Julie M.K. Ojango

Genetic evaluation of growth of Kenya Boran cattle using random regression models

Data consisting of 18 884 weight records collected from 1273 Boran cattle from birth to 24 months of age were used to estimate covariance functions and genetic parameters for growth of Boran cattle using random regression (RR) models under a situation of small herd size and inconsistent recording. The RR model fitted quadratic Legendre polynomials of age at recording for additive genetic and permanent environmental effects. Genetic variance increased from birth, reaching an asymptotic value at 455 days and was maximum at 525 days of age after which it gradually dropped. Permanent environmental variance increased throughout the trajectory. Estimates of temporary environmental variance were heterogeneous across ages. Direct heritability and permanent environmental variance as a proportion of phenotypic variance fluctuated greatly during the early ages but later stabilized at intermediate to later ages; the estimates ranged from 0.11 to 0.33 and from 0.18 to 0.83, respectively. Genetic correlation estimates were positive, ranging from 0.10 to unity. The estimates declined with increasing in lag between the age points. Phenotypic correlation pattern was erratic between early ages, negatively low (−0.02) between the extreme data points and moderate to highly positive (>0.50) between intermediate and later points, with prominent spikes along the diagonal. It is concluded that RR models have potential for modelling growth of Boran cattle, notwithstanding conditions of small herd sizes and inconsistent recording.Évaluation génétique de la croissance de bétail Boran au Kenya en utilisant des modèles de régression aléatoireRésumé – Des données consistant en 18 884 enregistrements de poids recueillis auprès de 1273 têtes de bétail Boran de la naissance à 24 mois d’âge ont été utilisées pour estimer les fonctions de covariance et les paramètres génétiques de croissance du bétail Boran en utilisant des modèles de régression aléatoire (RR) sous une situation de petite taille de troupeaux et d’enregistrements irréguliers. Le modèle RR a adapté des codes polynomiaux quadratiques de Legendre à l’âge à l’enregistrement pour la détermination des effets génétiques additifs et environnementaux permanents. La variance génétique a augmenté depuis la naissance, atteignant une valeur asymptomatique à 455 jours et un maximum à 525 jours d’âge après quoi, elle a progressivement diminué. La variance environnementale permanente a augmenté tout le long de la trajectoire. Les estimations de la variance environnementale temporaire ont été hétérogènes à travers les âges. La variance de l’héritabilité directe et la variance environnementale permanente à titre de proportion de la variance phénotypique ont fluctué considérablement durant les âges précoces mais se sont stabilisées plus tard à des âges intermédiaires à plus avancés ; les estimations se sont situées à entre 0.11 et 0.33 et 0.18 à 0.83 respectivement. Les estimations de la corrélation génétique ont été positives allant de 0.10 à une unité. Les estimations ont diminué avec l’augmentation du retard entre les points d’âge. Le schéma de corrélation phonotypique a été irrégulier entre les âges précoces, négativement bas (−0.02) entre les points de données extrêmes et modérés à hautement positif (>0.50) entre les points intermédiaires et avancés avec des pics proéminents le long de la diagonale. Il en a été conclu que le modèle RR avait malgré tout le potentiel de modéliser la croissance du bétail Boran, les conditions de petites tailles de troupeaux et un enregistrement irrégulier.Evaluación genética del crecimiento del ganado Boran de Kenia utilizando modelos de regresión de efectos aleatoriosResumen – Se utilizaron datos consistentes en 18884 registros de peso recogidos de 1273 reses de ganado Boran, desde el nacimiento a los 24 meses de edad, para estimar las funciones de covarianza y los parámetros genéticos para el crecimiento del ganado Boran, utilizando modelos de regresión de efectos aleatorios (RR, en inglés) en una situación de tamaño de rebaño pequeño y registros no regulares. El modelo RR se ajustaba a polinomios de Legendre cuadráticos de edad al registrar los efectos genéticos aditivos y ambientales permanentes. La varianza genética aumentaba a partir del nacimiento, alcanzando un valor asintomático a los 455 días y un máximo a los 525 días de edad, después de lo cual decrecía gradualmente. La varianza ambiental permanente aumentaba a través de toda la trayectoria. Las estimaciones de la varianza ambiental temporal resultaron heterogéneas a través de todas las edades. La heredabilidad directa y la varianza ambiental permanente como proporción de la varianza fenotípica fluctuaba enormemente durante las edades más tempranas pero luego se estabilizaba en edades intermedias a más avanzadas; las estimaciones variaban de 0.11 a 0.33 y de 0.18 a 0.83, respectivamente. Las estimaciones de la correlación genética fueron positivas variando de 0.10 a la unidad. Las estimaciones declinaban al aumentar el lapso entre los puntos de edad. La pauta de correlación fenotípica fue errática entre las edades más tempranas, negativamente baja (−0.02) entre los puntos de datos extremos, y de moderada a altamente positiva (>0.50) entre los puntos intermedios y posteriores con picos importantes a lo largo de la diagonal. Se concluye que los modelos RR poseen potencial para representar el crecimiento del ganado Boran; a pesar de las condiciones empleadas de tamaños de rebaños pequeños y registros no regulares.

