Dairy tick disease refers to a blood-sucking ectoparasitic disease caused by arthropods parasitic on the body surface or body of dairy cows. It generally causes anorexia, weight loss, metabolic disorders and tick paralysis in dairy cows, and there are many diseases transmitted by ticks. Spreading a variety of zoonoses and infectious diseases among animals has brought great harm to human health and animal husbandry, resulting in more serious indirect hazards.
1. Pathogeny
Ticks are blood-sucking animals of Arthropoda, Insecta, and Acaridae. They are harmful arthropods that specialize in blood-sucking and are widely distributed all over the world. There are many kinds of ticks. There are more than 800 known ticks in the world. There are more than 100 known ticks in China. The common ticks are micro-ticks. Ticks parasitize on the skin of dairy cattle, mainly sucking the blood of dairy cows, affecting the feeding and rest of dairy cows, resulting in poor growth and development of calves. Toxins produced by ticks also affect milk production in dairy cows. Ticks are the transmitters of some infectious and parasitic diseases, such as spirochetes, cockroaches and Taylor's protozoa.
The body is oval, flattened abdomen and back without blood-sucking, slightly raised, and the adult body is 2-10 mm long. After full-blooded, it swells like red beans or castor seeds. The adults can reach up to 30 mm in length. The epidermis is leathery, and the back or shelled shield plate is flat on the back and abdomen. The insect body is divided into two parts, the jaw, and the body. The jaw is located at the front of the body and visible from the back. It consists of the jaw base, chela limb, sub oral plate, and whisker limb.
The jaw base is connected with the front end of the body and is a well-defined ossified area, which is hexagonal, rectangular or square. Female ticks have a pair of foramen areas on the back of the jaw base, which can sense and secrete body fluids to help lay eggs. A pair of chelates, extending from the center of the back of the base of the jaw, is an important piercing device. The sub oral plate 1 is located on the ventral surface of the chela limb and forms an oral cavity when it is closed with the chela limb. The inverted teeth on the ventral surface of the sub oral plate are the attachment organs fixed in the host skin during blood suction.
The two sides of the chelator are whisker limbs, which are composed of four segments. The fourth segment is short and embedded in a small depression on the ventral end of the third segment. The body is bag-shaped, mostly brown, symmetrical on both sides. The male tick shield almost covers the entire back, while the female tick's shield only accounts for a part of the front part of the back. Some ticks from different flower ornaments on the back edge of the shield, which are called edge stacks. There are four pairs of feet on the ventral surface, six in each foot, namely, basal ganglion, metatarsal ganglion, thigh ganglion, tibial ganglion, posterior tarsal ganglion, and tarsal ganglion, usually with distances on the basal ganglion.
The proximal end of the dorsal margin of the first tarsal joint of the foot has a Harrington organ with olfactory function, and the end has a pair of claws and a cushioned inter claw process. The genital foramen is located in the front half of the ventral surface, often on the horizontal line of the second and third pairs of foot base ganglia. The anus is located at the back of the body, often with an anal groove. One pair of valves, located at the posterolateral side of the foot IV basal ganglion, with a wide valve plate. There are several butyric plates on the ventral surface of male ticks. The number of these plates varies according to the genus and species of ticks.
The life cycle of ticks can be divided into four stages: eggs, larvae, nymphs, and adults. The ticks are nourished by the blood of their host. Insects only come to the body of cattle when they are sucking blood. They can attach to the body of cattle for 5 to 6 days. After sucking blood, they fall off from the host. Ticks can be divided into ticks and ticks. Ixodes ticks are reddish-brown or grayish-brown, long ellipse, millet grains to soybean size. Females are several times larger than males after bloodsucking. Before bloodsucking, females are light gray and become gray-black after bloodsucking.
2. Epidemic characteristics
The occurrence of ticks has obvious seasonal and regional characteristics and has a strong ability to adapt to the cyclical changes in the environment. Usually in the warm season, especially in the northern area, it is mainly harmed by several ticks, of which the ticks are three-host ticks. The life cycle of the ticks is about 50 days, and three generations can occur every year. Especially in the spring after the warm winter, it is easier to break out in cattle farms when the temperature rises faster.
3. Clinical symptoms
Usually, it occurs in the cow skin thinner place, such as the cow's ear root, inner ear shell, groin, tail root, vulva and so on, you can see a lot of ticks. Beef cattle with anxiety, loss of appetite, fatigue, rough and dull fur, anemia, emaciation, if infected with other diseases, serious cattle can cause death.
4. Prevention and control
For ticks hiding in stables, a 1% trichlorfon (o-aminobenzoic acid) solution can be sprayed. Because ticks only attach to the host in a short time and then hide in the crevice of the surrounding environment, it is necessary to kill ticks at the same time in the mattress, wall, ground, ceiling, fence, pillar and other places of the cowshed. When spraying medicines, cattle ranchers should keep the environment sanitary.
It can be sprayed with 1.0%~1.5% trichlorfon solution, usually killing the worms within 48~72 hours. It can also be sprayed with 0.2% dimethylamine emulsion, 0.05% solution or 0.0025%~0.0050% deltamethrin solution, which also has a good effect. Epril, a special insecticide for dairy cattle, has the characteristics of broad-spectrum, safety, no residue and no milk abandonment period.
It can kill both internal and external parasites at the same time with one injection, and its efficacy can last 42 days. In epidemic-prone areas, the walls and ground of cowshed can be sprayed with the high temperature in time, especially in the cracks and damp places below 1.0-1.5 meters before the temperature rises in spring. At the same time, the environment around the cowshed was disinfected by high temperatures.