Workshop on Funding of Agricultural Research

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Date
1997
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Kenya Agricultural Research Institute
Abstract
This study was conducted to characterise production systems which utilise the Kenya Sahiwal and dairy-type cattle (Sahiwal Crossbreds) and to evaluate productivity of the breed types in agro-ecological zones III and IV. Production systems studied included extensive beef production systems, extensive dual-purpose production systems and intensive rotational grazing systems. Extensive beef production systems was conducted using Sahiwal herds at Elkarama Ranch in Laikipia and Ilkerin-Loita Ranch in Narok, whereas extensive dual-purpose production systems was conducted using Sahiwal herds at Deloraine Estate and Oljorai; Sahiwal and Friesian-Sahiwal herds at the National Animal Husbandry Research Centre in Naivasha and the Sahiwal crossbred herd at Mariakani Research Sub-Centre. In the intensive rotational grazing systems study the Ayrshire-Sahiwal herd at Deloraine Estate, Friesian Sahiwal herd at Loldia Estate and the Ayrshire-BrownSwiss - Sahiwal herd at Kilifi Plantations were used. Data were collected from ten herds on the economically important performance traits which were: survival rate by sex and age; age at first calving interval; body growth; and milk yield. Data from each herd were subjected to least squares analysis of variance to obtain unbiased estimates for assessment of overall herd productivity of the breed types. For productivity evaluation PRY was used. Simulation of production systems provided a method of simultaneous consideration of factors affecting productivity. PRY assesses herd productivity at the stationary state in terms of gross monetary return per unit dry matter intake. Modelling components were survival rate by sex and age, age at first calving, calving interval, mature age and size, selective culling rate per parity for heifers and cows, milk yield and unit product values. Optimal culling ages for breeding females, surplus females and male youngstock were determined and used to calculate productivity indices. The cull-for-age threshold of breeding females of different herds ranged from 166 to 180 months. To maintain herds viable and in stationary state, the set minimum culling age of breeding females varied from 50 to 87 months. The disposal age for surplus females and male youngstock were from 20-31 months. Productivity indices for the herds ranged from 2,170 to 9,520 Kenya Shillings per ton of dry matters intake. Crossbreds were more profitable than Sahiwal herds. Among Sahiwal herds, dual-purpose herds were more profitable than beef herds. The three-breed crossbred, the Ayrshire-Brown Swiss-Sahiwal at Kilifi Plantations had the highest overall herd productivity (167%), followed by Friesian-Sahiwal Crossbreds-Supplemented (136%), Ayrshire-SahiwalCrossbreds (118 %), Friesian-Sahiwal-unsupplemented (113%), Sahiwal dualpurpose herds (66-103%), and Sahiwal beef herds (55 - 61 %), based on total output value per unit dry matter intake with the Sahiwal herd at Naivasha as a reference herd.
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