Effect of Environmental Factors and of the Proportion of Holstein Blood on the Milk Yield and Lactation Length of Crossbred Dairy Cattle on Smallholder Farms in North-east Tanzania |
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| Authors: | Msanga YN Bryant MJ Rutam IB Minja FN Zylstra L |
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| Institution: | (1) Livestock Research Centre, PO Box 5016, Tanga, Tanzania;(2) Department of Agriculture, University of Reading, Reading, RG6 6AT, UK;(3) Tanga Smallholder Dairy Development Programme, PO Box 1474, Tanga, Tanzania |
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| Abstract: | A study was carried out on the lactation performance of crossbred dairy cattle in a smallholder farming system in north-east Tanzania. Data were collected from the records for 6 years and the factors considered were district, proportion of Holsteins, season of calving, year of calving and herd size. The data were considered separately for animals with a single lactation record. The least-square means for first lactation length and yield were 331 days (SD 77.0) and 2332 L (SD 283.0), respectively, while for cows with data on more than one lactation record the yield was 2477 L (SD 840.1) in 324 days (SD 74.0). First lactation yield was significantly affected by year of calving. For repeated records the lactation yield was significantly affected by district, proportion of Holsteins and herd size, while lactation length was significantly affected by district and herd size. The calculated repeatabilities for lactation yield and length were 0.27 and 0.12, respectively. For the pooled data the correlation between lactation length and yield gave r = 0.569 (p<0.0001). |
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| Keywords: | breed cows lactation management milk yield serum |
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