Participatory definition of breeding objectives for sheep breeds under pastoral systems—the case of Red Maasai and Dorper sheep in Kenya

Crossing local breeds with exotic breeds may be an option for increased livestock productivity. However, there is a risk for endangerment of the local breeds. One such case is in Kenya where the imported Dorper breed is used for crossbreeding with Red Maasai sheep. The aim of this study was to investigate farmers’ trait preferences as a basis for determination of breeding objectives for Red Maasai and Dorper sheep at two sites, Amboseli and Isinya, in Kenya. Within their own flock, each farmer identified three ewes representing the best, average and poorest within each breed group: Red Maasai, Dorper and Crosses. Farmers gave reasons for their ranking. Body measurements and weights were also taken. At the harshest site, Amboseli, differences between breed groups in body weight were small and breeds were equally preferred. In Isinya, where environmental conditions are better and farmers are more market oriented, Dorper and Crosses had significantly higher body weights and market prices and were thus preferred by the farmers. Red Maasai were preferred for their maternal and adaptive traits. Breeding objectives should emphasize growth traits and milk production in both breeds at both sites. Body condition needs to be specifically considered in the breeding objectives for sheep in Amboseli, whereas adaptive traits need to be generally emphasized in Dorper.

Dairy production systems and the adoption of genetic and breeding technologies in Tanzania, Kenya, India and Nicaragua

espanolEl desarrollo del sector ganadero y su papel en la mitigacion de la pobreza en paises en desarrollo dependen de la capacidad de adaptacion de los sistemas de produccion a contextos ambientales y economicos cambiantes. Este articulo caracteriza los sistemas de produccion lechera en India, Tanzania, Kenya y Nicaragua y describe la genetica y las tecnicas de seleccion con las que se pretende alcanzar los objetivos mundiales de desarrollo. Con vistas al desarrollo, se ha dado prioridad a la cadena de valor de la leche en el marco del programa de investigacion CGIAR sobre Ganaderia y Pesca en Tanzania (Africa Oriental), India (Asia Meridional) y Nicaragua (America Latina), mientras que en Kenya ha sido el ILRI quien ha asumido la investigacion sobre el desarrollo del sector lechero. En todos los paises, un gran numero de pequenos ganaderos, que operan sistemas agropecuarios mixtos, juegan un papel destacado en la produccion lechera. En Tanzania, Kenya y Nicaragua, la leche es producida principalmente por ganado bovino de genotipos que difieren entre paises y de unos sistemas de produccion a otros dentro del mismo pais. En India, las bufalas contribuyen en mayor proporcion que el ganado bovino a la produccion nacional de leche. Sin embargo, es escasa la informacion sobre la productividad por animal y sobre los genotipos optimos a utilizar en los sistemas de produccion de los pequenos ganaderos de estos paises. Los cruzamientos y la inseminacion artificial fueron identificados como las estrategias reproductivas y de seleccion mas ampliamente utilizadas. Unicamente en Kenya existe una organizacion nacional que lleva a cabo el registro del ganado y el seguimiento de la productividad, si bien el porcentaje de ganado bovino lechero inscrito en este registro es bajo ( Palabras clave: produccion lechera, tecnicas de seleccion, paises en desarrollo francaisLe developpement du secteur de l’elevage et son role dans la reduction de la pauvrete dans les pays en developpement dependent de l’adaptabilite des systemes de production a l’evolution des contextes environnementaux et economiques. Cet article caracterise les systemes de production laitiere en Inde, Tanzanie, Kenya et Nicaragua et decrit la genetique et les methodes de selection avec lesquelles l’on cherche a atteindre les objectifs mondiaux de developpement. La chaine de valeur du lait a ete une priorite pour le developpement dans le cadre du programme de recherche du CGIAR sur l’Elevage et la Peche en Tanzanie (Afrique Orientale), Inde (Asie du Sud) et Nicaragua (Amerique Latine), alors qu’au Kenya c’est l’ILRI qui a pris en charge la recherche sur le developpement du secteur laitier. Dans tous les pays, un grand nombre de petits eleveurs exploitant des systemes agropastoraux mixtes jouent un role important dans la production de lait. En Tanzanie, Kenya et Nicaragua, le lait est principalement produit par des bovins de genotypes qui different a la fois entre les pays et entre les systemes de production dans le meme pays. En Inde, les bufflonnes contribuent plus que les bovins a la production nationale de lait. Cependant, il existe un manque d’information sur la productivite par animal et sur les genotypes optimaux a utiliser dans les systemes de production des petits exploitants de ces pays. Les croisements et l’insemination artificielle ont ete identifies comme les strategies reproductives et de selection les plus amplement utilisees. Seulement au Kenya il existe une organisation nationale qui procede a l’enregistrement des animaux et qui fait le suivi de la productivite, bien que le pourcentage de bovins laitiers inscrits dans ce registre est faible ( Mots-cles: production laitiere, methodes de selection, pays en developpement EnglishDevelopment of the livestock industry and its role in poverty alleviation in developing countries depends on how adaptive the production systems are to changing global environmental and economic trends. This paper characterizes dairy production systems in India, Tanzania, Kenya and Nicaragua, and describes the genetic and breeding technologies that hold promise for the advancement of global development goals. The dairy value chain has been prioritized for development under the CGIAR research programme on Livestock and Fish in Tanzania (East Africa), India (South Asia) and Nicaragua (Latin America), while ILRI is involved in research on dairy development in Kenya. In all the countries, a large number of smallholder farmers operating mixed crop–livestock production systems play a significant role in dairy production. In Tanzania, Kenya and Nicaragua, milk is predominantly produced by cattle of genotypes that differ both across countries and among production systems within the same country. In India, buffaloes contribute to a larger proportion of the national milk than cattle. Information on productivity per animal and on optimal genotypes to utilize within the smallholder production systems of all the countries is however limited. Crossbreeding and artificial insemination were identified as the most widely utilized breeding and reproductive technologies. Only in Kenya is there a national organization conducting livestock recording and monitoring productivity, however, the proportion of the dairy cattle population enrolled in the recording system is small ( Keywords: breeding technologies, dairy production, developing countries

