Impacts of Animal Science Research on United States Sheep Production and Predictions for the Future1
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ASAS CENTENNIAL PAPER: Impacts of animal science research on United States sheep production and predictions for the future1 C. J. Lupton2 Texas AgriLife Research, Texas A&M System, San Angelo 76901-9714 ABSTRACT: One hundred years ago, there were more genetics, selection, nutrition, fiber, meat, hides, milk, than 48 million sheep in the United States. In 1910, growth, physiology, reproduction, endocrinology, man- they were valued at $4/head, with 43% of income com- agement, behavior, the environment, disease, pharma- ing from the sale of sheep, lambs, and meat and 57% cology, toxicology, and range, pasture, and forage uti- coming from wool. Over the years, fluctuations in this lization such that a vast amount of new information ratio have challenged the breeder and researcher alike. was accrued. Our understanding of sheep has benefit- By 2007, sheep numbers had declined to 6.2 million, ed also from research conducted on other species, and with the average sheep shearing 3.4 kg of wool (repre- vice versa. Many factors that have contributed to the senting <10% of income), 0.2 kg more than in 1909 but decline in the sheep industry are not influenced easily 0.5 kg less than fleeces in 1955. Sheep operations have by academic research (e.g., low per capita consumption declined by more than 170,000 in the past 40 yr. A cur- of lamb meat, predation, reluctance to adopt new tech- sory examination of this information might lead one to nologies, cost and availability of laborers with sheep- conclude that animal science research has made little related skills, and fewer young people pursuing careers impact on sheep production in the United States. On in agriculture). The size of the US sheep industry is the contrary, lamb crops in the new millennium (range expected to remain stable, with possible slow growth in = 109 to 115%) are greater than those recorded in the the foreseeable future. To remain profitable, producers 1920s (85 to 89%) and dressed lamb weights increased will take advantage of new (or previously unused) tech- from 18 to 32 kg from 1940 to the present. In the past nologies, the desire of the public for things natural, do- century, researchers conducted thousands of investi- mestic niche and international fiber markets, and the gations, with progress reported in new, existing, and ability of the sheep to control noxious weeds and thrive crossbreed evaluations, quantitative and molecular in suboptimal ecosystems. Key words: future, impact, research, sheep production ©2008 American Society of Animal Science. All rights reserved. J. Anim. Sci. 2008. 86:3252–3274 doi:10.2527/jas.2008-1148 INTRODUCTION impacts that research had ever made on sheep pro- duction. If, on the other hand, you asked a group of “If a tree falls in the forest and no one is around to informed breeders, producers, or sheep researchers, hear it, does it make a sound?” This age-old philosophi- they would all likely be able to produce a short list of cal riddle may have a parallel in sheep research and research topics that have made a significant impact on production. “If a sheep research project is conducted the industry. In fact, all research that has ever been and no producers hear (or read about) it, does it have conducted (and reported) has made a measurable im- an impact on the industry?” Of course, the answer de- pact on today’s sheep industry, although it may be in- pends on whom you ask. If you asked a group of unin- finitesimal in some cases. My task in preparing this formed lamb-eating or wool-wearing consumers, they manuscript was to delve into 100 yr of animal (but pri- might respond by saying they were not aware of any marily sheep-related) research literature and decide (with the assistance of 21 colleagues) which research has made an impact. Therefore, this is our collective opinion, with apologies to the thousands of animal sci- 1 I am grateful to my colleagues for sharing their sheep-related entists whose research will not be mentioned. It is un- knowledge with me and to B. S. Engdahl for her valuable assistance fortunate that so much technology produced by sheep with the references and proofreading. 2 Corresponding author: [email protected] researchers was or may never be used by the industry Received May 1, 2008. because of the constraints of earlier and current pro- Accepted June 27, 2008. duction systems. 