The study was to find out the changes of hormone levels in blood serum and milk of Holstein cows during the estrous cycle. The progesterone, estradio 1-17beta from the blood serum and milk samples were assayed by radioimmunoassay methods. During 20 to 25 days after artificial insemination, the accuracy of pregnancy diagnosis from the blood serum progesterone levels were 87.5% for non pregnant cows (2.Ong/ml) and 83.3% for pregnant cows (3.Ong/ml). The accuracy of pregnancy diagnosis from the milk progesterone levels were 75.0% for non-pregnant cows (2.4ng/ml), and 94.4% for pregnant cows (3.2ng/ml)

Five Korean native goats were used to test the effectiveness of the 2 modified techniques (Method 1 and 2) of Pawlow's pouch method. Both methods turned out to be successful and simpler than the original Pawlow's pouch method. In both methods, the miniature rumens were formed on the junction of 2 veins; vena ruminalis sinistra and vena ruminalis dextra. Both method 1 and 2 have the advantage of shortening the operation time, but caution was necessary to prevent the fistual formation between the rumen and miniature rumen in Method 1.

As a fundamental study to increase the reproductive efficiency in cattle, highly motile sperm were separated and collected from raw semen, extended semen and frozen semen by different methods using various concentrations of bovine serum albumin or Tyrode's solution. Various characteristics and light microscopic and electron microscopic morphology of sperm separated by different methods were compared

The in vitro activity of penicillins (penicillin G, ampicillin, carbenicillin, methicillin and cloxacillin) and gentamicin to Staphylococcus aureus and coagulase-negative staphylococci isolated from bovine mastitic milk samples was determined. The growth of all isolates of staphylococci tested was inhibited by cloxacillin and methicillin at concentration of 0.78 micro g/ml and by gentamicin at a minimum inhibitory concentration (MIC) of 1.56 micro g/ml

An experiment was conducted to measure the cellular immune response in guinea pigs by sensitizing the animals with 2,4-dinitrochlorobenzene (DNCB). The guinea pigs could be sensitizing with one application of DNCB. The sensitizing and challenge dose was standardized. The histological response was characteristic of a delayed hypersensitivity reaction

Fecal material from cattle, which was confirmed to be infected with Johne's disease by clinical and pathological symptoms, was decontaminated with 4% NaOH and inoculated into the Lowenstein-Jensen media supplemented with 1% of heat-killed Mycobacterium bovis. After 2-4 week-incubation at 37 deg C, typical acid-fast mycobacteria was isolated. The requirements of mycobactin for growth and the other biochemical properties, isolated mycobacteria was identified as Mycobacterium paratuberculosis