Thomas Muasya

• PhD (Dr. rer. agr)
• Senior Lecturer at Egerton University

The evolution of body weight under the natural trypanosome challenge and its association with disease tolerance to trypanosomosis is of utmost economic importance in cattle. This study estimated heritability for growth traits and packed cell volume (PCV) and their genetic correlations in the N’Dama cattle in the Gambia. A total of 2,488, 2,442, 1,4...

The evolution of body weight under the natural trypanosome challenge and its association with disease tolerance to trypanosomosis is of utmost economic importance in cattle. This study estimated heritability for growth traits and packed cell volume (PCV) and their genetic correlations in the N’Dama cattle in the Gambia. A total of 2,488, 2,442, 1,4...

The profitability of indigenous chickens (IC) reared in different production systems in South Sudan was evaluated using a bio-economic model. Three production systems considered were free-range system (FRS), where chickens foraged for feed through scavenging without any form of supplementation; intensive system (IS), in which chickens were housed a...

The current study aimed at generating essential information on breeding practices and traits of the economic importance of indigenous chicken (IC) farmers in the three historical regions of South Sudan (Bhar el Gazel, Upper Nile and Equatoria). Data on perceived important traits according to farmers (n=385), marketers (n=100) and consumers (n=100)...

This study tested the hypothesis that the use of pooled genetic and phenotypic parameters and genomic selection would optimize selection response in indigenous chicken breeding programmes. This premise was tested with deterministic simulation in three breeding schemes based on the sources of information used to estimate breeding values. These schem...

It was reasoned that, incorporating reproductive technologies and genomic selection in the current dairy goats breeding programme would generate higher response to selection compared to use of natural mating in the current conventional breeding programme. This premise was tested by deterministic simulation approach and compared to the current breed...

Selection for increased milk yield based on lactation breeding values estimated using random regression test day models leads to improvement of lactation milk yield. However, animals with the same lactation breeding value can have different shapes of the additive genetic lactation curve, implying differences in persistency of lactation. Since envir...

Previous genetic and economic evaluation of beef cattle breeding programmes have used genetic and phenotypic parameter estimates obtained in different studies. Such parameters are heterogeneous because they are obtained from different locations, using different sample sizes and estimation methods. The consequence of using such parameters is underes...

Length and weight data for three species of fish Oreochromis niloticus, Lates niloticus, and Sydontus victorianus was collected from three East African lakes, Lake Victoria, Lake Baringo and Lake Naivasha. Correlation were done on weight and length based on the fish species, the lake collected from, sex, and the age. Correlation was found not to be...

The objective of this study was to evaluate the effect of breed and age on scrotal measurements and semen characteristics of Saanen and Toggenburg bucks raised under extensive system in the tropic. The study was conducted using Toggenburg and Saanen bucks; the bucks were allocated into two different groups based on breed and age in 2 × 2 factorial...

This study investigated the hypothesis that the use short-term synchronisation protocol following single fixed-time artificial insemination (AI) with extended cooled semen and natural mating in fertility management of dairy goats could be as good as or better than traditional long-term protocol. This was tested by designing an experiment using Togg...

Genetic and phenotypic parameter estimates obtained in different studies, may be heterogeneous. This is because they are obtained in different locations, using different sample sizes and estimation methods. The choice of which parameter estimates to use, is in most cases subjective and this may lead to underestimation or overestimation of potential...

ABSTRACT Genetic and phenotypic parameters for longevity, genetic relationship between longevity and growth, milk yield and fertility traits and rate of inbreeding were estimated for Sahiwal cattle in Kenya. The aim was to assess the genetic diversity and inbreeding depression for performance traits. Data utilized were for cows born between 1972 an...

Context In the present study we assessed the use of average relationship as a means to control future rates of inbreeding in small cattle closed nucleus and its effect on genetic gain for milk yield as a means of managing genetic variability in livestock improvement programs. Aim The aim was to strike an ideal balance between genetic gain and loss...

Genomic selection is a new breeding strategy which is rapidly becoming the method of choice of selection. It is useful in predicting the phenotypes of quantitative traits based on genome-wide markers of genotypes using conventional predictive models such as ridge regression BLUP. However, these conventional predictive models are faced with a statis...

