We welcome the comment by Crawford and Lassiter on our earlier paper, which was based on fieldwork completed in 1977. As they point out, the labor requirement coefficients for maintaining a pair of oxen under eastern Burkina Faso conditions were guesstimates based on experience with range herds, subject to all the well-known problems of attributing herd size overhead on a per capita basis.' This was necessary because farmers did not use cattle for draft cultivation in Delgado's fieldwork zone, despite three decades of extension to the contrary. Since the time our article was written, the commentators have been major contributors to a growing literature on the impact of animal traction based on empirical work somewhat to the east of Delgado's research zone (Lassiter, Barrett et al.). They therefore have a potentially major contribution to make to our understanding of a complex, and very important, puzzle in Sahelian agricultural development. Generally, we accept two of Crawford and Lassiter's points. First, it appears on the basis of their empirical results that maintenance times for a pair of oxen are lower than we estimated originally. Second, other constraints, such as high overhead investment, long learning periods, liquidity constraints, risk, and failure of institutional support systems, are undoubtedly important issues in explaining low adoption rates. Of course the second point in no way contradicts our earlier assertion that lack of profitability within a reasonable time span is a sufficient, if not necessary, explanation of nonadoption. However, we have considerable difficulty with the gist of Crawford and Lassiter's other points and with their interpretation of the significance of their results generally. In fact, we still feel that the main message of our earlier article is correct. This was that the opportunity cost of farm resources tied up in oxen cultivation technology is prohibitive under the conditions of eastern Burkina Faso in the late 1970s. Thus, the main policy issues are the adequacy of technologies proposed and incentives, not the suitability of support institutions such as extension, as implied by the comment. First, lack of financial profitability over a fourto six-year period, as stated by Crawford and Lassiter, surely is a sufficient condition for nonadoption of a technology by Sahelian smallholders. Second, Crawford and Lassiter's comments, and the work on which they are based, only assess the financial returns to oxen cultivation in a multiyear perspective (Lassiter, Barrett et al.). Their contention is that, given enough time, the enterprise will become financially profitable. Presumably, this is offered as a reason for forebearance by farmers and subsidies by the state. However, the real issue, the opportunity cost of these investments, is not mentioned. It is regrettable that Crawford and Lassiter do not explore the financial opportunity cost at the household level of using oxen for cultivation. Our article hypothesized that this financial opportunity cost was incurred through diversion of labor away from cropping to team maintenance. Data in Lassiter and Barrett et al. suggest that this is not a problem. However, the true opportunity cost problem may be, in fact, only slightly different. Their detailed data on sources of farm household income show that for oxen cultivation, mean nonfarm income was nearly three times as high for hoe farm households as for oxen cultivation households (Barrett et al., p. 75). Thus, we believe that Crawford and Lassiter's implication that "ATO adopters in Upper Volta ... [had] proportionally more nonfarm cash income than nonadopters," because of the existence of relatively larger households among the adopters, is misleading. Furthermore, given that oxen cultivation households were 67% larger on average than hoe cultivation households (Barrett et al., p. 74), it appears that nonfarm income per person in the hoe households was nearly five times as high as in oxen cultivation households. Using Barrett et al.'s data for the twenty-four hoe farms and the forty-four oxen farms that are truly comparable, coming from the same locations, it can be shown that total household income per active worker for the hoe farmers was 12% above that for oxen workers (Delgado 1984). Furthermore, the source of this difference lay not in the direct financial costs of oxen maintenance but in the relatively much higher income from nonagricultural trading and artisanal activities by hoe farmers. Since these activities require both capital and dry season labor, as does maintenance of a plow team and equipment, this is strongly supportive of the prohibitive financial opportunity cost of resources hypothesis, although small sample size must be kept in mind. Christopher L. Delgado is Coordinator for African Research at the International Food Policy Research Institute, Washington DC. John McIntire is an economist at the International Livestock Center for Africa, Addis Ababa, Ethiopia. Views expressed are strictly personal. 1 The Republic of Upper Volta was renamed "Burkina Faso" on 4 Aug. 1984.