HERD SIZE AND UNIT COSTS OF PRODUCTION IN THE ENGLAND AND WALES DAIRY SECTOR
研究了1976/7至1986/7年间英格兰和威尔士乳制品行业牛群规模与单位生产成本的关系，发现长期平均成本曲线呈U形但高度偏斜，技术变革偏向大型牛群。
This paper examines the relationship between herd size and unit costs of production in the England and Wales dairy sector. Following the two‐stage estimation procedure of Dawson & Hubbard (1987), longrun average cost (LAC) functions are estimated from cross‐section data for five separate years between 1976/7 and 1986/7. Results show that the LAC curves are U‐shaped but highly skewed, implying that considerable economies of size are present at low output levels but diseconomies at larger levels are much less marked. Over time, technological change in particular has been shifting the LAC curves downward and to the right and away from the sector's long‐run equilibrium. The differential shift of cost curves, depending on the size of production, implies that technological change has been biased in favour of larger herds.