Genomic selection is a new breeding strategy which is rapidly becoming the method of choice of selection. It is useful in predicting the phenotypes of quantitative traits based on genome-wide markers of genotypes using conventional predictive models such as ridge regression BLUP. However, these conventional predictive models are faced with a statis...

Pedigree data of 18315 animals born from 1961 to 2008 from the National Sahiwal Stud, Kenya was used to assess and predict genetic diversity for the Kenyan Sahiwal population. Current (Nec) and predicted effective population sizes (Nef) were calculated from rates of inbreeding (∆F) and coancestry (∆f) per generation, respectively. Population struct...

Performance data of Sahiwal cows born between 1972 and 2004 with milk records between 1976 and 2008 were analysed to estimate genetic parameters for longevity in Sahiwal cattle in Kenya. Measures of longevity related to productive life were: time between birth and last milking record in months (Long_1), time between first calving and last milking r...

Performance data of Sahiwal cows born between 1972 and 2004 and with milk production records between 1976 and 2008 from the National Sahiwal Stud, Kenya, were anlysed to estimate genetic parameters for longevity in Sahiwal cattle in Kenya. Longevity was defined alternatively as related to productive life or survival. Measures of longevity related t...

Pedigree and performance data for the Sahiwal cattle from the National Sahiwal Stud (NSS) in Kenya were used to evaluate the effect of inbreeding on first lactation milk yield (LMY), age at first calving (AFC), calving interval (CI), and lactation length (LL). Effects of inbreeding on the traits were determined by fitting four regression models (li...

Data on breeding practices and traits of economic importance for the indigenous chicken (IC) were collected through personal interviews using structured questionnaires and direct observations of chicken management practices. The study was conducted from November 2015 to January 2016 in Rwamagana, Rulindo, Ruhango, Kicukiro and Muhanga districts of...

The primary emphasis of the long-term Sahiwal cattle breeding programme is to increase milk yield by selecting cows based on their performance in first three lactations. It is therefore important to have knowledge on the extend of additive genetic variance and genetic parameters for these traits. Genetic and phenotypic parameter estimates normally...

Characterization of indigenous chicken (IC) production systems in Rwanda was conducted from November 2015 to January 2016 with the aim of understanding socio-economic characteristics, management of IC, production parameters, feed resources, and constraints faced by farmers rearing IC. A survey involving 206 households was carried out in 5 districts...

A total of 19,313 test-day milk yield records for 1,892 Sahiwal cattle from first three lactations were used to describe variation in milk yield using Random Regression Model (RRM) with Legendre Polynomials (LP). Data were recorded between 1978 and 2002. Variance components were estimated by Restricted Maximum Likelihood method. Thirty models from...

Abstract Indigenous chickens (IC) are a valuable genetic resource due to their adaptability to local climatic and environmental conditions and the need to improve and conserve them has been recognized. Worldwide, tremendous genetic improvement of chicken has been achieved through a combination of pure breeding and crossbreeding programs. In Kenya,...

Pedigree analysis using genealogical information of 18 315 animals born between 1949 and 2008 was done to quantify genetic variability of the Sahiwal population in Kenya. Generation intervals for sire pathways were longer than dam pathways and increased over year periods, from about 4–16 years. The later was due to use of old bulls for breeding in...

longevity in sahiwal cattle in kenya

This review gives insights into genetic and feeding regime development for indigenous chicken genetic resources. We highlight and combine confirming evidence of genetic diversity and variability using morphological and molecular techniques. We further discuss previous past and current genetic attempts to improve on reproduction and production trait...

Body weight at 12 weeks of age records of 443 indigenous chicken, progeny of 44 sires were used to estimate preliminary results of selection for growth in indigenous chicken in Kenya after two generations of selection. Estimated breeding values were estimated using a sire model. Mean body weight at 12 weeks (BW12) among males and females was 666.7...

Selection and production environments may differ in level of management. In production environment the majority of animals may have, especially in tropical environments, lower milk production due to inadequate feed intake and other constraints associated with flat or decreasing lactation curves. Holstein-Friesian herds in Kenya were separated in se...

