When examining the contents of the udder of lactating cows with Masttest, a subclinical form of mastitis was in 28.98% of the animals. Most often, the defeat of one lobe of the udder was noted (35.1%). The occurrence of subclinical mastitis in two udder lobes was recorded in 34.31% of cows, in three lobes - in 18.63%. The occurrence of a subclinical mastitis form  in all lobes of the mammary gland was only in 1.96% of animals. The course of treatment of cows with subclinical mastitis up to 5 days with mastomycin, vakkamast and mastivex is more effective compared to their use for 2-3 days. It is most expedient to use mastomycin, vakkamast, which are not inferior in therapeutic efficacy to the foreign preparation mastivex (Spain), but 1.6–1.7 times cheaper and exclude dependence on the market of foreign medicines.

The article presents a technical solution for the intrauterine pressure sensor in cows, based on the use of the piezoelectric effect. The results obtained indicate a sufficiently high sensitivity of the sensor and reliable performance of the device that provides registration of uterine contractions in cows after calving. This can be used to conduct hysterographic studies in cows at various times after the fetus has been bred, as well as in the development of new drugs to correct the contractility of the uterine muscles. It has been established that after 6 hours the amplitudes of uterine contractions are more pronounced than 12 hours after the fetus has been removed.

The article presents the results of the overretained afterbirth expulsion in cows. It was found out that retention of placenta is recorded in 39.04% of cows. Most often, incomplete retention of placenta was noted in 36.98%,  and complete one in 2.05%. The efficiency of afterbirth expulsion with uteroton was 58.82%, with metrostim and metrostim in combination with enroflon - 64.71%. Fertility of cows turned out to be the highest after intramuscular use of metrostim in combination with intrauterine administration of enroflon (76.47%) with the best insemination index (1.6±0.01). According to experimental studies, for a conservative method of  overretained afterbirth expulsion in cows, it is advisable to use a myotropic drug in combination with a drug that has a bactericidal effect on the microflora of the uterine cavity. This helps to accelerate the involution of the uterus, increase fertility and prevent the occurrence of various forms of endometritis.

V accination continues to be one of the most effective and safe ways to protect against infectious diseases (Clapp et al., 2011; Clements and Griffiths, 2002). However, the high price of vaccines and their repeated administration throughout the year are serious deterrents to their use in large numbers of animals. Therefore, there is a need to develop new vaccines that have low cost and are used either once or for long periods of time (1-2 years) in order to facilitate the work of both veterinary workers and cattle breeders (Zuhair BI, 2017) Vaccines enhanced with an ad-juvant cause a longer and more intense immune response (Harandi et al., 2009; Peek et al., 2008). The word "adjuvant" comes from the Latin adjuvara, that is, "to help" (He et al., 2000). The adjuvant capacity of minerals was first discovered by Gleny et al. in 1926, after the precipitation of aluminum sulfate suspension of diphtheria toxoid, which increased the immunogenicity of this drug. Later, a large number of inorganic salts were tested, but alum, phosphate, aluminum hydroxide, aluminum hydroxide hydrophosphate and calcium phosphate were only approved. Adjuvants are substances that, in combination research Article Abstract | Vaccination continues to be one of the most effective ways to protect against infectious diseases; therefore, there is a need to develop new vaccines that have low cost and are used either once or for long periods of time.The current study aims to test organic hydroxyapatite in bacterial vaccines on laboratory and farm animals and determine its adjuvant and immunogenic properties. In pre-clinical tests, white mongrel mice weighing 18-20g and rats weighing 250-300g were used. Adjuvant (organic hydroxyapatite) separately and as part of vaccines was administered subcutaneously, intraperitoneally and intramuscularly at a dose of 0.5 ml. Clinical tests of adjuvant were carried out on Holstein-Friesian cows and calves. Experimental vaccines were used: 1) a split-conjugated vaccine against animal brucellosis (as antigens it included the components of brucella (Br. Abortus); 2) a vaccine against mastitis of cows. Results showed that PhA, neutrophils and monocytes in the blood smears of the control group were 1.4 times lower, and twice as much compared to the vaccine without the adjuvant. The maximum PhI(FI) was observed in animals immunized with a split-conjugated vaccine against brucellosis of animals with the adjuvant. The disappearance of vaccine antibody titer in the blood after 30 days was stated, which is positive in the diagnosis of brucellosis. The anti-mastitis vaccine with the adjuvant demonstrates prophylactic properties. In conclusion: Organic hydroxyapatite, obtained from the bones of animals by pyrolysis, displays adjuvant and immunogenic properties when used in bacterial vaccines.

Experimental studies were carried out to analyze the pharmacokinetics of the active ingredients of the antibacterial preparation "Entrikim": tilmicosine phosphate and enrofloxacin. The data obtained showed that the use of this preparation meets the requirements for the safe use of meat of various animal species. At the same time, some restrictions have been established: after the use of "Entrikim", pigs are allowed to slaughter animals no earlier than after 4 days, cattle - after 6 days; milk can be sold after 36 hours.