3252 Impacts of animal science research on sheep production 3253 This report examines the impacts of animal science weights at slaughter have increased steadily from research on US sheep production during the past 100 36.3 and 17.2 kg to 62.6 and 31.8 kg, respectively, and yr. Because it was prepared for the centennial celebra- lamb crops have increased from 87% in 1924 to 110% tion of the American Society of Animal Science (for- in 2007. Wool production declined commensurate with merly the American Society of Animal Production), the number of sheep shorn, with the greatest produc- scientists who conducted their research in this coun- tion, 176 million kg, occurring in 1942 and the least try and reported their results in the Journal of Animal amount, 15.7 million kg, being shorn in 2007. Wool Science have received primary attention. However, it prices in the United States tended to follow interna- is recognized that research resulting in major impacts tional trends, with US wools invariably lower priced on sheep production has been conducted and reported than wools of comparable grade from Australia, the elsewhere, and an effort was made not to overlook the leading exporter of high-quality wools. The recent low major contributions. greasy price of $0.73/kg occurred in 2000, whereas the most recent high, $3.04/kg, was received in 1988. The MATERIALS AND METHODS previous low price for wool, $0.43/kg, occurred in 1971 (prices not adjusted for inflation). Since 1965, the num- Data were obtained and summarized to provide a ber of operations with sheep had declined from 241,290 short overview of some of the major numerical changes to 70,590 by 2007, with a current average flock size of that occurred in the sheep industry during the previ- 88 sheep per operation. ous 100 yr. All sheep- and wool-related statistics were obtained or calculated from Quick Stats, an agricul- Searching the Journal tural statistics database maintained by the National Agricultural Statistics Service, USDA. A search of the Journal of Animal Science database Initially, 39 research and extension scientists who from January 1910 to April 2008 using the following are current (n = 33) or past (n = 6) members of 2 na- search criteria resulted in 3,917 titles being listed: the tional coordinating committees (Western Extension, key words sheep, wool, lamb, ewe, ram, ovine, fleece Research, and Academic Coordinating Committee 039, (with any of these words in the title or abstract). The “Coordination of sheep and goat research and educa- majority of articles reported research with sheep. How- tion programs for the western states” and North Cen- ever, a few were not bona fide sheep manuscripts but tral Extension, Research, and Academic Coordinating were concerned with topics such as rabbit and qiviut Committee 190, “Increased efficiency of sheep produc- wool or the like. This online search capability of the tion”) and 4 professionals that work for sheep associa- Journal is a tremendous resource. tions in marketing and promotion (n = 3) and a national feed company (n = 1) were contacted and independently Genetics asked to list research topics in their field of expertise that they considered had made a major impact on sheep This section comprises animal breeding, including production in the United States. Their responses (n = breed development, breed and crossbreed evaluations 21, 49% response rate) were combined and form the ba- (with particular emphasis on use of the Finnsheep to sis for most of the topics covered in this report. Subse- increase lamb production), improvement of existing quently, literature searches were conducted primarily, breeds through selection, and quantitative genetics to but not exclusively, in the Journal of Animal Science estimate genetic parameters and predict genetic merit database, and an attempt was made to recognize the of individual animals within a breed, all fields that work of those scientists that initiated or made a high- have greatly influenced sheep production in the United ly significant contribution to specific research areas. States. A recent addition to the field of study is analysis Needless to say, all contributions were not recognized. of QTL, this being a region in the genome that affects a My only excuses are the shortage of time in which to specific trait or number of traits. The QTL approaches conduct and space in which to report a more thorough require accurate phenotypic, pedigree, and genotypic review. I hereby apologize for all oversights and assure data from a large number of individuals. any affected scientists that none was intentional. Quantitative and Population Genetics RESULTS AND DISCUSSION The foundation of animal breeding research was Sheep Industry Trends undoubtedly the work of Mendel (1865). Principles of population genetics developed by Wright (1921) using The sheep population of the United States has fluc- guinea pigs were extended by Lush and his students, tuated considerably during the past 100 yr. Between who provided leadership in the application of quantita- 1908 and 1923, sheep numbers declined from 48.2 to tive statistics and genetic information to the breeding 36.8 million before increasing to 56.2 million by 1942. of farm animals. Lush (1937) authored a book that be- Since then, sheep numbers have declined to 6.2 million came a classic, Animal Breeding Plans, which greatly at present.