What problems exist in deer disease prevention and control in our country?

For half a century, with the development of the @#@253@#@ industry, the number of farmed deer has grown increasingly large, deer have come into broader contact with the external environment, and the variety of deer diseases has continued to increase. At some deer farms, the mortality rate has reached over 10% (including deer that should have been culled but were not). Deer diseases have become one of the important risks in deer farming production.

1 Historical review

Understanding of deer diseases has advanced and improved along with the development of deer farming production. Our country has a history of deer farming spanning several thousand years, but it truly flourished after the founding of New China. In the early days after the founding of the People's Republic, few deer were farmed and deer diseases were also few. In addition, there was superstition about deer, believing deer to be divine beasts; when sawing velvet antler, people still had to burn incense and pray, wrap the saw in red cloth so that women would not see it, and so on. When it came to deer diseases, people dared not treat them and did not know how to treat them; some were not treated at all. Take assisting difficult births in does, for example. At that time, because timely treatment was unavailable, cases in which both the doe and the fawn died often occurred.

In 1957, the Jilin Provincial Department of Agriculture edited the book "Deer Farming" (Jilin People's Publishing House). This was New China's first book on deer farming, and it included seven deer diseases: gastrointestinal disease, first stomach food impaction, acute gastrointestinal catarrh, rheumatism, joint rheumatism, esophageal obstruction, and deer necrobacillosis. Twenty years later, in 1979, the book "Deer Farming and Deer Disease Prevention and Control" (Agriculture Press), edited by Chen Yuhan and Chen Qiansheng, included 43 kinds of deer diseases, including infectious diseases, common diseases, poisoning diseases, parasitic diseases, and fawn diseases, more than three times as many deer diseases as in "Deer Farming." Another 20 years later, in 1998, "Great Compendium of Chinese Deer Farming," edited by Zhao Shizhen and Shen Guang, included 73 kinds of deer diseases, again more than three times as many as "Deer Farming and Deer Disease Prevention and Control," and only 1/15 of the more than 1,100 livestock diseases in "Merck's Veterinary Manual" (Jiangxi People's Publishing House, 1984), edited by Siegmund of the United States. This only shows that deer disease prevention and control, along with the expansion of deer farming scale and the passage of time, has also undergone a process of development from shallow to deep. In addition, the deer disease prevention and control workforce has continued to expand, and prevention and control techniques have continued to improve.

After the Great Leap Forward, with the implementation of the policy of consolidation, strengthening, and improvement, a large number of graduates of universities, colleges, and secondary schools poured into deer farms. Only then did the deer farming technical workforce and medical workforce gradually grow stronger. The main infectious diseases of deer, including tuberculosis, necrobacillosis, enterotoxemia, rabies, pasteurellosis, and leptospirosis, were basically brought under control. Common diseases such as gastrointestinal diseases, nutritional diseases, selenium deficiency, fluorine poisoning, and fawn diseases also received effective prevention and control.

2 Main achievements

Although China has a long history of deer farming, after the founding of New China deer farming was a new endeavor. Deer disease prevention and control went through a process from not understanding to understanding, breaking through conservative forces, and moving from no treatment to prevention and control, and achieved remarkable results.

2.1 Difficult births in does accounted for 40%-50% of all doe illnesses, and assistance in difficult births became an important technical task for deer farm veterinarians. In the mid-1960s, Ge Yuesheng of Dongliao No. 1 Deer Farm first used a calving aid strap to assist births, improving the quality and speed of pulling out the fetal head and increasing the success rate of assisted births. Subsequently, Zhao Shizhen introduced the use of a calving aid box for assisted births, changing assisted-birth does from prone restraint to standing restraint, making it more convenient to correct fetal position and fetal posture. In 1971, Miannaining was introduced, and anesthetic restraint for assisted births began. At the beginning of this century, Zhao Shizhen also developed deer calving aid strap hands, changing the application of the calving aid strap from manual operation to mechanized operation, further increasing the success rate of assisted births. Assisting difficult births in does was no longer a difficult problem, and the success rate of timely assisted births was almost 100%.

