YEMI AKINBAMIJO, S. NOUALA, SUSANNE MÜNSTERMANN
International Trypanotolerance Centre, The Gambia
In order to improve our understanding of the adequacy of milking cow nutrition in the periurban dairy systems of West African cities, live weight trends, milk yield and metabolic profiles of experimental animals were investigated using 27 lactating cows (nine N'Dama, nine HolsteinXN'Dama and nine JerseyXN'Dama).
For each genotype, cows were randomly allocated into medium and high dietary levels. Diets consisted of ad libitum groundnut hay (medium) and ad libitum hay supplemented with locally sourced concentrates (high). The objective was to determine the adequacy or otherwise of two test feed regimes through milk yield and the metabolic responses of the milking cows. All cows were offered ad libitum dietary intake on 120% of voluntary feed intake. The cows were milked in accordance with traditional practices and milk yield was measured daily. Blood samples were taken for tests for energy and protein metabolites at weekly intervals.
The milk yield was 1, 3.2 and ld for medium and 1.4, 4.1 and ld for high diets offered N'Dama, NDxJ and NDxH-F respectively. There was significant (p < 0.05) breed and diet effects on milk yield. The live weight trend was --74, -345 and --gday (medium diet) and --11, -140 and --gday (high diet) for N'Dama, NDxJ and NDxH-F. The difference in weight gain was significant between the two regimes and across the breeds.
The concentrations of all metabolites observed in the study were within normal ranges albeit with a significant breed effect. Diet did not affect concentration of energy metabolites within breed but for N'DamaXJersey cows, the high plane diet induced a higher degree of energy metabolism. Data from live weight suggest that the N'Dama lost the least weight through the study and that although statistically different, metabolic profile of other breeds did not suggest undue nutritional stresses as concentrations of the metabolites were within normal ranges. The study concludes on the adequacy of the high plane diet for the crossbred cows but raises concerns on the appropriateness of high plane diets for lactating N'Dama cows from an economic perspective.
Keywords: Crossbreed, Feeding strategy, Milk yield, N'Dama, West Africa