The on-farm evaluation of three feeding strategies for smallholder campesino dairy herds was undertaken in the highlands of Central Mexico with cooperating farmers: traditional, alternative and intermediate feeding strategies. All three incorporated grazing of cultivated pastures, but concentrate use was 4.0 and 7.0 kg per cow per day in the rainy and dry seasons respectively for the traditional feeding strategy, 3.3 for the alternative feeding strategy in both rainy and dry seasons and 5.0 and 9.0 kg per cow per day in the rainy and dry seasons respectively for the intermediate feeding strategy. Feeding during the dry season was based on maize straw in the traditional strategy, on pasture complemented with maize silage in the alternative feeding strategy, and with some maize silage but mostly maize straw in the intermediate feeding strategy. The trial ran between 25 September 1996 and 24 September 1997, divided by season into four, thirteen-week periods. Milk yields were recorded once per week, and live weight and body-condition score, every 28 days. Three cows per strategy that completed each period were blocked according to stage of lactation and used for the statistical analysis of a split-plot design with feeding strategies as main plots and weeks as split-plots. Overall mean milk yields were 15.5±2.05, 13.4±2.43 and 12.4±2.37 kg milk per cow per day for alternative, intermediate and traditional feeding strategies respectively, with significant interactions (P<0.05) for autumn, winter and summer. The alternative feeding strategy (with over 50% less concentrate) produced milk yields 0.24 and 0.38 higher than the intermediate and traditional feeding strategies in the dry season. In the rainy season, milk yields with the alternative feeding strategy (30% less concentrates) were 0.09 and 0.16 higher than the other two strategies. Margins per day of family labour were: alternative feeding strategy US$36.48 per day, intermediate feeding strategy US$9.22 per day and the traditional feeding strategy US$9.11 per day, although in the case of the last two there were two family members in charge of the dairy herds. Results demonstrate the successful integration of grazed pasture and maize silage for the efficient production of milk, and provide evidence on the productive use of limited campesino land resources in the face of unviable economic conditions for maize grain production.
Dynamic stability in dry season food webs within tropical floodplain rivers