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6 The U.S. Dairy Sheep Industry D airy sheep production is a new agricultural venture in the early stages of becoming an economically important agricultural indus- try in the United States. The first U.S. dairy sheep flocks and the first commercial dairy sheep farms were established in the mid-1980s with nondairy breeds of sheep because true dairy sheep were not present in North America until the early 1990s. European dairy sheep genetics of the East Friesian (EF) and Lacaune (LA) breeds were first imported into North America by Canada in 1992 and 1996, respectively (Thomas et al., 2001) and subsequently into the United States from Canada. Initial research in the United States showed that EF-crossbred ewes produced almost twice as much milk as domestic nondairy ewes (Thomas et al., 1999, 2000). The majority of dairy sheep farms in North America now milk crossbred ewes containing â¥ 50 percent EF and/or LA breeding. The proportion of dairy sheep genetics in flocks is increasing. The largest concentrations of dairy sheep farms in the United States are found in two regions: (1) the Upper Midwest, specifically northwestern Wisconsin and east-central Minnesota and (2) New York and New England, specifically Vermont, New Hampshire, and Maine. There is excellent inter- action between U.S. and Canadian dairy sheep producers. Most Canadian dairy sheep farms are located in southern Ontario and southern Quebec near the U.S. border (Figure 6â1). Much of the information in this chapter is based on the report by Thomas (2004), which summarizes the results of a survey of dairy sheep producers in the United States and Canada conducted in 2003â2004. 295
296 CHANGES IN THE SHEEP INDUSTRY IN THE UNITED STATES FIGURE 6-1â Location of dairy sheep 6-1.eps the United States and Canada in Fig farms in 2003. bitmap image Source: D. L. Thomas, personal communication (2004). Copyright 2004 by David L. Thomas. Used with permission. DAIRY SHEEP MILK PRODUCTION Few official records are kept at the state or national level on the popu- lation of dairy sheep or their production. The Dairy Sheep Association of North America (DSANA) and the University of WisconsinâMadison sur- veyed dairy sheep producers in the United States and Canada in 2003â2004 (Thomas, 2004; Thomas and Haenlein, 2005). The Wisconsin Agricultural Statistics Service surveyed Wisconsin producers in 2005 (Wisconsin Agri- cultural Statistics Service, 2006). Thomas (2004) estimated that 44 farms milked ewes in the United States in 2003. The greatest numbers of producers were in Wisconsin (14) and Vermont (10). Table 6-1 presents the estimated number of dairy sheep producers in the eastern and western regions in the United States. According to Thomas (2004), the average U.S. flock size in 2003 was 145 milking ewes with little difference between the East and West (Table 6-1). However, there were large differences between regions in the variation in flock size. Flocks in the East
THE U.S. DAIRY SHEEP INDUSTRY 297 TABLE 6-1â Estimated Number of U.S. Dairy Sheep Producers and Number of Milking Ewes per Flock, 2003 Milking Ewes Per Flock (number) U.S. Estimated Number of Region State Producers ââ Ave. Median ââ Range East Maine 2 â â â New Jersey 1 â â â New York 5 â â â Pennsylvania 1 â â â South Carolina 1 â â â Virginia 1 â â â Vermont 10 â â â Total East 21 138.1 54 5â850 â West California 1 â â â Colorado 1 â â â Iowa 1 â â â Minnesota 3 â â â Missouri 2 â â â Nebraska 1 â â â Wisconsin 14 â â â Total West 23 149.4 145 80â305 Total United States 44 145.4 100 5â850 Source: Adapted from Thomas (2004). region were more variable in size than flocks in the West region as indicated by the range in flock size. The median values presented in Table 6-1 are the flock sizes that are in the middle of the range. In the East region, half of the flocks were smaller than 54 ewes; in the West region, half of the flocks were smaller than 145 ewes. Overall, half of the flocks in the United States milked fewer than 100 ewes in 2003. Milk production per ewe in the flocks of producers in the two regions surveyed by Thomas (2004) is presented in Table 6-2. He reported large differences between the two regions. Respondents in the East region re- ported milk production per ewe at 212 kg whereas those in the West region reported perâewe production at 140 kg. Production per ewe was much more variable among flocks in the East region than among flocks in the West re- gion. The median milk production among all flocks was 146 kg milk/ewe, with an average production of 174 kg/ewe. In the 2005 Wisconsin survey, the 11 licensed dairy sheep producers in Wisconsin reported average milk production per ewe of 168 kg, higher than the 140 kg/ewe production re- ported for the West region in the Thomas (2004) survey. Table 6-3 presents the Thomas (2004) estimate of the total number of
