[Clinical and endocrinological studies of the puerperium in cows]

A total of 85 cows were used to study the clinical course of the involution processes in the genital tract following calving. According to the season of calving the animals were divided into two groups: 1st group consisting of 29 cows whose calving and puerperium had taken place during the spring/summer period; IInd group of 56 cows with which these processes were observed in the autumn/winter period. Seven cows of each group were subjected to endocrinologic studies for the evaluation of the pituitary gonadotropic hormones (FSH, and LH) in the blood plasma, applying Brown's method and Parlow's method, respectively. The following conclusions were drawn: 1. The intensity of the involution processes in the sexual apparatus of cows depends on the season. In the spring/summer period they usually last 34.3 days, and in the autumn and winter -- 37.5 days. 2. Fast involution of the uterus has been observed during the first two weeks after calving. This process is considerably delayed during the third week. 3. The yellow body regresses in the course of 14 days following calving. Up to the 35th day this has been established only im 3.5 per cent of the cows. Clinically, follicles in the ovaries are established as early as the 15th day after calving. 4. The FSH and LH level in the blood plasma during the first days after calving has been low -- 73.7 mg/% for FSH, and 7.04 mg/% for LH, both showing a rising trend. The peak values have been established between the 15th and 40th, and the 22nd and 28th day, respectively.