aimed to evaluate the effects of dietary tannin on nutrient intake and digestibility, blood serum metabolite levels, growth performance, carcass characteristics, and meat quality in small ruminants. Ninety-seven studies were included in this meta-analysis. The effects of tannins were analyzed using a random-effects model to determine the weighted mean difference between treatments with tannins and the control (without tannins). Publication bias and heterogeneity between studies were explored, and meta-regression and subgroup analyses were performed. The results indicated that tannin significantly increased the intake of dry matter, crude protein, nitrogen (N), fecal N, and meat fatty acids (FA), such as C18:2 ω6, C18:3 ω3, C20:4 ω6, C20:5 ω3, total ω3 and ω6 FA, and total polyunsaturated FA (PUFA). However, NH₃-N, urinary N, blood urea nitrogen, cold carcass weight, subcutaneous fat thickness, drip loss, and nutrient digestibility decreased. In conclusion, tannin in small ruminants did not affect animal productivity and antioxidative status, but mainly modified nitrogen metabolism and improved the fatty acid profile of meat.

Many breeding programs have been implemented in developing countries, many of which have been unsuccessful. To better understand the failure of these breeding programs, it is proposed to analyze their adequacy with innovations that are actually adopted by smallholders. The proposed methodology takes account of these innovations, the reasons for their adoption and the objectives of livestock keeping. The N’Dama cattle-breeding program in Senegal was used as a case study. Surveys were carried out among 54 farmers: 27 breeders who participated in this program, 17 of whom recently resigned, and 27 breeders who have never participated. Feeding was the most frequently cited area of innovation, followed by infrastructure. Genetics, animal health and reproduction held the third rank. Milk production appeared as an important objective of breeders, although the context remains one of strong multifunctionality. Principal component analysis highlighted three categories of breeders according to the innovations they adopted: institutional, modernizing, and integrating innovators. The groups of institutional and modernizing innovators dominate, gathering each 41% of the farmers. In the first category, breeders have organized themselves in an association and use N’Dama sires, livestock aiming at an insurance objective. In the second category, artificial insemination with exotic breeds and other technical innovations (cowshed, vaccination, urea treatment of straw) are used to improve production of milk and meat. The third group is termed ‘integrating innovators,’ since their innovations aim at integrating livestock and crop production. Gathering 18% of the sampled breeders, this group presents intermediate features between the two previous groups, using animals as draught power and for manure production. These results indicate that a process of intensification is at play and that the genetic improvement through the selection of N’Dama cattle for production criteria does not meet the breeders’ demand. However, the N’Dama’s adaptive traits justify its use as part of the breeding strategy of farmers, either in pure-breeding or in crossbreeding. The study thus tends to show the interactive link between genetic improvement and other innovations. It suggests that the success of a breeding program depends on its adequate positioning within the set of innovations adopted by breeders and proposes a method to inform breeding programs accordingly.

This study aimed to compare digestive and metabolic characteristics in Sahelian (S) and Majorera (M) goat breeds. Six lactating females from each breed, with an average weight 27.0 ± 1.93 and 23.7 ± 1.27 kg, respectively, were used. Cowpea hay, variety 58/74, was offered as sole feed ingredient, at a rate of 2 kg of fresh matter per animal per day. The animals were placed in metabolic cages and a digestibility test was conducted according to an adaptation period of 15 days and a collection period of 7 days. The daily chemical components offered and refused and recovered faeces, urine and milk were measured in order to assess energy and nitrogen utilization. The M and S goats had similar levels of dry matter (DM) intake as well as nutrient digestibility. On a metabolic weight basis, dry matter intake, gross energy intake, metabolizable and energy intake, digestible energy and energy lost as methane production were significantly higher (p < 0.01) in M than in S goats. Urinary energy excretion was similar (p = 0.9) between breeds, while faecal energy output was higher in M than in S goats. The milk energy output from the M goats was higher than that the S goats (p < 0.05). However, metabolizable to net energy conversion efficiency (klm) was not affected by breed (p = 0.37), while N intake, milk N yield and faecal N losses, relative to metabolic weight, were significantly higher (p < 0.05) in M than in S goats. Similarly, the percentage of dietary N intake excreted in urine (UNIN) was higher in S than in M breeds. The breed factor had no effect on N retained, N digestibility, urinary N and N use efficiency. In conclusion, the M and S goats were similar in terms of energy and nitrogen use efficiency, despite higher daily milk production and DM consumption in the M goat. This suggests that the M breed is possibly more dependent on a dense nutrition diet than the S breed but requires less maintenance nitrogen.

La sélection génétique est un moyen pour augmenter la productivité des races endémiques dans des environnements hostiles. La trypanotolérance du bovin N’Dama a été l’argument central de la mise en œuvre des programmes de sélection de cette race en Gambie, au Mali et au Sénégal. Ces programmes ont eu des trajectoires différentes selon les objectifs, le processus de conception et les stratégies développées. L’analyse de ces trajectoires aiderait à mieux comprendre leurs succès et leurs échecs. Pour ce faire, une étude comparative de ces programmes a été réalisée en se basant sur une littérature scientifique publiée et non publiée et des entretiens avec les acteurs. L’analyse a d’abord consisté à décrire chaque programme. Une discussion a ensuite été menée pour évaluer les facteurs de succès et d’échec. Cette analyse a montré que ces facteurs dépendent de l’intérêt des éleveurs en lien avec leurs objectifs de production et leurs pratiques, de la stratégie utilisée tenant compte de l’intégration ou non de la trypanotolérance dans les critères de sélection, et de la mobilisation des ressources financières et humaines. Ces programmes de sélection ont aussi généré un capital d’expériences, dont la valorisation permettrait d’améliorer les systèmes actuels et de bâtir des programmes durables de sélection pour les systèmes d’élevage à faibles niveaux d’intrants dans les pays en développement. Genetic selection is a way to increase the productivity of endemic breeds in hostile environments. Trypanotolerance of N’Dama cattle has been the central argument for the implementation of breeding programs for this breed in Gambia, Mali and Senegal. These programs have had different trajectories depending on the objectives, the design process and the strategies developed. The analysis of these trajectories would help to better understand their successes and failures. To this end, a comparative study of these programs is carried out based on published and unpublished scientific literature and interviews with stakeholders. The analysis first consisted in describing each program. A discussion is then held to assess the success and failure factors. This analysis showed that these factors depend on the interest of farmers in relation to their production objectives and practices, the strategy used, whether or not trypanotolerance is included in the selection criteria, and the mobilization of financial and human resources. These breeding programs have also generated a wealth of experience that could be used to improve current systems and build sustainable breeding programs for low-input livestock systems in developing countries.