298 CHANGES IN THE SHEEP INDUSTRY IN THE UNITED STATES TABLE 6-2â Milk Production per Ewe in Flocks of Survey Respondents, 2003 Milk Per Ewe (kg) Flocks Total Milk Total Ewes U.S. Region (number) (kg) (number) Average Median Range East 9 282,674 1,332 212.2 142 5â600 West 8 167,216 1,195 139.9 94 54â222 Total U.S. 17 449,890 2,527 178.0 146 5â600 Source: Adapted from Thomas (2004). TABLE 6-3â Estimated Number of Ewes Milked and Milk Production in the United States, 2003 Flocks Total Milking Ewes Total Milk Production U.S. Region (number) (number) (kg) East 21 3,088 593,248 West 23 3,390 555,434 Total U.S. 44 6,478 1,148,682 Source: Adapted from Thomas (2004). ewes milked and the total amount of sheep milk produced in the United States in 2003. Each of the 27 flocks that did not respond to the survey were estimated to have the same average number of ewes (145.4) and aver- age milk production per ewe (178.0 kg) as the respondent flocks for a total estimated milk production of each nonrespondent flock of 25,881 kg. Based on this assumption, 6,478 ewes in the United States produced an estimated 1,148,682 kg of milk in 2003. DAIRY SHEEP MANAGEMENT SYSTEMS Types of sheep management and milking systems in use are quite vari- able among dairy sheep operations. Presented in Figure 6-2 is the annual cycle for a dairy sheep operation lambing in the late winter or early spring. Some dairy sheep flocks receive only pasture during the grazing season. Others are grazed on pasture but supplemented with concentrates. Still oth- ers are fed harvested roughage and concentrates in confinement. Starting to milk ewes after weaning the lambs at 30 to 60 days postpartum (DY30 system) was quite common in the early 1990s. An increasing number of
THE U.S. DAIRY SHEEP INDUSTRY 299 February March April May June July August September October November December January Ewes Bred for Spring Lambing Season Spring Lamb Crop Ewes milked starting as early as 48 to 72 hours after lambing or as late as 30 days after lambing Fresh milk processed immediately into cheese, yogurt, etc. milk frozen for later processing Frozen Milk Frozen Milk Processing Processing Lambs fed milk replacer until 30 days of age and then finished on grain or lambs weaned from ewes at 30 days of age and finished on grain Milk Fed and Finished Lambs for Slaughter Prelambing Shearing of Ewes FIGURE 6-2â Annual dairy sheep and lamb cycle. Fig 6-2.eps producers, however, milk the ewes from shortly after parturition. Ewes may be milked only once per day during early lactation while the lambs are nursing and then switched to twice-per-day milking after the lambs are weaned at 30 days of age (MIX system). Alternatively, the ewes may be milked twice-per-day from shortly after parturition with the lambs reared on milk replacer (DY1 system). Research in the United States has shown that the MIX system results in the greatest net returns if milk is sold on weight or volume (McKusick et al., 2001). However, milk from MIX ewes during the 30 days when they are nursing their lambs has a significantly lower fat percentage than milk from DY1 or DY30 ewes and would receive a price discount if sold on the basis of fat content. Almost all farms use machine milking. Milking systems vary from el- evated platforms, with cascading yoke stanchions and milking into buckets, to double-24 milking parlors with a pit for the milkers and several milking units attached to a pipeline, to a carousel milking parlor. DAIRY SHEEP MILK QUALITY The U.S. Grade âAâ Pasteurized Milk Ordinance (PMO) requires sheep milk at the farm to have a bacterial count of not more than 100,000/ml of milk and a somatic cell count of not more than 750,000/ml of milk
