| Sumario: | Analyses trends in genetic and environemntal components of performance, to estimate levels of inbreeding and to quantify its effects on performance in order to identify which of these factors is responsible for the decline in performance at the Stud. Presents an evaluation of long-term breeding programme in a closed sahiwal herd in Kenya. Presents data on the analysis of trends in calving interval, on phenotypic, genetic and environmental trends in calving interval, birth weight, age at first calving, milk yield and liveweight. Presents records of Sahiwal cows kept at Kenya's National Sahiwal Stud (NSS) covering the period 1963 through 1988, to estimate genetic and environmental trends in production and reproductive traits, and to estimate levels and effects of inbreeding. Annual genetic, environmental and phenotypic changes in milk yield were 4.2, - 16.9 and - 12.7 kg, respectively.
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