Overview
Distribution of Goats
According to the Food and Agriculture Organization (FAO) of the United Nations, in 2020 there were an estimated 1.13 billion goats in the world, approximately 51.4% of which were in Asia, 43.4% in Africa, 2.9% in South and Central America, 1.4% in Europe, 0.3% in the Caribbean, 0.4% in Oceania, and 0.2% in North America.
Approximately 55.9% of the world's goats are found in 50 low-income, food-deficit countries as defined by the FAO (FAO 2022a). Goats are well adapted to a broad range of climatic and geographic conditions and are more widely distributed than any other mammalian livestock. Goats are managed under every imaginable production system, including feral, transhumant, nomadic, extensive, intensive, and total confinement systems.Use of Goats
Goats are exploited for diverse purposes, including meat production, milk and cheese production, cashmere and mohair fiber production, and skins for leather making. Specialty uses include brush and weed control, sometimes referred to as “goatscaping” (Putzier 2020), pack and draft use, research (particularly as models of ruminant digestion and human heart disease and as transgenic animals), commercial antibody production, transgenic production of recombinant biopharmaceutical proteins, and companionship. Goat horn and bone are sometimes used for ornamental purposes and musical instruments, while goat skins are also used for drum making.
Meat production is the major use of goats on a worldwide basis, particularly in Asia, Africa, the Middle East, and Latin America, and world goat meat production continues to expand dramatically, as it has for decades (Morand-Fehr et al. 2004; Skapetas and Bampidis 2016). In 2020, the ten leading goat meat-producing nations in descending order were China, India, Pakistan, Nigeria, Bangladesh, Ethiopia, Chad, Mongolia, Sudan and Myanmar (FAO 2022b).
A multitude of local and regional breeds exists around the world that are used mainly for meat. In recent years, more attention has been paid to selective breeding in goats for meat production, leading to the development of two highly efficient, purpose-bred meat goat breeds. These are the South African Boer goat (Mahan 2000) and the Kiko goat of New Zealand (Batten 1987), both of which have gained popularity in the United States.Goat Medicine, Third Edition. Mary C. Smith and David M. Sherman. © 2023 John Wiley & Sons, Inc. Published 2023 by John Wiley & Sons, Inc.
The major milking breeds of goats originated primarily in Europe. These breeds include the Saanen, Toggenburg, Anglo-Nubian, and Alpine breeds. The more recently developed La Mancha breed originated in the United States. The Jamnapari and Beetal breeds of India are also important dairy breeds that are well adapted to and becoming more widely distributed in the humid tropics. The use of goat milk to manufacture cheese is an important industry in France, Spain, and some other European countries. The global situation regarding dairy goat production has been reviewed (Miller and Lu 2019).
Angora goats, the source of mohair fiber, have traditionally been concentrated in a number of distinct regions, notably Turkey, where they originated, South Africa, Texas, Argentina, and some central Asian republics formerly in the USSR. Cashmere or Pashmina goats, which produce cashmere fiber, are found primarily in the mountainous regions of Central Asia, including parts of Tibet, China, Mongolia, Iran, Afghanistan, Kazakhstan, Kyrgyzstan, and Tajikistan. Skins are usually a byproduct of goat slaughter for meat, but skins of certain goat breeds such as the Red Sokoto of Niger are prized for high-quality leather goods such as kidskin gloves and purses. Details of the various goat industries are beyond the scope of this veterinary text. The interested reader is referred to other sources (Gall 1981; Dubeuf et al.
2004; Morand-Fehr et al. 2004; Skapetas and Bampidis 2016).Current Interest in Goats
Worldwide interest in goats continues to increase dramatically. There is a greater understanding of the importance of goats in agricultural systems in low-income countries and the factors involved in improving their worth and productivity for smallholders and herders (Devendra 2013). Some humanitarian and development organizations, such as Heifer International and FARM-Africa, have recognized the value of using goats as a tool in rural development programs to improve the social and economic conditions of subsistence farmers and the rural poor. Methodologies for improved goat production in the tropics in support of rural development have been published (Peacock 1996). The impacts of climate change on rural livelihoods have also brought increased attention to goats, as studies indicate that goat ownership can help buffer households against climate shocks, most notably drought (Acosta et al. 2021).
There is also increased demand for goat products in developed countries, especially goat cheese, cashmere goods, and goat meat. Demand for goat meat in the United States, for example, has exceeded domestic supply in recent years. In 2014, 43 188 million pounds of goat meat were imported for a total value of $94.7 million, compared to 2994 million pounds in 1990 for a total value of $1.9 million (Luginbuhl 2015). Increases in the global trade in goats and goat products is associated with certain risks for the spread of goat-associated diseases, which veterinarians need to be aware of from both a clinical and a regulatory standpoint (Sherman 2011).