300 CHANGES IN THE SHEEP INDUSTRY IN THE UNITED STATES (USDHHS, 2002). Unlike goat milk that has a naturally high somatic cell count (Thomas and Haenlein, 2005), sheep milk produced under sanitary conditions does not have difficulty meeting these minimum standards. Mea- sures of milk composition and quality from 355,000 liters of sheep milk marketed cooperatively in the United States in 2002 and 2003 were 453,000 somatic cells/ml, 41,000 bacteria/ml, 6.2 percent fat, 4.9 percent protein, and 17.1 percent total solids (Thomas, 2004). DAIRY SHEEP MILK MARKETING, TRANSPORTATION, AND PRICING The biggest concern for someone considering entry into dairy sheep production is the marketing end of the business. The problem generally is not a lack of demand for sheep milk but rather the production of small amounts of sheep milk on individual farms that are great distances from a milk processor willing to process sheep milk. One solution to this problem is for dairy sheep producers to pool their milk and ship larger quantities of milk periodically to processors. The Wisconsin Sheep Dairy Cooperative (WSDC) is the only U.S. dairy sheep milk marketing cooperative. The co- operative collects milk from its members and markets it to processors. The cooperative is increasing the amount of its milk that is custom-made into cheese with the cheese marketed by the cooperative as well. This adds value to the producersâ milk and results in greater net returns. Cooperatives require a tremendous commitment of volunteer time on the part of members, especially in the initial years of the organization. The effort to establish the WSDC occurred at the same time that producers were establishing their own dairy sheep farms and is now paying dividends. For example, the WSDC has seen over a 20-fold increase in the amount of milk sold in 2007 compared to 1996 when it was established (Figure 6-3). De- mand for its milk continues to grow. Without the WSDC, the dairy sheep industry in the Upper Midwest of the United States would not be as viable as it is today. Much of the milk sold from farms is first frozen in plastic bags in large commercial freezers on the farm. Bags of frozen milk are accumulated on the farm and shipped in large quantities in refrigerated trucks to proces- sors. Research has shown that this milk can be frozen at â27ÂºC for at least 12 months with no detrimental effects on processing characteristics (Wen- dorff, 2001). The ability to freeze milk and make a quality product from the thawed milk has allowed small producers who are great distances from processors to enter the industry. A small producer can accumulate the milk produced from his flock in a freezer during the milking season and send the milk individually or along with that of other producers to a processor in a large shipment only once or a few times per year. Since sheep are seasonal
THE U.S. DAIRY SHEEP INDUSTRY 301 418 391 450 369 400 277 350 Milk, x 1,000 kg 300 204 250 169 149 200 114 85 150 38 100 21 36 50 0 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Year FIGURE 6-3â Milk sales by the Wisconsin Sheep Dairy Cooperative (WSDC), 1996â2007. Sources: Sales through 2003 from Thomas (2004). Sales for 2004 through 2007 from Fig 6-3.eps WSDC Board of Directors (personal communication). Copyright 2004 and 2007 by David L. Thomas. Used with permission. breeders and most sheep milk is produced during the spring and summer, a frozen stockpile of milk also allows processors access to milk year-round. Frozen milk, however, is not without its problems. The costs of installa- tion and maintenance of a large commercial freezer and of freezer bags are large expenses for dairy sheep producers. Processors experience increased costs in storage of frozen milk and in the amount of time required to thaw milk prior to processing compared to fluid milk (Clark, 2004; Cook, 2004). Some frozen-thawed milk separates and has a large amount of sediment that does not allow its use in all sheep milk products. Failure to keep the milk cold enough while frozen on the farm or partial thawing during transporta- tion to the processor may be the cause (Clark, 2004). In areas where there is a large concentration of dairy sheep farms in close proximity to a major processor, the accumulation of large quantities of fresh milk during peak lactation periods is possible for shipping directly to processors in bulk tank trucks. This is greatly preferred by processors (Cook, 2004). As the industry grows and more milk becomes available, fluid shipments of milk will in- crease. For example, the WSDC shipped 63 percent of its milk to processors in fluid rather than frozen form in 2007 (WSDC, personal communication, 2007). However, there will still be a need for some frozen milk to sustain processors during times of the year when sheep milk is not produced and processors are large distances from producers. According to the Thomas (2004) survey, the price for dairy sheep milk
