The influence of days carried calf and dry period on milk and fat production in Tennessee DHIA herds

A number of items influence production records of dairy cows. Most dairy farmers recognize some of these, while many are generally overlooked. Items usually accepted as influencing production records are: age, body weight, frequency of milking, quality and amount of feed, general care and management, and length of lactation. Other items, affecting production, that are often given little attention are: the length of dry period, the number of days open during lactation, and calving interval. Conversion factors are available and in common use for age and milking frequency. Factors have been devised to adjust for the influence of days carried calf, but have not been widely accepted. With the growth of artificial insemination the problem of sire selection committees has been compounded. They have a tremendous respon-sibility to dairy cattle owners since they are making selection for all stud patrons. As sire selection is so hazardous, it is very important to account for all possible variables which may influence production records in order to improve the accuracy of selection procedure. Owners have the same problem in selecting foundation or replacement animals. However when considered on a herd basis, individual female selection will not exert nearly the influence on total potential improvement as male selection. The purpose of this study is to attempt to evaluate the importance of dry periods, and days carried calf as they influence production in DHIA herds in Tennessee

The Transition to Agriculture: Climate Reversals, Population Density, and Technical Change

Until about 13,000 years ago all humans obtained their food through hunting and gathering, but thereafter people in some parts of the world began a transition to agriculture. Recent data strongly implicate climate change as the driving force behind the agricultural transition in southwest Asia. We propose a model of this process in which population and technology respond endogenously to climate. The key idea is that after a lengthy period of favorable environmental conditions during which regional population grew significantly, an abrupt climate reversal forced people to take refuge at a few ecologically favored sites. The resulting spike in local population density reduced the marginal product of labor in foraging and made agriculture attractive. Once agriculture was initiated, rapid technological progress through artificial selection on plant characteristics led to domesticated varieties. Farming became a permanent part of the regional economy when this productivity growth was combined with climate recoveryorigins of agriculture, foraging, hunting and gathering, climate change, population density, technical change, domestication, archaeology, anthropology, economic prehistory

ALCOA #1 (41AN87): A Frankston Phase Settlement along Mound Prairie Creek, Anderson County, Texas

The ALCOA #1 (41AN87) site is a Frankston Phase (ca. A.D. 1400-1650) site located on a high alluvial terrace of Mound Prairie Creek, about seven kilometers northeast of Palestine, Texas. Mound Prairie Creek, a perennial stream, flows southeast to east across the county and drains into the Neches River. The site is approximately 10 meters above the Mound Prairie Creek floodplain, and the creek channel is 300 meters to the south. Although the investigations at the site have been rather limited to date, it appears that the ALCOA #1 site is a single component Frankston Phase homestead, or possibly a small hamlet. Other Frankston phase sites are known on Mound Prairie Creek, Hurricane Creek, Walnut Creek, and Brushy Creek, all Neches River tributaries, and the possibility exists that these may be part of a larger related Caddo community and settlement system

Conjunctive Water Use Planning with Water Quality Constraints in Tooele Valley, Utah

The need for more efficient water management is gaining recognition due to the increased cost of water supply, the growth in the demand for water, and greater environmental and social impacts of water programs. Conjunctive use of surfact and groundwater resources provides opportunities for increasing net benefits to the water users. Past conjunctive use studies, however, have usually not included water quality constraints. In Tooele valley, Utah, spatial variation of groundwater qualtity (total dissolved solids) is significant. The areas of good (400-500 mg/1), fair (500-1,000 mg/1), and poor (1,000-3,000 mg/1) quality groundwaters were identified in an earlier study by the USGS. The water quality dimension was incorporated into the conjunctive use planning to account for crop yield changes due to changes in salinity levels in irrigation water. The possibilities for increasing total net benefits by blending surface and groundwater of different qualities were examined by developing a linear programming optimization model. The optimization model provides for mixing the different qualities of water available for the cops to maximize benefits. It applies linear programming to the Tooele Valley water supply system and optimizes over three locations, four coprs, and five qualities of water of differing costs. The groundwater withdrawals at the locations dictated by the optimization model were input to the Tooele Valley groundwater simulation model developed by USGS to study the effects on the valley\u27s principal artesian aquifer. Economic analyses of the probable scenarios of future agricultural development in Tooele Valley did not suggest that extensive increases in groundwater with drawals will occur. Economic infeasibility of major increases in groundwater extraction is a limiting factor for agricultural development in most parts of the valley. Groundwater mining therefore does not seem like a major future problem. The areas where new wells can be drilled without interference causing technological diseconomies are indicated. Profitable application of blending technology to irrigated agriculture in Tooele Valley is not possible without making a drastic shift to some higher valued crop such as fruit trees. All surface water sources should be fully utilized before developing additional and expensive groundwater. Even though an additional 20,000 to 25,000 ac-ft of groundwater can be extracted without mining, there would be a high risk of destroying natural phreatophyte habitats and degradation of water quality in at least some parts of the artesian aquifer

Case studies and benchmark transaction costs for select food products

Producer-distributors can use the information in this set of case studies to identify commercial advantages and disadvantages that can affect the success of their enterprises