2.2 Necrobacillosis is a common disease that poses a relatively large threat to deer farming. The incidence rate in adult deer is 23.5%-23.9%, and the mortality rate is 17.6%-25.1%. Among these, male deer account for more than 90%, and cases in autumn and winter account for 82% of the annual total. In the 1950s-1960s, treatment methods mostly followed those for reindeer necrobacillosis in the Soviet Union, such as local treatment with potassium permanganate powder, formalin, and sulfur ointment. In 1964, Zhao Shizhen and others first used iodine-boron mixture to treat necrobacillosis. With local treatment plus systemic treatment, the cure rate was 100% for early-stage treatment, 80% for mid-stage, and in late-stage cases, as long as the lesions had not spread to the lungs, the cure rate was still 40%-50%. Because this disease was generally recognized domestically as involving poor immune function, no vaccine had been developed for several centuries. At the end of the last century, Qian Guocheng and others at the Specialty Products Institute first isolated a virulent strain of necrobacillosis, and Wang Kejian and others developed a deer necrobacillosis vaccine, bringing the disease fundamentally under control. This achievement won the second prize for provincial science and technology progress.

2.3 In 1959, an infectious disease with hematuria and jaundice as the main symptoms broke out sporadically in deer farms in the mountainous areas of eastern Jilin Province. It later gradually spread to deer farms in western Jilin Province, as well as Liaoning, Heilongjiang, and other provinces. At some deer farms, 78% were affected, and the mortality rate was 8%-15%. In 1962, Gao Yun and others at the Specialty Products Research Institute, under the guidance of Professor Yang Fuhai of Bethune Medical University, confirmed it as leptospirosis. This is a zoonotic disease, and early high-dose penicillin can cure it. Moreover, vaccines for livestock had long been available. This achievement won a provincial science and technology conference award.

2.4 From 1968 to 1978, an infectious disease mainly characterized by neurological symptoms in deer broke out in Jilin Province. At the time it was called deer neuropathic epidemic disease. The incidence rate was 30%-40%, and the mortality rate was almost 100%. Treatment with all antibiotics, as well as Chinese medicines and folk prescriptions, was ineffective. At that time, the theory of viral interference was popular. Zhao Shizhen proposed whether rabies vaccine, forest encephalitis vaccine, and Japanese encephalitis vaccine could be injected into deer to see whether there was any interference among them. After trial use, rabies vaccine had the best protective effect, so non-standard human rabies vaccine was purchased and injected subcutaneously into deer at 50 mL, bringing the disease under control. In 1970, Qian Guocheng and Yan Zhongcheng of the Specialty Products Research Institute and Wang Mingzhi and others of the Military Veterinary University successively isolated the virus from the brains of diseased deer. In 1972, Qian Guocheng and others inoculated the disease into sheep brain and produced a sheep brain rabies vaccine. Later, the Veterinary University established a special research group and, under the guidance of Academician Yin Zhen, with Hu Jingyao and Hou Shikuan leading systematic research, confirmed the disease as deer rabies. This research won the first prize for military science and technology progress. However, the saliva of rabid dogs has strong infectivity, while the saliva of diseased deer has no infective ability toward sheep, dogs, pigs, or humans; only brain inoculation is infectious. There are still several unclear aspects of this disease.

2.5 The research group led by Professor Wei Xubin of the Veterinary University first discovered sika deer copper deficiency syndrome in our country. The disease has as its main symptoms swaying of the hindquarters (locally commonly called "swaying waist disease"), ataxia, and progressive paralysis. The incidence rate is 10%, and the fatality rate is 100%. At some deer farms, the barren rate of does due to this disease reached as high as 43%, causing enormous harm to deer farming production. Through systematic epidemiological investigation, hematological examination, pathomorphological and pathophysiological research, trace element testing of serum, liver, and hair, analysis of related factors in feed, drinking water, and soil, and disease regression experiments, it was finally diagnosed as copper deficiency syndrome. By adding the copper-rich Chinese medicine Gouji San to feed and administering it, the occurrence of the disease was completely controlled. This research won the second prize for Jilin Province science and technology progress.