302 CHANGES IN THE SHEEP INDUSTRY IN THE UNITED STATES sold to processors ranged from $1.20 to $1.65 per kg in 2003. Producers in Wisconsin received an average price of $1.22 per kg for sheep milk in 2005 (Wisconsin Agricultural Statistics Service, 2006). The vast majority of the milk is sold by weight with no premiums or discounts for milk composition or quality. Value-based pricing of sheep milk could become a reality in the future as the supply of milk increases. Of course, milk cannot be sold if it does not meet the minimum quality standards for bacterial and somatic cell counts established by the federal government. DAIRY SHEEP MILK PROCESSING The few sheep milk processors in North America appear to be pleased to have sheep milk available. Most have increased the amount of sheep milk they process each year as the supply slowly increases. The largest commercial U.S. sheep milk processor produced 115,000 kg of cheese and 4,500 kg of yogurt in 2003 (Thomas, 2004). A sheep milk cheese was the champion specialty cheese from more than 725 cow, goat, and sheep milk cheeses entered in the American Cheese Societyâs 2004 annual competition. The maker of the champion cheese runs a commercial processing plant and purchases dairy sheep milk from the WSDC. Several other U.S. sheep milk cheeses have received major honors at national and international cheese competitions in the last few years. Farms that are not members of a marketing cooperative have a number of marketing options, including selling their milk directly to a commercial processor, processing their milk into cheese or other products on their farms, having their milk custom processed into cheese by a commercial processor, or selling their milk to another dairy sheep producer who processes their own milk plus purchased milk. The lack of local commercial processing factories for sheep milk in most areas has led many sheep producers to make cheese on their farms in small batches and market it directly to individuals, food stores, and restaurants. Of the 24 respondents to the Thomas (2004) survey who had milked sheep between 2000 and 2003, 11 (46 percent) processed milk on their farms into value-added products (Table 6-4). The percentage of producers in the East region that processed milk on their farms (71 percent) was much higher than the percentage that processed milk on their farms in the West region (10 percent). This difference in the percentage of farms processing their own milk in the two regions may be because the WSDC was formed in 1995, giv- ing producers in the West region a marketing outlet for fluid milk. In other areas, there were no options except to process the milk produced. Also, the northeast United States may have had more of a tradition of producing farmstead cheeses than the West region. Wisconsin requires all cheese mak- ers to be licensed. Passing an examination and a one-year apprenticeship
THE U.S. DAIRY SHEEP INDUSTRY 303 TABLE 6-4â Proportion of Survey Respondents That Process Milk on Farm, Purchase Milk from Other Producers for Processing, or Wish to Start Processing Milk, 2003 ----------------------------------------- Number (%) --------------------------------------- Do Not Now Process Milk on the Process Milk on the Farm Farm but Wish to in the Future U.S. Region Yes No Yes No East 10 (71) â 4 (29) 3 (75) 1 (25) West â 1 (10) â 9 (90) 3 (33) 6 (67) Total U.S. 11 (46) 13 (54) 6 (46) 7 (54) Source: Adapted from Thomas (2004). are required to obtain a license to make cheese in Wisconsin. These require- ments do not encourage producers to become farmstead cheese makers. Of the 13 producers in the Thomas (2004) survey that did not process milk on their farms, almost half expressed a desire to process milk in the future. However, there were large differences among regions in the desire to enter into processing of milk. About 75 percent of the nonprocessing farms in the East region wished to process in the future, whereas only 33 percent of the nonprocessing farms in the West region wished to process in the future (Table 6-4). This result again