Open nucleus dairy cattle breeding schemes (ONBS) in developing countries are advantageous due to lower operational costs. However, genotype by environment interaction (GE) between the selection (SE) and production environment (PE) should be considered. Records of 5,468 cows, daughters of 251 sires with at least a first lactation record between 199...

Pedigree data from 11 267 animals born between 1960 and 2004 were used to analyse population structure and genetic variability of the Holstein–Friesian population in Kenya. Parameters estimated were the pedigree completeness index, average inbreeding coefficient, number of founders, effective number of founders and ancestors, and genetically import...

A study to assess the role of markets and marketing integration for enhancing efficiency of Small Ruminant Value Chain (SRVC) and the contribution of sheep and goats to human food security and to the general livelihoods in Semi-Arid Lands (SALs) of Kenya was conducted between May and July in 2008. Several districts were selected and sampled based o...

The Sahiwal breeding programme in Kenya has been run as a closed nucleus for over 50 years. The population structure of the Sahiwal breed in Kenya was studied using pedigree analysis. Pedigree data from 18315 animals born between 1949 and 2008 was used to analyse population structure in the current study. The ENDOG program was used to compute pedig...

Variance components and genetic parameter were estimated for piglet growth traits of Large White (LW) pigs managed under intensive production systems in Kenya. Data were on piglet performance of LW pigs born between 1982 to 1996. Growth performance traits of the piglets that were considered, were body weight (BW, in kg) at birth (BW0), three weeks...

A total of 1599 dairy records comprised of 710 calving interval and number of services per conception, and 179 age at first calving records were used to evaluate the performance of dairy cow kept at the University of Nairobi farm, Kanyariri, from 1989 to 2001. The data were analysed using fixed models with breed, year, season, parity and lactationa...

Growth data from 6800 progeny of straightbreds, intermediate crosses and the resulting Kenya Dual Purpose Goat (KDPG) composites from 1982 to 2004 were used to estimate additive and non-additive genetic parameters. The KDPG was developed by crossing Toggenburg (T), Anglo-Nubian (N), Small East African (E) and Galla (G) breeds in equal proportions....

The aim of this study was to evaluate milk production and reproductive performance of Sahiwal cattle in semi-arid Kenya. Milk production traits considered were lactation milk yield, lactation length and test-day milk yield, while reproductive traits included age at first calving, calving interval and number of services per conception. Various fixed...

Milk yield data (n = 12307) from 116 Holstein-Friesian herds were grouped into three production environments based on mean and standard deviation of herd 305-day milk yield and evaluated for within herd variation using univariate animal model procedures. Variance components were estimated by derivative free REML algorithm, and significance tests do...

Milk yield data (n=120307) from116 Holstein-Friesian herds were used to group herds into clusters and carry out genetic characterization of the production environments in Kenya. Herds were clustered based on herd mean 305-day milk yield, and herd standard deviation of 305-day milk yield. Variance components for the clusters were estimated by univar...

A total of 19 376 test day (TD) milk yield records from the first three lactations of 1618 cows daughters of 162 sires were used to estimate genetic and phenotypic parameters and determine the relationship between daily milk yield and lactation milk yield in the Sahiwal cattle in Kenya. Variance components were estimated using animal models based o...

Data comprising 7211 lactation records of 2894 cows were used to estimate genetic and phenotypic parameters for milk production (lactation milk yield, LMY and lactation length, LL) and fertility (calving interval, CI; number of services per conception, NSC and age at first calving, AFC) traits. Genetic, environmental and phenotypic trends were also...

Data consisting of 2757 records from ten Kenyan Ayrshire herds made between 1980 and 2005 were used to examine environmental factors affecting age at first calving (AFC) and calving intervals (CI) and consequently estimate genetic and phenotypic parameters and trends. The overall means and standard errors for AFC and CI were 39.4 ± 7.2 months and 4...

The Kenya Dual Purpose Goat (KDPG) is a synthetic goat population that is being developed to combine hardiness and increased milk production for use on smallholder farming systems. Breeding has been on-going, and the flock being a closed nucleus, risks the adverse effects of inbreeding on performance. The objective of this study was to determine th...