Sahiwal cattle in semi-arid Kenya: genetic aspects of growth and survival traits and their relationship to milk production and fertility |
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Authors: | E D Ilatsia S A Migose W B Muhuyi A K Kahi |
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Institution: | (1) Institute of Animal Production in the Tropics and Subtropics, Department of Animal Breeding and Husbandry, Hohenheim University, Garbenstrasse 17, 70593 Stuttgart, Germany;(2) Kenya Agricultural Research Institute, National Animal Husbandry Research Centre, P.O. Box 25, 20117 Naivasha, Kenya;(3) Kenya Agricultural Research Institute, National Beef Research Centre, P.O. Box 3840, 20100 Nakuru, Kenya;(4) Animal Breeding and Genetics Group, Department of Animal Sciences, Egerton University, P. O. Box 536, 20115 Egerton, Kenya |
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Abstract: | The aim of this study was to estimate genetic and phenotypic parameters for growth and survival traits of Sahiwal cattle in
Kenya and determine their relationship to milk production and fertility. Performance records of 5,681 animals were obtained
from the National Sahiwal Stud and the traits considered were: birth weight (kilogrammes), weaning weight (kilogrammes), pre-weaning
average daily gain (grammes per day), post-weaning average daily gain (grammes per day), yearling weight (kilogrammes), mature
weight at 36 months (kilogrammes), pre-weaning survival rate (SR), post-weaning survival rate (PSR), lactation milk yield
(kilogrammes), age at first calving (days), and calving interval (days). The data was analysed using univariate and bivariate
animal model based on restricted maximum likelihood methods, incorporating all known pedigree relationship among animals.
The additive direct effects were more pronounced than maternal genetic effects in early and in post-yearling growth performance.
The additive genetic variance and heritabilities were low for SR and PSR. The correlation between direct additive genetic
and maternal genetic effect were negative for pre-yearling traits. Genetic and phenotypic correlations among growth traits
and between growth and milk yield were positive, whilst those between growth and fertility were weak and negative. Correlations
between survival and growth were generally low and positive. The estimates obtained in this study provide the necessary technical
parameters for evaluating alternative breeding programmes and selection schemes for sustainable improvement of Sahiwal cattle. |
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