seems to indicate the satisfaction that West region producers have with their milk marketing alternatives and, perhaps, the lack of good outlets for fluid sheep milk in the East region at the present time. DOMESTIC AND IMPORTED DAIRY SHEEP MILK SUPPLY The United States is the largest importer of sheep milk cheese in the world. Approximately half the world exports of sheep milk cheese in 2005 came to the United States (FAO, 2007). Sheep milk cheese imports to the United States have increased from 14,476 metric tons (tonnes) in 1985 to 33,359.5 tonnes in 2005, a 30 percent increase in 20 years (FAO, 2007). The five European countries of Italy, France, Bulgaria, Greece, and Spain accounted for 93.4 percent of the sheep cheese exports to the United States in 2005 with Italy alone accounting for 56.7 percent of those exports (Table 6-5). The total U.S. sheep milk production was estimated at 1,149 tonnes in 2003. If total production increased at the same rate as the volume of milk marketed by the WSDC from 2003 to 2005 (+ 81 percent), total U.S. sheep
304 CHANGES IN THE SHEEP INDUSTRY IN THE UNITED STATES TABLE 6-5â U.S. Sheep Milk Cheese Imports by Exporting Country, Quantity, and Value, 2005 Volume Value Tonnes % $1,000 Per kg Italy 18,910.0 56.7 $101,227 $5.35 France 4,660.0 14.0 $27,855 $5.98 Bulgaria 3,553.0 10.7 $11,348 $3.19 Greece 2,245.0 6.7 $15,085 $6.72 Spain 1,803.0 5.4 $18,552 $10.29 All other countries 2,188.5 6.6 $11,156 $5.10 Total 33,359.5 100.0 $185,223 $5.55 Source: FAO (2007). milk production in 2005 may have been 2,080 tonnes. This amount of sheep milk could produce approximately 416 tonnes of sheep milk cheese (5 kg of sheep milk per kilogram of sheep milk cheese). Therefore, domestic production of sheep milk cheese in 2005 was probably less than 1.3 percent of the total supply available to U.S. consumers, suggesting considerable potential for a large increase in domestic production to displace some of the imported product. Imported dairy sheep products present some pricing challenges for do- mestic products. The average landed value of imported sheep milk cheese in the United States was $5.55 per kg in 2005 (Table 6-5). At current values of U.S. sheep milk ($1.20/kg to $1.65/kg) and 5.0 kg of sheep milk required to produce 1 kg of sheep milk cheese, the milk alone in 1 kg of domestic sheep milk cheese costs between $6.00/kg and $8.25/kg. Obviously, domes- tic sheep milk cheeses cannot compete with imported sheep milk cheeses on price in the current economic environment. Continued growth in produc- tion of domestic sheep milk cheese will depend on the ability of U.S. cheese makers to continue to produce high-quality specialty sheep milk cheeses that command a higher price than imported products. MAJOR ACCOMPLISHMENTS, OPPORTUNITIES, AND CHALLENGES OF THE U.S. DAIRY SHEEP INDUSTRY Major Accomplishments of the U.S. Dairy Sheep Industry â¢ Developing industry. The dairy sheep industry has developed from nothing in the early 1980s to a small but growing industry with potential for continued growth. As with all new industries, the U.S. dairy sheep in-
THE U.S. DAIRY SHEEP INDUSTRY 305 dustry owes its existence to the hard work of a few pioneer producers and processors. â¢ Domestic sheep milk cheeses now available. Prior to the early 1980s, there were no domestic sheep milk cheeses available to U.S. consumers. Now, cheese cases in many specialty cheese stores and even stores of national grocery chains contain domestic sheep milk cheeses. This is due to the pro- duction of highâquality milk by producers, the manufacture of highâquality cheeses by processors, and the promotion of these cheeses by both national (e.g., The American Cheese Society, http://www.cheesesociety.org/) and state (e.g., Vermont Cheese Council, http://www.vtcheese.com) organizations. â¢ Formation of milk marketing cooperative. The Wisconsin Sheep Dairy Cooperative (http://www.sheepmilk.biz/), a sheep milk marketing co- operative for producers in the Upper Midwest and the only such marketing cooperative in the United States has served as a catalyst for the continued growth of the industry in that region. â¢ Dairy sheep producer organization established. The Dairy Sheep Association of North America (DSANA) was established in 2002 to foster the North American dairy sheep industry (http://www.dsana.org/index. php). The association publishes a quarterly newsletter and