Through the National Animal Health Monitoring System (NAHMS), the US Department of Agriculture has tracked the expansion of the goat industry and its use of veterinarians (USDA 2020). The number of goats increased from approximately 2 250 000 in 1997 to approximately 2 700 000 in 2017, and the number of goat operations increased from approximately 76 500 in 1997 to approximately 136 400 in 2017.
The proportion of goat operations identified as primarily dairy increased from 11.9% in 2009 to 18.7% in 2019, while the proportion of goat operations that consider themselves to be multipurpose (e.g., meat and dairy) has also increased. This expanding interest in and exploitation of goats have been associated with an increased demand for goat-related clinical veterinary services, with the number of US goat operations that consulted a veterinarian increasing from 39.5% in 2009 to 49.7% in 2019. In response to this growing demand, interested veterinarians must familiarize themselves with goats as a species distinct from sheep and cattle, recognizing their characteristic behavior and physiology, the diseases that affect them, and the proper diagnosis and management of those diseases.Fortunately, the growing interest in goats has been accompanied by a growth of organizations and information focused on the species. The International Goat Association (https://www.iga-goatworld.com) sponsors a quadrennial international conference on goats and regularly publishes the peer-reviewed, international research journal Small Ruminant Research, which reports research findings on all aspects of goat production including health, nutrition, genetics, physiology, and husbandry from all over the world. The American Sheep Industry Association regularly produces a similar, multidisciplinary research publication, Sheep and Goat Research Journal, which focuses specifically on small ruminant production in North America and is available on the internet (https://www.sheepusa.org/sheep-goat-research-journal).
The American Association of Small Ruminant Practitioners (AASRP) is an excellent resource for veterinary practitioners in North America. This member organization produces a regular newsletter, Wool and Wattles, full of current, relevant information on regulatory and clinical issues as well as an e-mail discussion forum for AASRP members. The AASRP website (www.aasrp.org) provides links to other useful resources for goat health and production.
Another useful web-based resource for veterinarians is Consultant, which generates differential diagnoses based on clinical signs entered by the user on a species basis, with goats recognized as a distinct species. It is available on the internet at http://consultant.vet.cornell.edu. Finally, many state extension agencies now have much more information available on goat husbandry and production than they had in the past, with much of it accessible on the internet.Distinguishing Goats from Sheep
Source of Confusion
For those whose experience with sheep and goats is limited to the common European wool breeds of sheep and the European dairy breeds of goats, the notion that individuals of the two species could be confused may seem ridiculous. However, in tropical and subtropical regions, various breeds of hair sheep are common. These breeds are often maintained in mixed flocks with local breeds of goats, and may not be readily differentiated. The following information can help in distinguishing the two species.
Genetic Distinctions
Goats have 60 chromosomes and sheep have 54. Though very uncommon, fertile goat-sheep hybrids have been reported. These hybrids have 57 chromosomes. The phenomenon is discussed in Chapter 13. Efforts to map the entire goat genome are well advanced (Bickhart et al. 2017).
Behavioral Distinctions
A major difference between sheep and goats is feeding behavior. Sheep are grazing animals, consistently feeding at ground level, while the goat is more of a browsing animal, readily feeding on shrubs, bushes, and trees. While both species are social, individual goats are less anxious than sheep when separated from the group. Goats are less tolerant of rain and more readily seek shelter in wet weather.
The males of both species will fight, buck goats by rearing up on their hind feet and coming down forcefully to butt heads, while rams back up and then charge forward to butt heads. The anatomic structure of the horns, frontal sinuses, and neck muscles of each species is appropriate to its method of fighting, minimizing the risk of injury to combatants (Reed and Schaffer 1972).
When young bucks and rams are maintained together, the rams become dominant because they preemptively strike bucks in the abdomen while the male goats are still in the act of rearing up.Whereas lambs are almost constantly at the side of ewes in early life, goats practice “lying-out” or “planting” behavior, with kids left in “camps” for a good part of the day while does feed.
Anatomic Distinctions
When wool is not obvious in sheep, other anatomic differences may be observed. Most goat breeds have an erect, upright tail, while the tail of sheep always hangs down. The sheep has an upper lip divided by a distinct philtrum and the goat does not. Male goats, and to a lesser extent female goats, have beards, which are lacking in sheep. Goats do not have infraorbital, interdigital, or inguinal glands, while sheep do. Goats have sebaceous glands beneath the tailhead that sheep lack.