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概要

Cross-breeding in Cattle for Milk Production: Achievements, Challenges and Opportunities in India-A Review

Singh CV

This paper reviews experiences with cross-breeding for milk production in India. Data were compiled from different studies evaluating the performance of different grades of cross-bred animals as well as local breeds. Relative performance of indigenous breeds compared with different grades of cross-breeds was calculated. Traits considered were milk yield per lactation, age at first calving, services per conception, lifetime milk yield and total number of lactations completed. Exotic inheritance of around 50% is the most ideal for growth, reproduction and milk production, and the yield in higher crosses falls short of theoretical expectations. The grading up, therefore, to a total replacement of genes will not lead to higher production in cattle. The crosses of temperate with improved indigenous breeds (Sahiwal, Red Sindhi, Gir, Tharparkar) attained the same level of performance under uniform feeding and are superior to crosses from other native cattle. Holstein crosses were superior to other temperate breed crosses for growth and production while Jersey crosses have better reproductive efficiency. Decline in milk yield from F1 to F2 generations on account of inter se mating among F1 crossbreds is small. The Friesian crossbreds excelled in milk yield, but were slightly older at first calving and had slightly longer calving intervals than Jersey crosses. A serious decline in performance from F1 to F2 was observed in both crosses: F2 were about eight months older at first calving and produced about 30% less milk. They had also much longer calving intervals. The combination of ART with advanced molecular genetics plus the availability of simple recording schemes provide great opportunities for developing and multiplying synthetic breeds at a much faster rate than in previously conducted breeding programmes. Although cross-breeding faces a number of challenges such as better infrastructure, higher demand for health care, there are many advantages of using it. These are higher production per animal, higher income for the families and provision of high-value food. It is therefore likely to continue to be an important livestock improvement tool in the tropics in the future, where farmers can provide sufficient management for maintaining animals with higher input requirements and access to the milk market can be secured.