has taken over the organization of the annual Great Lakes Dairy Sheep Symposium started by the University of WisconsinâMadison and the Wisconsin Sheep Breeders Cooperative in 1995. The symposium now rotates each year among sites in Wisconsin, the northeastern United States, and southern Ontario and Quebec, Canada. Speakers include North American scientists, producers, and processors, as well as international experts. The proceedings of these symposia contain the most up-to-date information available to the North American dairy sheep industry. Past proceedings can be viewed at http:// www.uwex.edu/ces/animalscience/sheep/. Major Opportunities of the U.S. Dairy Sheep Industry â¢ Large domestic market for sheep milk cheeses. The greatest oppor- tunity for the dairy sheep industry is the increasing consumption of sheep milk cheese by U.S. consumers. The consumption of sheep milk cheeses in the United States, as measured by imports, has increased by 30 percent in the 20-year period from 1985 to 2005. In 2005, it was estimated that < 1.3 percent of total sheep milk cheese availability was domestically produced. â¢ Demand for locally raised food. The growing movement among consumers to eat locally raised and produced products should also be good news for the domestic sheep milk industry. â¢ Viable option for small farms. Dairy sheep production is an agricul- tural enterprise that requires a relatively small amount of land, and sheep are small enough to be handled safely by most members of the family. The
306 CHANGES IN THE SHEEP INDUSTRY IN THE UNITED STATES enterprise is a viable alternative for small-scale farmers. Returns to labor and management per year, including capital costs, are estimated to be be- tween $51/ewe (high debt load) and $110/ewe (low debt load) for a 300-ewe flock producing and marketing milk, lambs, and cull sheep (Berger, 2002). Major Challenges of the U.S. Dairy Sheep Industry â¢ No genetic improvement program. There are no regional or national genetic improvement programs for dairy sheep traits in the United States. Annual increases in production that have been noted in most flocks over time have been a result of improved management and an increase in the percentage of dairy breeding in the ewe flock. However, as the industry matures, there will be a desperate need for proven sires with high estimates of genetic value for economically important traits. The industry should establish a national genetic improvement program for dairy sheep. The two logical organizations to carry out these genetic evaluations are either the Animal Improvement Laboratory of USDA, which conducts the genetic evaluations for dairy cattle and dairy goats, or the National Sheep Improve- ment Program, which conducts the genetic evaluations for meat and wool sheep. â¢ Limited research and extension support. There is limited research and extension support for dairy sheep production, sheep milk processing, and sheep milk product marketing. The only dairy sheep research flock in North America was established in 1995 at the University of WisconsinâMadison at the Spooner Agricultural Research Station. This flock is composed of approximately 300 milking ewes of various percentages and combinations of East Friesian and Lacaune breeding. The University of Vermont has an Extension Small Ruminant Dairy Specialist to work with producers of dairy goats and sheep in Vermont. In addition, the University of Guelph, Cornell University, the University of Vermont, and the University of Wisconsinâ Madison have research and/or extension programs in sheep milk processing and/or dairy sheep production. Potential producers or processors in states other than those listed above are very limited in the information and as- sistance they can obtain to enter the industry. â¢ Few marketing options for sheep milk. There is a lack of marketing options for most U.S. sheep dairy producers. The Wisconsin Sheep Dairy Cooperative serves the milk marketing needs of the majority of the produc- ers in Wisconsin and Minnesota. Potential producers in other areas of the United States are at a great disadvantage because there is no ready market for the milk they would like to produce. Their only option is to become a sheep milk producer and a farmstead cheesemaker and marketer, but these skills may not be present among the personnel (generally the family mem- bers) to be a farmer, processor, and marketer. While there appears to be a
