Dairy feed efficiency and urbanization - A system approach in the rural-urban interface of Bengaluru, India

Efficient resource use is essential for sustainable dairy production. Urbanization, however, challenges resource availability and thus the feeding strategy of dairy producers living in urbanizing environments. As an emerging megacity, Bengaluru, in Southern India, combines rapid urbanization with a high demand for dairy products. To assess the impacts of urbanization on feeding strategy and resource use efficiency of dairy producers, measured as feed efficiency (milk production divided by feed offered), 28 dairy farms, from four dairy production systems (DPS) coexisting within Bengaluru's rural-urban interface, were monitored at 6-week intervals during one year. Out of the four DPS, one was extensive and found along the whole rural-urban interface (ExtDPS), two were rural and semi-intensive (Semi-ADPS and Semi-BDPS) but differed in the genotypes of dairy cattle kept, and one was rural and intensive (IntDPS). Feed intake and quality, milk offtake and quality, were monitored at each visit. Nutritional requirements of productive dairy cattle were estimated on the basis of production data. Daily intake of dry matter was high in IntDPS, intermediate in Semi-ADPS and Semi-BDPS, and low in ExtDPS, in which dairy producers were mostly landless and did not cultivate forages but relied on market wastes and public grounds for grazing and forage collection. Feed intake in Semi-ADPS, Semi-BDPS and IntDPS resulted in mostly adequate supply or oversupply of metabolizable energy and crude protein, whereas the feeding strategy of ExtDPS lead to mostly adequately supplied to undersupplied cattle. Daily offtake of energy-corrected milk (ECM) was the lowest in one semi-intensive DPS (Semi-ADPS = 8.2 kg cow(-1)) but, despite a similar feeding strategy, highest in the other semi intensive DPS (Semi-BDPS = 10.2 kg cow(-1)) and in IntDPS (10.9 kg cow(-1); P < 0.05). Milk offtake corrected for body weight was affected by days-in-milk, daily feed intake, metabolic disorders and temperature-humidity index. Feed efficiency was highest in ExtDPS with 1.0 kg ECM kg(-1) dry matter. Average feed efficiency per DPS ranged between 0.7 and 0.9 kg ECM kg(-1) dry matter in the three other DPS, despite more intensive feeding strategies. By relying on easily available local resources and grazing, dairy producers in ExtDPS achieved the highest feed efficiency system-wise with minimum inputs in land and labor, while feed resources were wasted in more intensive DPS. Bengaluru's case study indicates that within an urbanizing environment, dairy producers might choose distinctly different feeding strategies that lead to differences in intensification level and resource use efficiency.