Economics of crossbreeding for dairy production in the coastal lowland tropics of Kenya

Publication Type

Contribution to conference

Authors

Kahi,A.K.; Thorpe,W.

Year of publication

2000

Published in

Proceedings of the 7th KARI Scientific Conference

Editor

Kenya Agricultural Research Institute

Page (from - to)

nnb

Conference name

7th KARI Scientific Conference

Conference location

Nairobi, Kenya

Conference date

13th - 17th November 2000

Economic data from crosses of Ayrshire (A), Brown Swiss (B), Friesian (F) and Sahiwal (S) cattle collected over a 21-year period from a dairy ranch in the lowland tropics of Kenya were analysed to estimate additive and non-additive genetic effects on economic performance and to predict performance of alternative crossbreeding strategies. Performance was predicted from parameters of a genetic model based on additive-dominance and additive x additive interaction effects for the following: first cross (F x S), two-breed rotation (AS)Rot, three-breed rotation (BFS)Rot and two- (F and S), three- (B, F and S) and four (A,B,F and S) -breed synthetic (Syn) breeds based on equal and unequal contributions of the foundation breeds. Profit values were calculated for individual animals. For profit per day of herdlife (PLD), the B and F additive breed effects were not significantly different from that of A. The additive breed effect for S was negative and significant (P<0.01) indicating that it was inferior to the Bos taurus for PLD. Dominance effects for PLD in the crosses A x S and B x S were substantial and significant (P<0.05). The additive x additive interaction effects were negative and significant in all the crosses. Predicted performance showed that PLD would be lowest in (ABFS)Syn and highest in F x S. The (3/4F 1/4S)Syn would be the second-best strategy giving 90 % of the expected F x S profit, while (FS)Syn would give 87 %. However, the costs of maintaining the purebred populations for the F x S strategy were ignored. The absence of a significant difference between the Bos taurus breeds for PLD showed that comparable economic benefits were derived by use of either of the breeds for continuous crossbreeding in a production system with management achieving 3000 kg lactation yields and may be expected in production systems achieving lower yields (e.g., in many smallholder units), from the development of either an A-, B- or F-based two-breed synthetic breed.