THE U.S. DAIRY SHEEP INDUSTRY 307 demand for more sheep milk, the infrastructure is not in place throughout the United States to get milk from the producers to the processors. â¢ Lower-priced imported sheep milk cheeses. The lower price of imported sheep milk cheeses relative to domestic sheep milk cheeses will remain a continual challenge. The domestic industry must compete with im- ported product by continuing to develop cheeses that are unique compared to imported cheeses, by producing higherâquality cheeses or the perception of higherâquality cheeses, and by capitalizing on the movement among con- sumers to eat more locally produced foods. REFERENCES Berger, Y. M. 2002. Economics of winter milking for medium to large dairy sheep operations. Pp. 118â126 in Proceedings of the 8th Great Lakes Dairy Sheep Symposium. University of WisconsinâMadison, Dept. of Anim. Sci. Online at: http://www.ansci.wisc.edu/Extension- New%20copy/sheep/Publications_and_Proceedings/res.html. Accessed April 17, 2008. Clark, J. T. 2004. Processing of frozen milkâCurrent procedures and difficulties encoun- tered. Pp. 153â156 in Proceedings of the 10th Great Lakes Dairy Sheep Symposium. University of WisconsinâMadison, Dept. of Anim. Sci. Online at: http://www.ansci.wisc. edu/Extension-New%20copy/sheep/Publications_and_Proceedings/res.html. Accessed April 17, 2008. Cook, S. 2004. Marketing of sheep milkâProblems faced by processors. Pp. 157â158 in Proceedings of the 10th Great Lakes Dairy Sheep Symposium. University of Wis- consin-Madison, Dept. of Anim. Sci. Online at: http://www.ansci.wisc.edu/Extension- New%20copy/sheep/Publications_and_Proceedings/res.html. Accessed April 17, 2008. FAO (Food and Agriculture Organization of the United Nations). 2007. FAOSTAT data base. Online at: http://faostat.fao.org/. Accessed September 30, 2007. McKusick, B. C., D. L. Thomas, and Y. M. Berger. 2001. Effects of weaning systems on com- mercial milk production and lamb growth of East Friesian dairy sheep. J. Dairy Sci. 84:1660â1668. Thomas, D. L. 2004. Overview of the dairy sheep sector in Canada and the United States. Pp. 166â180 in Proceedings of the 10th Great Lakes Dairy Sheep Symposium. University of WisconsinâMadison, Department of Animal Science. Online at: http://www.ansci.wisc. edu/Extension-New%20copy/sheep/Publications_and_Proceedings/res.html. Accessed April 17, 2008. Thomas, D. L., and G. F. W. Haenlein. 2005. Panorama of the goat and sheep dairy sectors in North America. Pp. 23â28 in Proceedings of the International Symposium on the Future of the Sheep and Goat Dairy Sectors, Zaragoza, Spain. Special issue 200501, Part 1. International Dairy Federation. Online at: http://www.fil-idf.org/content. Accessed April 17, 2008. Thomas, D. L., Y. M. Berger, and B. C. McKusick. 1999. Milk and lamb production of East Friesian-cross ewes in the north central United States. Pp. 474â477 in Milking and Milk Production of Dairy Sheep and Goats. Proceedings of the 6th International Symposium on the Milking of Small Ruminants. F. Barillet and N. P. Zervas, eds. EAAP Publication No. 95. Wageningen, the Netherlands: Wageningen Pers. Thomas, D. L., Y. M. Berger, and B.C. McKusick. 2000. East Friesian germplasm: Effects on milk production, lamb growth, and lamb survival. Proc. Am. Soc. Anim. Sci., 1999. Online at: http://www.asas.org/jas/symposium/proceedings/0908.pdf.
308 CHANGES IN THE SHEEP INDUSTRY IN THE UNITED STATES Thomas, D. L., Y. M. Berger, B. C. McKusick, R. G. Gottfredson, and R. Zelinsky. 2001. Comparison of East Friesian and Lacaune breeding for dairy sheep production systems. Pp. 44â51 in Proceedings of the 7th Great Lakes Dairy Sheep Symposium. University of WisconsinâMadison, Dept. of Anim. Sci. Online at: http://www.ansci.wisc.edu/Extension- New%20copy/sheep/Publications_and_Proceedings/res.html. Accessed April 17, 2008. USDHHS (U.S. Dept. of Health and Human Services). 2002. Grade âAâ Pasteurized Milk Ordinance, 2001 Revision. Online at: http://www.cfsan.fda.gov/~ear/pmo01toc.html. Accessed April 17, 2008. Wendorff, W. L. 2001. Freezing qualities of raw ovine milk for further processing. J. Dairy Sci. (E. Suppl.):E74âE78. Wisconsin Agricultural Statistics Service. 2006. Wisconsin Dairy Sheep Industry Overview. Online at: http://www.nass.usda.gov/Statistics_by_State/Wisconsin/Publications/Dairy/ dairysheep.pdf. Accessed April 17, 2008.