New sustainable concepts for efficient smallholder dairy nutrition: A comparative evaluation of response to and carry-over effects of undernutrition in indigenous tropical and Western dairy breeds

Borana pastoralist herding cattle along the road

Pastoralists selling butter in tin cans on a marked day

The objective of this project was to obtain data from a controlled long-term experiment to be able to develop recommendations for tropical smallholder milk producers on how to allocate scarce feed resources depending on the choice of the cow genotype. The project was carried out in collaboration with the International Livestock Research Institute, Ethiopia, and is now completed.

Boran (zebu) cattle were compared with their crossbreds with Holstein cattle from the onset of puberty as heifers until the end of the third lactation. On a very low feeding level, body condition was always maintained better by Boran than by crossbreds, but crossbreds, producing more milk, were still able to reproduce and to successfully carry out working exercise. Characteristic for Boran cattle was their almost complete lack of response in milk yield to additional feed both when provided from the very beginning and when allocated only in lactation 3 as changes led to corresponding shifts in body reserves. Crossbreds responded to feeding level in growth and milk yield. Metabolic indicators of energy partitioning and metabolic energy status confirmed that Boran and crossbreds obviously developed different metabolic pathways to react on fluctuations in energy supply. Boran responded to energy deficiency exclusively by mobilizing body reserves. Crossbreds, by contrast, seemed to vary milk production relative to the energy supply, yet carry-over effects of previous undernutrition affected milk production of re-alimented cows. These results give clear indications on which genotype is suited best for various situations such as remote areas with long periods of feed scarcity (Boran) and periurban areas with better access to sufficient feed resources (crossbreds).