Research Overview of Fungal Abortion in Cattle

During the pregnancy of a cow on a cattle farm, the interruption of pregnancy due to the disturbance of the physiological process of the fetus or the mother, or the destruction of the normal relationship between them is called abortion. In abortion, the embryo can be absorbed (early), or a dead fetus or premature fetus is expelled from the uterus. So what are fungal abortions in cattle? Let's study the overview below.

There are many reasons for cow abortion, which can be generally divided into infectious abortion, parasitic abortion and common abortion. Common abortion is caused by the following factors:

① Nutritional abortion. Extensive feeding management, simple feed, and unbalanced nutrition cause the cows to be weak and thin, with reduced resistance, so that the fetus cannot get enough nutrition; the feed lacks vitamin A, vitamin E, vitamin D and certain trace elements such as calcium, phosphorus, iron, manganese, and cobalt, which not only makes it difficult for the fetus to develop, but also directly or indirectly causes reproductive organ lesions or reproductive hormone disorders, causing abortion.

② Mechanical abortion: Traumatic and managed abortion are important causes of sporadic abortion.

③ Stress-induced abortion. When the temperature exceeds 35℃, cows will have a reduced appetite and an increased breathing rate. Improper grazing can easily lead to heat stress and heat stroke. It is reported that abortions in cows are concentrated in the second and third quarters, and the most prominent is from May to July, accounting for more than 40% of the total abortions in the whole year. Summer abortions, such as high temperature and humidity in the southern region, enter the rainy season, the relative humidity is often above 90%, which is most suitable for the growth and reproduction of bacteria. All kinds of silage are most likely to spoil and mold. After feeding, it will inevitably lead to metabolic disorders in dairy cows and cause abortions.

④ Hormonal disorder abortion. It will not disappear during the entire pregnancy. Under the combined action of progesterone and a certain proportion of estrogen, the uterus proliferates, and the embryo can attach and develop. Progesterone can also make the cervix secrete mucus, forming a uterine plug to prevent abortion. If the corpus luteum of pregnancy atrophies and the secretion of progesterone decreases, it will cause abortion.

⑤ Spontaneous abortion: One is due to incomplete development of the fetal villi or chorion, which prevents the fetus from getting enough nutrition and causes the interruption of pregnancy; the other is due to inflammation of a part of the endometrium. When the fetus grows larger, the villi on the chorion cannot combine with the inflamed endometrium, which disrupts the nutrient exchange between the fetus and the mother, causing the early death of the fetus and its expulsion from the body.

⑥ Medical abortion. Ignoring the characteristic factor of pregnancy and misusing some diarrhea drugs, corticosteroids, uterine contraction drugs, anesthetics, etc. can cause abortion.

So what is fungal abortion in cattle? Fungal abortion in cattle has been reported in many countries around the world. After the pathogen enters the body through the respiratory tract or digestive tract of pregnant cattle, it spreads through the blood circulation, causing placental inflammation, which causes poor placental circulation and causes abortion. Fungal abortion in cattle often occurs in the last three months of pregnancy, and there is no feasible diagnostic method before abortion. After abortion, the placenta and fetus can be examined for fungi, and the cow can be diagnosed with serology. Only those who are positive for both can be diagnosed with fungal abortion. However, in the past decade or so, abortions caused by fungi and fungal toxins have been continuously discovered, and the proportion of their incidence in abortion cases has gradually increased, which has attracted people's attention and attention.