Short communication: Genomic selection in a crossbred cattle population using data from the Dairy Genetics East Africa Project

Due to the absence of accurate pedigree information, it has not been possible to implement genetic evaluations for crossbred cattle in African small-holder systems. Genomic selection techniques that do not rely on pedigree information could, therefore, be a useful alternative. The objective of this study was to examine the feasibility of using genomic selection techniques in a crossbred cattle population using data from Kenya provided by the Dairy Genetics East Africa Project. Genomic estimated breeding values for milk yield were estimated using 2 prediction methods, GBLUP and BayesC, and accuracies were calculated as the correlation between yield deviations and genomic breeding values included in the estimation process, mimicking the situation for young bulls. The accuracy of evaluation ranged from 0.28 to 0.41, depending on the validation population and prediction method used. No significant differences were found in accuracy between the 2 prediction methods. The results suggest that there is potential for implementing genomic selection for young bulls in crossbred small-holder cattle populations, and targeted genotyping and phenotyping should be pursued to facilitate this.

Assessing actors in rural markets of sheep and goats in the Nyando Basin of Western Kenya: a key to improving productivity from smallholder farms

Livestock traders are a key conduit for incentives in livestock production systems. Their actions affect producer prices, investment decisions, and their livelihoods. However, smallholder farmers in rural communities of eastern Africa often have limited understanding of the marketing process and the interactions among market actors. This study was undertaken following the introduction of improved indigenous goat and sheep breeds in Climate Smart Villages of Nyando in western Kenya. We sought to understand the marketing of sheep and goats in five key rural markets used by the smallholder farmers of Nyando, to generate information on key market actors, their functions in the value chain, and their preferences for attributes in sheep and goats. Most traders (65%) in all the markets were men. Four different types of traders operated in the markets, producers, retailers, wholesalers, and brokers, each making a profit. Preference for selling sheep or goats and the animal attributes desired by the traders differed depending on the surrounding community. Markets in Kericho County of Nyando traded more goats than sheep while those in Kisumu County of Nyando traded more sheep than goats. There were no clear policies guiding pricing of animals. Prices offered to producers depended on previous days, and the number of animals available for sale at the marketing point. The collaborative group actions of the producers in the Climate Smart Villages did not extend beyond the level of production to the marketing of their livestock. A critical change is required for the smallholder farmers to derive better incomes from improved quality of animals following adoption of improved breeding and management practices. The results illustrate the need to engage rural market actors when implementing livestock improvement programs for smallholder farmers for better farm gate prices of animals, and thus achieve the improved incomes envisioned.

Goat Production in Eastern Africa: Practices, Breed Characteristics, and Opportunities for Their Sustainability

It is estimated that 14% of the livestock in Eastern Africa are comprised of 146 million goats. The goats are in varying agroecological zones under farming systems ranging from small-scale mixed crop–livestock systems with a few animals raised on limited land resources, to extensive pastoral systems where large numbers of animals are raised on large tracts of land. The goats are raised primarily for meat, with milk treated as a secondary trait. Use of goat products at rural household levels in the region is not well documented. The goat populations have been developed over time through selection processes resulting in diverse goat breeds, with some adapted to harsh environmental conditions. In recent years, a strong drive to increase the productivity of goats has resulted in changes in breeding and management strategies and practices, including introduction of foreign breeds, mainly from temperate environments for use in crossbreeding programs, and a narrowing of the range and diversity of indigenous breed types. This, in addition to a lack of detailed information on the characteristics of the indigenous breeds, threatens the existing diversity of goat populations. This chapter presents an overview of the present-day indigenous goat breeds and the production systems under which they are raised in Eastern Africa. The chapter also highlights key constraints to improving goat productivity and outlines opportunities and changes to mitigate threats within the farming systems. The growing populations of goats and their potential for improving the livelihood of different communities call for innovative strategies to reduce their environmental footprint in the existing ecosystems.